study final report en

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04.OR.VM.057.1/RR

Stocktaking study on the current status and developments of technology and regulations related to the environmental performance of recreational marine engines Contract ETD/FIF.20030701 FINAL REPORT

January 10, 2004 R.C. Rijkeboer (TNO-Automotive, overall co-ordinator)

R.J. Vermeulen (TNO-Automotive) R.H. Jongbloed and J.T. van der Wal (TNO-MEP) E. Gerretsen and H.W. Jansen TNO-TPD) J.A. Visser and M. Quispel (NEA - subcontractor) P. Handley (consultant)

European Commission, Directorate-General Enterprise

Directorate E - Environmental aspects of enterprise policy, resource based & specific industries Mr. Daniel Bunch, Head of Unit Unit E5 - Aerospace, Defence, Rail and Maritime Industries Office" AN88 6/55 1049 Brussels, Belgium

Approved by (Head of the section)

P. Hendriksen

009.01481 November 2003 - November 2004

200 5 All rights reserved. No part of this publication may be reproduced and/or published by print, photoprint, microfilm or any other means without the previous written consent of TNO. In case this report was drafted on instructions, the rights and obligations of contracting parties are subject to either the Standard Conditions for Research Instructions given to TNO, or the relevant agreement concluded between the contracting parties. Submitting the report for inspection to parties who have a direct interest is permitted. © 2005 TNO

TNO report | 04.OR.VM.057.1/RR 2 / 200

Summary

General outline of the study This report investigates the environmental impact of the use of propulsion engines of recreational craft. This impact can be subdivided into the following aspects: The impact on air quality, subdivided into:

− The impact on overall Europe-wide emissions to air − The impact on local air quality

The impact on local water quality, subdivided into: − The water quality as related to ecosystems − The water quality as related to the production of drinking water

The impact of noise, subdivided into: − The impact of noise on ecosystems, both birds and aquatic wildlife − The impact of noise on nuisance as perceived by humans

For the purpose of the study an evaluation was made of the pre-Stage 1 situation (Stage 0), the known Stage 1 situation and three options for a possible future Stage 2 situation. These three options were: − Option 1: All petrol engines have to comply with the requirements for the Stage 1

4-stroke engines. Diesel engines have to comply with the NRMM Stage IIIA limits for commercial marine engines.

− Option 2: All petrol engines have to comply with limits that lie at 75 % of the Stage 1 limits for 4-stroke engines. Diesel engines have to comply with the NRMM Stage IIIA limits.

− Option 2A: As option 2, but petrol engines < 30 kW will be exempted; they will stay with the option 1 limits (= Stage 1 4-stroke limits).

In a further evaluation of the situation concerning diesel engines, an option 2B was added. This option assumed that inboard diesel engines would have to comply with the NRMM stage II requirements. Executive summary of the report

An executive summary of this report is contained in a separate volume of 28 pages, carrying the same title and report number as this main report, but with the indication “Executive Summary” added. The “Summary” below will only outline how the report has been structured.

Structure of the report 1. Introduction Section 1 outlines the developments that led to the study, its purpose and its scope. 2. The fleet Section 2 outlines the composition of the fleet and the various types of craft and engines and drive systems that need to be considered. It gives some examples of national fleet


compositions for four different countries with widely differing geographical circumstances and hence conditions of use. 3. The market Section 3 describes the demand side of the market, in terms of numbers sold per type of engine, and per region in the world. It also describes the supply side of the market in terms of number and size of the major and minor suppliers. Finally it describes technologies and trends, in relation to the two main markets: North America and Europe. 4. Exhaust emissions – Status quo Section 4 describes the existing situation concerning the emissions of exhaust gases and the resulting air and water quality aspects. Concerning water quality a literature survey documents the existing knowledge concerning pollution and criteria and a small scenario study investigates to what extent local situations might exceed those criteria. 5. Sound – Status quo Section 5 describes the existing situation concerning sound. It outlines the sources of sound from vessels in general and recreational craft in particular. It gives a short summary of the relevant aspects of the theories of sound, sound propagation and sound perception by observers, in relation to airborne sound and underwater sound. It outlines what is known concerning sound perception by wildlife and by humans. A small scenario study investigates to what extent local situations might exceed existing criteria. 6. Additional issues Section 6 describes fuel evaporation and spillage as possible other routes by which contaminants may enter the environment. It outlines what is known about the sources and gives estimates for the extent to which such effects may actually take place, and what measures might be possible. This section also discusses the benefits of synthetic lubricants as a possible means to reduce the impact of lubricants that do enter the water body. 7. The possibilities for technological improvement Section 7 gives an overview of the possibilities to reduce exhaust emissions and sound. The special case of marine engines and the possible resulting limitations are discussed per type of engine and driveline configuration. 8. The impact of technological improvements Section 8 selects three different concrete options for a possible Stage 2 legislation. The consequences in terms of emissions, air quality aspects and water quality aspects are investigated by means of a model calculation. In the interest of a valid comparison the baseline and Stage 1 situations have been recalculated in the same way. Some further variants are investigated in a more limited approach. The economic consequences are discussed in Section 12. 9. Durability and related issues Section 9 investigates the need for additional requirements concerning the durability of emission abatement measures, and discusses the possibilities for an in-use compliance check, if such a check would be deemed necessary or desirable.


10. Manufacturer related issues Section 10 discusses the issues that concern the manufacturers, both in relation to the existing legislation and in relation to a possible Stage 2. It also presents the view that the industry itself has concerning these matters. 11. User related issues Section 11 discusses the issues that concern the owner/user of recreational craft and their engines. It also discusses the influence the owner/user has on the ultimate environmental impact of the use of recreational craft, and the possibilities to involve him in the complete chain. 12. Economic consequences of RCD Stage 2 options Section 12 outlines the various economic consequences of the Stage 2 options of which the environmental consequences were investigated in section 8. 13. The possibilities for international harmonisation Section 13 outlines the similarities and differences in the environmental paragraphs of the US and EU legislation concerning recreational craft. It discusses the possibilities to align the legislative requirements for these two main markets. 14. Review of RCD boat design categories Section 14 discusses whether there is a need to change the number of design categories as currently prescribed in the Directive. This topic is not related to the environmental issues that are dealt with in the previous sections, but is still of relevance to the next amendment of the Directive. 15. Approval under the New Approach Section 15 gives a sumarised overview of the characteristics of the type approval and conformity control under the New Approach, and a proposal for a possible restructuring of the ‘Modules’. APPENDICES

A. Answers to the questionnaire Appendix A gives a summary of the answers received to the questionnaire sent out to the stakeholders.

B. Emission factors Appendix B lists exhaust emission data collected from literature and the more recent exhaust emission data, received from the industry, that have been used in this study.

C. Scenario studies concerning various environmental aspects Appendix C lists the situations modelled and the input data used for the various environmental scenario studies used in this study.

D. Sound: animal hearing Appendix D lists some additional data concerning animal hearing.

E. Comparison between the TNO and TÜV water quality studies Appendix E compares the in and output of the current study with the in and output of a study made by the German TÜV on behalf of the UBA.


Contents

SUMMARY.....................................................................................................................................2

CONTENTS ....................................................................................................................................5

1 INTRODUCTION .......................................................................................................10 1.1 Historical overview......................................................................................................10 1.2 Purpose of the present study.......................................................................................10 1.3 Scope of the study ........................................................................................................11

2 THE FLEET ................................................................................................................13 2.1 Types of engines involved ...........................................................................................13 2.1.1 Installation aspects.........................................................................................................13 2.2 Types of craft ...............................................................................................................15 2.2.1 Open sailing boats .........................................................................................................15 2.2.2 Cabin sailing boats ........................................................................................................16 2.2.3 Open motor boats ..........................................................................................................16 2.2.4 Cabin motor boats..........................................................................................................16 2.2.5 Personal Watercraft .......................................................................................................16 2.3 Composition of the fleet ..............................................................................................16 2.3.1 The European Fleet........................................................................................................16 2.3.2 Some national fleets ......................................................................................................17

3 THE MARKET............................................................................................................20 3.1 Manufacturers and engines types ..............................................................................20 3.1.1 Manufacturers................................................................................................................20 3.1.2 Types of engines involved.............................................................................................20 3.2 Outboard engines and engines for PWCs..................................................................22 3.2.1 Engine technologies.......................................................................................................22 3.2.2 The size and shape of the market...................................................................................23 3.3 Inboard petrol engines ................................................................................................28 3.4 Inboard diesel engines .................................................................................................29 3.5 Marinisers ....................................................................................................................31

4 EXHAUST EMISSIONS - STATUS QUO................................................................33 4.1 Introduction .................................................................................................................33 4.2 The overall emissions to air ........................................................................................34 4.3 Local emissions to air ..................................................................................................35 4.4 Fate and behaviour of exhaust emissions in aquatic systems ..................................36 4.4.1 Fate of the contaminants in water..................................................................................37 4.4.2 Factors affecting the fate of HC compounds .................................................................38 4.4.3 Influence of fuel and lubricants .....................................................................................39 4.4.4 Calculation of concentrations and risks .........................................................................39 4.4.5 Recommendations .........................................................................................................40 4.4.6 Perceived measures for improvement (questionnaire)...................................................41 4.5 Existing environmental quality standards.................................................................41 4.5.1 Air quality standards......................................................................................................41 4.5.2 Water quality standards .................................................................................................42


4.5.3 Effects on aquatic organisms and aquatic systems ........................................................43 4.6 Estimated environmental concentrations ..................................................................44 4.6.1 Introduction ...................................................................................................................45 4.6.2 The different scenario’s and their results.......................................................................47 4.7 Determination of the actual model input and output ...............................................51 4.7.1 The aeration effect .........................................................................................................51 4.7.2 The consequences of the pulsed input ...........................................................................52 4.8 Evaluation of the modelling results based on comparison with environmental

quality standards and goals set by the European Water Framework Directive ....53 4.9 Conclusions ..................................................................................................................56

5 SOUND – STATUS QUO ...........................................................................................60 5.1 Introduction .................................................................................................................60 5.2 Current sound emissions.............................................................................................61 5.2.1 General ..........................................................................................................................61 5.2.2 Airborne sound emission ...............................................................................................63 5.2.3 Underwater sound emission...........................................................................................65 5.3 Existing environmental targets...................................................................................67 5.3.1 Environmental sound targets concerning humans .........................................................67 5.3.2 Environmental sound targets concerning wildlife .........................................................69 5.3.3 Airborne sound emission targets ...................................................................................72 5.3.4 Restrictions of use .........................................................................................................73 5.4 Evaluation of impact on wildlife.................................................................................74 5.5 Evaluation of impact on humans................................................................................74 5.5.1 Environmental sound transmission................................................................................74 5.5.2 Typical use and sound emission of recreational craft....................................................75 5.5.3 Estimate of environmental sound impact; typical cases ................................................75

6 ADDITIONAL ISSUES ..............................................................................................78 6.1 Evaporation..................................................................................................................78 6.1.1 Outline of the problem...................................................................................................78 6.1.2 Crankcase losses ............................................................................................................78 6.1.3 Refuelling losses............................................................................................................78 6.1.4 Diurnal breathing losses ................................................................................................79 6.1.5 Tank permeation losses .................................................................................................79 6.1.6 Hot soak evaporation losses from the fuel system.........................................................79 6.1.7 Running losses...............................................................................................................80 6.1.8 The situation in the marine case ....................................................................................80 6.1.9 Possible solutions for the marine case ...........................................................................81 6.2 Spillage .........................................................................................................................84 6.3 Synthetic lubricants .....................................................................................................84

7 THE POSSIBILITIES FOR TECHNOLOGICAL IMPROVEMENTS................86 7.1 Important characteristics of the recreational marine sector ...................................86 7.2 Exhaust emissions ........................................................................................................86 7.2.1 Petrol outboard engines .................................................................................................86 7.2.2 Petrol inboard engines ...................................................................................................89 7.2.3 Practical aspects of catalytic aftertreatment ..................................................................90 7.2.4 Diesel inboard engines ..................................................................................................92 7.2.5 Comparison with the NRMM Directive ........................................................................96 7.2.6 Engines certified for lower emission levels in other regions.........................................98 7.3 Concerning sound emission ........................................................................................98


7.3.1 Air-borne sound emission..............................................................................................99 7.3.2 Concluding remarks on sound control .........................................................................101 7.3.3 Underwater sound emission.........................................................................................103 7.3.4 Remarks on sound target values and the measurement protocol .................................103

8 THE IMPACT OF TECHNOLOGICAL IMPROVEMENTS..............................104 8.1 Exhaust emissions ......................................................................................................104 8.1.1 The options for the exhaust emissions.........................................................................104 8.1.2 Emissions to air ...........................................................................................................105 8.1.3 The contributing classes of engines.............................................................................109 8.1.4 Further reduction by catalyst .......................................................................................110 8.2 Emission trends..........................................................................................................111 8.3 Emissions to water .....................................................................................................112 8.4 Sound emission ..........................................................................................................114

9 DURABILITY AND RELATED ISSUES ...............................................................115 9.1 Introduction ...............................................................................................................115 9.2 Description of an all-including legislative system ...................................................115 9.2.1 The type approval test .................................................................................................115 9.2.2 The conformity of production test ...............................................................................116 9.2.3 In-use compliance testing ............................................................................................116 9.2.4 Periodical inspection ...................................................................................................118 9.3 The situation for recreational craft..........................................................................119 9.4 Durability in the case of recreational craft propulsion engines.............................119 9.5 The need for durability control ................................................................................120 9.6 Major obstacles for a durability check ....................................................................122 9.7 Practical possibilities for a durability check ...........................................................124 9.8 Summary, conclusions and recommendations ........................................................125

10 MANUFACTURER RELATED ISSUES................................................................127 10.1 Important characteristics of the recreational marine sector .................................127 10.1.1 Manufacturing aspects .................................................................................................127 10.1.2 Installation aspects.......................................................................................................127 10.1.3 Operational aspects......................................................................................................128 10.1.4 Operational aspects concerning the use of catalysts ....................................................128 10.1.5 Customer satisfaction ..................................................................................................129 10.1.6 Safety aspects ..............................................................................................................129 10.1.7 Engine reliability .........................................................................................................129 10.1.8 Liability aspects...........................................................................................................130 10.1.9 Trade aspects ...............................................................................................................131 10.2 Potential risks ............................................................................................................131 10.3 Conditions for implementation.................................................................................132 10.3.1 Fuel specification.........................................................................................................132 10.3.2 The supporting trade sector .........................................................................................132 10.4 Economic considerations...........................................................................................132 10.4.1 A clear long-term strategy ...........................................................................................133 10.4.2 A considerate timing....................................................................................................133 10.4.3 Introduction from the top end of the market................................................................133 10.4.4 No market disturbance.................................................................................................134 10.5 Special views of the industry.....................................................................................135 10.5.1 Harmonisation .............................................................................................................135 10.5.2 No technology dependant limits ..................................................................................136


10.5.3 Similarity in approach .................................................................................................136

11 USER RELATED ISSUES .......................................................................................137 11.1 Environmental awareness of the users ....................................................................137 11.2 Maintenance...............................................................................................................137 11.3 Lubrication oil ...........................................................................................................138 11.4 Refuelling ...................................................................................................................139 11.5 Fuel quality problems................................................................................................139 11.6 Evaporation................................................................................................................139 11.7 Registration ................................................................................................................139 11.8 Summary ....................................................................................................................140 11.9 Comments...................................................................................................................140 11.10 Biodegradable lubricants ..........................................................................................141 11.10.1 The water pollution aspects .........................................................................................141 11.10.2 Active promotion of the use of synthetic lubricants ....................................................142

12 ECONOMIC CONSEQUENCES OF RCD STAGE 2 OPTIONS........................143 12.1 Introduction ...............................................................................................................143 12.2 Scenario description ..................................................................................................144 12.3 Qualitative description of the impacts on the industry ..........................................145 12.3.1 Petrol engines ..............................................................................................................145 12.3.2 Diesel engines..............................................................................................................146 12.4 Determination of the economic consequences .........................................................149 12.5 Quantification of effects for the manufacturers......................................................151 12.6 Option 2B ...................................................................................................................153 12.7 Secondary effects .......................................................................................................154 12.8 Conclusions regarding economic impacts of RCD Stage 2 ....................................156 12.9 References to this Section: ........................................................................................157

13 THE POSSIBILITIES FOR INTERNATIONAL HARMONISATION..............158 13.1 The existing legislation ..............................................................................................158 13.1.1 Petrol engines ..............................................................................................................158 13.1.2 Diesel engines..............................................................................................................165 13.2 Engines certified for the BSO ...................................................................................168 13.3 Legislative aims and tendencies................................................................................169 13.4 Aspects of harmonisation..........................................................................................171 13.4.1 Harmonisation so far ...................................................................................................171 13.4.2 The relative stringency of the requirements ................................................................171 13.4.3 Components .................................................................................................................172 13.4.4 Categories of engines ..................................................................................................172 13.4.5 Threats and opportunities ............................................................................................172

14 REVIEW OF RCD BOAT DESIGN CATEGORIES ............................................174 14.1 Introduction ...............................................................................................................174 14.2 Background to RCD Boat design categories ...........................................................174 14.3 Interpretation of the Design Categories ..................................................................175 14.4 Amendments to the Design Categories ....................................................................176 14.5 Development of the harmonised standards .............................................................177 14.6 The RCD and other regulations ...............................................................................177 14.7 Use of wind strength and wave height as design parameters ................................179 14.8 Natural Categories for recreational boats ...............................................................180 14.9 Conclusions and recommendations..........................................................................180


15 APPROVAL UNDER THE ‘NEW APPROACH’..................................................183 15.1 Introduction ...............................................................................................................183 15.2 General description ...................................................................................................183 15.3 The procedure in the case of the RCD .....................................................................184 15.4 Short description of the modules..............................................................................185 15.5 Summary of the approach ........................................................................................187 15.6 Concerning exhaust emissions and noise.................................................................188 15.7 Proposal for a simplified structure ..........................................................................188

REFERENCES ...........................................................................................................................193

ABBREVIATIONS.....................................................................................................................199 A Answers to the questionnaire B Emission factors C Scenario studies concerning various environmental aspects D Sound: Animal hearing E Water quality: comparison between the TNO and TÜV studies


1 Introduction

1.1 Historical overview

The European history concerning the limitation of the environmental impact caused by engines for recreational craft started in the late eighties with an initiative by the local Kantons and Länder of Germany, Switzerland and Austria bordering on Lake Constance (the ‘Bodensee’), to limit the exhaust gas emissions from boats and ships using the lake. Their declared concern was the quality of the water as a source of drinking water. And their basis of action was the ‘Prevention Principle’ (Vorsorge Prinzip). In other words: there was at the time no direct problem, but the local authorities concerned sensibly wanted to avoid one coming about. Although this was an initiative of local authorities, which did not require notification with the Commission, Germany decided to notify it nevertheless. This, coupled to the intentions of other local authorities elsewhere in Europe to adopt similar measures, caused the Commission to look into the matter and to commission a study into the problem, into the available technologies and into a possible legislation and a set of emission limits. This study was performed by TNO-Automotive and reported in the TNO report 733160022: “Study on exhaust gas regulations for pleasure boat propulsion engines”, August 1991 [Rijkeboer 1991]. This report, produced after intensive consultation of the stakeholders, described the relevant industry, the impact of outboard engine emissions on Lake Constance, the influence of 2-stroke lubrication oil on the water quality, the possibilities for a European exhaust gas legislation, an evaluation of a few suggested alternatives, and finally a proposal for an EC approach. This approach advocated a two-stage introduction of exhaust gas legislation, with concrete proposals for a procedure and for limit values for the two stages. The first reaction of the Commission to the proposal was favourable, but subsequent political developments caused the proposal to be shelved. More recently the Commission received information that several EU Member States, or local authorities in EU Member States, contemplated the introduction of an exhaust gas and noise emission legislation for recreational craft propulsion engines, and significant doubts arose about the negative effects this might have on the functioning of the internal market. This resulted in the decision to introduce an environmental paragraph into the existing Directive 94/25/EC concerning the design of recreational craft. The main aim of this paragraph would be to obtain a uniform set of requirements for the manufacturer, and thereby to safeguard the unity of the internal market. The approach was a two-stage one. There is a first stage in Directive 2003/44/EC. This made use of the earlier study by TNO. The amendment contains a legislation and a set of limit values for the exhaust gas emissions largely corresponding to those suggested as stage 2 in the 1991 TNO report, coupled to a limitation of noise levels. In a second stage the final level would have to be determined.

1.2 Purpose of the present study

A clause in Article 2 of 2003/44/EC specifies that the Commission has to submit a report ‘on the possibilities of further improving the environmental characteristics of [recreational craft propulsion] engines’. To this end the Commission has decided to


commission a study into the various aspects of the environmental impact caused by propulsion engines for recreational craft. The study presented here, is intended to be (or to be the basis for) that aforementioned report. The specification of the study, however, specifically asked to investigate (inter alia) “the need to further reduce emissions of air pollutants and noise in order to meet environment protection requirements”. For the contractor this means that the study has not to be limited to the possibilities of further improvement, but also has to deal with the needs for such further improvement.

1.3 Scope of the study

The exact nature of the question and its answers The environmental impact caused by recreational craft propulsion engines can be divided into the following items: • The impact on local air quality • The impact on local water quality, subdivided into:

− The water quality as related to ecosystems − The water quality as related to the production of drinking water

• The impact of noise, subdivided into: − The impact of noise on ecosystems, both birds and underwater wildlife − The impact of noise on nuisance as perceived by humans

Although it was understood that at present it is basically air quality and noise that is the main concern, this study includes the aspect of water quality as well. By making a differentiation between the aspects mentioned, a picture is presented as transparent and relevant as possible, avoiding the risk that, at a later point in time, in the formulation of the required policy, any ambiguity in this respect, which might confuse the issue, and hence retard the discussions, is avoided.

The study was approached on the basis of the following considerations. When the environmental compartment ‘air’ is targeted, the exhaust emissions of boat engines are only one source, likely to be additional to others (depending on the specific characteristics of the area concerned), whereas when the environmental compartment ‘surface water’ is concerned, the exhaust gases from boat engines are more likely to be the main source of local pollution, but again depending on the specific characteristics of the area concerned. In the first case the question is relevant: what is the percentage of the pollution contributed by this particular source, and would reduction of this source result in sufficiently significant reductions in the overall emission? Whereas in the second case this particular source may be highly determining for the local water quality, although in the case of the earlier study [Rijkeboer 1991] concerning Lake Constance, ‘run-off’ from the surrounding land was identified as the most likely primary source. It was decided, however, that concerning water quality only those situations would be studied where no such additional sources would make a significant contribution. For the compartment ‘air’ all exhaust gas emissions may be of significance, except in so far as solved into the water, whereas for the compartment ‘surface water’ exactly those solved components are of importance. In theory that would also necessitate a distinction in engine exhausts emitting under water, or otherwise into the water, and those emitting to the air only. But since the study showed that the majority of engines used for recreational craft fall into the first category, and since commercial vessels are not


subject of this study, in actual practice such a distinction needed not to be made after all. With regard to water quality the requirements for ecosystems could (and actually do) vary considerably from those concerning drinking water. Since in every case the nature of the exact question will inevitably determine the final answer given, we like to point out that the reader should be aware of such differences, since e.g. a simple aggregation of exhaust gas components could easily lead to false, or at least misleading, answers. At the time of the Lake Constance discussion e.g. this aspect seemed to have been overlooked by the local authorities concerned. In that case the declared concern was water quality related to the use of the lake as a source of drinking water, yet the resulting legislation did not differentiate in any way between the compartments air and surface water, or between underwater exhausts and air exhausts, although both recreational and commercial craft were included in the Regulation. A comparable situation is relevant for the sound emission. Attention so far has been focused on sound emission into the air and the possible annoyance by human beings, but other impacts could also be relevant. The same sound emission can be of influence on birds, and in the case of boats also the sound emission under water is to be considered, since it can have its impact on underwater wildlife. This can be especially relevant considering the types of environment in which recreational craft are used. Although it was clear from the start that for these aspects much information is lacking, it was felt to be of importance to present at least the whole sound picture, indicating what we know and what we do not. The available data and knowledge The study obviously has the aim to determine the levels of the emissions of exhaust gases and sound and their impact on the environment. To this end the extent of the emissions are determined, in whatever way possible and with whatever accuracy available. A completely different question is the one that asks what is permissible in the environment. For in the end the question whether or not there is an environmental problem and, if so, what needs to be done to alleviate that problem, will have to be answered by confronting the pollution caused with the maximum permissible concentrations or sound levels. Air quality criteria are well established, but no local air quality is calculated in this study, although some general comparisons are made. Otherwise only the overall emission by recreational craft will be presented. First as shown in the Commission proposal for the stage 1 emission legislation for recreational craft, document COM (2000) 639 final, in relation to the emissions from other sources, both as shown in that same document, and as updated on the basis of more recent information from the European Environment Agency (EEA). And then as calculated by means of a more extended inventory model set up for this purpose. Any further reductions as potentially obtained by a stage 2 are determined in proportion to that last mentioned baseline. Water quality and noise aspects are determined on the basis of a scenario calculation, with a sensitivity analysis to determine the possible sensitivity for the assumptions.


2 The fleet

2.1 Types of engines involved

The following engines types may be distinguished: • Outboard engines: − (conventional) 2-stroke, spark ignition − DI (direct injection) 2-stroke, spark ignition − 4-stroke, spark ignition

• Inboard sterndrive engines: − 4-stroke, spark ignition (In Europe: rarely) − diesel (in Europe: most)

• Inboard shaftdrive engines: − 4-stroke, spark ignition (In Europe: rarely) − diesel (in Europe: most)

• As a special variant: saildrive, used on cabin-sailboats • PWC engines. Although technically they should be regarded as inboard engines, in

their technology they tend to follow the outboard engines, and are best classified in that part of the overall market.

2.1.1 Installation aspects The sketches illustrate these different options. They should be regarded as general system illustrations. Especially for the shaftdrive configuration different drive systems between the engine and the propeller do occur. Figure 2.1: Different engine installation configurations.

Outboard engines are a self-contained package. The engine crankshaft is placed vertical and the propeller is driven through a driveshaft and a set of gears. The engine exhaust is led through the ‘tail’ of the engine package that contains this drive (somewhat

outboard engine

inboard engineshaft drive

stern drive inboard engine: saildriveinboard engine


confusingly called the ‘shaft’ in English), and the boat is steered by turning the engine around the shaft centreline. This simply changes the direction of the propulsion. Sterndrive engines are mounted inboard, in a fixed position close to the boat’s stern, but drive the propeller through a similar ‘tail’ (shaft), mounted to the outside of the stern. In this case too the boat is steered by turning the shaft around its centreline, and in the majority of cases they too exhaust through that ‘shaft’. In the case of inboard engines with ‘shaftdrive’ (here ‘shaft’ has the usual meaning of a driveshaft, i.e. a rotating connection between the engine crankshaft and the propeller) the engine is installed in a special ‘engine compartment’ inside the boat and all systems, including the exhaust system, are installed by the boat builder, so its construction may have any possible configuration, although for reasons of noise reduction, on recreational craft underwater exhausts are common. Saildrive is a special case of inboard engines: as with shaftdrive, the engine is mounted much more forward than in the case of sterndrive, but still has the ‘tail’ (shaft) that is characteristic for both outboard and sterndrive. But in this case it does not rotate and steering is done by a rudder. This solution is typical for cabin-sailboats, but limited to only a few manufacturers. A relatively new class of craft, known as ‘personal watercraft’ (PWC), popularly often indicated as jet skis, use a kind of inboard engine installation, but use a waterjet rather than a propeller for their propulsion: Figure 2.2: The engine installation and propulsion of a PWC.

Outboard engines are particularly limited in space, since they have to fit into a compact, and often portable, overall package. Especially in the case of smaller units, size weight and ease of ‘handling’ are important aspects. Because of the theft risk, such smaller engines are usually not left on the boat permanently, but often transported in a car boot to and from the marina. Portability and stowability are therefore very important characteristics of such engines. Small 2-stroke engines are often preferred over 4-strokes for reasons of size and weight, but also to avoid the risk of oil leakage (in contrast to 2-stroke engines, 4-stroke engines do have a permanently filled oil sump). Within the confines of the cover, engine cooling and the avoidence of hotspots has a high priority. Inboard engines should be less limited in size and weight. But for various reasons, having to do with economic operating factors, recreational craft are often categorised by length, especially craft operated on inland waters. And since it is the obvious wish of the owner to have at his disposal as much useful inner space as possible, and since to him the propulsion aspect is little more than an unavoidable necessity, the volume of the engine compartment is habitually reduced to the bare minimum, often even smaller than in comparable automotive cases. In bigger seagoing boats engine rooms may be more spacious, but they are less numerous and such craft are less likely to be used on inland waters. Hence usable inner space is often an important competition element for the boat builder, and since (unlike e.g. the automotive case) the craft and the engine are produced by different manufacturers, the boat builder is likely to choose the most compact engine that will suit his demands. This is especially true for the European

PWCsteerable nozzle

waterjet


market, and especially so for craft (such as sailing boats) where the engine only has an auxiliary function. This leaves the manufacturer of the engine very little space for built-on equipment. Additionally he has to watch aspects like heat rejection, since the size of the coolers and the size and routing of the cooling medium will add further to the overall package volume, and radiated heat will inevitably cause problems in a confined space (see also under ‘safety aspects’, subsection 10.1.6). The only class of craft that is somewhat less limited in installation space is the PWC, which has an inboard engine, but no inboard owner facilities. PWCs do have their exhaust under water when stationary or going slow (displacement mode); when going into planing mode the exhaust is above the water level.

Generally speaking the total package is very much optimised towards the particular application (inboard or outboard, main propulsion or auxiliary propulsion, displacement boat or planing boat or PWC, etc.). And apart from customer satisfaction aspects (see 10.1.5) the safety requirements are the main driver for the installation aspects.

2.2 Types of craft

For the purpose of this study it is relevant to distinguish between the different types of craft. With this subdivision of the fleet it is then possible to decide upon general types of use (intensity and duration) and typical engine sizes. The overview given below may be regarded as typical for the European situation. The following types of craft have been defined: • Open sailing boat: Usually fitted with a small outboard unit. • Cabin sailing boat: Either a small outboard unit or a relatively small inboard diesel

unit are likely to be the most common. Larger diesels may be prevalent in sea-going vessels.

• Open motorboat: Usually fitted with an outboard unit. The size of the engine is dependent on design and use. Small engines are likely for dinghies and runabouts; speedboats and craft used for e.g. water-skiing are likely to have larger engines.

• Cabin motorboat: Usually these are fitted with an inboard diesel engine. Displacement hull vessels are likely to have smaller engine sizes than planing hull designs do.

• Personal watercraft (‘jet skis’): These are mainly driven by 2-stroke petrol units. Some have a DI 2-stroke or 4-stroke unit. The engine power is used to drive a hydro-jet for propulsion. Considering the speeds at which these craft are operated, these will be mid-sized engines. Therefore the use of DI 2-stroke engines could already be fairly frequent in this category of craft.

2.2.1 Open sailing boats

This type of boat is not always fitted with an engine. However, in many locations, especially marinas, vessels of this type are required to have an engine for reasons of safety. Manoeuvring at low speeds and in restricted and crowded situations can be very awkward with only sails and or paddles; often a small outboard engine is available for just these situations. The use of these engines will be limited in time and for manoeuvring only.


2.2.2 Cabin sailing boats Depending on the overall dimensions and general characteristics of the marine environment on which these vessels are used, the type and size of the engine will vary. Almost all will have an engine of some kind available. Small inland craft will typically have an outboard engine fitted, larger vessels, especially seagoing ones, are likely to have a fairly powerful inboard or saildrive unit. The majority of these will be diesel fuelled. In most cases the engine will be used for auxiliary propulsion only.

2.2.3 Open motor boats Depending on the definition used, this category could also include dinghies, rowing boats and runabouts as well as more typical open motorboats as such, speed boats, water skiing boats etc. All possible engine types will occur within this category. Most, however, are expected to be either driven by an outboard petrol fuelled unit (mix of 2-stroke, DI 2-stroke and 4-stroke) or by an inboard or sterndrive petrol or diesel engine. The duration of operation will usually be limited.

2.2.4 Cabin motor boats This category is most likely dominated by vessels driven by inboard diesel engines, although especially smaller vessels from this category may also be driven by outboard units (mix of 2-stroke, DI 2-stroke and 4-stroke). This type of boat is primarily meant for cruising, and theoretically relatively long daily operation is possible, when in use. A recent Dutch economical investigation showed, however, that in practice during cruising on inland waters (of which there is an extensive network in the Netherlands) the money spent on fuel is less than € 10 per day. Even assuming relatively small engines, this does not point to prolonged daily operation.

2.2.5 Personal Watercraft This relatively new type of craft is typically very fast and driven by medium-range engines. Relative to the small size of the craft itself, the engine performance is high. Older models will be driven by traditional 2-stroke engines, in newer models DI 2-stroke engines will be used as well. In some recent models 4-stroke engines are used.

2.3 Composition of the fleet

2.3.1 The European Fleet The proposal for the stage 1 emission legislation to be introduced in Directive 94/25/EC (document COM (2000) 639 final), gives estimates for the size of the European fleet (EU/EFTA countries, including Switzerland), although recent communication with Icomia in combination with an approach to a reasonable estimate suggest that the figure for the motorboats may be on the high side. The figures are shown in Table 2.1, below.


Table 2.1: Number of recreational craft with engines in Europe. Source: COM (2000)

639 final. Type of boat number Motorboats 3 628 000 Inflatables (not included in above) 170 000 Sailboats 821 506 PWCs Approx. 50 000 TOTAL Approx. 4 670 000

No further subdivision was given. For the current study it was attempted to collect more information by means of a questionnaire to both user’s organisations and to the Member States. This would have enabled us to divide the overall emissions over the relevant countries. But very few reactions were received. Furthermore, in the answers that were received it was consistently pointed out that in most Member States boats are not registered, so no real numbers are available. A few organisations indicated that they might be able to supply estimated numbers for some particular country, but since this would only provide isolated pieces of information, it was decided to abandon this approach.

2.3.2 Some national fleets Just to give some idea about typical fleet compositions, available data are shown for The Netherlands, the UK, Sweden and Italy, by way of example. The Netherlands are a country with a large area of inland waters, both inland waterways and lakes, but also a large stretch of fresh water ‘inland sea’ (a dammed off former sea area) and a large stretch of sheltered tidal salt water between the Frisian islands and the coast. Figure 2.3: Historical size and boat categories for the Dutch recreational fleet (1940-

1990), projected figures for 1991-2005. Data derived from [ANWB 1993]

0

50

100

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200

250

300

350

1940

1960

1975

1977

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1981

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2003

2005

year

n of

shi

ps (x

100

0)

Open sailCabin sailCabin motorOpen Motor


Some data is available for the Netherlands [ANWB, 1993]. Based on these and a continuing growth since 1990 (of 1000 ships per category per year, which amounts to ca. 1.5 % per year for the total fleet), the Dutch recreational shipping fleet is growing towards an estimated 290,000 vessels in 2005. This does not include a large number of inflatables, rowing boats and runabouts, some of which are also equipped with outboard engines. Assuming similar growth rates, a current estimate would lie around the 400,000 to 500,000 mark [HISWA]. Figure 2.3 presents the resulting picture that illustrates the increasing size of the fleet, which has grown spectacularly in the sixties and seventies, and at a much more moderate rate since then. Similar trends may be expected for other European countries, even if not always on the same timescale. The distribution of boat types across the fleet is very close the data presented in [STOWA/Waterpakt, 1999]. Open boats, used for local daytime recreation, represent about half of the fleet, but cruising boats, with overnight accommodation, still constitute the other half. Both categories are roughly 50/50 divided over sailboats and motorboats. Figure 2.4: Composition of the Dutch recreational fleet by type of boat. Source

[STOWA/Waterpakt 1999]

Netherlands fleet

27%

23%30%

20%

Open sailCabin sailCabin motorOpen motor

Figure 2.5: Composition of the UK recreational fleet by type of boat. Source

[Benchmark]

UK fleet

45%

15%

40%

Sail cruisersMotor yachtsOther* and PWC

* inland waterway and dinghies


The UK fleet is used on inland waterways as well as on coastal waters and in offshore sailing. “Benchmark-Research” presents a recent estimate for the UK. Cruising boats (sail and motor) represent 60 % of the fleet here, with the remaining 40% made up of “inland waterway vessels, dinghies and personal watercraft”. Inland waterway vessels may also include boats with overnight accommodation. Sweden has many lakes, some of them big, and for some parts a coastline with islands, where people have weekend accommodations and a boat. Motorboats are more popular than sailboats, being used for local boating, but overnight accommodation is not required on the boat. This results in a significantly different fleet again. Figure 2.6: Composition of the Swedish recreational fleet by type of boat. Source:

Sweboat.

Swedish fleet

6%10%

16%

68%


Another fleet with non-average characteristics would be the Italian fleet. That fleet is concentrated on either the big, mainly alpine, lakes or the Mediterranean Sea. But in the latter case the conditions of use are significantly different from those on the North Sea. The following characterisation of the fleet had to be reconstructed from sales data, but is believed to present a reasonable picture. Not included in this figure are a large number of inflatables with outboard engines, which actually constitute about 60 % of the total fleet. Figure 2.7: Estimated composition of the Italian recreational fleet by type of boat.

Italian fleet (estimate)

5% 2%

30%

63%



3 The market

3.1 Manufacturers and engines types

3.1.1 Manufacturers There are two kinds of ‘manufacturers’ involved: original engine builders (OEM = original equipment manufacturer) and so-called ‘marinisers’. The latter category buys engines from engine manufacturers who produce engines for other markets (both general machinery use and automotive use) and convert or adapt them for marine use (see subsection 3.5). Usually (although not exclusively) their contribution is limited to the mounting of external parts and/or a change in settings; for the basic engine technology they have to rely on the original manufacturer. Some original manufacturers produce marine versions of their own basic engines. There are only 8 manufacturers of outboard engines world-wide, with annual production volumes ranging from more than 300,000 units to less than 10,000 annually (with the smallest one producing less than 4000 annually), and about 3 main manufacturers of diesel engines. The rest belongs either to the small volume manufacturers or to the marinisers. Personal Watercraft (PWC) sold on the European market are produced by 4 manufacturers, two Japanese (one of which is not involved in the outboard market) and two non-Japanese. The total sales of PWC in Europe and the Mediterranean amounts to about 10,000-12,000 units, or ~ 5 % of the equivalent outboard volume. There are a few main marinisers and a number of very small marinisers, often producing less than 500 units per year each.

3.1.2 Types of engines involved As already indicated in Section 2, the types of engines used in recreational craft may be subdivided as: − Outboard engines − Sterndrive (inboard) engines − Shaftdrive (inboard) engines − As a special variant: saildrive (inboard) engines − Engines used in ‘personal watercraft’ (PWC) In total numbers outboard engines far outnumber the inboard engines, as shown in figure 3.1. As further explained in subsection 3.4, exact numbers for inboard diesel engines are nearly impossible to obtain. Hence there is a certain degree of uncertainty in these figures, and the percentages shown should primarily be considered as indicative. Nevertheless they may be regarded as good enough for a general idea of the composition of the market.


Figure 3.1: The relative shares of different engine/driveline configurations world-wide (numbers of engines). The percentages should be regarded as indicative. Source: estimated sales for 2004, as supplied by a manufacturer.

Further analysis shows that concerning the division over outboard engines and inboard engines there is not much difference between the two major markets, the North American market (the US and Canada) and the European market. This picture changes, however, when the inboard part is further split into its various options, see figure 3.2: Figure 3.2: The relative shares of sterndrive (petrol and diesel) and shaftdrive on the

two main markets (numbers of engines). The percentages should be regarded as indicative. Source: averaged estimated sales for 2004, as supplied by a few manufacturers.

As can be clearly seen, the North American market has a much bigger share of sterndrive engines, and most of those are petrol engines. The European boat owner obviously prefers a diesel engine for inboard use, and in the majority of cases this concerns shaftdrive engines. Outboard engines have traditionally been 2-stroke spark ignition (SI) engines. Recently an increasing number of 4-stroke outboard engines are appearing on the market, however. Inboard engines are for about 80 % compression ignition (CI) i.e. diesel engines. With some exceptions shaftdrive engines are mostly diesel, whereas, as shown above, sterndrive engines may be 4-stroke SI engines or CI engines. Due to the special requirements they have to fulfil, PWC engines have a relatively high power density (power/weight ratio). Originally they had, for that reason, mainly 2-stroke or DI 2-stroke engines, although 4-stroke engines are coming onto the market now. As a rule

North America

90%

1% 9%

sterndrive petrolsterndrive dieselshaftdrive diesel

Europe

15%

67%

18%

6%inboard

80%

13%

0.7%

0.5%

outboardsterndrivesaildriveshaftdrivewater jets

recreational marine enginesoutboard


shaftdrive engines have a mix of under water and above water exhausts, and PWCs have their exhausts emitting to the air when on speed (in planing mode), although close to the water level, whereas the other categories usually are fitted with underwater exhausts. Underwater exhausts are an effective means to reduce exhaust noise in a compact engine/drive package. Water injection systems close to the place where the exhaust gases leave the cylinders cools the exhaust gases, which is an important safety issue. This means, however, that in the case of exhausts that discharge above the water level the soluble components will effectively be discharged into the surface water too.

3.2 Outboard engines and engines for PWCs

3.2.1 Engine technologies As stated above, outboard engines have traditionally been 2-stroke engines. They are technologically simple and hence reliable and relatively cheap, and as indicated above they tend to be compact and lightweight. Inherent disadvantages were relatively high fuel consumption and high levels of exhaust gas pollution, but this did not outweigh the advantages. Similar considerations earned the 2-stroke engine a firm position in the field of small power driven equipment, the market for powered two-wheelers (PTWs), and in earlier times even in the bottom end of the automotive market. Exhaust gas legislation changed all that for road vehicles and, as indicated above, also in the boating market. During the discussions at the time of the previous TNO report [Rijkeboer 1991] the industry concerned declared itself willing to aim for so-called direct injection (DI) 2-stroke engines. At the time this was a truly ambitious commitment, since DI 2-stroke technology only existed in prototype form. The technology was nevertheless developed and introduced, although not without (sometimes serious) teething troubles. By now the technology seems to have reached a sufficiently mature level, capable of reliable operation in customer’s hands in most cases. It may be pointed out that a similar transition is currently aimed for by the moped manufacturers, since there too it is perceived as the more desirable option for complying with coming exhaust gas legislation. Exhaust gas aftertreatment systems do not exist in the boat engine market; they are viewed as extremely difficult to apply, because of the water injection mentioned before. This is above all a safety issue, much more than just an operational issue (see subsection 10.1.4). Another clear development since the early nineties is the switch to 4-stroke engines. Although it has proved possible to develop efficient and clean 2-stroke engines by switching to DI technology, by then they are no longer technologically simple or cheap, although still compact and lightweight. This means that for a number of manufacturers the 4-stroke became a viable alternative. Honda (traditionally a 4-stroke manufacturer, even in the PTW market) was the first to come with a few 4-stroke models on the outboard market, but several others have followed on the basis of various market forces. For modern 4-stroke engines reliability is no longer a problem, and size and weight are no longer felt as an obstacle for all but the most high performance applications; it is mainly the PWC that is still dominantly served by high performance 2-strokes.


Figure 3.3: The sales of 2-stroke and 4-stroke outboard engines in 5 main areas. Numbers of engines. Source: Icomia.

annual sales in 5 main areas - 2003

0

50

100

150

200

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300

350

Europe USA Canada Australia Japangeographical area

sal

es /

1000

4-stroke2-stroke

3.2.2 The size and shape of the market World-wide the size of the outboard engine market is about 800,000 units annually, of which some 200,000 for Europe. To put this in perspective the comparable situation for passenger cars and motorcycles is given in round figures (order of magnitude) in the table below: Table 3.1: Annual sales in three different market fields, compared with two other fields of application. Approximate figures. Sources: the relevant industries.

Europe Eur./USA/Japan World-wide Passenger cars 15 x 106 42 x 106 Motorcycles 1 x 106 5 x 106 13 x 106 * Outboard engines 0.2 x 106 0.8 x 106 Inboard engines 0.03 x106 0.12 x 106

* excluding China. On the basis of the available statistical data figures may be given for the following regions: • North and South America: − The USA − Canada − Central and South America

• Europe: − Western Europe (EU plus Norway and Switzerland) − Eastern Europe

• Middle East • Africa • Asia and Far East − Japan − Asia − Australia/Oceania


As can be seen in figure 3.4 the USA and Western Europe are the main markets. Eastern Europe and the non-European Mediterranean countries do not represent a significant market at the present time. Japan by itself is not a significant market either, but the Far East in total does represent some volume in the overall sales. Figure 3.4: The relative sales of outboard engines for various regions of the world.

Numbers of engines. Source: Icomia

An average player may have an annual production of ~ 100,000 units, divided over as many as 30-35 different types (i.e. in the order of 3000-4000 units per type). For the marine engine manufacturers it would therefore be very difficult to design engines for each particular market separately. Any drive towards advanced engine technology aiming at reduced exhaust emissions would therefore need a significant degree of international harmonisation to be successful. Otherwise manufacturers would opt to pull out of that particular market instead. Figure 3.5: The distribution of the sales over the eight manufacturers involved.

Numbers of engines. Source: Icomia

The distribution of the overall sales over the manufacturers involved is shown in figure 3.5. There are two very big players, two medium players, three small ones (one of which does not sell on the European market) and one very small one (which sells on

World outboard market 2003

41%

5%4%

26%

4%

1%

2%

3% 7%7% USA

CanadaC/S Amer.W.EuropeE.EuropeM.EastAfricaJapanAsiaOceania

World outboard market 2003

33%

12%

10%

5%7%

<0.1%

31%

2%


the European market only). Three of those are North American, whereas the others are Japanese and one Italian selling its own production 2-stroke engines plus some 4-stroke types based on original Japanese products. Two Japanese manufacturers are also serving the PTW market whereas one North American manufacturer is exclusively operating on the boating market. Figure 3.6: Total European sales of SI engines over a six-year period, as a function of

engine power range. Source: Icomia.

European sales distribution of outboard engines and PWC 1996-2002

0

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150

200

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300

350<3

3-12

12-2

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20-3

0

30-4

5

45-7

5

75-1

10

110-

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>150

engine power [kW]

num

ber/1

000

2-s4-s

Figure 3.7: Total American sales of outboard engines over a five-year period, as a function of engine power range. Source: Icomia.

US sales distribution of outboard engines 1998-2002

0

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150

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250

300

< 4

4-10

10-3

0

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0

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00

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> 20

0

engine power [hp]

num

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Figure 3.6 shows the total sales of outboard engines in Europe over a period of 6 years, split over the engine power ranges. This figure shows that the majority of sales takes place in the lower power ranges. In the USA the picture is appreciably different, see Figure 3.7.


The spread of the annual sales over the various countries of the West-European region is very uneven, see figure 3.8. The figure shows a remarkable increase in 4-stroke engines, which takes place mostly in the lower power ranges, however. Iceland (0.1 %) and Luxembourg (no known data) have been excluded here. The markets may be described as a small number of big markets (France, Italy Germany, the Nordic countries) some medium markets (the UK, the Netherlands, the Iberian peninsula, Greece and Denmark), and a number of very small markets (the alpine countries, Ireland and Belgium). Figure 3.8: The European annual sales of outboard engines per country for 1996 and

1999, showing the increasing tendency towards 4-stroke engines. Source: Icomia.

Sales 1996

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France Ita

ly

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4-s2-s

Sales 1999

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4-s2-s

If the shift in technology is further analysed, it becomes clear that the increased market share of 4-stroke engines has mostly taken place in the lower power regions, whereas the introduction of DI 2-stroke engines is mostly limited to the higher power ranges (see e.g. figure 3.9). For the moment this represents a remarkable difference from the PTW (powered two-wheeler) market, where the upper range is exclusively 4-stroke, and the


lower range still mostly 2-stroke. The DI 2-stroke technology that is being introduced or is shortly to be introduced on that market is limited therefore to that lower end of the market. Figure 3.9: The European annual sales for two different power categories over the

period 1996-1999. In the low power category there has been a remarkable tendency towards 4-stroke engines, whereas in the high power category the tendency has been mainly towards DI 2-stroke engines. Source: Icomia

The main reason for this different situation on the boating market is more geographical than technological, however. The American manufacturers have to a large extent adopted DI 2-stroke technology, and they are also the manufacturers who have the largest production of high power engines (compare figures 3.6 and 3.7). The Japanese manufacturers, on the other hand, have to a large extent switched to 4-stroke technology, and they are mainly the ones that serve the lower end of the market. Additionally it should be pointed out, however, that the DI 2-stroke relies heavily on its injection system, which demands an advanced electronic engine management system. And the much more hostile marine environment (water proofing) inevitably does result in higher cost than in the roadgoing case (see also subsection 7.2.1). Another consideration is the risk of moisture getting into the system during winter storage of the

3- 12 kW sales

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1996 1997 1998 1999 2000 2001 2002year of sales

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110 - 150 kW sales

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1996 1997 1998 1999 2000 2001 2002year of sales

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2-sDI 2-s4-s


boat or the engine. Such considerations make the manufacturers of smaller, less expensive, outboard engines more hesitant than in the case of small PTWs.

3.3 Inboard petrol engines

Inboard petrol engines are in the majority of cases installed as sterndrive engines, and as such they are much more popular on the US market than on the European market. European boat owners much sooner prefer small diesel engines, even for sterndrive application. Figure 3.10 shows the geographical distribution of sterndrive petrol engines, and it is clear that this is predominantly a North American application. Figure 3.10: The geographical distribution of inboard (sterndrive) petrol engines.

Source: industry.

Figure 3.11: The areas where in Europe the petrol sterndrive engines are sold. Source:

industry.

sterndrive petrol engines

0

500

1000

1500

Italy

Nordic

coun

tries

France

Spain

German

y UK

Benelu

x

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and

Country or region

num

ber/a

nnum

Unlike the situation with the outboard engines, there are no engines specially designed and built for these applications. In particular the sterndrive petrol engines in Europe are ‘marinised’ versions of engines designed for other primary applications, such as

Sterndrive petrol engines

93%

1%0.1%

0.2%6%

EuropeNorth AmericaAustraliaJapanSouth America


industrial or automotive use. For this reasons exact figures are hard to obtain, but generally speaking the annual sales of inboard petrol engines is estimated at 80,000 – 85,000 units, of which some 5000 are sold in Europe. Since in Europe ‘marinising’ usually (although not exclusively) consists of the mounting of dedicated inlet and exhaust systems and the addition of marine types of coolers and possibly oil/water heat exchangers, in the majority of cases the emission behaviour of such engines is largely determined by the original design. See further subsection 3.5. Figure 3.11 shows where in Europe these sterndrive engines are sold. As can be seen the greatest numbers are sold in the Nordic countries (Norway, Sweden, Finland and Denmark) and in countries in the Mediterranean area.

3.4 Inboard diesel engines

As already indicated in subsection 3.1 the market for inboard engines is much smaller than the one for outboard engines and the market for inboard diesel engines is primarily a European one. As for inboard petrol engines exact figures are hard to obtain, since the engines are not exclusively produced for marine use, and certainly not for recreational marine use. Especially the inboard diesel engines are just marinised versions of industrial engines produced for a large range of applications, and even for the marine applications there is a sliding scale from small recreational craft to large commercial vessels, and everything in between. This makes the typical diesel engine for recreational marine use hard to distinguish with any accuracy. Moreover the engine manufacturer delivers his product to a shipyard and has only limited knowledge about the type of vessel it is going to be used in, and no insight into the final geographical destination of that vessel. Figure 3.12: The relative size distribution of the manufacturers involved in the

European market for recreational marine diesel engines. Source: based on the information of one particular company.

Overall data therefore proved to be unavailable, and what data we finally did receive were based on in-house data collected by individual players in the field, provided to us on a confidential basis. Nevertheless a rough comparison of data provided by different sources turned out to present a relatively consistent picture, even when the actual numbers were not always strictly comparable.

44%

28%

1%1% <1%

5.5% =>

7%

7%

2%2%

2% many others


World-wide sales is estimated at about 65 000 units a year, of which about 45 000 in Europe. The biggest player would have an annual sales in the order of 20 000 engines a year, and the smallest one in the order of 200 per year. Depending on what one would call a ‘manufacturer’ (i.e. to what extent one would see a consortium as one or as more manufacturers) there are world-wide something like 40-50 manufacturers, half of them in Europe. Of these only a few are OEMs (original equipment manufacturers) and the rest are marinisers (subsection 3.5, below). The biggest marinisers would have a sales figure of roughly 3000 units a year. Figure 3.13 shows clearly that the inboard diesel engine is primarily a European phenomenon, and figure 3.14 shows where in Europe they mostly go. Figure 3.13: The geographical destination of diesel engines sold on the world-wide

market for recreational marine applications. Source: industry. Sterndrive diesel engines

10%

81%

2%4%3%

EuropeNorth AmericaAustraliaJapanSouth America

Shaftdrive diesel engines

24%

5%2%

1%

68%

Figure 3.14: The division of annual sales per country or region of inboard diesel

engines in Europe. Source: industry.

diesel engines

0%

5%

10%

15%

20%

25%

30%

France

Nordic

coun

tries Ita

ly

German

y UKSpa

in

Benelu

x

Switzerl

and

Country or region

perc

enta

ge a

nnua

l sal

es sterndriveshaftdrive

An analysis of the characteristic power levels of the engines sold, shows that in Europe the biggest individual class is the one below 100 kW (usually in the range 30-50 kW), with a second peak in the class 200-300 kW, for bigger motor yachts. In North America the distribution is much more ‘even’ although for very different numbers, whereas in


the rest of the world there also seems to be a predominant share of the smaller engines, like in Europe. See figure 3.15: Figure 3.15: Sales per power class in the different markets. Source: industry.

An analysis of the manufacturers shows that there are a few relatively big players and a host of very small ones. The bigger players usually have a product range that continues into much higher power ranges for commercial use, whereas the smaller players are always marinisers that assemble and sell marine versions of other manufacturer’s engines. Figure 3.12 shows a size distribution spectrum as provided by one individual player in the field, and although it may differ from someone else’s data, in a general sense the picture presented will be reasonably correct.

3.5 Marinisers

Marinisers are firms that convert existing engines (usually either automotive or industrial engines) for use in marine applications. Conversions are usually limited to the mounting of adapted inlet and exhaust manifolds (exhaust manifolds have to be water-cooled), heat exchangers (engine coolant is itself cooled against outside water rather than against air as in automotive and most industrial applications), and bell housings (adapted to the installation of a reversing gear). Additionally they have to install the means to inject water into the exhaust for cooling purposes. In a more general sense marinisers have to ready the engine in all respects for installation into a boat. Apparently in the US some marinisers do change fuelling characteristics and ignition timing as well. According to information collected in Europe such practices are much less common, and would in any case not be performed without support by the original engine manufacturer, and then usually at his premises. These differences are likely to be connected with the much wider spread use of (big) automotive petrol engines for marine use on the US market. It should be noted that in the majority of cases they do little to nothing to the engine that would in any way influence its emission behaviour, nor do they usually have the means to do so. Concerning exhaust emissions the general situation in Europe is that they have to rely on the design of the OEM as it is delivered to them, and also on his emission measurements when it comes to certification. As concerns noise, like the OEMs he can provide engine mountings that might reduce the transfer of sound to the surrounding

Inboard diesel engines

0

5000

10000

15000

20000

25000

<100

100-2

00

200-3

00

300-4

00

400-6

00>60

0

power class [kW]

num

ber s

old/

annu

mEuropeN.Americaother


structure, and he might advice the boat builder as to the exhaust silencers to be used. But the ultimate selection of that silencer and its installation is the responsibility of the boat builder. According to the information supplied by one of the larger marinisers, there are about 20 marinisers in Europe, ranging from a size of about 60 employees and about 3000 engines delivered per year to a size of less than 20 employees and about 200 engines delivered per year. The majority would have a size of around 25 employees and a production of between 500 and 1000 units per year. Marinisers tend to operate on a regional market rather than world-wide as OEMs would do.


4 Exhaust emissions - Status quo

4.1 Introduction

This Section documents the study, and its results, into the emissions by recreational craft to air and water. To be more specific, the assessment is done for air, water and sediments. The results are evaluated for environmental impact. To estimate the total emissions from recreational craft the following data is required: • size of the fleet • breakdown of the fleet by engine type and categorised by engine power category • information on the location and intensity of recreational boating. A first attempt to arrive at fleet data was already discussed in section 2. It was attempted to generate the data needed by sending out questionnaires to Member States, boating associations and environmental organisations. Unfortunately the response to these questionnaires was extremely poor. Only a few Member States reported information on their fleets and/or its use. No information was presented on possible problem areas. Only one national boating association responded, and did so by pointing out that in their country boats are not registered, and hence no information about the fleet was available. The environmental organisations reported that they had no interest in inland waters. An attempt to generate the information needed by an indirect route, based on sales figures and educated guesses, had to be abandoned when at the 1st stakeholders meeting several parties pointed out that the numbers arrived at were too far removed from a possible reality. This meant that the original intention to study a number of local environmental ‘hot spots’ was clearly impossible to carry through. After consultation with the client, the approach chosen instead, and reported below, is therefore based on the following: • Air pollution is primarily considered on a Europe-wide scale, based on an

aggregation of measured emissions from individual engines, via a reconstructed fleet composition and size.

• The possible impact on a local scale is estimated by comparing the results of a similar exercise for a hypothetical local case with the calculated results for some cities from the Auto-Oil II study.

• Water pollution is illustrated by means of a model-based calculation for a scenario-like typical situation. Variations in this scenario-like description will show the sensitivities of the outcome for the main determining parameters.

• A similar approach is followed to illustrate the sound aspects. The aim of the environmental impact part of the current study is to clarify whether or not engines of recreational boats are causing unacceptable problems with respect to air and water quality. However, this is a complicated matter because site-, time- and use specific factors are involved and therefore general applicable statements may not be derived. The current section is confined to implications of the use of boat engines during boating activity (exhaust gases and lubrication oil emission). Other potential risks to the environment like spillage of fuel, re-suspension of sediment and taste and odour effects, etc., are not covered in this section. Some of them are covered in Section 6. Furthermore this section focuses on effects of exhaust components on aquatic


organisms and the quality of raw water supply for drinking water production. Information from literature was collected and evaluated. Calculations were carried out in order to assess the emission to the aquatic environment and the resulting concentrations of major contaminants in water and sediment. A comparison is made with the available EQOs (environmental quality objectives) for these contaminants in order to assess whether there may be a problem with the water quality under different conditions. For this purpose 13 scenarios were defined, allowing to evaluate the influence of separate factors like fleet growth, engine technology, water temperature and density of suspended particles.

4.2 The overall emissions to air

Document COM(2000) 639 final listed the following emissions estimated for the baseline and reductions expected for the stage 1 legislation: Table 4.1: Emissions for recreational craft in the EU in t/year, as reported in

COM(2000) 639 final. CO NMHC NOx PM

Rec. craft SI baseline 154 011 65 148 3 424 - Rec. craft CI baseline 868 478 6 779 544 Total baseline 154 879 65 626 10 203 544 Rec. craft SI stage 1 89 791 6 911 5 995 - Rec. craft CI stage 1 821 368 4 668 385 Total stage 1 90 612 7 279 10 663 385 Reduction [t/year] 64 267 58 347 - 460 159 Reduction [%] 41 % 89 % - 4.5 % 29 % The increase in NOx emissions between the baseline and stage 1 is caused by a switch to 4-stroke and DI 2-stroke engines that generally emit far less HC, but do so with a penalty in NOx. Since the NOx emissions are extremely low to begin with, this penalty is accepted as a reasonable price to obtain a significant reduction in HC, since it is much easier to compensate for this NOx penalty elsewhere than to find a similar HC reduction elsewhere. Similar considerations led to a similar technology switch for small powered two-wheelers. These figures were supplied at the time by the industry as a first estimate. They do not contain evaporative emissions. In Section 8 it will be attempted to supply more up to date figures, and evaporative emissions are dealt with in Section 6. Table 4.2: Emissions for EU-15 in kt/year, as reported by the EEA;

Recreational craft emissions as in Table 4.1. CO NMHC NOx PM

Total anthropogenic EU-15 1990 1998

50 000 37 000

16 000 12 500

11 700 9 300

2 300 2 000

Road transport EU-15 1990 1998

32 000 22 000

6 500 4 250

8 000

~ 4 000 *

700

~ 350 * Rec. craft SI (1998) 154 65 3.4 na Rec. craft CI (1998) 0.9 0.5 6.8 0.5 * estimates by the Auto Oil II study for 2000 Table 4.2 shows emission data of 15 EU member states as reported by the EEA (European Environmental Agency). From these figures it can only be concluded that the


contribution of recreational boating to the overall air pollution must be regarded as negligible. On the other hand Warrington (1999) points out that, depending on local circumstances, in critical areas the ozone concentration at ground level may rise to levels causing human pulmonary and respiratory problems. This statement is further investigated in the remainder of this subsection.

4.3 Local emissions to air

Since no local problems were reported to us in response to our questionnaire, we were not in a position to comment on any specific cases. Instead we like to present the following considerations.

CALCULATION EXAMPLE: The majority of European lakes used for water recreation are roughly between 5 and 50 km2 in overall surface. Only a few big ones (like the Bodensee, Lake Geneva, Lake Garda) fall in the category 300-500 km2. In subsection 4.6 a typical small lake (“Lake Fun”) with a size of 7 km2 is used for a scenario study. For this situation overall emissions are calculated. For the case presented here, a “Lake Fun-plus” is assumed that has five times the size (i.e. 35 km2), although with a lesser density of boats. This would bring it near the upper limit of that class of lake. On the basis of available Dutch data a total of 3200 boats is assumed for Lake Fun (see Appendix C). Such a number could be reached on a fine summer weekend day with many boats taking the opportunity. With an average operational time of 0.9 h/day for each boat (as assumed), the total number of operational hours then comes to 411 h/km2. Bigger lakes would have a lower density of boats. The German study by TÜV (see Appendix E) assumes a number of operational hours of 250 h/km2. A big lake like the Bodensee has something like 100 h/km2. For Lake Fun-plus a figure of 200 h/km2 was arbitrarily selected. For such a big lake this would make it a ‘wost case’ situation. For an evaluation of the results the data of the Community study ‘Auto Oil II’ is used. In that study the air quality in 10 European cities was studied, for the baseline situation in 1995, and into the future up to 2020. Out of that study the cities Athens, Lyons and Utrecht were selected. Of these three cities the NMHC emissions were extracted for 1995, 2005 and 2020. NMHC was chosen since it is indicative for ground level ozone formation. Athens figured in the Auto Oil study as a heavily polluted city, where limitation of the transport vehicle emissions would not be sufficient to cure the existing problems and additional measures would be necessary. Lyons was selected as the most severe emission situation where the limitation of transport vehicle emissions, together with the likely measures to the non-transport sources, might change the balance, depending on the level of the measures (the ‘Lyons option’). Utrecht figured as an ‘average case’, with no serious problems, where even moderate measures would be sufficient to guarantee acceptable air quality. The size of Utrecht would be roughly half the size of Lake Fun-plus. It should be noted that in the context of ‘Auto Oil II’ for air quality the priority lay with NO2 emissions, not ground level ozone formation, but the situations were not largely different for ozone. The Auto-Oil study resulted in the emission figures as shown in Table 4.3.

The water quality was calculated for a typical (Dutch) inland water fleet, and for the average European fleet, although many of the biggest European boats would be


operated on salt water rather than inland water. The double figures in the last two rows of Table 4.3 represent these two situations.

Table 4.3: Total NMHC emissions for three cities of the Auto Oil II study, compared

with calculated emissions for a hypothetical lake with intensive boating (rounded figures).

Location Year or Stage

All sources *

Total transport

Passenger cars

t/day t/day t/day Athens 1995 260 90 40 2005 200 35 10 2020 175 15 1.5 Lyons 1995 95 20 15 2005 72 6 3.4 2020 65 2.5 0.7 Utrecht 1995 30 4.5 3.25 2005 25 1.4 0.85 2020 20 0.6 0.17 Lake Fun-plus Stage 0 2.5-7 Stage 1 0.6-0.9

* approximation derived by scaling down the national emissions

The figures indicate that the high and low boat emissions calculated for the base case (Stage 0) are comparable with the projected total transport emissions for Lyons 2005 and 2020 respectively. The boat emissions for the Stage 1 case are at the projected passenger car level of Utrecht 2005 and the total transport level of 2020. This means that already in the baseline (Stage 0) situation only in cases with sizeable other sources around the lake there would be a significant chance of ground level ozone formation in the area. In the RCD Stage 1 case the contribution of boating to a possible ozone problem would be sufficiently small that it can not be expected to be a significant contributor to a possible problem.

4.4 Fate and behaviour of exhaust emissions in aquatic systems

NOTE TO THE READER: Subsections 4.4-4.6 consist of a literature survey that documents the existing knowledge, or the lack of it, followed by a small scenario study to illustrate the influence of some typical parameters.

In this subsection a concise overview will be given based on publications on the fate, effects and risks of exhaust emissions of outboard engines to the aquatic environment. The review by Warrington (1999) appeared to be a very useful source. It should be noted that most studies based on actual measurements of the effects of outboard engines are based on existing conventional 2-stroke engines, which have significantly high scavenge losses (emission of unused intake mixture).


4.4.1 Fate of the contaminants in water The exhaust of a boat engine contains many different chemical compounds. The most important groups of chemicals are COX, SOX, NOX, and hydrocarbons, with PAHs (PAH = polycyclic aromatic hydrocarbon). It should be noticed that there are also small amounts of unknown substances which may be relevant due to persistence and/or toxicity in water. However, such substances cannot be considered in this study, due to a lack of information on their characteristics and a lack of environmental quality objectives for most of them. The exhaust of most modern marine engines is emitted below the water surface (see subsection 3.1). The major part of the emission is in the gas phase and is released directly to the atmosphere. The remainder will condense and suspend in the water column or form a film on the water surface for a certain length of time. The emissions retained in the water are subject to several routes of degradation or atmospheric release by a combination of physical, chemical and biological processes [Warrington, 1999]. The gas phase includes water vapour, oxygen, hydrocarbons, carbon oxides and nitrogen oxides. Carbon monoxide is poorly soluble in water and more than 80% of the CO emitted is immediately lost to the atmosphere. Carbon dioxide is mainly lost immediately to the atmosphere (approx. 65%) but still contributes to the aquatic carbon cycle which may stimulate growth of aquatic plants. Nitrogen oxides are only a minor component of marine engine exhaust emissions, except in the case of diesel engines. The loss of NOX to the air compartment ranges from 33 to 100% [Warrington, 1999]. NOX can cause acidification in poorly buffered water systems. The same is true for SOX compounds. The organic composition of the gas phase exhaust (HC = hydrocarbons, and VOC = volatile organic compounds) resembles the composition of the fuel. In the review by Warrington (1999) it is estimated that approximately 40% of the hydrocarbons emitted are retained in the water phase, whereas the rest escapes to the atmosphere in exhaust gas bubbles. Hydrocarbons do not accumulate in the bulk water column but accumulate in the water surface microlayer. The composition of the condensable organic portion of the exhaust consists of two fractions: unburned fuel (aromatics, alkanes, alkenes) and partially oxidised hydrocarbons (phenols, carbonyls). The mass of condensed material amounts to 1.5% to 7% of the fuel used by outboard engines. The higher percentage is typical for conventional 2-stroke engines. The group of hydrocarbons consists of aliphatic and cyclic compounds, like PAHs. The volatile hydrocarbons contain less than 11 C-atoms. PAHs are poorly degradable and poorly soluble in water. PAHs strongly absorb to organic matter like suspended matter and sediment and are therefore often found in the sediments and are then a reason for clean-up of these contaminated sediments. In a laboratory study the uptake of HC-compounds in water from engine exhaust was measured. The amount of compounds dissolved in water was positively correlated with the volume of gas emitted to the water. The VOC in water decreased with time with a high rate of decrease in the beginning, but the decrease levelled off after a certain period of time. Benzene was considered more problematic than xylene and toluene;


however the HC concentrations remained under the environmental limits [Egashira et al., 2002]. The introduction of VOC into water by the exhaust of a 4-stroke outboard engine was studied under laboratory conditions. The VOC consisted mainly of benzene, naphthalene, indene and indane and their ethylderivates. Formaldehyde was the only aliphatic compound present in substantial amount. The pattern of VOC resembles the one found in waterways used by intensive motor boat traffic, like parts of Lake Constance [Jüttner et al., 1994]. In a field test with intensive use of a conventional 2-stroke outboard engine on an artificial pond, run on two different lubricants (a conventional mineral oil based one and a synthetic one) hydrocarbon concentrations in water increased to some extent, but much less than expected on the basis of known emission factors. The concentrations were relatively highest in the surface layer and subjected to wind effects. The HC concentrations remained far below known acute toxicity levels of both lubricants applied in the test. Long term effect levels were not investigated [Wachs et al., 1991].

4.4.2 Factors affecting the fate of HC compounds The fate of the contaminants in water is affected by a number of physical and biological processes, like water currents, adsorption and biodegradation. Some studies have been carried out to examine this. The removal rate of hydrocarbons from water was higher in experiments with propeller-on as compared to propeller-off, which was usually attributed to the stirring and resultant ‘aeration’ of the water. It was estimated that at least 90% of outboard hydrocarbon emissions move to the surface as a film. Wind and surface currents increase dispersal of the surface film. This may result in an increased surface area, which will stimulate evaporation and degradation of hydrocarbons. Evaporation is the process causing the fastest removal. The rate-limiting step in the loss of fuel from the water to the air appears to be the mixing of exhaust products in the water and their subsequent rise or diffusion to the surface, not the evaporation at the surface. The evaporation half-life for VOC dispersed at a depth of 1 meter in static water was 11 days, whereas it was only 1 day under aerated conditions. This is in line with the observation that exhaust products in water behind outboards, which is in motion, are removed even faster: about 65% removal in 1.5 hours [Warrington, 1999]. Hydrocarbons can be degraded by different kinds of organisms, with a major role for micro-organisms. The rate of degradation depends on water temperature, availability of oxygen, carbon substrates and nutrients like nitrogen and phosphorus. Microbial degradation of hydrocarbons has been demonstrated with fuel as well as exhaust products. Some studies demonstrated greater microbial activity in water with use of outboard engines, while water quality was not reduced in larger and deeper lakes [Warrington, 1999]. Hydrocarbons can adsorb to suspended material in the water and after sedimentation reach the sediment. The organic matter content and the clay content of suspended sediments enhance adsorption. There are no indications, however, that heavy outboard use over longer periods of time causes a build-up of hydrocarbons in the sediment. Relatively high levels of hydrocarbons in sediment are probably linked to other types of origin, such as run-off from the surrounding environment into the lake. Possibly


hydrocarbons adhered to suspended material are not sedimented due to turbulence and thermocline keeping them in upper water layers and/or an effective degradation process is involved [Warrington, 1999].

4.4.3 Influence of fuel and lubricants The emission and subsequently the contamination of aquatic systems by recreational craft may be improved by application of more environmentally friendly types of fuel and lubrication oil. Some studies have been conducted on this subject. Jüttner et al. (1995) demonstrated that replacing petrol by ethanol is effective with regard to reduction of aromatic compounds, but higher emissions were found for formaldehyde and acetaldehyde emissions. The difference between mineral and degradable lubricating oils on emissions of aromatic compounds from two-stroke engines was small. Effects on emission of oil and polar degradation were not studied, however, but are relevant. Van Donkelaar (1990) pointed out that spilled lubrication oil from 4-stroke engines contains a high level of PAHs and can be a serious environmental problem when it is leaving the engine and entering the environment by leakage, uncontrolled oil spills or via particulates. 2-stroke engines do not need to have this kind of risk because of their lost-lubrication system with which they can be run more readily on easily degradable lubricants. In a recent study (in prep.), Kelly et al. compared the emission of a 2-stroke outboard engine when using an environmentally adapted lubricant and an equivalent mineral lubricant. The pollutants remaining in the water after combustion were characterised and quantified. The results revealed that naphthalene, phenanthrene and benz(a)anthrene were the compounds among the PAHs with the highest concentrations remaining in the water. The VOCs benzene, toluene, ethylbenzene and xylene were emitted at much higher rates than the PAHs. The fuel was the major cause of the high VOC emission. Emission factors can be derived from this study. The lubricant had little effect on the overall emission rates of PAHs and VOCs. The emission rate of the pollutants increased with increasing throttle setting level. The major advantage of the environmentally adapted lubricant was the low toxicity and high degradability.

CONCLUSION: The type of lubricant has little effect on the overall emission rates of PAHs and VOCs. However, the biodegradability of the lubricant itself may be relevant in cases where lubricants are released to the aquatic environment by spillage.

4.4.4 Calculation of concentrations and risks Model calculation studies on the emission and distribution of outboard exhaust gas components in aquatic systems are rare, probably due to the complexity of the emission route, fate and behaviour of the contaminants in aquatic systems and the variation in environmental conditions. However the STOWA/Waterpakt study (1999) provided such calculations. These were carried out for a large range of compounds, to wit 45 hydrocarbons and other compounds and 37 PAHs. CO and NOX were also included in


the calculations of concentrations in water. The impact of the variant called ‘the IMEC scenario’ (a scenario based on IMEC figures) on the water quality was calculated for three typical situations with high recreational boating activity: a small river, a shallow lake and a marina with 1200 berths. The outcome of the calculations showed that the IMEC scenario would not be sufficient to attain the water quality objectives over 30 years (up to approx. 2030) in the small shallow waters of the study. The maximum permissible concentrations (MPC) of substances like PAHs (as anthracene and phenantrene) would be exceeded. The picture is better for larger waters. So the actual dimensions of the waters considered are important in the sensitivity analysis. The authors also conclude that the annual growth in recreational boat traffic contributes significantly to the failure to meet water quality objectives. Important assumptions are that 60% of the emission is retained in the water; that there is an annual growth of recreational boating of 2%; and that there is a 50-50 distribution of newly sold 2-stroke and 4-stroke outboard engines. It should be noted, however, that in fact this situation has significantly changed in more recent years.

In the present study it was decided to select five compounds for the calculations: four VOCs and one PAH. The choice is based on the high concentrations in water and sediment among the chemical group, the relatively high toxicity and the availability of environmental quality objectives. The design and outcome of the calculations are described in subsections 4.5 and 4.6.

In some cases it has been recommended to protect the water quality, especially in the area where the water is used for tap water production, by putting restrictions on recreational boating, even in cases where it is not clear whether quality objectives are approached or exceeded. An example of this is the agreement to reduce the VOC burden by restricting the usage of the PWC on part of a river in Japan [Egashira et al., 2002].

4.4.5 Recommendations Warrington (1999) provided relevant recommendations for further research and measures. A selection of the most relevant recommendations within the context of this study is made below.

• Guidelines for levels of boating use cannot be generalised and management of boating use must consider each water body individually.

• In the case of normal recreational boating activities, there seems to be no need to close lakes to outboards or to restrict engine power or engine type in order to maintain bulk water column quality.

• Studies should be carried out on the concentrations of exhaust components in the surface microlayer together with the effects on the (life stages of the) aquatic organisms living in this layer.

• The effects of long-term exposure of aquatic organisms to realistic exhaust component concentrations of lakes with heavy use of recreational boating should be tested.


• To eliminate taste and odour problems, the use of boats with combustion engines should be restricted in the vicinity of shellfish beds and the water supply intakes of fresh waters serving as domestic water supplies.

4.4.6 Perceived measures for improvement (questionnaire) In an investigation concerning general opinion, in the Netherlands users, manufacturers and politicians were asked to give their opinion on the most important issues concerning the environmental impact of recreational craft and the feasibility for improvement [Blankendaal et al., 2002]. Emission of exhaust gas to air was considered as an important issue by nature- and environmental organisations and boat manufacturers. Propeller shaft grease was regarded as an important environmental threat by nature- and environmental organisations only. Feasible solutions were foreseen for propeller shaft grease (nature- en environmental organisations and policy makers). The proposed measures to solve the problems are introduction of low-emission engines, electric motors, fuel cells, biologically degradable lubricants, water lubricated propeller shaft. These measures, with the exception of the fuel cell, were considered as 1st and 2nd generation technical measures providing improvement at a medium to long term. The fuel cell in combination with the electric motor for the propulsion was seen as a 3rd generation solution with a long term agenda.

4.5 Existing environmental quality standards

For the purpose of this part of the study, environmental quality is limited to only two environmental compartments: air and water. For each of these an overview of relevant existing environmental quality standards (EQSs) is given. This overview starts by outlining the Dutch situation and extends from there to make clear what the situation is elsewhere. For a number of contaminants harmonised EQSs for Europe do already exist. In addition to the EQOs (environmental quality objectives), information on the effects of exhaust gas from outboard engines on aquatic organisms was collected from literature.

4.5.1 Air quality standards In Table 4.4 the air quality standards (EQS) for the Netherlands are listed. Table 4.4: Air quality standards for the Netherlands. Source: InfoMil, 2000.

Compound

MAC

MPC annual mean

Target value annual mean

EU target value annual mean

CO 10 mg/m3 0.1 mg/m3 NOx1 3 mg/m3 0.03 mg/m3 0.2 µg/m3 Aromatics 25-500 mg/m3 Benzene 3.25 mg/m3 0.03 mg/m3 0.005 mg/m3 Formaldehyde 25 mg/m3 0.01 mg/m3 0.001 mg/m3 PAHs 1 ng/m3 1 ng/m3 0.01 ng/m3

1expressed as NO2 equivalent. MAC = maximum allowable concentration (allowed for a labour situation over an 8-hour working day) MPC = maximum permissible concentration (in the general environment), which represents a ‘no effect’ level. In Table 4.5 some air quality standards as they apply in the United States are given.


Table 4.5: Air quality standards for the U.S.A. Source: EPA, 2004.

Com pound Period Value Unit Remark CO 1h average 35.5 ppm not to be at or above this level:

more than once per year

8h average 9.5 ppm not to be at or above this level:

more than once per year PM10 24 h average 155 µg/m3 3yr average or annual 99th percentile

for each monitor within area is not to be at or above this level

annual average

51 µg/m3 3 yr average or annual arithmetic mean of each monitor within area is not to be at or above this level

PM2.5 24 h average 66 µg/m3 3yr average or annual 98th percentile for each population-oriented monitor within area is not to be at or above this level

annual average 15.1 µg/m3

3 yr average or annual arithmetic mean from single or multiple community-oriented

monitors within area is not to be at or above this level

4.5.2 Water quality standards In the EU, environmental quality standard (EQS) values are in development for priority substances. It should be stressed that these EQS values are not yet final and should be considered as indicative values. Two kinds of EQS are used. The definitions of these EQS are given in Article 2 of Directive 2000/60/EC. The description is as follows: “annual average environmental quality standard (AA-EQS)” shall mean a concentration established to ensure protection against long-term exposure, and which is included in Annex I, part I, that shall be compared with the annual average concentration of measurements of a pollutant in the aquatic environment. “maximum allowable concentration environmental quality standard (MAC-EQS)” shall mean a concentration established to ensure protection against short-term exposure, and which is included in Annex I, part I, that shall not be exceeded by any individual measurement of a pollutant in the aquatic environment, which is established for: - All inland and transitional waters; or,

- For bodies of water used for abstraction of drinking water identified in accordance with article 7 (1) of Directive 2000/60/EC.

The available EQSs for the selected compounds in water are listed in Table 4.6. At the moment EQS values are proposed for benzene and naphthalene, but not yet for toluene, xylene and formaldehyde. These values may be adjusted with respect to the first EQS values for freshwater as proposed by Lepper (2002).


Table 4.6: Environmental Quality Standards (EQS) for water, harmonised in the EC (subject to revision depending on the opinion of the CSTEE)

AA-EQS inland waters

AA-EQS transitional,

coastal, territorial waters

MAC-EQS inland,

transitional waters

MAC-EQS drinking water

abstraction * µg/l µg/l µg/l µg/l Benzene 1.7 1.7 49 1.7 Toluene Xylenes (ind) Formaldehyde Naphthalene 2.4 1.2 80 < 0.2

* This MAC-EQS applies to surface waters intended for drinking water abstraction, and that have been in accordance with article 7.1 of Directive 2000/60/EC.

EQS values for The Netherlands are also shown here because they are available for some of the selected compounds for which no (proposed) EQS values are available. In The Netherlands EQS values are available for four of the five selected compounds. Next to water, EQS values are also published for sediment. The values are listed in Table 4.7. The Maximum Permissible Concentration (MPC) is an upper limit protection value that should never be exceeded. For PAHs there is an EQS that is related to drinking water and raw water (surface water used for the preparation of drinking water); compounds of this group should have levels below 0.2 µg/l. Table 4.7: Environmental quality standards for water and sediment in The

Netherlands. Source: CIW, 2000; RIVM, 1999. MPC = maximum permissible concentration

MPC water

MPC sediment

MPC drinking water

& raw water µg/l (total) mg/kg dw µg/l (total)

Benzene 240 1 Toluene 730 4 Xylenes (ind) 380 14 Formaldehyde ~ 9200 n.a. Naphthalene 1.2 0.1 PAH 0.2

Note: For Formaldehyde no actual EQOs have been defined (in the Netherlands). The presented MPC is indicative and has been estimated based using ETX-2000 [Van Vlaardingen, Traas and Aldenberg,

2003] from a dataset of 181 ecotoxicity endpoints extracted from the EPA-Ecotox-database.

4.5.3 Effects on aquatic organisms and aquatic systems Warrington (1999) concluded that studies carried out to measure the effects of outboard exhaust on bulk water quality and the aquatic organisms are not suitable to answer the crucial biological questions. However, significant hydrocarbon pollution of the water column and overt signs of toxic effects of exhaust on aquatic organisms (zooplankton, phytoplankton, periphyton) at the normal recreational use level are not found. There are


indications, however, that mussels and oysters are vulnerable to the components of exhaust emission in the water. Aquatic plants may be stimulated in growth due to the extra dissolved CO2 and increased water circulation. An interesting experiment was carried out by Tjärnlund et al. (1995) who exposed fish to pollutants from exhaust gas of a 2-stroke outboard engine in two types of experiments. In the first experiment exhaust water was diluted appropriately and led into a tank where the fish were exposed. In the second experiment pollutants were extracted from the affected water and used in intraperitoneal injection of juvenile fish and embryo’s. Toxicological effects were found in the liver, kidney and blood of the exposed fish. It should be noticed that realistic exposure levels are difficult to assess and therefore conclusions on actual risks of fish are not really possible. Nevertheless the authors assume that the biological effects of the exhaust from conventional 2-stroke outboard engines are a serious risk to the environment. In contrast with the water column, the surface microlayer of the water may accumulate hydrophobic aromatic organic pollutants such as PAHs. This layer is of special importance for the aquatic ecosystem because it is the place for the reproduction of many species, many eggs float and larvae feed here [Warrington, 1999]. The current study is focussed on the impact of chemicals; however, important conclusions on other types of effect of motor boat exhaust emission are mentioned in literature. It is reported that odour threshold concentrations of fuel in water are very low (1 part of fuel per 3 million parts of water). This level is not unrealistic for smaller lakes with intensive boating activity, for instance as on summer holiday weekends. Of course many other factors are involved (lake water exchange rate, evaporation loss, weather conditions, etc.). However, restrictions can be considered for lakes with a drinking water supply function and specific vulnerable conditions like small volumes and low exchange rates [Warrington, 1999].

CONCLUSIONS: Final EU harmonised environmental quality criteria (EQC) are lacking for the compounds concerned. For a minority of these compounds preliminary EQSs are available and can be used in the present study, together with the criteria (MPCs) developed in the Netherlands. For many other compounds in exhaust emission, EQCs are not available at all. The effects of long-term exposure of aquatic organisms to realistic exhaust component concentrations in lakes with heavy use of recreational boating are as yet unknown.

4.6 Estimated environmental concentrations

As stated in subsection 4.4.4 model calculation studies on the emission and distribution of outboard exhaust gas components in aquatic systems are rare, due to the complexity of the problem. The attempt presented here should therefore certainly not be viewed as a routine calculation.


4.6.1 Introduction In the current study calculations have been made for a number of theoretical situations (scenarios), which can be considered as realistic, although ‘worst case’, for different local situations encountered in Europe (see the introduction in subsection 4.1). Environmental concentrations of the contaminants were calculated for a number of important constituents of exhaust gases from recreational craft. The total amount emitted is partitioned across air, water, suspended solids, sediment etc. For the longer term, degradation (e.g. by microbes or under the influence of light) is also taken into account, as is evaporation of the substances from the water column to the atmosphere. In Appendix C an account is given of the selection of the specific parameters that are relevant for this calculation. They are summarised below. The calculation model used Subsection 4.4.2 listed the various aspects that play a part in the removal rates of HC compounds from the surface water. The reader is referred back to this subsection. In summary, however, they are: The percentage of the input that escapes directly back into the atmosphere. More

about this is said in subsection 4.7.1. The adsorption/desorption rates to/from particles suspended in the water. This is

very dependant on the concentration of suspended matter. In clear water the retention of hydrocarbons will be much less than in more turbid water.

The water temperature, which influences the rate of evaporation. For the first calculations an existing model SimpleBox 2.0 [Brandes et al., 1996] has been used. This model was selected since it is capable to describe, although still in an elementary way (hence the name SimpleBox), the various removal routes. The model needs values to be specified for the parameters mentioned above. The documentation for the model describes the default values for all other model parameters. Obviously these values will vary from location to location. It should therefore be noted that, since the results of the calculation are fully dependant on the set of input parameters, results would vary per location with the characteristics of the lake, its use and the local climatic circumstances. It was nevertheless expected that by assuming either average or ‘worst case’ values, the results could be taken as an indication of a typical order of magnitude, possibly as of a worst case, depending on the exact input parameters chosen. They will indicate if a local water quality problem on a typical European locality is likely, possible or unlikely. For the model an average emission-intensity is needed as input. For the current purpose a maximum load has been defined as representative for a busy summer day. An important characteristic of the model is that is has been set up for a static situation, that moves towards an equilibrium output. In actual fact the input is likely to be concentrated on daytime hours during weekend days, after which a kind of recuperation may take place. This aspect will be further discussed in subsection 4.7.1. For the estimate a virtual lake, “Lake Fun”, has been defined. This lake is modelled on the Dutch lake “Nieuwkoopse Plassen”. This is typical for a shallow and relatively small lake, which is not constantly refreshed, although it is part of the Dutch water


system that eventually discharges its water to the sea. It has been used in earlier studies [STOWA/Waterpakt, 1999] on the same subject. The major characteristics are: • an overall area of 7 km2 • an average depth of 2.3 m • a suspended matter concentration of 22 mg/l • a water temperature of 12 ºC This water temperature selected is the default value of the model; it represents a broad overall average. Since Lake Fun is a virtual lake the selection of an actual temperature was not possible. Instead, the influence of the temperature will be shown by a small sensitivity analysis. Insofar as it might be a low value (at least for a shallow lake) it will lead to a kind of worst case calculation. In the majority of the scenarios the other parameters are also set to their default values. These default values are representative for the Netherlands and other European countries with a moderate Atlantic climate. For the calculation of the emission from recreational craft the number of vessels for Lake Fun has been selected as shown in table 4.8. Table 4.8: Number of recreational craft on Lake Fun for three different pilot years.

Year Number of recreational craft 1995 2600 2005 3200 2015 3800

It is estimated that on a peak day each vessel would be used for about 0.9 h. In fact some vessels will remain in the marina and others will be used more intensively. However for the calculation an average is adequate. The technology mix used for the petrol engines of these fleets has been selected as typical for the years considered. The diesel share has been selected as a high value, since the naphthalene concentrations are more than average determined by the diesel emissions. So in this way the model shows more discrimination. Two sets of engine size distribution have been used: first an estimate characteristic for the Netherlands and another set which is arrived at by taking the average engine size across all available European countries. This second set is referred to as the EU-engines. Both sets of engine sizes per technology are presented in Appendix C. For the modelling of the 1995 situation the emission data have been used that were provided by Icomia (see Appendix B) and for the 2005 and later situation the limit values of the Stage 1, as set out in Directive 2003/44/EC have been taken. The compounds selected for the evaluation In this scenario study five compounds of the exhaust emission were selected based on findings in literature, relatively high known concentrations in water or sediment, and high toxicity (low ‘environmental quality objectives’). They are: • Benzene • Naphthalene • Toluene • Xylene • Formaldehyde


Although other compounds may be relevant as well, they could not be assessed due to a lack of information on the characteristics of such compounds. The results for the five selected compounds will give a fairly representative picture, however. In combination with emission profiles that give the fraction of a compound in relation to the total HC-emissions an estimated total emission per compound was calculated. A final conversion of the unit then yields an emission-intensity as required by the model.

4.6.2 The different scenario’s and their results The scenarios have been laid out as follows. • Scenario 3 should be regarded as the base case. Scenario 3 describes the Dutch fleet.

Scenario 7 describes the same situation for the average EU fleet. • Scenarios 1-4 describe the influence of the changes in fleet composition and the

technology improvement for the Dutch situation. • Scenarios 5-8 describe the influence of the changes in fleet composition and the

technology improvement for the EU situation. • Scenarios 9 and 10 describe the influence of the water temperature (± 4 ºC, relative

to the 12 ºC of scenario 3). • Scenarios 11 and 12 describe the influence of the amount of particles suspended in

the water (5 and 30 mg of suspended matter per litre of water respectively, relative to the 22 mg of scenario 3).

• Scenario 13 was added to understand the influence of stratification. This scenario was not actually calculated, as the model is not suited to this kind of problem. A qualitative approach was taken to address such a situation adequately.

The scenarios are detailed in table 4.9 and the results calculated are shown in table 4.10 below. Additionally three more scenarios have been calculated for possible Stage 2 legislation. These are dealt with in Section 8. Table 4.9: Listing of the scenarios.

fleet year

techn. mix emission engines lake approach compounds

Scenario 1 1995 1995 Stage 0 NL Standard Quant. All


Scenario 3 2005 2005 Stage 1 NL Standaard Quant. All

Scenario 4 2015 2005 Stage 1 NL Standard Quant. Two

Scenario 5 1995 1995 Stage 0 EU Standard Quant. Two




Scenario 9 2005 2005 Stage 1 NL Warmer Quant. Two

Scenario 10 2005 2005 Stage 1 NL Colder Quant. Two

Scenario 11 2005 2005 Stage 1 NL Less particles Quant. Two

Scenario 12 2005 2005 Stage 1 NL More particles Quant. Two

Scenario 13 2005 2005 Stage 1 NL Deeper/Strat. Qual. #N/A


Table 4.10: Estimated emission intensities (kg/day) for Benzene, Naphthalene,

Toluene, Xylenes, and Formaldehyde with an indication of the scenario in which these are used.

Emissions Benzene Naphthalene Toluene Xylenes Formaldehyde

Scenario 1 3.21 2.17 3.22 3.22 3.19 Scenario 2 3.96 2.67 3.96 3.96 3.93 Scenario 3 1.00 1.00 1.00 1.00 1.00 Scenario 4 1.19 1.19 1.19 1.19 1.19 Scenario 5 9.48 5.95 9.49 9.49 9.36 Scenario 6 11.66 7.32 11.68 11.67 11.52 Scenario 7 1.45 1.74 1.45 1.45 1.48 Scenario 8 1.72 2.07 1.72 1.72 1.76

Scenario 9 1.00 1.00 1.00 1.00 1.00

Scenario 10 1.00 1.00 1.00 1.00 1.00

Scenario 11 1.00 1.00 1.00 1.00 1.00

Scenario 12 1.00 1.00 1.00 1.00 1.00

Scenario 13 0nly qualitative Figure 4.1 shows what category of engines contributes to these emissions. As can be seen in Stage 0 the emissions are almost completely determined by the conventional 2-stroke engines, with the exception of naphthalene. In the Stage 1 that is already significantly different.


Figure 4.1: The percentage contribution of the various engine technologies to the

total emission of the five compounds for scenarios 1 (Stage 0) and 3 (Stage 1).

Benze

ne

Naphta

lene

Toluen

e

Xylene

Formald

ehyd

e

Diesel4-sDI 2-s 2-s

scenario 1

Benze

ne

Naphta

lene

Toluen

e

Xylene

Formald

ehyd

e

Diesel4-sDI 2-s 2-s

scenario 3

0

100

Benze

ne

Naphta

lene*

100

Toluen

e

Xylene

Formald

ehyd

e

emis

sion

[kg

/day

]

Diesel4-sDI 2-s 2-s

scenario 1

0

100

Benze

ne

Naphta

lene*

100

Toluen

e

Xylene

Formald

ehyd

e

emis

sion

[kg

/day

]

Diesel4-sDI 2-s 2-s

scenario 3

For the compounds benzene and naphthalene all scenarios were calculated. For the compounds toluene xylene and formaldehyde only the scenarios 1-3 were calculated. The results for these three turned out to be reasonably proportional to the benzene results. Figure 4.2 gives a first impression of the reductions in emissions from the 1995 situation (1995 fleet and technology mix, all vessels Stage 0) to a hypothetical 2005 situation (2005 fleet and technology mix, all vessels Stage 1), with the influence of the fleet growth 1995-2005 and the one for 2005-2015 (increase in numbers, but unchanged technology) added for comparison.


Figure 4.2: Calculated change in emission intensities from recreational craft resulting

from Stage 1 on the one hand and fleet growth on the other, for the Dutch situation (scenarios 1-4) and the EU situation.(scenarios 5-8).

02468

101214

compound and region

rela

tive

emis

sion

(N

L st

age

1, 2

005

= 1)

1995 situation (Stage 0)fleet growth 2005 (Stage 0)base case (Stage 1, 2005 fleet)fleet growth 2015 (Stage 1)

benzene NL benzene EU naphthalene NL naphthalene EU

Conclusions The impact of various measures and developments during the last and coming decade can be assessed by comparing the outcome of the calculations of the 12 scenarios. Scenarios 3 and 7 can be taken as reference for this study, because they reflect the situation in the Netherlands and across the EU if all engines would comply with the Stage 1 emission limits. The results of the benzene and naphthalene calculations were selected for further comparison (Table 4.11). The following conclusions can be drawn. • In the baseline situation [1995, Stage 0] water contamination by benzene was about

3-4 times as high as in [2005, Stage1], and the water contamination by naphthalene a factor of 1.5-3 (comparing scenario 1 with 3 and 5 with 7). The change is a result of the combination of better technology and a shift in technologies on the one hand, and the growth of the fleet on the other.

• The positive influence on the water quality by the changes in technology mix and the limitation of the emissions (so: without the growth in fleet size) already obtained by the current Stage 1 is a factor 3.5-5 for benzene and 2-3.5 for naphthalene, respectively (comparing scenario 2 with 3 and 6 with 7).

• Growth of the fleet in the next decade may increase the water contamination in approx. the same proportion when the technology mix of the fleets does not change (comparing scenario 4 with 3 and 8 with 7).

• In southern and northern Europe the water temperatures are higher or lower and therefore concentrations in water may be different (lower for a higher temperature and higher for a lower temperature). This depends, however, on the compound concerned. A variation of ± 4 ºC results in a variation of about ± 10 % in the estimated concentration for benzene whereas no effect is seen for naphthalene (comparing scenario 9 with 3). This shows that the results are not very sensitive to the water temperature.

• For sediment the effects of the water temperature were more substantial with values of about – 50 % to +90 % for benzene and - 40 % to + 70 % for naphthalene.

• The amount of suspended matter does not have a noticeable influence on the estimated concentrations of benzene and naphthalene in water. However, an effect of the estimated concentrations in sediment of ± 40-60 % is noticed.


• For scenario 13 (stratification in deep lakes) no calculations were made. The upper layer is isolated from the lower layer with respect to physical exchange processes due to large temperature differences, especially in the summer. This means that most of the chemical contamination entering the upper layer will be mainly contained in that upper layer. Therefore a stratified lake can be compared to a shallow lake without stratification with regard to the water compartment dimensions playing a role in the distribution of the contamination. The depth of the upper layer in a stratified lake can vary much due to the prevailing conditions. As a first approximation it may be assumed that a deeper stratified lake can be compared to the shallow lake used as the standard case in the other scenarios. It is clear that a deeper lake without stratification will be less vulnerable for contamination by exhaust chemicals in the water compartment. This is due to the higher dimensions of the water compartment.

• The difference between the EU scenarios and the NL scenarios is based on the higher engine power in EU versus NL. This results in higher concentrations in water for the EU scenario, to wit +80% and nearly 4 times for benzene and naphthalene respectively (comparing scenario 7 with 3).

4.7 Determination of the actual model input and output

The model output is influenced by two important parameters: − The escape rate of the HC compounds caused by aeration of the water due to the

propeller. − The non-continuous character of the input of the HC compounds. From further analysis with the aid of another model (Toxswa, see Appendix E) it could be demonstrated that the daytime input effect (an input extended over 10 hours of daytime, followed by a 14 hours period of ‘rest’) did cause a significant effect, but that the weekend input effect (two days of high input, followed by five days of lower input) did not have a very large influence on the final result. This further analysis meant that the input would have to be adjusted for the escape rate due to aeration, and that the output of the SimpleBox model would have to be ‘corrected’ for the influence of the pulsed input as indicated by the Toxswa model. Unfortunately it was not possible to do the complete calculation with the Toxswa model, since this is not suited to greater water depths than 2 m.

4.7.1 The aeration effect After the comparisons and considerations discussed in Appendix E it was decided to assume the aeration rates shown in Table 4.11.


Table 4:11: Assumed average aeration rates, with the bandwidth assumed in the

model calculations. estimate benzene naphthalene toluene xylene form-aldehyde average 90 % 45 % 90 % 60 % 60 % low estimate 80 % 40 % 80 % 40 % 40 % high estimate 95 % 47.5 % 95 % 73 % 73 % The bandwidth was obtained by doubling or halving the remaining fraction for benzene and toluene. In the case of naphthalene it was assumed that about half the emissions are produced by (inboard) diesel engines (see Figure 4.1), where the aeration effect was assumed to be negligible, since the exhaust gases are not emitted through the propeller plane. The other half was assumed to have the same aeration rates and bandwidth as benzene and toluene. For xylene and formaldehyde a lower aeration rate was assumed and the bandwidth was calculated by taking a factor of 1.5 instead of 2, up and down. With these rates the effective input for the model resulted in the figures shown in Table 4.12, with a bandwidth as outlined above. Table 4:12: Estimated effective model input, corrected for aeration (in µg/l) for

benzene, naphthalene, toluene, xylenes, and formaldehyde with an indication of the scenario in which these are used.

Emissions Benzene Naphthalene Toluene Xylenes Formaldehyde Scenario 1 0.22 0.0077 0.58 1.58 0.34 Scenario 2 0.27 0.0095 0.72 1.95 0.42 Scenario 3 0.07 0.0036 0.18 0.49 0.11 Scenario 4 0.08 0.0042 0.22 0.58 0.13 Scenario 5 0.65 0.0212 1.73 4.66 1.00 Scenario 6 0.80 0.0261 2.12 5.74 1.23 Scenario 7 0.10 0.0062 0.26 0.71 0.16 Scenario 8 0.12 0.0074 0.31 0.85 0.19 Scenario 9 0.07 0.0036 0.18 0.49 0.11 Scenario 10 0.07 0.0036 0.18 0.49 0.11 Scenario 11 0.07 0.0036 0.18 0.49 0.11 Scenario 12 0.07 0.0036 0.18 0.49 0.11 Scenario 13 Only qualitative

4.7.2 The consequences of the pulsed input The output concentrations of the SimpleBox model were modified for the effect of the pulsed input as determined by the Toxswa model. The SimpleBox model predicted a significant accumulation effect (see Appendix E), but the Toxswa model showed that this accumulation was lower, although still present, due to the possibility of overnight recovery. The final equilibrium concentration of benzene e.g. amounted to the equivalent of about 5 times the daily input in the case of a continuous input rate, whereas in the case of a pulsed input it amounted to about 1.6 times the daily input. On this basis the resulting concentrations for scenario 3 would work out at the figures shown in Table 4.13.


Table 4.13: The modelled average output concentrations (in µg/l) of the SimpleBox model, ‘corrected’ for a pulsed input as determined with the aid of the Toxswa model.

benzene µg/l

naphthalene ng/l

toluene µg/l

xylenes µg/l

formaldehyde µg/l

average 0.10 0.010 0.29 0.63 0.11 range 0.05-0.19 0.009-0.010 0.15-0.58 0.42-0.94 0.7-0.16 The output of the SimpleBox model, in terms of relative water concentrations for the different scenarios is shown in Table 4.14. Table 4.14: The relative water concentrations as calculated by the Simple Box model.

benzene naphthalene toluene xylenes formaldehyde Scenario 1 3.21 2.17 3.22 3.22 3.19 Scenario 2 3.96 2.67 3.96 3.96 3.93 Scenario 3 1.00 1.00 1.00 1.00 1.00 Scenario 4 1.19 1.19 Scenario 5 9.48 5.95 Scenario 6 11.66 7.32 Scenario 7 1.45 1.74 Scenario 8 1.72 2.07 Scenario 9 0.89 1.00 Scenario 10 1.10 1.00 Scenario 11 1.00 1.03 Scenario 12 1.00 0.99 Scenario 13 Only qualitative

These relative concentrations can then be set against the absolute concentration for scenario 3 of Table 4.13, resulting in a table of absolute concentrations for water and, by a similar process for sediment. This is done in the Tables 4.15 and 4.16.

4.8 Evaluation of the modelling results based on comparison with environmental quality standards and goals set by the European Water Framework Directive

The estimated concentrations of the five compounds resulting from the considerations outlined above can then be compared with the environmental quality objectives shown in the tables 4.6 and 4.7 in subsection 4.4.2 (water quality standards) of this section. As stated earlier, at the moment, these EQSs are either definitive, proposed or indicative. As the process of EC harmonisation of EQS continues it may be expected that in the future EQS values will be available for more substances. For some of the substances with a proposed EQS, an adjustment of the EQS may occur. Therefore in the current study conclusions on meeting or exceeding the (proposed) EQSs are a reflection of the situation at this stage. In the coming years, conclusions may change for some substances. In addition a more complete picture may be gained as for more substances EQS become available.


Table 4.11: The modeled concentrations for benzene and naphthalene, compared with the EQSs as listed in tables 4.6 and 4.7.

benzene concentrations naphthalene concentrations water sediment water sediment ng/l ng/kg (wet) ng/l ng/kg (wet) scenario 1 160-630 0.17-0.68 20-23 110-140 scenario 2 190-770 0.21-0.84 24-28 140-180 scenario 3 50-190 0.05-0.21 9-10 50-70 scenario 4 60-230 0.06-0.25 11-12 60-80 scenario 5 460-1850 0.50-2.00 54-62 310-390 scenario 6 570-2280 0.62-2.45 66-76 380-480 scenario 7 70-280 0.08-0.31 16-18 90-120 scenario 8 80-340 0.09-0.36 19-21 110-140 scenario 9 40-170 0.03-0.11 9-10 30-40 scenario 10 50-210 0.10-0.41 9-10 90-110 scenario 11 50-190 0.04-0.17 9-11 20-30 scenario 12 50-190 0.06-0.23 9-10 70-80 environmental quality objectives AA-EQS 1700 2400/1200 MAC-EQS 49 000 80 000 ditto (drink.w) 1700 < 200 MPC (NL) 240 000 1000 1200 100 Comparison with the proposed EQSs in EC The MAC-EQSs can be considered as most appropriate for the comparison with the estimated environmental concentrations. For both benzene and naphthalene, MAC-EQSs are not exceeded. In this table the AA-EQS values for benzene in water are exceeded for the Stage 0 scenarios but this is not considered as relevant. The AA-EQS are much less relevant than MAC-EQS because at most locations recreational boating activity is periodically concentrated in the summer period and in weekends. Furthermore concentrations of most contaminants in water can be expected to drop soon after the introduction. Annual average concentrations are therefore expected to be much lower than the peak concentrations. The AA-EQS for naphthalene in water is never exceeded. It should be noted that the concentrations shown here represent only the contribution of boating. In actual cases there may be significant other sources, in which case the maximum allowable concentrations for drinking water may be exceeded. This could be the case for benzene, where the upper concentration of the bandwidth comes to a large percentage of the limit, meaning that if the limit is exceeded, boating might be one of the major sources. Overall it can be concluded that there does not seem to be a serious threat to the environment based on the MAC-EQS and the two selected compounds benzene and naphthalene. However, in the Stage 1 situation for a locality as modelled the supply of drinking water may be at risk. This would imply that in such cases there might be a need to prohibit intensive recreational boating in the vicinity of intake points for drinking water production.


Table 4.12: The modelled concentrations for toluene, xylenes and formaldehyde, compared with the EQSs as listed in tables 4.6 and 4.7.

toluene

concentrations xylenes

concentrations formaldehyde

concentrations water sediment water sediment water sediment

µg/l µg/kg (wet)

µg/l ng/kg (wet)

µg/l ng/kg (wet)

scenario 1 0.5-1.9 0.9-3.5 1.4 - 3.0 63-140 0.25-0.50 6-13 scenario 2 0.6-2.3 1.1-4.3 1.7 - 3.7 77-172 0.30-0.65 7-16 scenario 3 0.15-0.6 0.3-1.1 0.4 - 0.9 20-43 0.07-0.16 2-4

environmental quality objectives AA-EQS

MAC-EQS ditto (dw) MPC (NL) 730 4 380 14000 ~9200 n.a.

Note: For Formaldehyde no actual EQOs have been defined (in the Netherlands). The MPC shown is indicative and has been estimated using ETX-2000 [Van Vlaardingen, Traas and Aldenberg, 2003] from a dataset of 181 ecotoxicity endpoints extracted from the EPA-Ecotox-database. Comparison with the EQS published in the Netherlands Conclusions on the risk of water and/or sediment quality problems due to contamination with toluene, xylenes and formaldehyde should be drawn with great caution due to the absence of EU harmonised EQS for water and sediment. Based on these data it can be concluded, however, that for none of the five compounds the (indicative) MPC in water is exceeded. The MPC in sediment is not exceeded for benzene and xylenes in any of the calculated scenarios. In case of toluene the MPC in sediment is (nearly) exceeded in scenarios 1 and 2 (both Stage 0 situations), but not in scenario 3 (a Stage 1 situation). It can be argued that exceedance of the MPC of toluene in sediment may also occur in the EU Stage 1 scenarios. The MPC for naphthalene in sediment is closely approached in scenarios 3 and 4 (Stage 1 situations) and exceeded in most of the others.

This means that for the situation modelled (Lake Fun) the criteria for short-term exposure (MAC-EQS and MPCs) of the five selected components of motorboat exhaust were not exceeded by the estimated concentrations in water and sediment, with exception of the contamination of sediment by toluene. The criteria for benzene in water were approached in the Stage 0, however, but not in the Stage 1 calculations. Therefore serious problems with the environmental water quality are not expected.

The calculations would seem to suggest that the drinking water supply function of water systems can be at risk by motor boat exhaust. An assessment could only be made for benzene and naphthalene indicating that for Stage 0 and the EU fleet the drinking water EQS for benzene is exceeded, and for the NL fleet closely approached. One should realise, though, that the situation modelled (Lake Fun) is exceptionally sensitive in this respect, since it is a very shallow lake. As pointed out in the conclusions of subsection 4.5 (7th bullet point) a deeper lake is much less likely to reach similar concentrations, certainly not at greater depths. If such concentrations occur nevertheless, then intensive recreational motor boat activity in the vicinity of raw water inlet points for the production of drinking water needs to be prohibited.


These conclusions seem to be in accordance with that of the ‘IMEC scenario’ referred to in subsection 4.3.4. Since, however, EU harmonised EQSs are hardly available for the compounds of concern, these criteria are only indicative. For the time being these criteria can be used in combination with the EQSs for the Netherlands. For many other compounds on exhaust emission (indicative) EQCs are not available at all. It will be worthwhile to repeat the comparison of estimated environmental concentrations with EQS as soon as more EU harmonised EQS are published for more substances of concern. Not only the substances selected in the present study but also other relevant substances in exhaust emissions. It can be expected that MAC-EQS for drinking water production will often be more critical than the MAC-EQS for surfacewater.

4.9 Conclusions

Calculations were made for theoretical situations, representing realistic, although modelled, situations for past and present situations and future developments. The selected hypothetical lake represents a ‘worst case’ situation in many respects: shallow water, slow refreshing rate, relatively low water temperature, high share of diesel engines. It may therefore be reasonably assumed that the majority of local situations in Europe (water systems with recreational boating) are covered by the scenarios applied to the theoretical situations. It is obviously not possible to assess on the basis of these calculations the environmental impact of recreational boating on a national level or for specific lakes or other water systems with recreational boating activity, which will depend on the actual fleet and technology mix concerned. But if the results from the calculations are taken as an indication of the general order of magnitude of the water concentrations to be expected from recreational boating this allows some general conclusions to be drawn that apply to the EU. For the purpose of more specific checks we would recommend to collect such data, to gain insight in the variation among EU countries and especially in those actual cases where a specific problem is expected, or where it is decided to check if such a specific problem may be present. It will be clear that if in some actual case the fleet size, technology mix or engine power level would differ significantly from the EU average this would be significantly reflected in the impact on the environment. We like to suggest, though, that exactly such local problems, provided that they are low in number, might be better solved by local regulations tailored to the specific case, than by a Europe-wide legislation. Local measures can still address the use of recreational boating, even if a limitation of the emission of per boat falls outside the competence of a local authority. With these general cautions and suggestions the following conclusions would seem to result from the scenario study. Overall conclusions • The contribution of motorboat exhaust emission to air pollution on national and

regional level is negligible. • The calculation of environmental concentrations of benzene and naphthalene shows

that the impact on the aquatic environment is reduced by approx. 50% by the Stage 1 emission limits. This effect can be attributed to changes in engine technology and mix of the fleet. This improvement is only partly offset by the assumed growth of the fleet (for this calculation: 20% over the period 1995-2005).


• Water contamination is expected to be higher in Northern European countries and lower in Southern European countries at a comparable intensity of recreational boating due to the influence of the water temperature on the rate of the dissipation processes. The differences depend on the compound and the environmental compartment. The extent of this effect seems to be limited for water but can be substantial for sediment, with deviations from the average amounting to a maximum of 10% for water and 90% for sediment for the interval that was checked (± 4 ºC).

• The concentration of particles suspended in water influences the concentrations of

contaminants in sediment. This effect depends on the properties of the compound with a more pronounced effect on naphthalene than on benzene. The maximum effect on naphthalene content in sediment is estimated to be about 60%.

• In these calculations the MAC-EQSs and MPCs (maximum allowable/permissible

concentrations) of the five selected components of motorboat exhaust were not exceeded by the general order of magnitude of the estimated concentrations in water and in many cases not by those in sediment either. Therefore serious problems with water quality are not expected.

• In this study these five compounds of the exhaust emission were selected based on

findings in literature, relatively high known concentrations in water or sediment, and high toxicity (low ‘environmental quality objectives’). In theory other compounds may be relevant as well, but these cannot be assessed due to a lack of information on the characteristics of such compounds. A major gap is in fact the lack of environmental quality objectives for most of such compounds. The results for the five selected compounds will give a fairly representative picture though.

• Water contamination is obviously positively correlated with fleet size and boating

activity. These factors do not seem to be the major targets for measures to reduce the impact on water quality, however. Indeed, the calculations seem to confirm that in the case of normal recreational boating activities, there is no need to close lakes to motor boats or to restrict engine power levels or to exclude certain types of engine as far as environmental protection is concerned. However, attention should be paid to contamination of sediment for substances with a high affinity for adsorption to organic matter. In addition EQS values for these compounds in sediment should be established. Sediment contamination may be a more serious problem caused by exhaust emission than contamination of water. Indications are provided by the estimations for toluene. Nevertheless, if in any particular case a problem with water or sediment quality is identified, a restriction of use can be an effective alternative to a general emission legislation, since it can be applied locally.

• In order to protect surfacewater used for the intake of water for drinking water

production, the intensive use of recreational motor boats near intake points may have to be restricted.

General reservations It should be noted that a fully complete and reliable general conclusion for the presence or absence of risks of exhaust emissions to water quality could not be made with the calculations elaborated here. Such a complete picture cannot be achieved due to several factors:


• A lack of environmental quality objectives for the majority of the compounds in exhaust gas from motor boat engines.

• The potential presence of unidentified exhaust components which could be very persistent in combination with a high toxicity for man or environment and therefore pose a threat to water quality.

• Not all local situations can be assessed: local conditions with extreme conditions, such as high boating activity in small shallow static water bodies, may be found at some places and at certain time periods in Europe, and such situations should not be ignored.

Guidelines for levels of boating use cannot be generalised and management of boating use must consider each water body individually.

Lacking information and recommendations Concerning the knowledge still lacking for a more complete evaluation, we like to point out the following: • For more precise calculations better insight is needed in the aeration rates that occur

in the emissions from outboard engines. • Another major problem concerning such calculations is a lack of insight into the

accumulation effects that may occur during frequent use of the locality, and their dependence on the rhythm of the emissions.

• An important gap in knowledge exists regarding inboard engines. In some cases

these engines have an exhaust system that emits above the waterline, which would lead one not to expect such engines to have an emission route towards the water body. However, since in boats the exhaust is usually cooled by injecting water into the exhaust, in practice such a route does exist. Unfortunately no data is known to exist on the composition of this coolant water as its exits the exhaust and gets mixed into the receiving body of water. As this coolant water has been in intensive contact with the exhaust gases it is expected to carry an appreciable amount of pollutants with it. A study into the water exiting from inboard engine exhausts and its composition would improve the accuracy of emission estimates for recreational craft. Also the modelling of environmental concentrations of exhaust components in the water column would greatly benefit from the availability of such data.

• EU harmonised environmental quality criteria are lacking for some of the compounds

concerned. For the time being in such cases the criteria for the Netherlands have been applied in this study. For many other compounds in exhaust emission, EQCs are not available at all.

• Studies should be carried out on the concentrations of exhaust components in the

surface micro layer together with the effects on the (life stages of the) aquatic organisms living in this layer.

• The effects of long-term exposure of aquatic organisms to realistic exhaust

component concentrations in lakes with heavy use of recreational boating should be tested.


• It can be recommended to eliminate taste and odour problems by restriction of boats propelled by combustion engines in the vicinity of shellfish beds and the water supply intakes of fresh waters serving as domestic water supplies.

CONCLUSION: It is obviously not possible to assess on the basis of a general model study the environmental impact of recreational boating all across Europe. For specific lakes or water systems this impact does depend on the actual fleet, use and technology mix. Consequently specific measures may be necessary in specific cases. Special attention should be paid to the protection of surfacewater area close to intake points for the production of drinking water. Generally speaking, however, on a national or regional level the impact on air pollution seems negligible. Concerning water quality, in the scenario study made, known MPC (maximum permissible concentration) levels were not exceeded. Detailed assessment is hampered, however, due to a lack of EQOs (environmental quality objectives, i.e. standards) for most of the compounds that could be of interest.


5 Sound – Status quo

NOTE TO THE READER: This chapter consists of a short summary of the existing knowledge, or the lack of it, concerning the impact of sound emissions, followed by a small scenario study to illustrate the influence of some typical parameters. The ecological aspects have been divided into airborne sound emission and underwater sound emission.

5.1 Introduction

Sound is a physical phenomenon that can be defined as a ‘vibration phenomenon’ in a certain medium (solid material, gas or liquid). For marine craft in general sound refers to the following phenomena: − airborne sound; the transfer of vibrations via air; − structure-borne sound; the transfer of vibrations via a solid material (for instance a

ship structure); − underwater sound, the transfer of vibrations via water. The sound level received at a certain position, in the air or under water, is caused by a sound source (emission) and transmitted over a certain transmission path to the receiving point (immission). During that transmission there will be a certain amount of energy loss; the sound level will attenuate over distance from the source. The received sound at a relevant receiver position is expressed as the A-weighted sound pressure level, LpA. The A-weighting of the broadband sound pressure level takes into account the reduced sensitivity of human hearing for low frequencies. Due to their different hearing capacity, see appendix D, the sound disturbance of animals is better related to an unweighted broadband sound pressure level. The airborne sound emission of sources is normally expressed in the A-weighted sound power level, LWA. However, is can also be expressed as an A-weighted sound pressure level at a specified distance in a well-defined transmission situation. As that approach is taken in some measurement documents, it will also be adopted here. Though the sound level itself is mainly responsible for some negative effects, like communication disturbance or - at a much higher level - hearing damage, the annoyance as experienced by human beings depends on many more aspects. And an annoying sound is simply called noise. The annoying effect depends on the type of sound (level, frequency content, temporal variation, etc.), the type of surrounding (harbour, recreational area, parkland or conservation areas, etc.), time of occurrence (type of day, day or night, etc.) and several subjective and personal aspects like the feeling about the type of source and the usefulness of the source and its use. So the use of a recreational craft can be just as important as the sound emission of that craft; and even the sound emission of the craft is determined largely by its user.


5.2 Current sound emissions

5.2.1 General A recreational craft produces sound that is radiated into the environment both above and below the water. The origin of the sound depends on the type of craft and type of engine: • outboard engine: The engine is located outside on the rear of the boat. The engine is

covered with a cowl, possibly lined with sound reducing material. For all outboard engines the exhaust is located underwater via the stern and will therefore have a major contribution to underwater sound. The transmission gear is located underneath the waterline and therefore also contributes to underwater sound. In brochures of outboard engine manufacturers, the air intake of the engine is stated to have an important contribution to the total sound emission. In most cases outboard engines use petrol as a fuel.

Figure 5.1: Location of the engine cowl and compartment, transmission and exhaust in

an outboard and an inboard set-up.

• sterndrive engine: The engine and gearbox are built-in in the stern of the boat. So the

stern structure covers the engine. The transmission to the propeller is contained in a construction similar to that of an outboard engine. Hence, further sound sources are identical to the outboard engine. Both diesel and petrol engines are used as sterndrive engines.

• inboard engine: The engine and gearbox are located inside the boat structure in an

engine compartment. The main sound sources for the airborne sound emission are the exhaust and ventilation openings in the engine compartment. If the exhaust is located above the waterline, the exhaust contributes to the airborne sound emission. On pleasure craft the exhaust gases usually are emitted below the waterline, however. For the underwater sound emission the construction of the whole craft is relevant. Diesel engines are commonly used as inboard engines.

• personal watercraft: Nearly all Personal Watercraft (PWC) or ‘jet skis’ utilise

conventional two-stroke engines, producing airborne sound as well as underwater sound. Propulsion is by a water pump (jet) and not by a propeller. Steering is performed by ejecting water at high force through a movable nozzle, also a source of under water sound. The general constructional and operational character of this type of craft (continuous jumping and slamming back into the water) puts them in a separate category.

engine cowlengine compartment

exhaust gastransmission

exhaust gas

outboard engine inboard engine


Figure 5.2: Typical engine and propeller set-up of a PWC.

For the outboard airborne sound the main sources for recreational craft are: − the engine and its radiating hull; − the air inlet; − the hull-water interaction (also called water sound). It is hereby assumed that the exhaust is underwater, as is often the case, otherwise this would also be an important source. For underwater sound the relevant components causing radiated sound are: − engine vibrations exciting the boat structure and the hull; − airborne sound from the engine, causing vibrations in boat structure and hull; − underwater sound from the propeller; − exhaust; − flow sound around the hull and in piping systems, exciting the hull structure; − human activities on board. Figure 5.3: Schematic representation of the underwater sound components of a vessel.

Figure 5.3 depicts the components causing radiated underwater sound. It is emphasised that underwater sound is radiated by the entire boat structure, not only by the propulsion engine and propeller. It is difficult to indicate the most important sources for underwater sound. It is not by definition true that the propulsion engine is the dominating source; the quality of sound reduction measures is a more important factor. On commercial vessels even auxiliary machines, like hydraulic winches, may be more important than a propulsion diesel engine. The acoustic quality of the propeller(s) is another factor. Cavitating propellers will produce more underwater sound than the entire machinery system. The most important components in boats for underwater sound and exterior airborne sound are listed in table 5.1.

PWCsteerable nozzle

waterjet


Table 5.1: Overview of important sound sources for underwater and outboard airborne sound of recreational craft.

Source Underwater sound Exterior airborne sound (cavitating) propellers x - propulsion engines x x main gearboxes x x auxiliary machinery x x inlet - x exhaust x x ventilation openings - x hull/water interaction x x

Though the sound from the waves as produced by recreational craft does not contribute much to the total underwater sound, the wash of the boat itself is probably an important aspect for the impact on wildlife. For outboard airborne sound however, water/hull interaction is known to have an important contribution to the airborne sound emission of recreational craft.

5.2.2 Airborne sound emission From extensive IMEC studies [Icomia 2003, IMEC] the emitted sound pressure levels at 25 m were determined as a function of rated power. The measurement procedure was according to ISO 14509-1. Also the sound pressure level for towed hulls, without engine sound, was determined. Best-fit lines from the measurement results were determined; they are shown in the figures 5.4 and 5.5. The curves shown in figures 5.4 and 5.5 are within an accuracy of ± 2 dB(A). For the PWCs the scatter is somewhat larger. More accurate data on inboards in the higher power range and on sterndrives was reported to be available from the ‘sound boat project’ (a 5th framework project), but this study is classified as confidential and supposedly useful data has never been received. Since full throttle operation is a poor representation of the level of acoustic energy produced by recreational craft in normal use, a representative duty cycle has been developed. This duty cycle consists out of five operational modes, which represent typical boat usage. According to studies conducted by IMEC [Lanpheer 1994], the sound emission at the duty cycle corresponds well with the noise levels at 60% throttle. These are about 8 dB lower than at full throttle. The actual duty cycle has been changed in the meantime, but it is still possible to obtain some general insights and to draw some general conclusions from these measurements.

CONCLUSION: Figure 5.4 shows that the contribution of the outboard engine noise to the total noise level is about equal to the contribution of the wave induced hull noise for the higher power range. For high power ratings of about 150-200 kW the noise level difference between the hull noise and the noise of an outboard at full throttle (consisting of engine noise and hull noise) is 3 dB. This implies that engine noise and hull noise are two equally strong acoustic sources at this power rating. If engine noise would be reduced by 10 dB, the total noise level would only drop 3 dB.


Figure 5.4: Maximum sound pressure levels at 25 m of various types of recreational craft at full throttle as a function of rated power (see text for details).

100

101

102

103

50

55

60

65

70

75

80

Rated Power [kW]

LpAmaxS

in dB(A) re 2e-5 Pa

outboard; full throttle

PWC; full throttle

inboard; full throttle

towing

2003/44/EC

Figure 5.5: Maximum sound pressure levels at 25 m for outboards and PWCs at full

power and at duty cycle as a function of rated power (see text for details).

100

101

102

103

50

55

60

65

70

75

80

Rated Power [kW]

LpAmaxS

in dB(A) re 2e-5 Pa

outboard; full throttle

PWC; full throttle

outboard; duty cycle

PWC; duty cycle


5.2.3 Underwater sound emission Apart from airborne sound emission, in the case of marine engines there is also waterborne sound emission. This will further be referred to as underwater sound emission. Especially when the influence of sound emissions on wildlife is considered, underwater sound should be expected to play a part. Airborne sound may be expected to play a role when the impact on birds is considered, and underwater sound may be expected to play a part when the possible impact on aquatic wildlife is considered. This subsection therefore lists what is known about underwater sound. In fact it is found to be impossible to give general data for underwater sound levels for recreational craft in relation to some relevant boat parameters. The spread in the measured levels is very large. Furthermore there is no relation between boat size and underwater sound level. Big boats may be quiet and small fishery cutters may be extremely noisy. Levels depend on the amount of sound reduction measures, not on size. Although some influence of the ‘installed power’ is certainly present, speed is a more important factor in sound production. Another very important factor is that the location (sometimes called the ‘sound range’), where the underwater sound is measured has a large influence on the measured levels. Measured levels depend on many (physical) factors, such as the sound range geometrics, the geologic bottom conditions, bottom layers, ‘wall’ details, water depth, water condition and temperature, etc. Water depth is an extremely important factor and, in fact, boats should not be measured in shallow water. Even with a water depth of 100 m the measurements are still influenced by the site. For these reasons results of measurements carried out at different locations cannot be compared properly. Such results have to be standardised and should e.g. be converted to ‘free field’ conditions. As an illustration figure 5.6 shows averaged underwater sound pressure levels of five, normal propeller driven boats (not recreational craft) without sound reduction measures, varying in length from 15 to 100 m. It is emphasised that these levels are only examples; other results (higher and somewhat lower) are possible. Boats with water jet propulsion or thrusters may have very different levels and it will be clear that underwater sound of high-speed (catamaran) boats will be higher as well. Figure 5.7 depicts underwater sound levels of two motorboats, measured at two speeds. The spread appears to be relatively small (which is rather unusual). These results have been converted to a 1 m reference distance from the boats, but no corrections have been applied for measurement site propagation effects. Hence the spectra show a shallow water damping effect of up till 30-40 dB and at low frequencies the actual levels will exceed 170 dB. The spectrum will correspond to the average curve of figure 5.6.

CONCLUSION: Though these data can give a very global impression of the underwater sound levels that could also be expected for recreational craft, it is quite clear that reliable data should be based on a standardised measurement method that is relevant for the type of craft and its use. Such a method is not yet available. For personal water craft no underwater sound level data are known at all.


Figure 5.6: Example of measured boat underwater sound pressure levels; linear

average and limits of five boats between 15 and 100 m length, speeds between 8 and 14 knots. Measured in deep water conditions, in 1/3-octave bandwidths (level in dB re 1 µPa at 1 m reference distance from the boat).

Figure 5.7: Example of measured boat underwater sound pressure levels; two different

boats of about 25 m length at two different speeds around 10 knots. Due to the large propagation effects in shallow water, levels below 500 Hz are reduced up till 30-40 dB; consequently, the actual levels of the boats exceed at low frequencies the 170 dB level. At one speed one of the boats radiated a large pure tone in the 63Hz-band (levels shown are in dB re 1 µPa at 1 m reference distance from the boat, measurement bandwidth 1/3-octaves).


5.3 Existing environmental targets

5.3.1 Environmental sound targets concerning humans The sound produced by the use of recreational craft can cause disturbance and annoyance in the surroundings. As far as known no regulations on maximum allowable sound impact (referred to as sound immission) exist. Only for certain type of boats there is a maximum allowable sound emission level (see section 5.3.3). There are regulations that prohibit the use of engine powered craft in certain (conservation) areas or that limit the permitted speed in certain areas; though that might stem from other considerations, it clearly has an effect on the sound impact too. Only a very limited number of specific studies have been found on the disturbance by recreational craft. However, it is generally known that the annoyance caused by various sources of sound depends on a number of aspects. As in all cases with sound sources the effects depend on the type of sound (level, spectrum, temporal variation, etc.), time of occurrence (type of day, day or night, etc.), the type of surroundings (harbour, recreational area, parkland or conservation areas, etc) and several subjective and personal aspects, like the feeling about the type of source and the usefulness of the source and its use. Spectrum and temporal variations are normally summarised in the A-weighted time integrated sound level when humans are considered; for some applications a clearly tonal character of the sound is penalised by 5 dB. The influence of the type of source is illustrated in figure 5.8 were it is clearly shown that at the same sound level (Lden in dB(A)) road traffic is considered more annoying than for instance railway traffic, but less than certain other types of source. Another illustration is a TNO study in 2002 about the annoyance caused by urban traffic: while mopeds hardly contribute to the overall traffic sound level, in social surveys they are always mentioned as the more annoying sources. This illustrates the influence of actual or assumed behaviour of the drivers in the use of their vehicles. Although no specific research is known of perceived annoyance by the sound of recreational craft, it could be assumed that the general assessment will not deviate substantially from the assessment of other transportation means or recreational motorised activities like traffic, or e.g. the use of off-road motorcycles. A survey in the Jervis Bay Marine Park (Australia) showed some effects for motorboats but more prominent effects for PWCs. Of the respondents 17% mentioned a conflict between PWCs and swimmers, but none for motorboats; 9% a conflict between PWCs and sound disturbance and none for motorboats and 20% a conflict between PWCs and environment, which was 7% for motorboats [The Port Hacking Protection Society Inc., 2001]. It was notable, however, that almost 30% of the respondents mentioned a conflict between commercial fishing and environment. It should be noted, however, that the Jervis Bay Marine Park is restricting the use of PWC in certain environmental sensitive areas. Nevertheless the responses seem to confirm that the perceived annoyance is not based on the sound levels alone. Other studies show that sound impact due to PWCs can be considerable [Asplund, 2000]. PWCs tend to have more variable sound levels and a higher pitch than other watercraft. PWCs continually thrust out of the water (20% of the time), which causes the sound of the engine to increase in level and pitch (typical increase of exhaust sound level by 15 dB(A) is reported). When the craft re-enters the water, it smacks against the


surface with a loud low frequency sound. This continual change in sound level and pitch during use, seems to make PWCs more disturbing than the sound levels at constant speed. [The Port Hacking Protection Society Inc., 2001].

THE ENVIRONMENTAL IMPACT OF SOUND: In line with other sound sources the environmental impact is not described by the A-weighted maximum sound level during an event, but primarily by the equivalent A-weighted sound pressure level over a considered period of time. This is an energetic average value where the averaging normally includes the number and duration of events over a relevant period of time, as well as the meteorological variations over a longer period like a year. In accordance with the recent European Directive on environmental noise [2002/49/EC, 2002] the impact is expressed as the so-called Lden, (day-evening-night level) where the average is taken over 24-hours with penalties for the long-term equivalent sound levels for the evening (5 dB) and night (10 dB) period. Note that this environmental impact is in no way comparable to the maximum permissible sound emission level as specified in the Directive.

For a complete characterisation of the sound impact the basic procedure as described in the box above might not be sufficient; indications of sound fluctuations, number of noisy events and low-frequency content may additionally be necessary [WHO, 1999]. In order to predict such a sound impact, for a global approach the sound emission could be expressed as the A-weighted sound power level under the relevant working conditions. Such a sound power level could also be used to specify and regulate the sound emission of recreational craft. Figure 5.8: Percentage of people highly annoyed with the sound impact expressed as

Lden in dB(A) for various sound sources (traffic, industry, shunting yard and only seasonal operating industries).


If we consider the targets for allowable sound impact, again the other types of sound sources could serve as a yardstick. Only moderate annoyance is to be expected during daytime with equivalent levels that do not exceed 50 dB(A), while 20% of the people is highly annoyed at levels of 60 dB(A) to 70 dB(A) depending on the type of sound source [WHO, 1999; Miedema, 1998]. Indeed in various European countries where the sound impact for traffic is regulated, the limits for urban areas vary from a desirable maximum level of 55 dB(A) to a maximum allowable level of 70 dB(A). Figure 5.8 gives an illustration of these dose-response relations for various sound sources. In parklands and conservation areas it is not so much the annoyance by sound as the disturbance of the character of the area that is important. To avoid interference the ratio of intruding sound to natural background sound should be kept low [WHO, 1999]. Typically this would mean maximum equivalent levels in the range of 30 dB(A) to 40 dB(A) during the daytime [de Jong, 1998].

CONCLUSION: The permissible levels are logically differentiated for different types of areas and their use. For residential areas a reasonable target would by a sound level Lden in the order of 55 dB(A). In case of recreational activities it is in some cases not so much the annoyance of inhabitants in the neighbourhood that determine what is acceptable, but rather the annoyance experienced by other recreating persons. And that is largely determined by the type of area and the accepted type of behaviour in that area. In parklands and conservation areas it is not so much the annoyance by sound as the disturbance of the character of the area that is important. To avoid interference the ratio of intruding sound to natural background sound should be kept low.

5.3.2 Environmental sound targets concerning wildlife As stated in subsection 5.2.3 the influence of sound on wildlife has to be separated into the influence on wildlife in the air and the influence on aquatic wildlife. In fact it turns out though that little is actually known in either case. The following subsection lists the existing knowledge.

5.3.2.1 Effects of sound World-wide a concern is emerging about the effects of anthropogenic (man-made) sound in the environment, including the underwater environment where, at present, most concern lies with marine mammals, i.e. cetaceans (whales and dolphins) and pinnipeds (seals, etc.). For these animals knowledge of the physiological effects of anthropogenic sound on the auditory system is more developed than from ‘lower’ animal species, such as fishes and amphibians. However, knowledge around acoustic disturbance and/or injury of marine mammals is still very limited, as well as detailed information on marine mammal hearing systems. Knowledge of effects of sound on lower animal species is almost absent; although studies are carried out in The Netherlands on the disturbing effects of man-made sound on North Sea fish species


[Seamarco]. Similar studies of a limited extent have already been carried out on harbour porpoises and common seals [Kastelein]. Studies of this nature are continuing (but at a very slow rate). Intense sounds may influence marine life in some way and can have negative physiological, hearing and behavioural effects on marine animals in general. The effect for a specific animal that is exposed to sound can be classified into following grades of influence: • just audible • disturbance (masking of activities, such as forage) • severe discomfort (behavioural disruption and habituation) • temporary threshold shift (TTS) of hearing perception • permanent threshold shift (PTS) of hearing perception • hearing injury (or even death due to severe injury) Anthropogenic sound can have very high levels for instance seismic surveys in gas and oil exploration and the construction of wind energy parks in marine areas (pile driving). Generally speaking one may assume that mitigation procedures to reduce the impact of anthropogenic sound, in water as well as above water, are at least recommendable to protect (marine) life. The contribution to under water sound by recreational craft could be relevant, at least for certain areas. As an example, a controlled study concluded that PWCs, with a lack of very low-frequency, long distance sound, do not signal surfacing birds or mammals (including humans) of approaching danger until they are almost on top of them. Here the character of the underwater sound and the speed of the craft are more relevant than the actual level of the underwater sound. [Woods Hole Oceanographic Institute]. Though the sound from the waves as produced by a recreational craft does not contribute much to the under water sound, the waves themselves could be an important aspect for the impact on wildlife. Due to their rapid, acceleration and turns, personal watercraft cause considerably more turbulence of the water than other watercraft, which will cause disturbance of underwater wildlife and sediment that will not be insignificant. Due to a lack of information also this impact can not be quantified and could best be treated through measures that influence the use of recreational craft, certainly in specific areas.

5.3.2.2 Hearing of animals Knowledge about the hearing abilities of fishes, amphibians, reptiles and marine mammals is essential to formulate criteria for underwater sound. For airborne sound criteria, knowledge about the hearing properties of birds and pinnipeds is relevant. In general the frequency range of bat hearing systems (in air) is outside the range of radiated sound from boats and therefore bats are at the most only of secondary importance here. In fact little is known about detailed hearing properties of animals and their disturbance by man-made sound. Information on the available knowledge is given in appendix D. Only relatively few audiograms have been determined and other important and necessary data, such as critical bandwidth, dose/response relations, etc., are lacking almost entirely. And such data as are available show a large spread in hearing threshold levels and frequency ranges. Most non-mammal species have their highest sensitivity in the low-frequency range, the range in which radiated underwater sound by marine craft


is highest. It is clear that the aquatic animals will hear underwater sound radiated by marine craft. To what extent this sound will influence their behaviour is not yet known. Anyhow, the ‘discomfort threshold levels’ of seals and porpoises are such that underwater sound by marine craft will influence their behaviour (in a certain range around the boat). The present lack of knowledge on ‘dose/response relations’ (the effects of sound on the behaviour of animals) means that, before criteria for underwater and airborne sound from small marine craft can be drafted, behavioural studies on the effects of sound for a broad range of animals need to be carried out. This will take considerable time. Furthermore it will be difficult to draft a general criterion for sound from boats (one for underwater sound and one for airborne sound). The spread in hearing properties of animals is so large that animals should be divided into ‘disturbance sensitivity groups’ each having their own criteria.

5.3.2.3 Possible criteria The fact that radiated ship sound levels are very dependent on the measurement method and location makes drafting underwater sound level criteria (maximum sound levels for boats and ships) very delicate. Criteria should include a firm prescription of the measurement method and in fact those measurements cannot be carried out in shallow inshore waters or only with a very precise definition of the measurement site. Drafting those criteria will be a time-consuming and complex activity. And again it will be very difficult to derive those criteria from the hearing properties of the relevant animals due to the lack of such information. Any criteria for sound levels of boats should, in some way, be coupled to the ‘discomfort threshold’ of the (most sensitive) animal species in a certain environment. The discomfort threshold is the sound level at which the behaviour of the animal is (negatively) influenced by the sound. However, hardly any discomfort threshold research has been carried out so far. In The Netherlands some studies in this respect have been carried out on harbour seals and harbour porpoises and studies are continuing on North Sea fish species.

CONCLUSION: At present no firm criteria have been prescribed in Europe to protect animals against sounds from small marine craft or other man-made sources. It will therefore be clear that drafting criteria, based on the aspects set out above, is not possible at this moment. Considerable research is needed before criteria for sound from boats can be created or, maybe a more realistic approach, these criteria have to be based on other factors than animal hearing capabilities, such as for instance practical feasibility in sound reduction measures. However, this means that these criteria still have to be verified against animal disturbance properties. In the field of ship sound reduction considerable experience exists in certain countries in Europe, which is of relevance to the recreational sector as well.


5.3.3 Airborne sound emission targets From literature several noise limits set for outboard noise emission can be found. The next section gives a brief description of legislation or proposed noise limits concerning outboard noise emission.

5.3.3.1 Nordic Ecolabelling According to the Nordic Ecolabelling the noise emission of all engines intended for the propulsion of boats, both outboard and inboard, should not exceed a maximum sound pressure level LpASmax of 75 dB(A) re 20µPa [Nordic Ecolabelling, 2002]. The noise level is allowed to exceed this value if the values for each 1/1-octave band, as listed in table 5.3 are not exceeded. Table 5.3: Maximum allowable noise level per octave band.

Freq [Hz] 31.5 63 125 250 500 1000 2000 4000 8000

Noise level (dB) 103.1 90.8 92.9 77.1 73.0 70.0 67.5 65.7 64.1 The noise of a boat pass-by at a distance of 25 m should be measured in accordance with ISO 14509-1.

5.3.3.2 British Water Ski Federation The British Water Ski Federation produced a ‘Code of Practice for Water Skiing & Noise’. In this Code noise limits are set [IWSF Environmental Handbook]: • the maximum allowable noise emission for one recreational boat is 75 dB(A) for a

boat travelling at 35.4 km/h at a minimum of 25 m from shore. • The maximum noise emission for any boat travelling outside an environmentally

sensitive area is 55 dB(A); further measurement conditions are not mentioned. It seems likely that this is actually a maximum immission level at a receiver position.

• The maximum noise emission for one boat for water ski racing (other conditions

stated in Code): − 98 dB(A) with boat travelling at constant maximum design engine speed, 30

m from shore − 105 dB(A) for international and World Championship IWSF sanctioned

events.

5.3.3.3 Resolution on Navigation on the river Rhine In the Netherlands the maximum allowable noise emission LpAmaxF of a boat navigating on the river Rhine is 75 dB(A) at 25 m measured from the side of the hull [CCNR 1976]. This noise limit holds for freight cargo ships with a load capacity of over 15 tons or ships, like passenger ships, with a water displacement over 15 m3. The Dutch Inspectorate of Shipping also requires this noise limit to be complied with for ships designed to carry more than 12 passengers, when sailing on any other river then the


river Rhine in the Netherlands. Until now, this is the only legislation known for noise emission by ships in the Netherlands. Although this legislation concerns large ships, it is addressed also in the ‘Resolution Hovercrafts of the Noise Annoyance Legislation’ [1989]. According to this resolution the noise emission of recreational hovercrafts should comply with the noise limits set in Resolution on Navigation on the river Rhine.

5.3.3.4 Recreational Craft Directive In the new Directive on recreational craft [2003/44/EC, 2003] noise limits are defined for recreational craft with inboard or sterndrive engines without integral exhaust, personal watercraft and outboard engines and sterndrive engines with integral exhaust. The noise emissions as determined according to ISO 14509-1 shall comply with the limits mentioned in table 5.4. For twin-engine and multiple-engine units of all engine types an allowance of 3 dB may be applied. Table 5.4: Noise limits for various intervals for the rated engine power PN

according to 2003/44/EC.

Single engine power in kW LpASmax in dB(A) re 20 µPa

PN ≤ 10 67 10 ≤ PN ≤ 40 72

PN > 40 75

CONCLUSION: Most environmental noise targets that were found are based on a maximum A-weighted sound pressure level at 25 m distance. However, the exact measurement quantity and conditions differ. The different sound limits proposed are comparable (maximum 75 dB(A) at 25 m); an exception are those by the British Water Ski federation, but these are likely to be partly immission levels rather than emission levels.

5.3.4 Restrictions of use The current practice in restricting the possible disturbance of humans or nature by recreational craft, especially fast craft, is to limit either their speed, or in extreme cases their use at all. In the Netherlands some environmentally sensitive areas are fully restricted to boating, or only open to users with special permits. In the latter case the speeds are severely limited and the boats used are frequently driven by electricity rather than by combustion engines. High speed boating is forbidden on the majority of Dutch waters, and only allowed in special designated areas. Fast boats have to be registered and are obliged to carry their registration number large and clearly visible on their hulls. Speeding is rigorously policed. The background of these restrictions is more the disturbance caused by the speed itself than the noise aspects, but it will be clear that the sound aspect is automatically affected as well.


In other countries high speeds are only allowed at certain distances from the coast, which sufficiently reduces the noise disturbance of the people ashore. Other users of the same recreational area would of course still be affected, but such measures automatically exclude narrow waterways, and on more open waters presumably the boat density would be correspondingly less. Marine wildlife might still be affected, although nesting birds would not be involved. Whether such restrictions of use are sufficiently effective as a solution to the acoustic problem fully depends on the extent of the problem; see subsection 5.5. If the problem would be mainly restricted to a relatively small number of sensitive areas, it would seem a much more cost-effective solution than a requirement for all boats or engines to be constructed to very severe standards. But if speed and/or noise would have a very widespread effect on humans and the environment, effective sound limitation seems unavoidable. Unfortunately at this moment no Europe-wide inventory of ‘hotspots’ is known. In this context it should be pointed out that on a questionnaire send out by the contractor no Member State has answered by indicating any known problems within its territory. Neither has the environmental movement reported any environmental problems in relation to recreational boating, notwithstanding active prompting by the contractor.

5.4 Evaluation of impact on wildlife

At present no firm criteria for airborne or underwater sound, nor reliable underwater sound level data are available to evaluate the impact of the use of recreational craft on wildlife, above (birds) as well as under water (aquatic wildlife). Considerable research is still needed to derive criteria and underwater emission data for boats and ships in general. A more realistic approach could be to base criteria for instance on the practical feasibility in sound reduction measures.

5.5 Evaluation of impact on humans

5.5.1 Environmental sound transmission The propagation of sound from recreational craft is likely to be estimated best by models for road traffic or industrial sites, since the spectra of the sound emission for such sources are comparable. However, the variation in frequency effect in the sound propagation of various sources is only moderate so the influence of this choice is not very important. Though large differences have been found between the estimates by different models within Europe [Gerretsen, 1996], some have shown to be comparable enough for global estimates. Such models could consider areas with random traffic of craft (lake) as well as flowing traffic of craft along a line (canal, river). Such models take into account the sound reduction due to distance, air absorption, ground effects and screening and scattering by objects. For a global approach, as is intended in this study, the predictions will be based on A-weighted levels; hence also the sound reduction will be treated on A-weighted levels. Since the spectrum shape of the considered sources influences the actual reduction effects, it is likely that a road traffic approach would best fit the situation with recreational craft. For water traffic in general this has also been the


conclusion of a partly European study into the modelling of urban impact [Gerretsen, 1999], hence the model as described for URBIS will be used also for recreational craft.

The model will be used to estimate the sound impact expressed as Lden at a receiver height of 4 m taking into account a long-term averaging over weather conditions (primarily wind direction). This is in accordance with the European Directive and the interim models as prescribed for road traffic, rail traffic and industrial activities [2002/49/EC, 2002]. For a description of Lden, see the explanation on page 71.

5.5.2 Typical use and sound emission of recreational craft Information on the number and types of craft in Europe and the use of these recreational craft is still very limited at the moment. Since sound immission is a local environmental impact, the need is not so much the total number of craft but mainly the distribution over the different types and the typical use of the craft. The largest group of craft concerns craft with outboard engines; for these engines a distribution over installed power is available from a German study [TÜV], with the nominal power and the power while in use. A similar approach was taken here. It is described in more detail in Appendix D. This Appendix also lists the sound emission levels used. Apart from these data on typical sound emission of the sources, it is necessary for an estimate of the sound impact in a given environmental situation to know or assume the number of craft in use per hour and the duration of that use for the day, evening and night period. Since no hard data is available at the moment, the prediction of the impact will be based on some estimated values that at least can give an indication of the resulting sound impact. The estimates are based on the results of a study made for some situations in the Netherlands, typical for a river, a lake and a marina [STOWA, 1999]. Also from statistical information in the Netherlands on items like time spent on sport and recreational activities and the number of marinas and watersports clubs, global estimates can be made of the number of craft and the duration of their use.

5.5.3 Estimate of environmental sound impact; typical cases The sound impact depends on the number and duration of activities (passing craft, circling craft), the sound emission per craft during that activity and the propagation to the observer. To give some estimate, based on the data presented so far, we will consider the situation along a typical canal or river, around a marina, around open water (lake) and on such open water. For the number and use of the boats we will use estimates for an average day in the summer season and a peak day in that season. Other situations could be estimated from these results. Possible speed restrictions have not been taken into account, as these would represent additional measures to limit the impact of sound emissions. Their possible influence is discussed separately. Canal, river Assume the canal or river has a width of 50 tot 100 m and the observers are living along the shores; the average distance between the passing craft and the observers is assumed to be 50 m. Since the use of PWCs is more restricted to a certain area and not so much passing, these craft will be neglected here. Furthermore it is assumed that the craft are


used for 80% during the daytime (7:00h to 19:00 h) and for 20 % during the evening (19:00 to 23:00h) and are not used during the night period; this division does not prove to be critical though. Table 5.6 presents the Lden in dB(A) in this situation for various assumptions. Open water In case of open water the craft will not so much pass the observer but will be distributed over (a large part of) the water, so partly at larger distance from the observer at the shore. As a representative average a distance of 200 m is chosen. The same distribution over day and evening is used as for the canal; in this case also PWCs are considered with a use of 1 h per day, equally divided over day and evening time. Outboard engines in this case are considered to be used only part of the time, leading to an engine use varying from 1/2 h (sailing boat) to 3 h (motor boat). Another aspect in this case could be the disturbance of people in one craft by another craft. For this situation a typical minimum passing distance of 25 m is chosen; all others assumptions are taken as identical. Also these results for various assumptions are presented in table 5.5. Marina For a marina also a distance of 200 m is arbitrarily chosen, but the global effect of other distances is indicated. It is assumed that engines are used for 1/3 h for each boat to leave and enter a marina. Other activities in the marina are neglected as well as sound reduction through screening by buildings and other obstacles. Also these results for various assumptions are presented in table 5.5. Table 5.5: Estimated environmental sound impact for some typical cases, expressed as

Lden in dB(A). See box on page 71 for the meaning of Lden . situation low intensity1) high intensity1) intensity

nr./h sound impact

Lden in dB(A) 2) intensity

nr./h sound impact

Lden in dB(A) 2) canal d = 50 m 15 43 45 47 lake d = 200 m 3) boats PWCs

10 0,2

50 42

40 0,8

56 48

marina d = 200 m 3) boats

1

40

7

49

passing d = 25 m boat PWC

2 2

38 (55-65) 4) 45 (68-80) 4)

20 20

48 55

1 intensity is the effective engine use per hour for an average season day (low) and a typical peak day (high).

2 since A-weighting is applied in the determination of Lden the unit dB(A) is used here for clarity, though the directive calls the unit dB

3 at 100 m the levels are 7 dB higher than at 200 m. 4 in brackets: the maximum level LpA,Smax, excluding exceptional situations as planing and exhaust

above water level These levels may be compared to the following target values as given in subsection 5.3.1:


Table 5.6: Environmental airborne sound criteria in dB(A) situation target value

Lden in dB(A) Residential area 55 Recreational area 40 - 60 Parkland / conservation area 30 - 40 Additional remarks The results presented for sound impact are based on the average sound emission of the craft as given in section 5.2.2 for assumed normal power settings. It should be clear from the emission data that the sound production is lower when less power is used (lower speeds) and higher when more throttle and thus higher speeds are used. For outboard and inboard engines the data show about 8 dB(A) higher levels by using full throttle than the conditions assumed here as normal; for PWCs higher levels by up to 15 dB(A) have been reported depending on the use of the craft. Though these circumstances have a direct effect on the higher or lower maximum sound levels, the effect on the equivalent levels is much less, due to the effect of an also changed passing speed. As with the example of the mopeds (subsection 5.3.1), it is questionable whether the disturbance in case of increased use of power is mainly due to the higher sound level or due to the disapproval of the type of behaviour and other disturbing effects like higher waves.

CONCLUSION: The environmental sound impact on humans varies for normal use between 38 dB(A) and 56 dB(A), which is not critical for residential areas and some types of recreational areas. For other types of recreational areas this could be too high and for parklands and conservation areas it is clearly too high. In those cases additional measures will be necessary such as speed limits and restrictions of use. Speed limits alone might not be enough, especially for low power engines where the sound from the engine dominates over the sound from the moving hull.


6 Additional issues

This Section deals with other environmental issues than those of Sections 4 and 5. The subjects discussed here are: − Evaporative emissions − Spillage of fuel − The benefits of synthetic lubricants

6.1 Evaporation

6.1.1 Outline of the problem In the automotive world evaporative emissions are or may be related to the following phenomena and sources: • Crankcase losses • Refuelling losses from the fuel tank • Diurnal breathing losses from the fuel tank. • Tank permeation losses. • Hot soak evaporation losses from the fuel system. • Running losses from the fuel system. In marine applications two additional sources might be: • Fuel hose permeation • Spillage of fuel during refuelling The subject of spillage is dealt with in Section 6.2.

6.1.2 Crankcase losses Crankcase losses have their origin in ‘blow-by’ of combustion gases past the piston into the crankcase. To prevent pressure build-up in the crankcase, it is therefore ventilated to the outside. Since under operational conditions the atmosphere inside the crankcase is saturated with hydrocarbon vapour (‘oil mist’) the gases ventilated to the outside atmosphere do contain a significant degree of HC-content. Avoiding this source of HC-emission was one of the very first environmental measures on passenger car engines taken in the original emission legislation. This was done by rerouting the crankcase ventilation to the engine inlet system and combusting the hydrocarbons in the combustion process. Since then much effort has been spent to minimise the blow-by that caused it in the first place. The problem is a typical 4-stroke one, since 2-stroke engines have a closed crankcase that discharges into the engine’s cylinder anyway. As in the automotive world the phenomenon has been solved for marine engines long ago.

6.1.3 Refuelling losses Refuelling losses take place when a fuel tank is refilled with fuel and the air mixed with fuel vapour inside the tank is driven out while it is replaced by the liquid of the fuel. These losses are generally regarded as belonging to the fuel supply chain rather than to vehicle operation, and in the past calculations by the oil companies have shown that overall they actually amounted to only a few percent of the total traffic caused HC-emissions. Locally, at a fuel station, they may have a much bigger impact, of course. In the course of time various types of vapour recovery systems have been proposed, but at


least in Europe they have not been applied in practice, due to practical difficulties, in connection with the perceived relative insignificance of this particular source. Another proposal was to increase the size of the carbon canisters, currently used to accept the diurnal breathing losses (see below), to a size large enough to deal with these refuelling losses. The larger size of the canister would be needed since, although the refuelling losses are much lower than the diurnal breathing losses when averaged over time, they come less frequently and then in much larger quantities whenever they do come. In Europe this proposal was fiercely resisted by the automotive industry on the basis of the space required to fit such large canisters and the assumed fire/explosion hazard this might cause in the case of an accident. An automotive canister for the recovery of diurnal breathing losses typically has a size of 1 litre, whereas, according to CONCAWE, a canister for the recovery of refuelling losses would typically have a size of something like 2-5 litres, depending on the size of the tank. The US-EPA mentions a size of 2 litres per 100 litres of tank capacity. In Europe the discussion about their acceptability effectively died when a number of Member State governments introduced so-called ‘Stage 2’ measures, which means provisions at the fuelling stations rather than on the cars, whereas other Member State governments were not sufficiently interested. The US, on the other hand, introduced such large canisters in 1998, so that they are a regular feature of current American cars. The EPA claims that no adverse consequences are known.

6.1.4 Diurnal breathing losses Diurnal breathing losses are caused by the fact that the day-night temperature cycle causes the air in the fuel tank to expand and contract, causing an outward flow of air /fuel vapour mixture during warming-up and an induction of ambient air during cooling down. This phenomenon is generally regarded as the main source of evaporative HC-emission from road vehicles. The solution generally adopted is to let the tank breath over a vapour recovery system (a ‘carbon canister’ filled with active carbon), which in turn is ‘purged’ during engine operation by returning the flow direction from the ambient atmosphere through the canister into the engine intake system, and to combust the hydrocarbons in the combustion chamber. In automotive applications the repeated switching of the flow direction is electronically controlled. For recreational boats the EPA aims for a system where the purging is done overnight when the tank cools down and the resulting ‘breathing in’ draws outside air back into the tank via the canister. This does result in a degree of purging, called ‘passive purging by the EPA. The EPA claims that this will still result in a reduction in evaporative losses in the order of 60 %.

6.1.5 Tank permeation losses A new source of evaporative losses appeared when plastic tanks began to appear on the market, and started to replace metal ones. Early versions proved to be permeable to hydrocarbons and the resulting evaporative losses were rather high. In the automotive case this was eventually solved by treating the material with a coating that did stop the permeation.

6.1.6 Hot soak evaporation losses from the fuel system Hot soak losses take place when an engine is switched off, after operation, and high temperatures of the engine or related components cause fuel evaporation from the fuel system, as from e.g. carburettor float bowls. In cases where this was, or still is, relevant it was solved by routing the ventilation of these components directly to the inlet system


or over the same carbon canister as used to capture the diurnal breathing losses from the tank. With the introduction of fuel injection systems this source is no longer an issue. In practice hot soak emissions involve the engine manufacturers rather than the tank manufacturers.

6.1.7 Running losses Running losses have the same nature as hot soak losses, but are caused by the components concerned being heated during engine operation rather than after switching off of the engine. Since in automotive applications usually some degree of cooling will be present during the running of the vehicle, this phenomenon was discovered as being less significant than that of the hot soak losses. The absence of such cooling after switching off, and the likelihood of the components concerned being then heated by temperature levelling processes, are usually resulting in higher temperatures and hence more evaporation. In summary it can be said that the major aspects in evaporative HC-emissions are the diurnal breathing losses and the permeation problem, with fuel line tightness as a possible third one.

6.1.8 The situation in the marine case According to information collected so far, it seems that the main problem in the marine case is tank permeability and the possibility of permeation of the fuel lines, plus diurnal breathing. The US EPA, in a large scale inventory, arrived at the following contributions: Table 6.1: Estimated relative marine evaporative emissions from boats with SI engines in the US (2000). Diurnal breathing 23% Permeation fuel tank 27% Permeation hoses 43% Refuelling 7% Hot soak <0.5% Total evaporative emissions 100% Apparently refuelling and hot soak are no important sources, but diurnal breathing and permeation problems are. In their case the total evaporative losses added up to about 7.5 kg/annum per boat. We feel that this is not the place to go into the details of their calculation, but it could be noted that the US fleet contains a large number of sterndrive/inboard petrol engines. These are rather large engines (at least by European standards) with generally bigger tanks and possibly longer fuel lines than a typical European petrol engine boat installation. Nevertheless these figures will at least give an idea about the order of magnitude we are talking about. And even if we arbitrarily assume that a typical European figure would be closer to, say, 3-5 kg/annum per boat, we are still left with a large figure when we compare it with the annual exhaust hydrocarbon emission, as set out in Table 6.2. The figures for the exhaust HC come from the calculations made in Section 8, including those for a possible Stage 2.


Table 6.2: Calculated average exhaust HC emissions as determined in Section 9 Stage and option Average exhaust HC

kg/annum per boat Stage 0 Stage 1 Stage 2 – option 1 Stage 2 – option 2 Stage 2 – option 2A

24.55 3.15 1.50 1.12 1.26

Evaporation (tentative) 3-5 So the conclusion seems to be that in the Stage 1 situation the overall evaporation may well be of the same order as the exhaust HC, and in a possible Stage 2 it might be the more significant source of the two. One should be aware, however, that the relative magnitude of the two sources is primarily stemming from the low values of the exhaust HC (due to a low number of overall operating hours) rather than from a particularly high evaporative emission. And the important difference in effect is, of course, that the evaporative HC does not end up in the water body, and hence only contributes to the air pollution, for which it is only a minor source.

6.1.9 Possible solutions for the marine case Diurnal breathing losses An inventory carried out by the US EPA estimates the diurnal breathing losses at about 0.25 g/day per litre of tank volume when the boat is out of the water, and about 0.07 g/day when the boat is in the water. The US boat building industry had a 5.5 m open runabout, with a 120 litre plastic tank, tested in the ‘SHED’ of an automotive test laboratory (SHED is an acronym for a sealed test room designed to measure evaporative emissions from passenger cars). By means of routing the tank breathing to an adjacent SHED, it was possible to measure the permeation and breathing losses separately. The test was the proposed automotive type ‘three-day test’. It was found that on this craft the fuel temperature cycled between about 25 ºC and 32 ºC, whereas the ambient temperature was set to cycle between the prescribed 22 ºC and 35.6 ºC. The temperature rise over the first test day was higher, however, from about 20 ºC to 32 ºC. Consequently the measured breathing losses were higher on the first day than on the other two days. The permeation losses were similar for all three days. See Table 6.3 below: Table 6.3: Diurnal breathing losses and permeation losses of a 5.5 m open runabout.

Rounded figures. Source: Haskew, 2002. Diurnal breathing Permeation Day 1 32 g 11 g Days 2 and 3 25 g 11 g

The total diurnal breathing losses worked out at roughly the estimated 0.25 g/day per litre of tank volume. The industry feels, however, that the use of canisters is insufficiently evaluated. They fear that in the marine case moisture or water may eventually find its way into the canister, and that the active carbon in the canister, once it is wet, will no longer respond to the passive purging.


Tank permeation In the current situation tanks are custom made by a large number of small enterprises, in very small series. Since in the majority of boats interior space is limited, boat builders tend to use every corner in the most optimal way, and tanks tend to be shaped to fill out otherwise unused spaces. This means that every type of boat is likely to have its own tank shape and the series size of that tank is necessarily linked to the series size of the boat type. The type of firm mentioned above is fully set up to deal with that kind of demand. Tank materials have to a large extent changed from metal to polymers. This is primarily a safety issue: metal tanks can corrode and would then start to leak. In boats fuel leakage is a much more serious safety issue than in automotive cases, especially when it concerns a volatile fuel such as petrol. In automotive cases any leakage or vapour venting would spill to the ground and dissipate, unless perhaps in a tightly closed and badly ventilated garage. In a boat any fuel vapour, which is heavier than air, would collect in the bilge and stay there, creating a potential fire and/or explosion hazard. Consequently, especially in the case of inaccessible tanks, or tanks placed well out of normal sight, potential corrosion poses an added, and in fact avoidable, risk. But in combination with the situation as outlined in the previous paragraph, this means that the manufacturing of such polymer tanks must be performed by means of processes that are easily adaptable and hence fit for low series volumes. In a ‘Public Hearing’ concerning US proposed rulemaking it was stated that US plastic tank manufacturers currently produce some 2500 different shapes [NMMA, 2003]. Concerning permeation the US NMMA (National Marine Manufacturers Association) states that the US EPA has based their proposal for intended standards “on fuel tank manufacturers either moulding a layer of ethylene vinyl alcohol or nylon between two layers of polyethylene, or by treating the surfaces of the fuel tanks with a fluorine gas (fluorination) or sulphur dioxide (sulfonation); a third method may be to use nylon in the moulding process in place of the cross-linked polyethylene currently used”. To this the NMMA states:

“Manufacturers of plastic fuel tanks used in the marine industry generally use a rotational moulding process, using cross-linked polyethylene. This process allows manufacturers of the plastic fuel tanks to keep cost competitive and to provide the wide variety of shapes needed for the numerous designs of vessels. The two most promising methods of reducing permeation of fuel vapours from plastic tanks are to barrier treat the tanks by fluorination or sulfonation. Both fluorination and sulfonation will require the tank manufacturer to have the space to install reactor equipment at their facilities, and obtain local building and state environmental permits to operate this equipment. A second option would be for the tank manufacturers to send the tanks out for treatment to the single company that operates fluorination or sulfonation treatment activities.” [NMMA, 2003].

They then proceed to outline their perception of the financial consequences and the potential environmental hazards of the fluorination and sulfonation processes, when carried out by SMEs. In reply to this statement the EPA stated that they are “evaluating several approaches for rotationally molded fuel tanks, including alternative materials, roto-moldable multilayer constructions, barrier coatings that are compatible with cross-link polyethylene and alternative constructions that are cost effective for low volume production runs”. This seems to mean that the problem is already extensively under discussion in the US, but that no final conclusions or solutions have been reached yet. The contractor likes to propose that the Commission waits for the outcome of this


discussion and then takes advantage of its conclusions, rather than to start its own investigation. Hose permeation Hose permeation was estimated by the US EPA at a level of 100-200 g/m2 per day for different kinds of hoses at an ambient temperature of 23ºC, which would increase to 330-630 g/m2 per day at 40ºC. There are hose materials that would cut this down to 15 g/m2 per day. The industry is trying to convince the EPA that these hoses would sufficiently solve the problem. There does also exist a class of hoses that would reduce the emissions to 5 g/m2 per day, but the industry complains that these hoses are far too stiff (resistance against bending) to be practical in actual use. The 15 g/m2 per day type would already provide a reduction of 90 % relative the current 100-200 g/m2 per day. Any legislation to be introduced on this account could simply be shaped in an obligation to use hoses of an approved material. This would put the obligation of testing and certification at the hose manufacturer; the boat builder would only have an obligation to use the appropriate certified hoses. Such a practice already exists in ECE Regulation 67. Refuelling In Table 6.1 refuelling losses do not play an important role. Of course, when the other three more significant causes are reduced in magnitude, the refuelling losses will increase as a percentage, even if not in absolute numbers. The reduction of refuelling losses have been studied in the case of cars, but no ultimate solution was established for Europe (see subsection 6.1.3). A real additional problem in the case of recreational marine engines would be the widespread practice of refuelling from jerrycans (see also Section 11). Any kind of vapour recovery system, whether it be on the filling station side (stage 2 solution) or on the fuel tank side (carbon canister) would require the use of a hose with a collar that closes off the filler opening, in order to prevent the escape of vapours to the atmosphere and to force them either to the vapour return hose or to the canister. In the case of refuelling by jerrycan such a provision would always be absent, and any on-board recovery system would of necessity be inoperative. A secondary aspect is that refuelling by jerrycan doubles the evaporative refuelling losses: they occur once when the jerrycan is filled at the fuel station, and a second time when the boat tank is filled from the jerrycan. Given the fact, however, that on the one hand even in the automotive case (with about 15 million vehicles sold annually) no such recovery system is required, and on the other that in the European case such a system on boats (with less than 0.25 million sold annually) is most likely not to be effective, the most obvious approach would seem to be that no Community legislation is introduced here. Tentative estimate of a realistic reduction If we tentatively assume that the current evaporative emission would lie in the order of 3-5 kg/annum per boat, and that the distribution of the total evaporative emissions is equal to the one shown in Table 6.1, and we assume that a moderately treated tank would have a 40-50 % reduction in permeation, and that hoses of the 15 g/m2 per day type would be used, the resulting evaporative emissions would be 1.4-2.4 kg/annum per boat, even without any use of canisters. That is about half the current value.


6.2 Spillage

Concerning spillage of fuel during refuelling, a reasonably extensive investigation into this problem was made on behalf of some local Dutch authorities in areas with much recreational boating. Although the report was confidential we were allowed to consult it, and to report its main conclusions. The investigation was based on a large number of inquiries with all parties involved in that part of the refuelling chain. The credibility of the answers was checked and it was decided that at least the order of magnitude of the figures derived for the extent of spillage was sufficiently credible. The main problem that was identified as the cause of spillage was the spreading practice to fill the tanks of recreational craft from jerrycans that themselves are usually filled at automotive fuel stations. The reasons for this are set out in Section 11. About one third of all the fuel is put in from a jerrycan and about two thirds from a fuelling point on the waterfront, by means of a hose. Those that refuel by means of jerrycans spill about 40 ml per year, and those that refuel from a pump spill about 5 ml per year. This amounts to less than 0.05 % of the fuel in the case of refuelling from jerrycans. This would put it in the same order as the refuelling losses. On the other hand, in this case, when it is spilled into the water it will end up as water pollution rather than as air pollution. In fact about 50-60 % of the fuel spilled ends up in the water, the remainder being spilled onto the boat or the shore where it is usually cleaned up. Obviously the amount spilled is higher for the fuelling from a jerrycan than for the fuelling by hose from a fuelling station. The report advises, however, not to try to discourage the fuelling by jerrycan (which will take place anyway) but rather to widely promote the use of a small siphonpump for this purpose, which would largely avoid the problem. Such a solution would lie outside the scope of the RCD and would need a combined effort from all parties concerned to make the boat owner aware of the problem and to advocate such a solution. See further subsection 11.10 for such approaches.

6.3 Synthetic lubricants

The major aspect of the lubricant in the context of the current study is the water pollution aspect. Early studies, quoted in the 1991 TNO report [Rijkeboer 1991] indicated that biodegradable lubricants disappear much quicker from the water body than mineral lubricants (see also subsection 4.3.3). From a report by the contractor to the European Commission concerning PM-emissions from mopeds with 2-stroke engines [Rijkeboer 2002] the following information is copied: “Lubricants for modern 2-stroke engines are moving away from mineral components and are more and more derived from synthetic components. Some years ago the Japanese industry started with a classification for 2-stroke lubricants. This classification was performance based, rather than application based as until then; it indicated FA, FB and FC. The classes FA and FB consist of a mineral base oil with additives. Mainly driven by the European industry ISO has adopted the same basic classification, but has skipped the class A and added a D-specification. The ISO indications are ISO-L-EGB, ISO-L-EGC and ISO-L-EGD. A class L-EGE was under discussion, but was finally dropped for the time being. Class L-EGC distinguishes itself from L-EGB in more stringent requirements for ‘exhaust smoke’ and ‘exhaust system blocking’; L-EGD has the same numerical requirements for these two aspects, but based on a longer test, plus more stringent requirements for detergency and piston varnish. L-EGC is part synthetic, L-EGD is often (and to an increasing degree) fully synthetic.”


“Synthetic lubricants consist of poly-isobutylene (PIB) blended into esters. These esters can be obtained from natural sources (in practice vegetable, but in theory also animal) or from oxidised components from the petrochemical industry (acids, alcohols). The production of PIB and esters is in the hands of specialised chemical firms who supply them to additive producers and selfblending lubricant suppliers (so-called ‘formulaters’). At high temperatures they decompose and subsequently fully combust, in principle without residue. L-EGD lubricant is composed of PIB and esters plus a solvent for blending purposes and viscosity adjustment. This combusts almost as readily as petrol, and practically without emissions. There is much variation possible in esters, which allows the blender to design the lubricant’s characteristics in fine detail. By now poly-ethyleneglycols and esters are judged on their combustion characteristics as much as on their lubricity performance. An advantage is that lubricity demands more pure components, which at the same time also combust better: whereas mineral lubricants contain a large variety of components, the bandwidth of the components in a synthetic lubricant is much narrower.” “Since for use ‘on the street’ fully synthetic lubricants are still relatively new (they already have a history in racing), the development potential is still large. In the recent past there was much attention paid to visible smoke, whereas by now the interest has shifted towards particulate emission. The research is moving into the direction of lubricants that decompose thermally, since in that case any possible scavenging loss would decompose in the exhaust port and oxidise (‘combust’) in the presence of a catalyst. In applications without a catalyst preliminary investigations suggest that the carcinogenity of the resulting particulate emission is less than that of mineral oils. Furthermore with modern (DI) 2-stroke engines the use of lubricant can be significantly reduced anyway, in some cases already below that of a 4-stroke engine. Specific experience with the requirements of DI 2-stroke engines to lubricants has still to be gained, however. A problem with poly-ethyleneglycol is poor miscibility with mineral oils. Hence future formulations will move into the direction of fully synthetic oils, although some mineral based oils will always be needed for certain purposes, so that such miscibility will still be required.” “In summary it can be said that the trend is towards synthetic lubricants that have an increased combustibility, resulting in significantly reduced PM-emissions. The major aspect of this trend is, however, that it cannot be fully controlled by the manufacturer but is partly left to the client/operator.”

The main conclusion of the overview of synthetic lubricants given above is, however, that they can be tailored to combust much better, leading to significantly less emission. So the main advantage of the use of synthetic lubricants should be perceived to be the possibility of less emission (through better combustion) rather than their tendency to disappear more rapidly from the environment when emitted.


7 The possibilities for technological improvements

7.1 Important characteristics of the recreational marine sector

When considering the aspects of a reduction of exhaust emissions and noise from marine engines, there are a number of elements that are characteristic for the marine sector that should be kept in mind. Extreme emission reductions have been obtained in some other sectors, notably the automotive one. But generally speaking different sectors may differ significantly enough to prevent solutions that have been developed in the one sector to be as successful, or even feasible at all, in the other. In this respect the following aspects must be regarded as of importance. On the petrol side of the market, outboard engines and engines for PWCs are dedicated designs, although some bigger outboard engines sometimes are based on existing automotive engines. Since the world-wide market is small, the renewal rate of engine designs is low, and in most cases will be limited to updating existing designs rather than launching completely new ones. Petrol fuelled inboard engines are usually derived from existing automotive engines, that are ‘marinised’ by specialised firms. In Europe this marinising is usually limited to the mounting of dedicated parts and equipment, and does not (in fact: in most cases cannot) change anything to the basic engine. If changes in engine settings, or even in design, are really necessary they will only be carried out in close co-operation with the original engine manufacturer, and more likely directly by that manufacturer himself. See further subsection 3.5. With the odd exception, diesel engines are exclusively inboard engines. There are a few diesel engine manufacturers operating on this market, and a large number of (usually smaller) marinisers (see Section 3 and subsection 3.5). But even the engines produced by original manufacturers are nearly always based on a ‘core engine’ developed for other markets (industrial or automotive) which is then, as it were, marinised by the OEM itself. This means that again the basic ‘architecture’ of the engine has been developed for industrial or sometimes automotive application, and that the specific requirements of the marine market are mainly met with add-on equipment.

7.2 Exhaust emissions

7.2.1 Petrol outboard engines Although marine engines are operating in a completely different environment and in a completely different way from by far the most other applications, the field of application that is closest to the outboard engine is that of the PTWs (powered two wheelers), with the small outboard engine being somewhat comparable to the moped engine, and the bigger outboard engine somewhat comparable to the motorcycle engine. Indeed several of the major outboard engine manufacturers are also PTW manufacturers. Very big outboards are closer to the automotive technology. Especially in the PTW market the same question of possibilities and costs had to be dealt with, more particularly the desirability or otherwise of changing over from 2-stroke to 4-


stroke and the feasibility and costs of aftertreatment systems. Disregarding for the moment the large differences in production volumes, we like to compare the technological aspects in this subsection. In another study for the European Commission [Rijkeboer 2002] the relevant aspects for mopeds were investigated. The relative stringency of the emission steps may be roughly indicated as follows: Table 7.1: Indication of the relative stringency of the emission steps of 97/24/EC.

97/24/EC stage 1 (moped stage 1) 100 % RCD stage 1 70 % 97/24/EC stage 2 (moped stage 2) 40 % Investigated moped stage 3 Option 1 30 %

About the technology the following remarks made in [Rijkeboer 2002] are of relevance for the current question: Conventional 2-stroke engines This technology suffers from high scavenging losses, leading to high HC-emissions. Catalytic afteroxidation is easily possible, but tends to lead to very high temperatures in the exhaust, which could be detrimental to durability. Carburettor adjustment and a simple oxidation catalyst are sufficient for moped Stage 1. For moped Stage 2 already a two-step catalyst is necessary, with SAI (secondary air injection) in between the two steps. With such a system very low homologation emissions have been demonstrated, that fulfil the Euro 2 standards with a large margin, although the emission performance in practice is very much dependant on the durability. The disadvantages quoted are in the first place low power and poor driveability. 4-Stroke engines In contrast to 2-strokes, 4-strokes have much lower HC-emission, since they lack the high scavenging losses, and consequently have also much less fuel consumption and ultimate CO2-emission. On the other hand it is a general experience that (at least in other applications) they run with higher CO-emissions, even though the data on actually measured emissions from marine engines as presented in Appendix B do not seem to confirm this. The cause of this discrepancy is not fully clear. On vehicles with a low state of emission abatement (running relatively rich) the NOx-emissions usually are still low, but higher than for 2-strokes; they have a marked tendency to increase with more stringent emission stages. Four-strokes can reach moped Stage 1 emission levels with carburettor tuning only. Moped Stage 2 requires SAI and an oxidation catalyst for CO-oxidation. Real environmental benefits are better durability of the abatement system and a much reduced fuel and oil consumption in comparison to the conventional 2-stroke. The disadvantages are reduced performance and relatively high cost. The system does depend on aftertreatment to a lesser extent but contains more electronic control. Further emission reduction is technologically possible but the costs are likely to become critical very soon (see table 7.2). DI 2-stroke engines Like the 4-stroke, the DI 2-stroke can reach Stage 1 without any aftertreatment. Additionally it does so without suffering in performance or driveability. Complying with Stage 2 limits may be obtained in two ways: either by engine modifications, or by


adding a catalyst. The first mentioned approach will affect the performance, although there would still be a certain advantage over a 4-stroke. An optimised catalyst would need an adapted coating so as to deal with very lean mixtures. The durability is good. According to the manufacturers concerned, the emission performance is largely electronically controlled. On the negative side DI technology is bought with relatively high cost and relatively high complexity. With respect to the cost it can be said that at the moment this is similar to 4-strokes, although bigger series may reduce this in the future. Further emission reduction comes at a lower price than in the case of 4-strokes, however. This situation is set out in Table 7.2 below: Table 7.2: Summary of the technology needed and the advantages and disadvantages of

various options for moped emission abatement. Conventional 2-stroke 4-stroke DI 2-stroke

Moped Stage 1 Oxidation catalyst Altered carburettor settings No special measures

Moped Stage 2 Secondary air injection Second oxidation catalyst

Secondary air injection Oxidation catalyst

a) Engine modifications, no catalyst, or b) Stratified combustion small catalyst

Advantages Cheap

Large margin in homologation

No smoke

Durability Better efficiency No oil consumption

No smoke

Durability Good efficiency Less oil consumption Good performance

Disadvantages

Poor efficiency

Poor driveability High start-up emissions

Lower performance

High cost Start-up emissions

High cost (as 4-stroke, but

may decrease) High complexity

Moped Stage 3, option 1

Two catalysts with SAI in between

Reduced engine performance

Adapted tuning Somewhat reduced engine

performance

Increased catalyst performance

Possibly somewhat reduced engine performance

It should be noted that in the table the conventional 2-stroke is the only one stated to need a catalyst for stage 1, that the 4-stroke needs catalytic aftertreatment for stage 2, and all three technologies would need catalytic aftertreatment for stage 3. Another point worth noting is that in all of these cases the catalyst is a ‘passive’ oxidation catalyst, in some cases supported by SAI (secondary air injection) to supply the necessary oxygen for the oxidation of CO and HC. Their efficiency in such applications would be in the order of 60 % when new, or perhaps 50 % on average after ageing. The reduction of NOx would require a closed loop 3-way catalyst on a 4-stroke engine. In the PTW report this option was rejected as unrealistically expensive; it is not so much the catalyst itself that is the problem, but the closed loop control equipment that, in the case of small engines, is going to provide an unrealistic financial aspect. A third point is that start-up emissions are not part of the marine engine test procedure (in contrast to the test procedure for road transport vehicles), but might be quite


significant in the case of auxiliary engines, that are only used for a short duration at a time, to exit or enter a marina. A last point is that roadgoing vehicles will much sooner make use of electronic control than marine engines, since in the latter case both the waterproofing and the reliability of the electronics are of much bigger importance. If failing electronics would result in an inoperative engine, in the marine case there may immediately be a safety issue . Although it is not possible to make a straight translation from road vehicles to marine engines, these remarks may serve to give an impression. Overview of the situation Forgetting for a moment the ‘allowance’ for smaller engine powers (most of the ‘B’ part of the formula, see Section 14), the current EU limit for HC+NOx (primarily the ‘A’ part) is set as in the table below: Table 7.3: HC+NOx levels in Europe and the US.

RCD Stage 1, 2-stroke RCD Stage 1, 4-stroke

42 g/kWh 22 g/kWh

EPA outboard, 2001 - 2005 and beyond 107 – 45 g/kWh CARB outboard, 2001 - 2008 45 – 16 g/kWh

This means that in the current situation the RCD Stage 1 levels for 2-strokes are at the EPA levels for 2005 and beyond, and those for the 4-strokes are already significantly below that, at some 35-40 % above the CARB levels for 2008. Taking into account the considerations given above, the current Stage 1 may already exclude all but the best of the conventional 2-stroke engines, and the room for further improvement is very limited without turning to aftertreatment. Already the current Stage 1 means a shift in technology away from the conventional 2-stroke, involving considerable development effort, especially for SME manufacturers, which in the majority of cases is hardly recoverable on the small series concerned. See Section 3 on market aspects and Section 12 on economical aspects.

CONCLUSIONS: The Stage 1 limits are equal to the most stringent limits for 2-stroke engines currently in force and even considerably more so for 4-stroke engines. The current Stage 1 limits are already likely to eliminate the conventional 2-

stroke engine to a large extent from the European market. Any further tightening of the limits would require aftertreatment, the

feasibility of which is seriously in doubt for small outboard engines, and has certainly not yet been demonstrated.

7.2.2 Petrol inboard engines In principle for petrol fuelled inboard engines the possibilities are larger. This is reflected inter alia by the fact that the CARB legislation (see Section 13) aims for more stringent limits in the case of inboard engines.


The CARB sterndrive/inboard rule stipulates an HC+NOx limit of 16 g/kWh (fixed value for all engines) as from 2003, and 5 g/kWh as from 2008, which is subject to a technical review. The industry feels that 16 g/kWh is the maximum limitation that would be possible without aftertreatment. The 5 g/kWh would certainly require sophisticated aftertreatment. The contractor feels that even the 16 g/kWh is not likely to be attained unless by modern engines, meaning inter alia electronic fuel injection. At the moment this is not yet state of the art in the field of marine engines. US data, provided by the EPA, show that only by the ‘averaging’ that manufacturers are allowed on that market are they able to meet that limit. This seems to support the statement just made. Older engine designs may well require SAI and an oxidation catalyst to comply with the 16 g/kWh limit. The 5 g/kWh therefore will indeed need some kind of aftertreatment. And aftertreatment in this case is likely to mean 4-stroke engines equipped with closed loop 3-way catalysts. This system then needs to deliver 70 % conversion efficiency, which does seem to be a reasonable requirement for a first generation system. Concerning aftertreatment see further subsection 7.2.3. Just for the record it may be mentioned that in the early days of US automotive emission abatement, with the 3-way catalyst still being a laboratory solution, one practical solution considered was to go for low NOx by means of (very) rich tuning in combination with EGR (exhaust gas recirculation). The resulting high concentrations of CO and HC could subsequently be dealt with by SAI and an oxidation catalyst. Although such an approach might comply with the required HC+NOx and CO standards, in these days of CO2-concern this route ought not to be considered.

CONCLUSION: Petrol inboard engines present more possibilities for emission reduction than outboard engines. The current CARB S/I rule of 16 g/kWh will just be possible without aftertreatment. The 2008 limit of 5 g/kWh will certainly need aftertreatment.

7.2.3 Practical aspects of catalytic aftertreatment In the opening paragraph of this section a warning was sounded that solutions that work well in the automotive field may not necessarily be as effective or feasible in the marine case. This is further elaborated in this paragraph. Significant differences between roadgoing engines and marine engines are: − The closed-in character of the engine installation, where thermal aspects will much

sooner create a problem, especially in the case of outboard engines. This may conflict with the thermal aspects of a catalyst, especially an oxidation catalyst on a conventional 2-stroke engine.

− The practice to inject water into the exhaust system close to the exhaust port or valve. This water is meant to cool the exhaust gases as quickly as possible, for safety reasons, but this tends to conflict with the requirements of catalyst temperature.

− Lack of space to accommodate a catalyst, not so much in volume as in required length between the engine exhaust port and the point of water injection, again especially in the case of outboard engines.

− As a general rule both outboard and sterndrive inboard engines, have underwater exhausts, creating the risk of backwash of water under transient engine operating conditions.


− The vertical distance between the water surface and the engine exhaust port is usually extremely short, creating the risk of water sloshing back into the system on a moored boat under non-operative conditions.

− As already on small PTWs much simpler monolith construction and catalyst formulation are needed than in automotive applications, which significantly reduces the conversion rate (e.g. 60 % rather than > 95 %).

− Furthermore any practical experience with catalytic aftertreatment on marine engines is still largely lacking.

The following potential problems are here dealt with in some more detail. Water resistance Some experiments have been performed both by engine manufacturers and catalyst manufacturers to evaluate the stability of catalyst monoliths against thermal shock. Hot monoliths were dropped in cold water. According to EPA Engelhard, a US catalyst manufacturer, reported no ‘measurable deterioration of the structure’ in the case of ceramic monoliths. Johnson Matthey, the world’s biggest automotive catalyst manufacturer, when asked reported similar experiments with a metal support catalyst, although at a small scale. Their interest had been the stability of the washcoat and catalyst coating. They reported no activity loss, but stated that the scale of the experiments did not allow conclusions concerning monolith stability. They regarded metal supports as the most logical solution anyway, for similar reasons as in the case of PTWs: better resistance against vibrations and shock. In the margin they stated that for this size of catalyst ceramic monoliths would not be cheaper, since the lower cost of the monolith itself would be offset by a more expensive ‘canning’. Yamaha, which applies catalysts on conventional 2-stroke engines as the quickest and most cost effective possibility to clean up the engines of certain PWCs (effectively inboard engines), reported cracking of ceramic monoliths. The conclusion seems to be that about thermal stability more experience is needed, but that metal support catalysts are the logical choice anyway. Salt contamination There is some concern that catalysts may become deactivated by salt contamination when used on seawater. Some early experiments have been conducted by Southwest Research Institute under contract to the EPA. No specific problems were encountered but the experience is extremely limited so far and true durability experience is still lacking. General experience Johnson Matthey reported that their activity had been limited to some very early reconnaissance without any field trials. Hence they were unable to supply any hard data. With some members of the engine industry they agreed that the lambda sensor of a closed loop 3-way catalytic system was likely to be the weak link in the system, and they had the strong opinion that any catalytic system would best be limited to an oxidation catalyst. Yamaha reports a high failure rate on the only engine fitted with a lambda sensor. Johnson Matthey felt sure that sound engineering solutions to the problems will exist and can be found, but there is no experience available yet. EPA feels confident that catalytic aftertreatment is possible, relying on the SwRI experiments. It should be noted, however, that the SwRI experiments concerned a couple of big American inboard engines of sizes that are hardly relevant for the European situation and hence with space possibilities for the systems that most engines in the European fleet would be lacking. Consequently practical experience with closed


loop 3-way catalysts on recreational marine engines should be regarded as still extremely limited.

7.2.4 Diesel inboard engines The current marine diesel engine is derived from an industrial diesel engine, or in a few cases from an automotive diesel engine. These engines are always installed as inboard engines. Current engines are likely to be certified for at least a standard requiring something like 9 or 10 g/kWh for NOx, and 0.7-1.0 g/kWh for PM in the case of smaller engines to 0.3-0.5 g/kWh for bigger engines. More advanced engines may be certified for something like 6-7 g/kWh NOx and 0.4 g/kWh PM. Compared to the automotive case (and taking into consideration the differences in duty cycle) this is roughly comparable to Euro 1 level (or earlier) in the former case and partly Euro 2 (especially NOx) in the latter. A level of approximately 4 g/kWh NOx and 0.2 g/kWh PM is regarded by the industry as the ultimate attainable without aftertreatment. If cooled EGR can be used (but see subsection 10.3.1) TNO diesel specialists feel that 2.5 g/kWh NOx would be possible, provided that PM remains ≥ 0.1 g/kWh. Table 7.5: The emission levels attainable with different technologies in the case of

heavy duty automotive applications, according to a recent TNO study [van Gompel].

aftertreatment Euro 2* Euro 3 Euro 4 Euro 5 Fuel system EGR

SCR DPF NOx

7.2 PM 136

NOx 5

PM 100

NOx

3.5 PM 20

NOx 2

PM 20

? EGR

SCR ?

MFI

EGR DPF

EGR SCR ? ?

EFI

EGR DPF

EGR ?

SCR

AEFI

EGR DPF ?

MFI = mechanical fuel injection possible EFI = electronic fuel injection AEFI = advanced electronic fuel injection (rate shaping) uncertain

EGR = exhaust gas recirculation SCR = selective catalytic reduction NOx values in g/kWh DPF = diesel particulate filter PM values in mg/kWh

* The actual limit values were 7 and 150, as measured on the original ECE 49 procedure The values shown are the officially established equivalents for the ESC procedure.

The measures taken by the automotive manufacturers to comply with stages Euro 1 and Euro 2 were more advanced internal engine design, high pressure fuel injection and (in most cases) electronic control of that fuel injection. Euro 3 (with 5 g/kWh NOx) then proved possible as well, in most cases without EGR. For further reductions some kind of EGR and/or aftertreatment is necessary. More advanced electronic fuel injection,

?


with so-called rate shaping and/or multiple injections have some advantage for further reductions but, more important, has a supporting function in enabling certain aftertreatment technologies and EGR. The aftertreatment systems currently considered are either SCR (selective catalytic reduction), to reduce NOx, or DPF (diesel particulate filter), for particulate matter (PM). Table 7.5 shows the possibilities as estimated in a TNO study for road transport vehicles [van Gompel]. As may be seen Euro 2 levels are possible with modern engine design and high pressure mechanical fuel injection. Euro 3 levels would require either electronically controlled fuel injection or aftertreatment, and anything beyond that would require some kind of aftertreatment in any case. Figure 7.1 shows in some more detail what kind of emission profiles may be expected with the technologies listed, in the automotive case, compared to the actually realised emissions for Euro 2 and Euro 3 engines, according to the TNO study mentioned above [van Gompel]. Figure 7.1: The emission profiles attainable with various technologies in the

automotive case (heavy duty engines). Source: [van Gompel] DOC = diesel oxidation catalyst. DPF = diesel particulate filter EGR = exhaust gas recirculation SCR = selective catalytic reduction

low emission diesel technologies

0.00

0.05

0.10

0.15

0 1 2 3 4 5 6 7 8NOx emission [g/kWh]

PM e

mis

sion

s [

g/kW

h]

Euro 3

EGR

EGR + DPF

SCR + DOC

SCR + DPF

Euro 2

EGR and aftertreatment systems EGR EGR (exhaust gas recirculation) is a means to reduce NOx-emissions from diesel engines. A certain proportion of the exhaust gas is re-routed (recirculated) from the exhaust side of the engine to the inlet, and mixed with the intake air. This exhaust gas can either be cooled or uncooled before mixing with the intake air. EGR tends to reduce the emission of NOx, at the expense of an increase of PM. Sulphur containing fuels (with > 500 ppm S) would exclude the use of cooled EGR, since otherwise corrosion would take place; this would reduce the power output. Furthermore the recirculated exhaust gas would need to be extracted from the exhaust well before the point of water injection.


DOC A DOC or diesel oxidation catalyst is mainly active in the removal of CO and HC, although the emissions of these components are already low anyway in the case of diesel engines. A DOC may also oxidise a significant percentage of the HC-part of the fuel and oil molecules, thereby avoiding part of the particle formation. And a DOC may effectively oxidise the heavy hydrocarbons, such as PAHs, that otherwise would adsorb to the particle. That way the measured PM-emission decreases and the HC-content adsorbed to the particle may be drastically reduced, rendering the particle much less harmful. On the other hand sulphur containing fuels may cause a significant emission of sulphates, which adds to the measured PM load, but also causes significant adverse health effects. To avoid the formation of sulphates a fuel with less than 50 ppm sulphur would be needed. SCR SCR or selective catalytic reduction is a process that, roughly speaking, reduces NOx to N2. This is done by adding a reagent and leading the exhaust gas through a catalyst where the reagent combines selectively with the oxygen atom(s) of the NOx rather than with the O2 already present in the exhaust gas. The reagent used is in principle NH3, but current thinking concentrates on the use of urea, that is easier and safer to store onboard. In the (hot) catalyst urea decomposes, forming the NH3 which is needed for the reduction process. The system requires a urea supply stored onboard, a metering system linked to the NOx-emission level at the operating point concerned, and a safeguard for urea shortage. The automotive world, together with the urea suppliers and oil companies, are currently working on the implementation of an infrastructure that has to supply urea at automotive fuelling stations. This is still in the study phase, however. The urea solution would be marketed under the name ‘ad blue’. The metering system has to link the urea metering to the NOx reduction need: an underdosage would insufficiently reduce the NOx, and an overdose would cause an unwanted emission of unused NH3 (ammonia slip), which would only exchange one environmental problem for another. This requires advanced electronics, and a supply strategy that is either based on a reliable NOx-emission mapping (not affected by the course of time), or on a kind of NOx-sensor, or a combination of both (especially for Euro 5 and later). The presence of urea in the supply tank has to be monitored for the system to operate reliably. Shortage of urea will not in any way affect the operation of the engine, and the user has no way to know if the system is still working, unless through a monitoring/warning system. Additionally, from the point of view of the legislator there needs to be a safeguard that the operator heeds any such warning of a shortage, and does not deliberately run the engine without any urea, either by running with an empty urea tank, or with another fluid (such as water) in it: when he has to pay for the urea, without any personal benefit whatsoever, he is likely to ignore the warning. In the automotive case the use of injection retard and/or some way of reducing the available power are studied as possible options. In marine applications, however, safety considerations would exclude a monitoring system that would reduce the available power or even shut down the engine completely in case of a shortage of urea.


Prototype systems for automotive applications do exist but there is no commercial experience yet. So at this moment actual field experience concerning the functioning or the durability of such systems is still completely lacking, and even more so any experience with monitoring systems as discussed in the previous paragraph. Application on big commercial marine engines as used for inland shipping may be an option when the automotive world has collected sufficient experience, or even before. The application on recreational marine engines would seem to be rather premature, however, in the current situation. DPF A DPF or diesel particulate filter is indeed a filter, catching particulates, rather than a catalytic reactor. The inevitable consequence is that the collected material needs to be removed periodically, since otherwise the filter would clog. In the case of diesel particulates (carbonaceous material) this is done by combusting it. The process is referred to as filter ‘regeneration’. By now the filtering process is well understood and can be performed reliably. The regeneration process is the real bottleneck of the DPF. It needs be reliable, to prevent clogging, but has to avoid run-away soot combustion which might damage the filter. In automotive applications ceramic monoliths are now used for the filters. In contrast to monoliths as ‘carriers’ for a catalyst, a ceramic monolith in a particulate filter has a flow-through function, and hence has to be sufficiently porous. In the past, wire mesh metal has been tried for ‘flow-over’ (rather than flow-through) particulate filters, but they were abandoned in favour of flow-through monoliths. No experience with the use of current automotive type DPFs in marine applications is known. At the very least any current experience with non-ceramic DPFs in marine applications seems to be lacking. Regeneration means combustion of the collected soot. The temperatures needed for such combustion are high, beyond 600 ºC. Such temperatures only occur with special engine control. Automotive manufacturers and system suppliers have therefore stopped relying on spontaneous regeneration in the very early stages of the development. Regeneration has to be provoked and the methods to obtain it can be of different kinds: • Reducing the necessary ignition temperature. This is done either by a catalytic

coating of the filter, or by the use of a fuel additive. Such measures, however, are not likely to lower the temperatures needed to a sufficient degree to guarantee reliable operation. Hence additional engine control such as post injection would be needed. Furthermore fuel additives usually are metallic, and inevitably cause an emission of metallic components, which may be unwanted.

• Increasing the available exhaust gas temperature. The approach currently used in commercial applications is to switch on all available electrical ‘users’ to increase the engine load, and to manipulate the injection timing in a way to cause additional late combustion, which together results in sufficiently high exhaust gas temperatures. Burners or electrical heaters are used as well, but there are no real series applications known.

Actual applications may, and often have to, combine several methods. The Peugeot passenger car system (one of the very few current commercial systems) e.g. uses both catalytic coating on the DPF and a fuel additive. The need for regeneration is determined by monitoring the pressure drop over the filter, and the actual regeneration moment is selected on the basis of a sufficiently high engine load (e.g by performing it during motorway driving). This engine load is then still further increased by switching on all electrical users. At the same time the injection system switches to post injection, which increases the exhaust temperature through late burning. In the resulting increased


exhaust gas temperatures the unburned fuel is oxidised over the catalytic coating of the DPF, thereby finally heating the filter up to beyond the minimum temperature needed for regeneration. This minimum temperature needed had on the other hand already been decreased by the use of the fuel additive. This whole complex of aspects and measures has to combine to create reliable repeated regeneration, although the DPF still has to be dismantled and cleaned from non-combustible ashes and sulphur containing compounds after 80,000 km of running. In contrast to truck applications, engines for marine applications rarely run full load. In practice boat owners have a tendency to have bigger engines installed than they actually need, so the engines run below their maximum, as a rule at no more than about 80 % at the maximum boat speed. Additionally engines may experience extended periods of low load operation, e.g. when they are run for power generation only, when the vessel is moored. Under such circumstances regeneration is likely to be unsuccessful. Eventually this may lead to either clogging of the filter or runaway regeneration once the engine is run under full load again. Smaller marine diesel engines would be more comparable to passenger car diesels, and in such cases practical experience with DPF systems on car engines may eventually lead to improved systems. Widespread use of DPF systems on passenger cars is currently under discussion for the stage Euro 5 (2008/10 and beyond). Until then the practical consequences for the marine sector would seem to be very uncertain.

7.2.5 Comparison with the NRMM Directive Since it seems logical to bring the requirements for marine diesel engines in line with the requirements of the Directive concerning Non-Road Mobile Machinery, The following comparison is made. Table 7.6 shows the emission requirements for the stages II, IIIA for general use, IIIA for engines meant for the propulsion of inland waterway vessels (‘commercial marine engines’), and IIIB. These data are also shown in Table 14.4. Please note that the comparability is somewhat hampered by the fact that not all sets of requirements use the same basis (i.e total engine power versus swept volume per cylinder), or the same power classes in cases where power is the basis. Table 7.6: The emission requirements for the NRMM stages II, III A and III B.

Engine size NRMM II power HC+NOx PM HC NOx PM 19-37 kW 1.5 8 0.8 37-75 kW 1.3 7 0.4 75-130 kW 1.0 6 0.3 130-560 kW 1.0 6 0.2 NRMM III A NRMM III B 19-37 kW 7.5 0.6 37-56 kW 4.7 0.4 4.7* 0.025 56-75 kW 4.7 0.4 0.19 3.3 0.025 75-130 kW 4.0 0.3 0.19 3.3 0.025 130-560 kW 4.0 0.2 0.19 2.0 0.025 cylinder size NRMM III A for inland waterway vessels <0.9 l/cylinder 7.5 0.4 * HC+NOx 0.9-1.2 l/cylinder 7.2 0.3 1.2-2.5 l/cylinder 7.2 0.2 2.5-5.0 l/cylinder 7.2 0.2


As can be seen stage IIIA mainly limits the NOx emissions relative to stage II, although a strict comparison is somewhat hampered by the fact that stage IIIA uses a combined HC+NOx limit instead of the separate limits of stage II. The PM emission is similar, except for the lowest power class where it is reduced from 0.8 to 0.6 g/kWh. The requirements for inland waterway vessels under stage IIIA are generally speaking less stringent for NOx than those of IIIA for general use, but put slightly more emphasis on PM. Stage IIIB is more stringent for NOx than stage IIIA for general use (and significantly more so for the very powerful engines), but especially a full order of magnitude more stringent for PM. On the basis of TNO experience as shown in Table 7.5 it would appear that the NOx level of stage IIIA for inland waterway vessels can be obtained with mechanical fuel injection, although turbocharging may be required on bigger engines. High power density engines, as used in planing boats, would require turbocharging (which they would already have anyway) with charge air cooling. The PM levels should not be regarded as prohibitive for such technology, but may require some retard of the injection timing (resulting in some increase in fuel consumption). The NOx levels of the stages IIIA for general use and IIIB are likely to require electronic fuel injection, and either EGR or multiple injections. The PM levels of stage IIIB would certainly require some kind of aftertreatment. High power density engines would have a higher natural NOx level, and would consequently need more EGR. In that case they would need either more engine swept volume or two-stage turbocharging, to obtain the necessary air for proper combustion (otherwise, with high EGR rates, too much combustion air would be replaced by EGR). These views were confirmed by some manufacturers. Others pointed out, however, that such conclusions are only valid for engines that are derived from basic engines designed for automotive use. In such cases where this is not the case, the basic engine technology would either require more flexible injection strategies, requiring electronically controlled injection, or a basic (combustion chamber) redesign. This would involve significantly higher cost. The requirements of NRMM stage II would not necessitate such measures, since they do not combine a reduction in NOx with a simultaneous reduction in PM, so that recalibration might be sufficient.

CONCLUSION: The maximum attainable emission stringency for inboard diesel engines without aftertreatment, not based on automotive technology, would lie at approximately the NRMM stage II level and for engines based on automotive technology on NRMM IIIA level for inland waterway vessels, in the case of mechanical fuel injection, and at the NRMM stage IIIA level for general use in the case of electronic fuel injection. Lower NOx levels might be attainable by the use of EGR, and possibly some further gain in PM might be obtained by a DOC. But both options would need considerably lower fuel sulphur contents than currently used. The use of aftertreatment, although more realistic from an installation point of view than in the case of outboard engines, would bring serious operational difficulties.


7.2.6 Engines certified for lower emission levels in other regions In Section 13 it is shown that a local regulation concerning the engines to be used on the Bodensee specifies for engines >30 kW considerably lower emissions than the RCD Stage 1 levels (see Figure 13.2). In view of the considerations discussed above, this poses the question if such levels are attainable in practice. As shown in subsection 13.2 there are currently no outboard engines and very few petrol inboard engines that have been actually certified for that level (see Figure 13.7). Very few manufacturers find it economically worthwhile to produce the advanced engines required for such levels for such a limited market, and apparently very few potential owners are prepared to spend the required purchase cost of such engines. In subsection 8.2 we will briefly consider the practical consequences of such a situation.

7.3 Concerning sound emission

A first step in sound control is to distinguish the various acoustic sources and possible sound transmission paths. A way to do this is by making a so-called sound path model. Figure 7.3 shows a possible sound path model for an outboard. Comparable sound path models could be made for sterndrives, inboards and PWCs. Figure 7.3: Possible sound path model of a boat with an outboard engine.

Structure-borne

Airborne

Waterborne


A sound path model provides an acoustic view of a machine or structure, giving insight into the sound sources (squares in figure 7.3), sound generation mechanisms (circles) and the air-borne, structure-borne or liquid borne sound transmission paths from source to receiver (lines). Structure-borne sound consists of structural vibrations travelling though the structure and can be radiated by the structure as airborne sound. The sound path model provides a basis on which sound control measures can be proposed. The model consists of the following elements: • Sound Generation Mechanisms (structure- or fluid-borne): these represent the

physical excitation mechanisms. • Components: these represent those components in an outboard, which are relevant

for sound generation, transmission and radiation. Also sound control devices belong to this group.

• Receivers: this represents the total sound pressure level on receiver locations both above and under water.

• Links between the above elements; − structure-borne (solid green line) − air-borne (dashed red line) − waterborne (blue line)

To decrease the total airborne sound level, sound control measures should be performed on the dominant sound source or its transmission paths.

7.3.1 Air-borne sound emission In the next paragraph all components of the sound path model will be discussed separately. Engine According to the industry, nowadays the knowledge from the technology of automotive engines is applied to engines for recreational craft. This has resulted in quieter engines throughout the years. The industry is of the opinion that a further decrease of the air-borne sound emission of combustion engines is possible, but the limits of the technical feasibility are nearly reached. Some manufacturers use their own flexible suspension system of the engine to decrease the transfer of structure-borne sound to the transom and cowl. However, the effect of this suspension on the total sound emission remains unclear. In PWCs the engine is resiliently mounted. This will decrease the transfer of structure-borne sound from the engine to the PWC body. In this way the PWC body will radiate less airborne sound. Inlet In recent sound studies peaks in the sound level spectrum at cylinder ignition frequency are addressed to the exhaust [Lanpheer]. This is not necessarily correct. Inlets are also known to emit sound at cylinder ignition frequency. Which source is responsible for the sound emission cannot be determined from a simple pass-by measurement. Labyrinth structures on the air inlet are reported to be successful, with reductions up to 14 dB. Again, it is not clear what the effect on the total sound level will be. The air inlet of 2-stroke engines is easier to sound control by labyrinth structures than that of 4-stroke engines. This is because the cylinder ignition frequencies of a 4-stroke engine are


smaller than those of a 2-stroke engine (a factor of 2 smaller in the case of an equal number of cylinders and approximately identical engine speed). Consequently, the wavelength at this frequency is smaller for a 2-stroke engine, which is beneficial for the dimensions of the labyrinth. For 4-stroke engines, larger dimensions would be required. On the other hand engines with less power may have a smaller number of cylinders. This results in lower cylinder ignition frequencies and thus larger wavelengths when compared to other engines with higher power output and more cylinders. Due to spatial reasons the inlet of engines with fewer cylinders is harder to sound control. Cowl The top-end outboard engine models of some manufacturers are lined with absorbing materials on the inside of the cowl. Especially for the high frequency sound emitted by the engine block, reductions are to be expected. The degree of success depends on the sound absorbing properties of the lining and of the applied thickness. For a good sound reduction a right balance between material type and thickness of the cowl, the degree of opening (with or without labyrinths) and the amount of lining material is required. Cowl structure can also radiate structure-borne sound induced by the engine. A relatively thick and stiff cowl structure will have a high radiation efficiency. A resilient decoupling layer between engine support and cowl may have a sound reducing effect. However, further research will be required to quantify this. Exhaust Most exhaust systems used in recreational craft are wet. The exhaust is located underneath the waterline in most cases. Sometimes both exhaust and propeller can lift above the waterline, e.g. during planing condition or at a certain trim angle. Since the measurement quantity used in ISO 14509-1 is a maximum sound level (with 1 s intervals) during a pass-by, the exhaust will be clearly present in the sound spectrum if the exhaust was above the waterline for a short period. Nowadays, for PWCs the exhaust and intake systems are integrated in the structure, allowing more space for (longer) mufflers. This is claimed to have resulted in considerable sound reductions. It is felt by the industry that for inboard engines the sound emission of the exhaust will decrease in the future because of the expected growing need of catalysts. This is only realistic if the exhaust damper will not be changed (e.g. made shorter). Propeller The propellers are designed with a view of efficiency and hull speed. From measurements on cruisers with inboard engines it seems that the propeller shows a relevant contribution to the airborne sound emission [Lanpheer]. Looking at the sound path model this could be explained by the propeller being out of the water for a short period, or by structure-borne sound transmission via the drive train. The application of a highly skewed profile for the propeller blades is known to reduce the pressure fluctuations caused by the propeller. Pinion Pinion gears make a contribution to the total sound level as recorded during a pass-by of sterndrives and outboards. Since the pinion is located underneath the waterline, the sound is expected to be caused by structure-borne sound transmission from the pinions to cowl and hull structure. Sound spectra shown in sound reports [Lanpheer] show that


the effect of the pinions on the total sound level is relatively small. Nowadays helical gears are applied, which are intrinsically quieter than spur gears. Hull The contribution of hull/water sound to the total sound is considerable, especially for higher rated power, even without the presence of engine, pinion or propeller induced vibrations (see towing data in figure 5.4). To reduce the total sound emission further, the water induced hull sound needs to be sound controlled. This is beyond the scope of an engine manufacturer.

7.3.2 Concluding remarks on sound control In the many sound reports were studied for this project, only a few frequency analyses of sterndrives could be found, in addition to a total A-weighted sound level. A detailed frequency analysis is indispensable to trace dominant acoustic sound sources. A simple pass-by measurement is often not sufficient for this purpose. Therefore more strategic air-borne and structure-borne sound measurements are required to further quantify the sound path model. To assess, e.g. if the sound radiation of a vibrating polycarbonate sound cover significantly contributes to the total sound level, accelerometers need to be installed on the cover to measure acceleration levels. In this way the effect of the various sound control measures as described in this chapter, can be quantified. From the few frequency spectra that could be found, exhaust and air intake systems look the most promising for further sound control. However, it is still a fact that great efforts have to be made for a total sound reduction of 3 dB for the engines in the higher power range (P > 40 kW), assuming that hulls are not sound controlled. For outboards in the higher power range a maximum total sound reduction of 3 dB seems feasible without having to sound control the hull structure. For this purpose the contribution of the outboard engine would have to be reduced by at least 6 dB at a power of 60 kW. Much effort will be required to obtain this. A thorough sound path study could indicate the most promising sound sources and sound paths to be sound controlled with sufficient measures. If the total sound reduction is to be 2 dB, the contribution of the outboard engine needs to be reduced by about 3 dB. The relatively high sound reductions of the engines required for the higher power range for a relatively low total sound reduction is explained by the high contribution of the hull sound to the total sound level during a pass-by, as is illustrated by figure 7.4. Figure 7.4: Illustration of the relative contributions of outboard sound and hull sound

to the total sound level.

Outboard engine

Hull

Outboard engine

Hull

Total

P~6 kW P~60 kW

Total


However, as can be seen from figure 5.4, for outboards in the lower end of the power range (P <10 kW), the effect of hull sound on the total sound is smaller. Therefore more benefit from sound control on the lower end engines (2-strokes, engines with less cylinders) can be expected. The total sound level will decrease 3 dB of the outboard engine contribution is decreased about 4 dB at a power of 6 kW. The total sound reductions that can be obtained from a certain sound reduction of outboard and PWC engines for respectively the high mid and lower power range, as defined in 2003/44/EC, are summarised in table 7.6. The numbers are based on figure 5.4 (based on IMEC measurements). Table 7.6: The total sound reductions ΔLp, total that can be obtained from various sound

reductions of outboard and PWC engines (ΔLp,engine) without sound controlling of the hull structure, for respectively the high, mid and low power range in 2003/44/EC.

Type of craft Rated power ΔLp, total in dB ΔLp,engine in dB

-3 -6/-8

-2 -3/-5

P ~60 kW

(High; PN > 40 kW) -1 -1/-2 -3 -4/-5

-2 -2/-3

P~25 kW (Mid; 10 ≤ PN ≤ 40 kW)

-1 -1/-2 -3 -4/-5

-2 -2/-3

Outboard

P~6 kW (Low; PN ≤ 10 kW)

-1 -1

-3 -4

-2 -3

PWC P ~60 kW

(High; PN > 40 kW) -1 -1

For inboard engines and to a certain extent also sterndrives, the sound emission is additionally determined by the boat builder. The design of the engine compartment, (resilient) installation of the engine, foundation structures and exhaust system and suspension all affect both airborne sound and underwater sound emission.

CONCLUSION: If only measures are taken for the engine, the maximum achievable total sound reduction for craft with outboard engines in the higher power range is about 3 dB(A). However, for this purpose the contribution of the outboard engine would have to be reduced by at least 6 dB, which is quite significant. For the lower power range the potential is somewhat higher: a total sound reduction by 3 dB(A) requires ‘only’ 4 dB(A) reduction for the outboard engine, still a significant reduction. Also for PWC’s the required sound reduction of the engine is about 4 dB(A) in order to obtain a total sound reduction of 3 dB(A). Due to a lack of sufficient acoustic data on sterndrives and inboards, useful comparable indicative considerations cannot be made for these types of recreational craft.


Whereas air inlet and exhaust outlet for 2-stroke engines are easier to sound control than for 4-stroke engines, due to spatial limitations, engines with a low number of cylinders require more space for muffler structures when compared to engines with a higher number of cylinders. A thorough sound path study will indicate the most promising sound sources and sound paths to be sound controlled with sufficient measures.

7.3.3 Underwater sound emission Since no sound spectra for underwater sound are available, it is not possible to indicate the most dominating sound sources under water. Further research is required for this. However, from experience with other (not recreational) boats it is to be expected that the propeller and the gear transmission will be important sound sources for underwater sound emission.

7.3.4 Remarks on sound target values and the measurement protocol All measurement results reported are conducted according to ISO 14509-1-1. The industry feels that the current sound targets, see table 5.4, are just right and technical realistic. With the current measurement protocol as per ISO 14509-1, some problems and issues are mentioned:

• The test boat is to be selected by the manufacturer. Hull material selection is free which can affect the hull slamming sound generation.

• The required ambient conditions are hard to find, especially in Europe.

• Consequently, a good engine in combination with a bad boat and unfavourable weather conditions (i.e. wave height) may result in bad test results.

• Within inhabited areas and distances within 300 m from the shoreline, speed limits are valid and engine rpm is sometimes limited to idle speed. Only 300 m or more out of the coastline a speed of 70 km/h is allowed. The sound targets set at 25 m distance with a prescribed speed of 70 km/h seem out of balance with this prohibition.


8 The impact of technological improvements

For the purpose of this study a number of possibilities (options) for a Stage 2 legislation has been investigated. This has been done in the usual way, by defining a number of scenarios that subsequently have been investigated on their impacts concerning: − Air quality − Water quality − Sound (just ashort note) − Economic consequences Three main options were defined for the exhaust emission situation and one for sound, and investigated in this manner. Additionally a few other possibilities were investigated with regard to their impact on exhaust emissions, without further investigation of their other impacts.

8.1 Exhaust emissions

8.1.1 The options for the exhaust emissions For the estimates concerning the impacts of possible technological improvements the following options have been defined for a Stage 2 limitation of the exhaust emissions: Option 1 For petrol engines it is assumed that the 4-stroke limits of Stage 1 will apply to all engines, 2-stroke and 4-stroke, outboard and inboard. This option was selected with the idea to force the best available engine technology (although still without aftrtreatment). It will effectively mean that all conventional 2-stroke engines will be phased out and that the market will concentrate on DI 2-stroke and 4-stroke engines.

For diesel engines it is assumed that for engines with a nominal power of 37 kW or more the limits of the future NRMM Stage IIIA for ‘engines for propulsion of inland waterway vessels’ will apply. This would bring the engines for recreational craft in line with those for commercial use, which would make sense since in the case of bigger engines the same diesel engine manufacturers would produce both. For engines of less than 37 kW the RCD Stage 1 limits would continue to apply, since the NRMM stage IIIA for inland waterway vessels does not include these engines. Many of these engines are produced by marinisers that would convert engines that would originally stem from the automotive market. Option 2 For petrol engines it is assumed that for all engines the emissions of HC+NOx will be limited to 75% of the Stage 1 limit values for 4-stroke engines; this would bring it close to the CARB 2008 limits (which are also considered for future legislation by the US-EPA). Such limits would be at the level of stringency that is just still attainable without a need for aftertreatment.

For diesel engines it is assumed that for engines with a nominal power of more than 18 kW the limits of the future NRMM Stage IIIA for general use will apply. For engines 18 kW or less the RCD Stage 1 limits would continue to apply, since the NRMM Stage IIIA (general use) does not include these engines. For engines of more than 18 kW, but less than 37 kW, the NRMM Stage II limits would apply, as in the


description of the NRMM stage IIIA. This would harmonise the RCD limits with the general NRMM limits as is also contemplated by the US-EPA.

The NRMM Stage IIIB stipulates NOx levels at roughly ¾ (for the smaller engines) to ½ (for the bigger engines) of the levels of the stage IIIA, and PM levels of 0.025 g/kWh. As stated in subsection 7.2.5 for such PM levels aftertreatment is required. The PM levels of stage IIIA are attainable without aftertreatment. Option 2A As an alternative to option 2 it is assumed that in the case of petrol engines the limit values as given under the heading ‘Option 2’ will only apply to engines of 30 kW or more, not intended for PWCs. For engines of less than 30 kW and for PWCs the limit values of option 1 would apply. The intention here is to investigate what the consequences would be of a restriction to Stage 2 that would reduce the economical impact on the smallest engines that are likely to be affected most in an economical sense, but may contribute less to the overall emissions. For diesel engines there is no change from option 2. Option 2B In the course of the economic study (see Section 12) it became clear that for certain manufacturers the two options for the diesel engines presented above would bring significant financial consequences for some diesel engine manufacturers, for very little overall environmental benefit. The Commission then requested that a further option be studied: introducing for the diesel engines the requirements of the NRMM stage II. This was done as a separate substudy and in the Tables 8.1- 8.3 this option for the diesel engines is combined with option 2A for the petrol engines, although any other combination would have been possible as well, of course. This variant is indicated as option 2B. In Table 8.3 the emission consequences for the diesel engines as a separate group are indicated.

8.1.2 Emissions to air In order to calculate the effects of the different options on the overall emissions to air a spreadsheet calculation was set up containing the different numbers of engines per technology and their typical emission factors for each stage and option. The relative shares of different engine types were derived from the data referred to in the Sections 2 and 3 (the fleet and the market). For want or any better data the fleet was assumed to have the same relative shares as the annual sales. The shares of the different power classes and that of the technology shares per power class were derived from Icomia sales data. The 1996 data were taken as representative for the 1995 fleet (no earlier data were available), the forecast 2006 data were accordingly taken to reconstruct the 2005 fleet and the 2010 data were taken to represent the 2015 fleet (no later data were available). The 2006 and 2010 data were, of course, projections. In addition to the Icomia data it was assumed that in the case of a Stage 2 the conventional 2-stroke engine would disappear; the remaining share (mainly in the very small engine powers) was redistributed over DI 2-stroke and 4-stroke technology. The shares of inboard petrol and diesel engines were derived from the industry data referred to subsections 3.3 and 3.4. This resulted in the figures of Tables 8.1 and 8.2. The contributions of petrol and diesel engines are shown in Table 8.3 below:


Table 8.1: The calculated emissions for the various stages and options. Based on the most credible estimates of the fleet size, and on reconstructed emission data.

Stage option fleet CO kton/y

HC kton/y

NOx

kton/y PM

ton/y Stage 0 1995 124 70 6.7 121 2005 144 82 7.8 140

Stage 1 2005 70 9.8 7.4 88 2015 77 10.8 8.1 97

Stage 2 option 1 2015 77 5.6 8.7 97 option 2 2015 59 4.2 6.1 91 option 2A 2015 64 4.7 6.5 91

option 2B 2015 64 4.8 7.2 95 Table 8.2: The calculated relative emissions for the various stages and options. Stage scenario fleet CO

kton/y HC

kton/y NOx

kton/y PM

ton/y Stage 0 1995 100 % 100 % 100 % 100 % 2005 116 % 116 % 116 % 116 %

Stage 1 2005 56 % 14 % 110 % 73 %

2015 62 % 15 % 122 % 80 %

Stage 2 option 1 2015 62 % 8 % 130 % 81 % option 2 2015 47 % 6 % 91 % 76 % option 2A 2015 52 % 7 % 97 % 76 % option 2B 2015 52 % 7 % 108 % 79 %

Table 8.3: The calculated emissions for the various stages and options, for the petrol

engines (mainly outboard engines) and the diesel engines (almost exclusively inboard engines)

stage and fleet

option fuel CO kton/y

HC kton/y

NOx

kton/y PM

ton/y Stage 0 petrol 124 70 1.25 1995 diesel 0.68 0.48 6.78 121

Stage 1 petrol 70 10 4.6

2005 diesel 0.44 0.14 2.8 88

Stage 1 Petrol 77 10.7 5.0 2015 diesel 0.48 0.15 3.1 97

Stage 2 option 1 petrol 77 5.5 6.5

2015 diesel 0.39 0.13 2.2 97

option 2 petrol 58 4.1 4.8 diesel 0.39 0.11 1.3 91

option 2A petrol 64 4.6 5.2 diesel 0.39 0.11 1.3 91

option 2B Diesel 0.39 0.16 2.0 95 For the diesel engines option 2B would result in a reduction of the NOx with about a third relative to Stage 1, and still some 10 % relative to Stage 2 option 1. The few percent difference in PM emission in Table 8.4 relative to that of Stage 2 option 1, is fully caused by the assumptions made for the actual emissions and actually falls within the margins of accuracy of the calculation.


About the absolute numbers it must be pointed out that such calculations of necessity have to contain a large number of estimated data. Especially the size of the fleet is a large unknown quantity. Even so the figures may serve to give an impression of the order of magnitude. Since the emission factors, and especially the regulated ones, can be much better estimated, and if the size of the fleet is handled with some consistency, the relative effects in fact do represent a greater degree of accuracy than the absolute numbers. When the figures are compared with those of the document COM (2000) 639 final, as shown in table 4.1, some significant differences are apparent. Table 8.4: Comparison of the current calculations for the baseline (Stage 0) and

Stage 1 with the earlier calculations. Stage and fleet

scenario fuel CO kton/y

HC kton/y

NOx

kton/y PM

ton/y Stage 0 COM(2000) 639 petrol 154 65 3.42 1995 diesel 0.87 0.48 6.78 544

Stage 0 This report petrol 124 70 1.25

1995 diesel 0.68 0.48 6.78 121

Stage 1 COM(2000) 639 petrol 88 6.9 6.0 2005 diesel 0.82 0.37 4.7 385

Stage 1 This report petrol 70 10 4.6

2005 diesel 0.44 0.14 2.8 88

The main discrepancy seems to be in the PM emissions (of the diesel engines) and the NOx emissions of the petrol baseline; some lesser discrepancies are notable in the other NOx emissions and the CO emissions. These differences can be attributed to differences in the input to the calculation. The main cause of this is the fact that Icomia, who made the earlier calculation, did at that time not possess very detailed figures. So they had to make a rather ‘rough’ approach and had to replace missing data by reasoned guesses. For the current study, with further help by Icomia, an improved approach proved possible, even if (as pointed out above) the situation is still far from ideal. The main differences are: The current calculation was made with much more differentiation between classes

and sizes of engines. The current calculation could rely on a dataset of actually measured emission data

for the Stage 0 engines. More, and more up to date, data are available for diesel engines. There is a clearer picture with regard to the likely shifts in technologies for the

Stage 1 and possible Stage 2 situations. Concerning the emission data: the dataset used for the current calculations was generated for the purpose of doing a similar calculation for the German situation, whereas the (much smaller) dataset that went into the earlier calculation had been put together from measurement data that at the time happened to be readily available at a small number of manufacturers. Furthermore: when the emission data are compared the impression exists that these data represented the emission situation at a much earlier date, possibly the late eighties. The current dataset looks like much better representing the current situation of pre-stage 1 engines. This is especially true for the PM emissions of diesel engines. With regard to the petrol engines the differences would be explainable by the assumption that modern engines run considerably less rich than before. This means that the ‘baseline’ of the calculations presented here is essentially a different one from that in COM(2000) 639 final.


Concerning the diesel engines mention should be made of another aspect. As stated before they are derived from engines designed for other applications, like road transport or NRMM. In those fields an ongoing legislation is already present. This means that design changes needed for those applications eventually, even if with some time lag, will also find their way into the marine engine field. If, on the basis of that fact, realistic emission factors are estimated for current and future generations of marine diesel engines the conclusion seems to be that, as long as engine design is going to be the main parameter, the emission situation will hardly be driven by the marine diesel engine emission legislation. On the other hand it was pointed out by some manufacturers that this conclusion has limited validity for manufacturers that do not base their marine engines on engines designed for automotive use. In such cases the estimates for the actual emissions under options 1 and of Stage 2 might show a too optimistic level. For this reason option 2B has been added, which in any case would produce more legislation driven emission levels. In any case when aftertreatment will be introduced on diesel engines for non-marine applications the situation will significantly change. In the assumptions made for the current calculation it is assumed that no aftertreatment will be needed. Figure 8.1: graphical representation of the emissions for the different stages and

options. All stage 2 options for the 2015 fleet size. Total emissions to air in Europe

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

CO HC NOx PMcomponent

rela

tive

emis

sion

baseline - 1995baseline - 2005stage 1 - 2005stage 1 - 2015stage 2 - scen 1stage 2 - scen 2stage 2 - scen 2Astage 2 - scen 2B

Total emissions to air in Europe

0

20

40

60

80

100

120

140

160

CO HC NOx PMcomponent

em

issi

on [k

ton/

y, P

M =

ton/

y]

baseline - 1995baseline - 2005stage 1 - 2005stage 1 - 2015stage 2 - scen 1stage 2 - scen 2stage 2 - scen 2Astage 2 - scen 2B

Tables 8.1 and 8.2 and Figure 8.1 show the results that would be obtained with the scenarios presented here. As can be seen the ‘loss’ incurred by limiting option 2 to engines >30 kW in the case of petrol engines (option 2A) is very limited indeed. The same is true for the ‘loss’ cause by option 2B relative to options 2 and 2A. Another


observation is that, whereas in Table 4.1 the emission of NOx increased from the baseline to Stage 1, due to the shift in technology for petrol engines caused by that legislation (replacement of conventional 2-strokes by 4-strokes and DI 2-strokes), the current calculation shows in fact an overall small improvement. This improvement is fully caused by a bigger reduction in NOx from diesel engines, even in the case of option 2B. In any case the emission of NOx is low in absolute terms, as can be seen in Table 8.1 and Figure 8.1. The very large reduction in HC (> 80 %) should be regarded as worth the price of a small absolute increase in NOx in the case of petrol engines, even apart from the larger reduction on the diesel engine side, since a compensation of that increase is easier to find elsewhere, than a comparable reduction in HC would be if such a shift in technology would not take place.

8.1.3 The contributing classes of engines So as to illustrate the classes of engines that contribute to the overall emission patterns, the contributions were calculated of the outboard and inboard engines with different technologies.These contributions are shown in Figure 8.2. Figure 8.2: The contribution of he various engine classes and technologies in the

overall emission picture. Stage 0 engines

0.0

0.2

0.4

0.6

0.8

1.0

1.2

CO HC NOx PM

component

frac

tion

outb. 2soutb. DI 2soutb. 4sinb. Petrolinb. Diesel

Stage 2A engines

0.0

0.2

0.4

0.6

0.8

1.0

1.2

CO HC NOx PM

component

frac

tion

outb. DI 2soutb. 4sinb. Petrolinb. Diesel

Stage 1 engines

0.0

0.2

0.4

0.6

0.8

1.0

1.2

CO HC NOx PM

component

frac

tion

outb. 2soutb. DI 2soutb. 4sinb. Petrolinb. Diesel

Stage 2B engines

0.0

0.2

0.4

0.6

0.8

1.0

1.2

CO HC NOx PM

component

frac

tion

outb. DI 2soutb. 4sinb. Petrolinb. Diesel

As can be seen in the Stage 0 situation most of the CO and HC was coming from 2-stroke outboard engines, and most of the NOx and PM from inboard diesl engines. The introduction of Stage 1 legislation is expected to bring an increased share of DI 2-stroke engines, and a much increased share of 4-stroke engines. This is immediately reflected in the contribution of this technology to all components except PM. The apparent increase in the relative contribution of inboard petrol engines is completely caused by the large decrease in absolute numbers of the emissions of CO and HC of outboard engines, and the assumed significant decrease of NOx from inboard diesel engines. In the Stage 2 (option 2A) situation the emission of CO, HC and NOx is dominated by the 4-stroke outboard engines, due to their large share in the overall picture, and still by the diesel engines in the case of PM. Inboard petrol engines play a modest part.


8.1.4 Further reduction by catalyst A limited scale study was made of the possible emission reduction that might be obtained by the use of a small oxidation catalyst on petrol engines. The conversion efficiency of such a catalyst is usually indicated as about 60 % for HC, which is regarded as the main component of interest for reducing the contamination of surface water. Since this will be the efficiency of a new (although ‘run-in’) catalyst, it is assumed that an aged catalyst at its half-life point (assuming that this represents its average lifetime performance) will not exceed 50 %. It was further assumed that such a catalyst will not effectively reduce the emission of an engine that is just used as an auxiliary on e.g. a sailing boat that only uses it to get out of or into the harbour or marina, since in such cases the engine would already be switched off again by the time the catalyst had reached its operating temperature. Variants of this option assumed that the catalyst would not be required on engines of less than 30 kW and/or that it would only be required on (petrol) inboard engines. Figure 8.3: The effect on the total HC-emission of a more stringent legislation for

inboard petrol engines requiring oxidation catalysts.

Given the somewhat crude assumptions concerning the number of engines involved, that had to be made, no exact figures will be given here, but a graphical representation is shown in Figure 8.3. Generally speaking the application of such an oxidation catalyst on all petrol engines (outboard as well as inboard) would result in a further reduction of HC in the order of 40 %; a few percent more if all engines are involved, and somewhat less if only engines of 30 kW or more are involved. In absolute terms this would amount to something like 1.3 kt/year on the basis of the figures in Table 8.1. If the provision is only required on inboard engines (including those installed in PWCs), since the possibilities for catalytic aftertreatment are better in those cases, the overall reduction would be in the order of 10 %, again somewhat less if engines of less than 30 kW are exempted and somewhat more if they are not. Over the whole of Europe this would amount to something in the order of 0.30-0.35 kt/year. This is in the order of ½ % of the baseline emission. A closed loop 3-way catalyst (in fact only possible on 4-stroke engines) on inboard engines would of course never be able to do more than double this figure (i.e. in the case of a 100 % conversion efficiency instead of the 50 % assumed here). The reason for this very small improvement is, of couse, the very limited number of petrol inboard engines in the European fleet, resulting in a limited overall contribution, as already illustrated in Figure 8.2 above. It will be clear therefore that in Europe such an additional requirement for inboard engines, over the one already being assumed for all petrol

oxidation catalyst on petrol inboard engines

0.0

0.2

0.4

0.6

0.8

1.0

option 2A 2A + oxicaton inboard

2A + oxicaton inboard

>30 kWoption for stage 2

Rel

ativ

e H

C-e

mis

sion

stage 1


engines, will not substantially contribute to cleaner air or water. If it will nevertheless be advisable in view of a harmonisation with US legislation is a political question which falls outside the scope of a technical investigation.

8.2 Emission trends

So as to give an idea as to the trends in HC-emissions as a result of the various legislative stages, a spreadsheet calculation was set up. This resulted in the trends as shown in Figure 8.4. Figure 8.4: Calculated HC-trends for the overall European fleet without a Stage 2

and with Stage 2, option 2A.

Figure 8.5: The effects of a strong limitation for all petrol engines >30 kW, and of a

resulting ‘buyer’s strike’ for that category (the ‘Bodensee effect’).

The emission factors used are those shown in Appendix C, and used for the calculations of the Tables 8.3 and 8.4 and Figure 8.1. The assumed sales are as known up to 2003 and projected up to 2010, according to Icomia figures. They seem to suggest a stabilisation of the sales after 2000. The lifetime of an engine was taken as 20 years. The introduction date of Stage 2 is set at 2010. The long duration of the downward slope is caused by the assumed 20 years average lifetime.

HC emission of the fleet

0

25

50

75

100

2000 2005 2010 2015 2020 2025

Year

tota

l HC

-em

issi

on

[kt/a

nnum

] Stage 0 / Stage 1Stage 2 option 2A

HC emission of the fleet

0

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30

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2010 2015 2020 2025

Year

tota

l HC

-em

issi

on

[kt/a

nnum

]

Stage 1Stage 2 option 2Aditto + 3-way cat'Bodensee effect'


By way of illustration two more variants were investigated. Variant 1 assumes that for Stage 2 3-way catalysts would be introduced on all petrol engines >30 kW (that is: including outboards), just ignoring the question if that is a realistic option. And variant 2 assumes that for that reason no new outboard engines >30 kW will be sold after 2010, except as needed for maintaining the size of the fleet, i.e. as replacement of engines that somehow are no longer serviceable, meaning that other Stage 0 and Stage 1 outboard engines >30 kW are not going to be replaced This is indicated as ‘the Bodensee effect’. The results are shown in Figure 8.5.

8.3 Emissions to water

The calculations of subsection 4.6 were repeated for the Stage 2 options, for the EU fleet only. So as to make the impact of a possible Stage 2 more explicit, the calculations were all made for the 2005 fleet size. Table 8.5: Estimated relative emission intensities per day (Stage 1 = 1.00) for the

compounds of Table 4.10 per stage and option. EU-fleet, 2005 size. Stage benzene naphthalene toluene xylenes formaldehyde Stage 0 8.04 4.20 8.07 8.06 7.77 Stage 1 1.00 1.00 1.00 1.00 1.00 Stage 2 (1) 0.46 1.20 0.46 0.46 0.51 Stage 2 (2) 0.34 0.74 0.34 0.34 0.35 Stage 2 (3) 0.39 0.83 0.39 0.39 0.39

Table 8.6: The modelled concentrations for benzene and naphthalene. Stage benzene

concentrations naphthalene

concentrations water sediment water sediment µg/l ng/kg (wet) µg/l µg/kg (wet)

Stage 0 1.1-4.6 0.54-2.18 0.070-0.080 0.48-0.62 Stage 1 0.14-0.57 0.11-0.44 0.017-0.021 0.24-0.31 Stage 2 (1) 0.07-0.26 0.03-0.13 0.020-0.025 0.11-0.14 Stage 2 (2) 0.05-0.19 0.03-0.10 0.012-0.016 0.10-0.12 Stage 2 (3) 0.05-0.22 0.03-0.13 0.014-0.018 0.10-0.12 MAC-EQS 49 80 ditto (dw) 1.7 < 0.20 MPC (NL) 240 1000 1.2 0.1 In the Stage 2 options the MAC-EQS for benzene is avoided by three orders of magnitude, whereas the one for naphthalene is avoided by more than three orders of magnitude, in all cases. This means that there is not likely to be a problem caused by boating activity anywhere. The graphs give no indication, of course, about other possible sources, but even then the contribution of boating could not make a serious difference.


Figure 8.6: The concentrations of benzene and naphthalene in water for the various

stages and options. EU fleet, 2005 size. benzene

0.00

0.02

0.04

0.06

0.08

0.10

stage 0 stage 1 stage 2-1 stage 2-2 stage 2-2A

stage and option

rela

tive

conc

entr

atio

n M

AC

-EQ

S =

1

Max value

Min. value

Ave. value EQS drinking water

naphthalene

0.0000

0.0005

0.0010

0.0015

0.0020

0.0025

stage 0 stage 1 stage 2-1 stage 2-2 stage 2-2A

stage and option

rela

tive

conc

entr

atio

n M

AC

-EQ

S =

1

Max value

Min. valueAve. value

EQS drinking water

The concentrations as calculated here are at or below the level of the MAC-EQS for drinking water in the case of Stage 1 emissions and significantly below the MAC-EQS for drinking water in the case of Stage 1 and later emissions. Given the closeness of the calculated concentrations to the MAC-EQS in combination with the spread in results that one would get for different lakes and situations, this might mean that in some places there may be a problem, whereas in other places recreational boating of this intensity might even be possible in the vicinity of an intake for drinking water production. In actual fact it should be borne in mind that the situation modelled (shallow lake in combination with very intensive boating) means that for the drinking water aspect this is an absolute ‘worst case’ situation. As stated in subsection 4.6 (last paragraph but one) the extraction of raw water for drinking water production is likely to be done in deeper lakes where the concentrations will be lower and/or the extraction will be done at greater depth, with the same effect. If such water extraction has nevertheless to be made in a shallow lake, a restriction of the intensity of boating would seem to be the most obvious way to avoid any water quality problems. So, although for drinking water there still might be a risk in some exceptional cases, for other situations there is absolutely no problem with water quality. Concerning the quality of sediment, the naphthalene concentration in sediment remains marginal, especially in combination with other sources, although exact statements cannot yet be made, because of a lack of criteria. Furthermore, naphtalene emissions are to a significant extent caused by diesel engine HC-emissions. It should be pointed out that


in order to make the calculations more discriminating in this sense, a high share of diesel-engined boats was specified for the model input.

8.4 Sound emission

Technological possibilities to reduce the sound emission are discussed in subsection 7.3, while the possibilities to reduce the exhaust emissions from subsection 7.2 could also have an effect on the sound emissions of recreational craft. The acoustically relevant improvements in that area could be the use of 4-stroke instead of 2-stroke engines and in theory the application of catalysts. Though there is often a spectrum difference in the sound between 2-stroke and 4-stroke engines, the sound levels as such are not essentially different and that spectrum difference may only be of marginal influence on the sound propagation. The use of a catalyst in itself can have a clear positive influence on the exhaust sound, but this is normally compensated by adjusting the applied silencer accordingly. Thus the only technological improvements that need to be considered are those aimed at lowering the sound emission of the craft. Two global scenarios seem possible from Section 7. One possibility is to aim at an overall reduction of the emission so as to reduce the sound impact proportional. To reduce the sound impact by a small amount as 3 dB(A), see the estimated current sound impact in table 5.5, it means a reduction of the sound emission of the PWC engines and outboard engines by at least 4 dB(A) up to about 8 dB(A) for the outboard engines with higher power. Another possibility is to aim at a reduction of the sound contribution of the engines, say by 3 dB(A). That would results in an overall reduction of the sound impact by craft with inboard engines and PWCs of only about 1 to 2 dB(A). Larger reductions of the sound impact than by these small amounts can be reached by appropriate limitations in use and speed of craft. For many types of craft an effective reduction of the sound levels would require well-balanced efforts for the engine, the craft design and the hull.


9 Durability and related issues

9.1 Introduction

For a legislation to be effective, a type approval scheme is not always sufficient. Depending on the details of the measures needed to comply with that legislation durability issues may have a significant influence as well. Generally speaking, emission durability issues involve both the durability of the design, as supplied by the manufacturer, the ageing of (aftertreatment) systems and the maintenance performed by, or on behalf of, the owner. In this Section we will first look at the legal approach as traditionally applied in some other sectors, to show the ‘maximum’ possible enforcement system. Then we will look at the actual need for each of the elements in the case of engines for recreational marine use (subsection 9.5), and finally at the realistic possibilities for such a check in that sector (subsection 9.7).

9.2 Description of an all-including legislative system

Since the first and oldest exhaust gas legislation is that involving passenger cars, the description of a system that does possess all possible elements will be illustrated using the car legislation. A ‘complete’ enforcement system then would contain the following four different elements: • A type approval procedure • A system to verify the conformity of production (CoP) testing • A system to verify the in-use compliance (IuC) control • A system to regulate a periodical inspection (in the automotive world known as

‘roadworthiness testing’: RW) Their function and set-up will be discussed one by one. We like to point out though that the important point is whether any kind of such verification will be carried out, independent of how it is performed, who will do it, or who is responsible.

9.2.1 The type approval test The function of a type approval procedure is to check if a new product does fulfil all its legal requirements. The test and the related procedure are described in detail in the relevant Directive. The set-up of the test (or tests) is designed so as to check all the relevant aspects of the product, in this case its emission behaviour, under simulated conditions of use. The test is usually performed on a preproduction prototype of the product. The legislation requires that the product does not exceed certain limits during the test. In the automotive case a Type Approval Authority (TAA) either performs or witnesses the test, or it issues a Type Approval (TA) on the basis of a ‘self certification’ test by the manufacturer. When the product has demonstrated its acceptability relative to the legal requirements it receives a registered type approval (TA), which is communicated to the other Member States of the EU (in the case of an EU type approval) or the other signatories of the Regulation (in the case of e.g. an ECE type approval). These other Member States or signatories accept the TA issued by the national type approval authority (TAA) that performed the type approval test. The TA has the status of a ‘licence to sell’ for the product in the markets concerned. This licence to sell is granted on the understanding that the manufacturer will guarantee the conformity of the products sold to the one that was tested.


When it would be established that such conformity would be lacking, the TAA could in principle suspend or withdraw this licence to sell and/or request adaptation of the products already sold and the products further to be sold on the basis of this TA. Within the existing system of mutual recognition of type approvals, it is only the TAA that originally issued the TA who can take such action.

9.2.2 The conformity of production test The CoP test has the function to check if the products that leave the production line do sufficiently conform to the one that was type tested. In principle this is an in-house procedure of the manufacturer, performed before the product leaves his hands to be delivered to the customer. In the current European automotive legislation the TAA has a ‘obligation to audit’ to satisfy himself if such checking is actually done with sufficient regularity by the manufacturer. In its most complete form a CoP test would be a complete functional repetition of the type test procedure. Since this may render the product insellable, or at least ‘used’ and hence only sellable at a reduced price, such testing can often only be performed on a reduced sample. As an alternative or additional procedure the conformity of certain specifications may be checked, by way of substitute. It does depend on the exact characteristics of the product and its behaviour whether this is a viable alternative. If the audit concerning the CoP testing would show that the conformity of the production is not guaranteed the TAA will certainly demand modifications to the product that will restore this conformity. Depending on how serious the non-conformity turns out to be, he may suspend the TA until such modifications have been realised in the production.

9.2.3 In-use compliance testing In-use compliance testing is meant to check the durability of the compliance of the product under actual conditions of use, in the customer’s hands. It is part of the durability paragraph in the legislation. In the automotive legislation for legal reasons the IuC was introduced as ‘conformity in use’, as a subparagraph of the conformity of production paragraph. In the case of the automotive legislation the durability aspect is approached in a number of different ways. The US legislation introduced durability when catalysts were appearing on the market. The durability of the low emission behaviour of cars suddenly became very much dependant on the durability of the catalytic aftertreatment system, which in turn depends on the durability of the catalyst itself and of the closed loop fuelling control system. The first step in this approach was to require a 50,000 mile durability test as part of the type approval procedure. This was an expensive and time-consuming procedure (approx. 3 months running on a fully automated test bed). The function of this durability test, however, was only to establish the degree of ‘ageing’ of the system. The test would result in ‘deterioration factors’ for each emission component. The requirement was then that the emissions measured during the type approval procedure, multiplied by their individual deterioration factor (df) still had to comply with the legal limit. This would guarantee that even with the ‘natural’ ageing of the system the emissions would continue to comply with the legal limits. It should be noted that, since the deterioration was


assumed to have a linear effect over the useful life of the system, the deterioration was established over the ‘half life’ of the car. Compliance with the limits over this half-life would then mean that the system would comply on average over its full life. Since the car was supposed to have a useful life of 100,000 mile, the durability was checked over a total of 50,000 mile, or 80,000 km. Later initiatives to extend the period, since the fully linear progression of the deterioration began to be doubted for cars of more extreme mileage, were logically combined with higher limits for the second half of the vehicle’s lifetime. They were meant to guarantee the linearity. The European legislation approached the ageing aspect by introducing flat rate deterioration factors. This gave the manufacturer the choice between the use of these flat rate factors, or establishing his own characteristic df, when he felt that these would be more favourable. Such an approach obviously requires that the flat rate df is on the unfavourable side of the spread, but although a discussion is possible whether this is actually the case, as a fundamental approach it is sound, since it will remove unnecessary expensive testing when the system behaviour is sufficiently well within the legal limits. Dutch IuC testing has repeatedly shown that although the deterioration in practice significantly exceeds the flat rate factors, the initial performance of the system is usually so good that the systems still comply after their legal half life. It may be mentioned that at the time when this system was under discussion there also was an initiative to determine the system deterioration by means of an accelerated ageing test. And although in the end it was not adopted, it is as such a sound approach as well: any catalyst manufacturer does use such an accelerated test for in-house testing. But the durability of a catalytic system has two distinctly different aspects: system ageing, causing relatively slow but steady and reasonably predictable deterioration of the system, and the possibility of catastrophic failure. In the early days of catalytic systems in the automotive field such catastrophic failures did occur on the European market. The general impression is, however, that they occur far less frequently nowadays. Nevertheless the way to find both such possible failures and the real-life extent of the normal deterioration is to test the emission performance of cars in the field. This is called in-use compliance testing. IuC testing can be done by the manufacturer himself, by the TAA that issued the TA, or by any other Member State. In principle, of course, anybody has the right to test; the relevant question is more: who has the obligation to test. And the underlying question of that one is: who pays for that testing. In the current automotive legislation the basic obligation lies with the manufacturer. He has to guarantee that his product has the required durability, and on request he has to demonstrate that to the TAA. That means that he has to do his own IuC checking, for which the Directive gives only rough guidelines. And the TAA performs an audit on such checking. Only when the confidence of the TAA in the manufacturer’s quality control (or his sincerity) has completely broken down, would the TAA be authorised to do his own IuC testing at the manufacturer’s expense. Apart from that the TAA, or that of any other Member State, would always have the right to do his own checking at his own expense, and some Member States do run their own extensive programmes in this field. When such checking does result in any relevant findings, only the original TAA is authorised to take measures. Another Member State that has found any irregularities has to inform the Member State that issued the original TA, who then has the obligation to react within a certain period of time, and to communicate that to the Member State that raised the issue.


When in the course of an IuC check any irregularities are noted, the TAA has to ask the manufacturer for a ‘remedial plan’, which basically involves modifications to his production so as to avoid any further future infringements, and in principle also modifications to the products already delivered to the market, if the irregularity (degree of exceeding the limits) would require that. Whether this will involve a public recall, or a free of charge modification whenever the owner of such a vehicle reports to his garage for a regular service (termed a ‘silent recall’ in the Dutch programme) will be part of that remedial plan and the resulting agreement between the TAA and the manufacturer involved. Since the IuC is meant as a check on the durability of the product as delivered by the manufacturer, a necessary condition is that any non-compliance is established beyond reasonable doubt as the responsibility of that manufacturer. That means that lack of maintenance or any gross improper use of the product by its owner needs to be excluded. Usually in-use procedures describe in some detail which cars are acceptable for IuC testing and which should be excluded. It means, however, that the maintenance required and the possible types of improper use are clearly described in the owner’s manual.

9.2.4 Periodical inspection Periodical inspection is meant to check the responsibilities of the owner/user rather than those of the manufacturer. This includes regular servicing and maintenance, the absence of any ‘tampering’ and possibly the exclusion of improper use of the product that might affect its emission performance, or restoring the original performance of the product after such use. In the case of cars the technical set-up of the periodical inspection, known as ‘roadworthiness testing’, is regulated in the relevant Directive, but it is left to the Member States to legislate the organisational aspects. As a rule the main objective of a periodical inspection concerns safety aspects, but in the case of passenger cars emission aspects have been included. The organisational aspects concern such aspects as the age of the vehicle at which it has to be inspected for the first time (e.g. 3 years) and the frequency of inspection thereafter (e.g. annually or biannually). It also stipulates whether the inspections are performed by a central organisation or by a decentralised system (authorised garages), or by a combination of both. In the case of a decentralised system it will contain a quality control approach concerning the inspection stations. In any case it will contain a monitoring approach allowing a central registration authority, and/or the police during a roadside inspection, to check whether the inspection has taken place (and if the vehicle did pass it), and the sanctions for not having it performed. In some Member States using a decentralised system, authorised garages offer the annual inspection free of charge when combined with a regular periodical service. Since the main purpose of the system is to act as an incentive for such regular service, this functions quite well. Some Member States combine the annual inspection with a system of roadside checks that are performed in the same technical way. And since the main object of the system is to guarantee regular servicing and maintenance, at least one country (not an EU member) uses an alternative approach by requiring an on-board ‘log-book’ to be present on the vehicle at all times, in which the maintenance is recorded by the garage that performs it (stamped and signed by an authorised person). This logbook can then be checked by roadside inspections on which occasion the necessity for maintenance can be checked against


the latest maintenance recorded. One interesting aspect of such a system is the fact that the maintenance may be linked to kilometrage rather than time.

9.3 The situation for recreational craft

For recreational craft the situation is less rigidly controlled. The certification is based on the “New Approach”, which means that the role of the Type Approval Authorities of Member States has been replaced by an involvement of ‘Notified Bodies’, and that the process lies in the hands of the manufacturer to a larger degree. There must still be a kind of type approval for the engines, followed by a procedure for the checking of the Conformity of Production, but there are several ways to do this. Nevertheless it is useful still to understand the four different steps in the process that, although the responsibilities have been redistributed, still aims at the same result: acceptable emission performance of engines in the field during their lifetime. The process as applied in the RCD is discussed in Section 15. As appears from the overview in that Section, for the exhaust emissions the minimum requirement is an EC type-examination in combination with any of the modules C-F. It should be noted that in this way it contains essentially only the elements ‘first approval’ (formerly: Type Approval) and ‘conformity’ (formerly: Conformity of Production). Hence the aspect of durability is addressed in subsections 9.4 – 9.7 below.

9.4 Durability in the case of recreational craft propulsion engines

In the case of pre-Stage 1 engines, or Stage 1 engines, durability was and is no big issue. The sensitivity of the basic design for deterioration is not big, as long as there are no special components that do have a bigger than average chance of failing and do have a significant influence on the emission performance when they do fail. By the very nature of the market, marine engines lag behind the automotive sector in their degree of sophistication (and hence sensitivity). They are to a larger degree based on tried design principles, making them more robust. Moreover at this level of technology any deterioration would sooner result in affecting the performance than the emissions, and thereby would cause the owner to take remedial action. The number of operating hours per season is low and hence maintenance of the engines is often infrequent. Boats themselves are seen as an investment and are usually meticulously maintained, but this is not habitually extended to their engines. Usually maintenance is performed annually, some time during the off-season. An increasing number of owners, especially of bigger boats, have the maintenance done by professional people like dealers or specialised maintenance firms. The others still do their own maintenance, although like in other sectors this is becoming increasingly impossible for modern engines. Obvious things like filters and lubrication oil are changed on a kind of regular, although often infrequent, basis. Engine parts are likely to be used until they break or otherwise stop functioning. For inboard engines, especially in small boats, the inaccessibility of the engine often prevents owners to give the engine a thorough check at regular intervals. In cases where lack of maintenance could bring serious safety risks (such as operation at sea, see subsection 10.1.7) owners may be more conscientious about it. On the other hand, with the tendency of manufacturers to design for an extension of the required maintenance periods, maintenance is quite likely to be performed well in time, even more often than the actual number of operating hours would require. See further Section 11.


Components that might change that situation are mainly added electronics and aftertreatment systems. Electronics have the problem that their operational reliability is difficult to guarantee in a wet environment. Electronics are, to a certain extent, already present on the bigger engines, especially the DI 2-strokes, for ignition and (where applicable) injection. Manufacturers are reluctant, though, to introduce (or extend) their use on smaller engines, because of cost aspects. More electronics would mean either more cost or cheaper electronics (or more simple ‘wetproofing’), creating potential reliability problems. When given time, electronics are likely to filter down from the bigger engines to the smaller ones, but a need for a ‘sudden’ introduction on all engines would have to cope with the existing lack of experience in the small engine segment. On the point of durability, which is the subject of this section, failing electronics would not endanger the emission performance when they affect the very operation of the engine, but they would when their failure would affect the emission performance only, in whatever way. The relevant aspect in this case is failure, however, rather than ageing. The introduction of aftertreatment systems would introduce an inevitable ageing effect, causing a gradual deterioration of the emission performance. Secondarily an aftertreatment system can fail, as the early applications in the automotive field have clearly shown. And although the automotive lead has resulted in much general experience, as pointed out in subsection 7.2.3 and Section 10 there are a number of special operational aspects about which there is no practical experience. These considerations would seem to lead to the conclusion that the introduction of aftertreatment systems would create a greater need for some kind of durability control.

9.5 The need for durability control

In order to obtain a feeling about the possible effect of an In-use Compliance system and a periodical inspection, the following data are derived from a study on the possible effects of an IuC and a road-worthiness test on the European motorcycle fleet [Ntziachristos]. Table 9.1: The calculated cumulative effect of an IuC for Euro 3 motorcycles, as a

percentage of the total motorcycle emissions. Period 2006-2012. Source: Ntziachristos.

CO exhaust HC

NOx

2-stroke 0.002 % 0.006 % 0.023 % IuC on all bikes 4-stroke 0.035 % 0.026 % 0.120 % 2-stroke 0.0004 % 0.001 % 0.005 % IuC on large volume bikes only 4-stroke 0.007 % 0.005 % 0.024 %

The study assumed levels for Euro 2 and 3 emission legislation that involves aftertreatment, whereas on Euro 1 some motorcycles would have aftertreatment and others would not. The study assumed that IuC would become effective as from 2006 for all Euro 3 motorcycles, and that 3 % of the newly registered vehicles would be defective, with an average exceeding of the limits by 20 %. Based on the current car experience this can be assumed to be a kind of worst case scenario. For cost reasons the study further assumed that either all Euro 3 vehicles would be subjected to an IuC, or only those produced in large volumes. The cumulative reduction in emissions over the period 2006-2012 is shown as a percentage of the total cumulative motorcycle emissions Table 9.1.


A similar analysis for the effect of a periodical inspection resulted in the figures shown in Table 9.2. Table 9.2: The calculated cumulative effect of a road-worthiness test for

motorcycles, as a percentage of the total motorcycle emissions. Period 2008-2012. Source: Ntziachristos

CO exhaust HC

NOx

2-stroke 0.31 % 0.50 % 0.75 % RW on all bikes as from 2006 4-stroke 2.24 % 1.68 % 5.12 %

2-stroke 0.43 % 0.68 % 0.97 % RW on all bikes as from 2008 4-stroke 3.07 % 2.25 % 6.57 % The higher percentages than for the previous case are due to the fact that in this case also the pre-Euro 3 bikes are checked. On the other hand it should be kept in mind that the feasibility of such a check in the case of boat engines is a different matter. See for this subsection 9.6. Generally it may be concluded though that, even though in the case of PTWs aftertreatment has already been introduced, the effect of IuC is limited, provided that the manufacturer does deliver a sufficiently durable product. In the case of non-aftertreatment emission abatement situations, the effects should be expected to be even less. As an illustration Figure 9.1 shows a number of measured df-values, as determined in EPA durability testing, adjusted to a total distance of 250 hours. Figure 9.1: Measured deterioration of marine engines (mostly outboards).

Source: Icomia

Each point represents between 2 and 9 engines of the same type. Since some df-values were based on the type approval emission rather than to the zero-hour emission, df-values of less than 1.0 do also occur, but generally speaking all values are within 10 % of the no-effect. Furthermore is clear that the largest differences from 1.0 occur for low power engines. This suggests that the values shown are at least partly due to measurement effects, and not to actual systematic changes. These results agree with the general observation already made that deterioration does not seem to be an issue for engines without aftertreatment, given suitable maintenance.

Deterioration factor over 250 hours

0.8

0.9

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1.1

1.2

0 50 100 150 200 250

nominal power [kW]

Df

4-strokeDI 2-strokePWC


9.6 Major obstacles for a durability check

To compare the possibilities for either an In-use Compliance procedure, or a periodical inspection there are a number of aspects that need to be taken into consideration. These are: • The series volume • The problem of locating the engines • The availability of engines for testing • The problems of what and how to measure • The problem of how to establish that an engine selected for IuC has been properly

maintained The series volume The volume of the series determines how many engines of a certain engine family are present in the field. Already in subsection 3.4 it was pointed out that the usual series volume is very limited. The following table will further illustrate this further: Table. 9.3: Average size of engine family per manufacturer. Engines as produced for

recreational craft; very small manufacturers not included. type of engine annual

world-wide production

number of manufacturers

engine families per manufact.

units per family per annum (average!)

Outboard 820 000 7 30 3900

SI inboard 130 000 8 7 2300

CI inboard 40 000 29 > 30 < 45

PWC 110 000 4 4 6900

Typical daily production of a car manufacturer (units per engine family) 2500 - 4000 This means that during the production life of an engine family type there are no more recent engines present in the field than at best a few thousand produced the previous year, scattered over Europe, if not world-wide. More for a very popular engine type, but correspondingly less for the less popular types. After 5 years of production (a typical production lifespan for an engine type) there are no more than a few tens of thousands, and by that time that version will have gone out of production anyway. This means that the possibilities to check the durability aspects by measurements on engines in the field are extremely limited. As a matter of fact this aspect is already regarded as a serious problem in the case of PTWs, with an overall annual production that is an order of magnitude higher than that of marine engines, and divided over considerably less engine family types. Locating the engines In many countries recreational boats are not registered, nor are their engines. Only roadgoing engines are consistently traceable, since they are linked in a strict way to a vehicle, and the vehicles are very rigidly registered (at least most of them). In every discussion concerning the durability aspects of engines (whether it be for in-use compliance or for periodical inspection) the fact that some categories of engines (mopeds, agricultural tractors, non-road engines, etc.) are not registered in any way at all, is therefore turning up as a hurdle that cannot be taken. Neither the authorities, nor the manufacturer/supplier is in a sure position to locate these engines after they have been delivered into customer’s hands. In the case of manufacturers a certain percentage of the buyers (at least of the bigger engines) send in their warranty certificate, so at that moment the manufacturer would know where to find the owner.


But when time elapses the owner may have moved, or sold the boat or the engine, and the engine is no longer traceable. The availability of engines for testing Since TNO runs the Dutch in-use compliance programme for passenger cars and trucks on behalf of the Dutch authorities, we have some 18 years experience with locating and obtaining passenger cars for such testing and some 10 years experience in the case of trucks. It turns out that it requires special incentives and guarantees to get people to make their car available for in-use compliance testing, and that even so car models that have an above average emotional value for their owner are very hard or impossible to obtain. The continued success of the programme is closely linked to the fact that the models sought for testing are by definition the most popular ones of which the potential availability (numbers in circulation) is high. Car manufacturers tend to do their monitoring by supplying vehicles to their employees and to take them periodically back for testing. This solves both the problem of how to locate them and the problem of how to obtain them. And by selecting employees that do a sufficient annual kilometrage, or by carsharing of company cars, they can be sure of sufficiently quick results. In other cases they sometimes try to ‘buy them back’ from their current owners, or to offer an exchange for a new one on favourable conditions. In either case this works only since they can spread the cost of such approaches over a sufficient number of vehicles produced and sold. It has already been observed that in the case of motorcycles these are considered to be no options. At the start of the truck in-use compliance programme, owners had sometimes to be convinced to co-operate on the basis of the fact that they had obtained subsidies under a ‘clean trucks’ tax incentive scheme on the condition that they would provide such co-operation when asked to. It should be noted that the supply of a replacement vehicle has always been part of the deal. The limited experience with motorcycles, in the cases where this was done on a project basis, has suggested so far that the problems are only bigger in that case. In the current case, given the very small numbers of any given type of engine in circulation, in combination with the high emotional value of a boat in comparison to that of a car, we can only assume that the task ahead in the case of an in-use compliance programme for boat engines must be regarded as a very big one indeed. What and how to measure In the case of roadgoing engines, mounted in vehicles, it is relatively simple, once the owner has agreed to make his vehicle available for testing, to exchange that vehicle for its temporary replacement and to transport it to a laboratory. The type testing is performed on a vehicle placed on a chassis dynamometer. So the in-use compliance testing of passenger cars can also be done by placing it on a chassis dynamometer and measure it according to the same procedure. In the case of trucks the situation already becomes more difficult. Truck engines are tested as a separate engine on an engine test bed, outside of the vehicle. Dismounting the engine from the vehicle is absolutely unacceptable, however, except in isolated cases: it would be very time consuming, extending the time the owner has to make his vehicle available, and increasing the overall cost per engine tested to an unacceptable degree. Furthermore dismounting and re-installing in the engine brings serious safety risks and liability aspects whenever anything goes wrong. For such reasons TNO has had to develop first an acceptable method to test such engines when mounted in their vehicles, while


still maintaining sufficient accuracy of the end results to allow the authorities to take action whenever such action is called for. In the case of boat engines the problems increase by an order of magnitude. In the case of outboard engines it would still be possible to ‘borrow’ such engines and bring them to a specialised laboratory for testing. In the case of small outboard engines this should bring no problems, still provided that the engines can be obtained. In the case of bigger outboard engines the handling of the engine may already prove to be an obstacle: the biggest ones do weigh as much as 300 kg. In the case of inboard engines the only realistic way to test it is to perform the testing onboard. Of necessity this must be either a ‘simulated’ test or a kind of diagnostic test. A simulated test is in fact what TNO does use for the truck engine in-use compliance testing. A diagnostic kind of testing is generally used in the automotive field for periodical inspection. A diagnostic test only checks the settings of the engine, and the general performance of an aftertreatment system, if applicable, and assumes that its emission performance will be OK when the adjustments are OK and the aftertreatment functions well. Both options do exist in principle, and can be incorporated in a legislative framework. The US-EPA is heading for an on-board test with portable equipment. The measurement can then be performed when the boat is sailing and even if the operational points do not fully coincide with those of the type approval test, an NTE (Not To Exceed) approach may tell if everything is still operating according to standard. TNO has once developed such a kind of test for commercial inland ships. The relevant report [Verbeek 2001] lists a number of manufacturers of such equipment. Typical weight of such equipment is listed as 30 kg (with, in the case of inland barges, an additional weight of about 50-100 kg for bottles containing calibrating gases). In the case of diesel engines a dilution tunnel would be needed if one wanted to measure PM. The report mentions a ‘microtunnel’ developed for this purpose weighing about 120 kg. An optical smokemeter, which was evaluated as a possible alternative, weighs up to about 50 kg. Obviously this kind of equipment, although portable, can be used on an inland barge, but less readily on a yacht. The average accuracy of the measurement was approx. ± 12 %, which increased to some ± 20 % when no exact data were available with regard to the specific fuel consumption of a correct engine. The report concludes nevertheless: “The method is suitable to establish differences with regard to the emissions resulting from an incorrect engine adjustment, from the use of emission-critical components that do not fulfil the requirements, or a lacking state of maintenance.” But again: concerning inland barges. Although TNO has therefore developed such a kind of test for commercial inland ships, no such test is known to exist for recreational craft, where the conditions are significantly different (not at the least concerning the accessibility of the engine). Until such a procedure has been developed and validated, we have to conclude that for the time being any kind of in-use testing lacks the necessary basis to perform it. The report mentioned above concludes with a list of recommendations for further work needed before even in the case of inland barges such a method could be applied for legal purposes.

9.7 Practical possibilities for a durability check

In summary it can be concluded that the major obstacles to an in-use compliance check at this moment are: − There are far too few engines of any given type, or even family, in the field,

spread out over to large a geographical area, to carry out such a test with any degree of significance.


− The willingness of the owner to have such testing done on his craft is likely to be extremely limited. The testing will take time, and more than likely he will want to be present in person when his boat is operated for the purpose, so it will also require time for himself. As long as there is no legal obligation for him to co-operate this will seriously limit the availability of engines available for testing even further.

− Once sold, the engines are either not traceable at all, or only for a limited period of time (the warranty period). Boats and their engines are not officially registered, and are likely to move about, from place to place or from owner to owner, or might even be kept in a marina in another country than the owner’s national residence.

− The possibilities to do sensible measurements on a small private craft during operation are extremely limited. There are ideas about possible methods, but the work needed to turn these into practice has not been finalised yet, or in fact hardly even started. There are still serious obstacles here that need clearing.

It should be realised that the above will hold in any case, independent of whether the engines are going to be checked by the national authority, a notified body, or the manufacturer. What is needed is first of all a firm basis for any checking to be done in the field, independent of who is going to do the checking. As things are, it would seem that a kind of registration, in whatever way, will be the first requirement. Then a way to check the engine for acceptability will have to be worked out. Our advice would be to charge a body like CEN or ISO with such a task. If the engine has been properly type approved, such a check needs only to be a diagnostic check, not a full emission measurement performance. What needs to be checked are the correctness of the engine and fuelling adjustments and the performance of any aftertreatment system, if applicable. Presumably some kind of emission analysis would be part of the check, if only to be able to calculate a lambda on a petrol engine in cases where that would be relevant. If that is indeed the case the RCD-amendment should require a attachment point for the probe to be provided at a point upstream of the point of water injection. To the extent that certain parts have been installed that decisively determine the emission performance (such as catalysts), the check could include the presence of such parts and the correctness of their part numbers. This could include an obligation to align the positioning of the numbers and the accessibility of the parts concerned in such a way that such checking is possible. To the extent that electronics are finding their way, or already have found their way, into the engine adjustments (like fuelling and ignition), in the middle term future it should become possible to monitor them in an electronic storage system (OBD, although not necessarily of identical description to the automotive version), that stores any fault codes. The check might then be limited to a read-out of the fault codes.

9.8 Summary, conclusions and recommendations

Concerning the necessity of in-use compliance testing: Under the current legislation durability is not an important issue. Durability generally concerns the aspects of deterioration and failure of components. The technology used is, however, well tried and robust, and failures would primarily result in operational consequences. This situation may reasonably be expected to remain during Stage 1 legislation. Furthermore the number of operating hours is generally low, meaning


that deterioration is a much less important aspect for this class of engine than it is for e.g. automotive engines. Even in the automotive field deterioration did not become an issue until the introduction of aftertreatment systems. In this study it is recommended not to introduce aftertreatment systems (with the possible exception of oxidation catalysts on inboard petrol engines). If this recommendation is accepted, deterioration would not likely be an issue under Stage 2 legislation either. Concerning failure, the main risk would be in the increased application of electronics. But failing electronics are likely to result in operational failures and hence will be dealt with adequately by the owner. So, no great necessity for a separate durability control seems to exist in this respect either. Finally a small model type of calculation for the PTW situation by another consultant to the Commission has shown that the numerical impact of an IuC would be very limited indeed. So in conclusion it may be stated that there does not seem to be sufficient necessity for an in-use compliance requirement in the Stage 2 legislation. Concerning the possibilities for in-use compliance testing Concerning the possibilities of an in-use compliance system the following can be concluded: Since the total number of engines of a given type or family is extremely small,

and scattered over Europe if not world-wide, and since in most places the engines, or the boats fitted with them, are not registered, it will be next to impossible to find the engines in the field.

It must be expected that owners will be very reluctant to make their engines or boats available for any in-use testing on a voluntary basis.

There is currently no accepted method to test engines installed in recreational craft.

Concerning such testing (the last bullet point) the US-EPA has some ideas, but no concrete proposals yet. In Europe some ideas have been worked out concerning the testing of ships for inland transport, but the size and weight of the equipment would not as such make such methods applicable to recreational craft. Recommendations In view of the above the following is recommended. If, notwithstanding the current lack of necessity, it is felt that a system for in-use

compliance testing should be developed, first a body like CEN or ISO should be asked to develop a realistic and generally recognised test method.

In such a case the Commission might want to propose to the US-EPA an international approach where a body like ISO would do the development under the supervision of an international working group comprising representatives of the Commission and the EPA and possibly of (some) Member States. In recent times such an approach has worked well for the development of recognised test methods for the certification and related checking of PTWs and trucks.

For the middle to longer term a version of electronic diagnosis, although not necessarily identical to that currently applied in the automotive field, might be part or all of such a method.

Until such a method has been developed, a check on the presence of essential emission determining components might be used as a means of checking whether engines in the field would comply with the requirements.


10 Manufacturer related issues

NOTE TO THE READER: This chapter is based on a number of interviews with engine manufacturers of both marine petrol and marine diesel engines; large producers, as well as typical small producers, and both OEMs as typical marinisers

10.1 Important characteristics of the recreational marine sector

When considering the aspects of a reduction of exhaust emissions and noise from marine engines, there are a number of elements that are characteristic for the marine sector that should be kept in mind. Generally speaking solutions that have been successfully introduced in one sector may be very difficult or even not feasible in another by the special operational conditions that are characteristic for that other sector. In this respect the following aspects must be regarded as of importance.

10.1.1 Manufacturing aspects On the petrol side of the market, outboard engines and engines for PWCs are dedicated designs, although some bigger outboard engines sometimes are based on existing automotive engines. Since the world-wide market is small (see Section 3), the renewal rate of engine designs is low, and in most cases will be limited to updating existing designs rather than launching completely new ones. Petrol fuelled inboard engines usually are derived from existing automotive engines, that are ‘marinised’ by specialised firms. According to representatives from the sector, as a rule such marinising is limited to the mounting of dedicated parts and equipment. In Europe any changes with farther reaching consequences will only be carried out in close co-operation with the OEM of the engine, if not straightaway by that OEM on request of the mariniser. See further subsection 3.5. With the odd exception, diesel engines are exclusively inboard engines. There are a few diesel engine manufacturers operating on this market, and a large number of (usually smaller) marinisers (see Section 3 and subsection 3.5). According to information by the main original diesel engine manufacturers, however, even the engines produced by them are nearly always based on a ‘core engine’ developed for other markets which is then, as it were, marinised by the OEM itself. This means that again the basic ‘architecture’ of the engine has been developed for industrial or sometimes automotive application, and that the specific requirements of the marine market are mainly met with add-on equipment.

10.1.2 Installation aspects Pleasure craft propulsion engines can be subdivided into: • Outboard engines • Inboard sterndrive engines • Inboard shaftdrive engines (almost exclusively limited to diesel engines) • As a special inboard variant: saildrive, limited to a few manufacturers, used on

some cabin-sailboats • Engines for PWCs


The installation aspects of these different configurations were detailed in Section 2. The reader is referred to subsection 2.1.1 for further information on the installation aspects.

10.1.3 Operational aspects In certain applications, especially planing craft, the power to weight ratio of the engine is of particular importance. This aspect may put limitations on the weight of an engine. It should be noted that where in (e.g.) a high performance road vehicle additional weight would only reduce the performance of the vehicle to a certain (limited) degree, the ability of a planing boat to get into planing or not has much bigger consequences: if a boat is not going onto plane, it will not achieve its speed, regardless of engine power. In displacement mode it is limited to the maximum hull speed. In such cases the power to weight ratio must therefore be regarded as an important parameter.

10.1.4 Operational aspects concerning the use of catalysts According to information received from the manufacturers, outboard engines are traditionally not fitted with air cleaners, since generally a marine environment is relatively clean. This does mean, however, that in a salt water environment the engine will breathe salt suspended in the atmosphere. When a catalyst would be fitted this could potentially result in catalyst contamination, but actual experience in this respect is still lacking. Some programmes set out by the US government are currently looking into such aspects, but there are no final conclusions yet. Bigger diesel engines are usually fitted with air cleaners, and sometimes inlet dampers to reduce the noise of turbochargers. On such engines the installation of silencers on the inlet and exhaust side is the responsibility of the boat builder, however, and not that of the engine manufacturer. For safety reasons water is injected into the exhausts of marine engines. Under transient operational conditions there is the serious risk of backwash of water into the catalytic system, potentially causing thermal shock in the catalyst monolith, and in a seawater environment causing salt contamination of the catalyst and the lambda sensor. One engine manufacturer indicated that this problem is to a large extent caused by the details of the boat design, but that the durability of the emission abatement system is the responsibility of the engine supplier. Especially a lambda sensor may fail very quickly under such circumstances. Monoliths need to be metal rather than ceramic to survive such conditions. Metal supports are also more shockproof, which is the reason why they are used in e.g. moped and motorcycle applications. According to information supplied by the industry, California has studied the problem of fresh water contamination and plans to study the problem of salt water contamination of catalysts, but has yet to start that part of the project. Southwest Research Institute in the US has done some limited testing under contract by the EPA. As a general rule both outboard and sterndrive inboard engines have underwater exhausts. Since the vertical distance between the water surface and the engine exhaust port is usually extremely short, on a moored boat sloshing water may get back into the catalyst. Although on a moored boat this does not create thermal shock, the contamination effect is comparable to the one addressed in the previous paragraph. Similarly PWCs have exhausts that are underwater when the craft is stationary (and hence when it is moored), although it is lifted above the water surface


once the craft is in planing mode. The horizontal distance between the water surface and the catalyst may be longer though. Generally speaking inboard shaftdrive engines do have a mix of underwater and above water exhausts. Johnson Matthey, the biggest automotive catalyst manufacturer, assumed that the thermal conditions would not be serious when metal support catalysts would be used (which they would advice anyway) but confirmed that a lambdasensor was likely to be the weak link in the chain. They assumed that the most logical way to go, if catalysts had to be installed on boat engines, would be to aim for an oxidation catalyst. See further subsection 7.2.3, especially the last paragraph.

10.1.5 Customer satisfaction The industry stated that in order to comply with customer wishes the engine manufacturer and/or the boat builder has to limit the size and weight of the engine itself or of the engine installation (in the case of an inboard engine). Additionally he has to limit sound radiated by the engine itself, since especially in the case of inboard engines low sound levels in and on the boat are an important selling point. Likewise the manufacturers of inboard diesel engines have to reduce smoke emissions to avoid soiling of white coloured polyester hulls, again as an important selling point.

10.1.6 Safety aspects The installation of inboard engines is usually rigidly controlled by mandatory safety requirements, such as those issued by the US Coast Guard. They include e.g. that generally the surface temperatures of components may not exceed 205 ºC (400 ºF). Additionally there exists a US ABYC Standard that calls for no surface temperature in the engine room to exceed 200 ºF (ca. 95 ºC). This requires water jacketing of exhausts. Internationally there are ISO standards with safety requirements, such as fire protection, fuel system installation etc.

10.1.7 Engine reliability Especially on seagoing craft (but also on bigger lakes) reliability is much more an issue than in e.g. the automotive world. In the automotive world a breakdown is mainly a matter of inconvenience. In the marine world it can very quickly develop into a major safety issue. A quick check with a few lifeboat societies (those of the countries whose fleets were detailed in subsection 2.3.2) concerning the percentages of calls related to engine failures, resulted in the following answers. They only concern emergencies at sea or on comparable waters. No data were available concerning the actual causes of such engine failures and at the third stakeholders meeting the EBA warned that these figures should not be used to prove a lack of engine reliability. The point we want to make here, however, is that engine failure, no matter by what cause, in any other situation than sheltered waters may very rapidly lead to emergencies rather than mere inconvenience.


EXPERIENCE OF THE LIFEBOAT SOCIETIES

• Dutch lifeboat society (KNRM): In 2003 engine breakdowns (both on commercial and recreational craft) were the cause of about 500 out of a total of about 1500 cases of assistance. That is one third of the total.

• British lifeboat society (RLNI): In 2003 engine breakdowns (both on commercial and recreational craft) were the cause of approx. 1600 out of a total of about 8000 cases of assistance. That is about 20 % of the total, but note the lower percentage of motor yachts in the British fleet (see subsection 2.3.2). Recreational craft constitute nearly 80 % of those 1600 cases.

• Swedish lifeboat society (SSRS): In 2003, with 173 out of a total of 1029 (17 %), engine breakdowns were the second biggest cause of SAR calls (SAR = search and rescue; they are the operations that concern life-threatening situations). Non-SAR assistances performed by the SSRS came to 312 for engine breakdowns, out of a total of 600; on this basis they estimate that overall this points to some 2000 out of an estimated 4000 cases of assistance by all bodies involved (i.e. including fire brigades and commercial salvage firms).

• Italian coast guard (Guardia Costiera), which deals with typical Mediterranean use: In 2003 engine breakdowns (on recreational craft) were the cause of over 800 out of a total of nearly 1300 cases of assistance to recreational craft over the 4 summer months (June till September), i.e. about 65 % of the total.

Such figures strongly underline the importance of reliable engine performance for recreational craft at sea or on big inland stretches of water.

10.1.8 Liability aspects The CARB legislation intends to include OBD (on board diagnostics) as part of a package including the use of catalysts. This means, inter alia, catalyst monitoring. In the automotive world catalyst monitoring is performed by a second lambda sensor after the catalyst. In marine applications especially that sensor is so close to the water that manufacturers regard this solution as unfit for marine use. At the moment the matter is under discussion between the manufacturers and the CARB; preliminary decisions are expected some time during 2005. On the other hand especially for the US market, manufacturers fear that, even if the CARB would drop the requirement of catalyst monitoring, they cannot afford to avoid catalyst monitoring because of liability aspects (see further subsection 13.2 on CO emissions). They therefore contemplate thermal monitoring instead, but for the time being any experience with such monitoring is lacking. It should be noted that, although in the automotive world by now OBD has been introduced on passenger cars, OBD on heavy duty (diesel) engines is still under discussion since there too no demonstrated solutions do exist yet. Up till now OBD monitoring of catalyst performance is only possible on closed loop 3-way catalysts, as used in combination with a petrol engine. According to the latest information, the US industry has requested the CARB for a delay in the introduction of catalyst monitoring, since so far they have not found a workable solution. The CARB is going to have separate meetings with the individual manufacturers about this issue in January and February 2005.


10.1.9 Trade aspects In our interviews with OEMs the point was repeatedly stressed that the European market of boat engines, beyond the engine manufacturers, is dominated by small firms who sell and/or maintain the engines. In contrast to dealers and garages in the automotive sector, they are not specialised in certain makes of engines, and are usually not equipped with the kind of specialised equipment that by now is state of the art in garages. Several manufacturers stated that in their opinion, under the present circumstances the sector might have serious difficulties when it would have to deal with a significant step-up in the level of sophistication of the engine and emission abatement technology. They feel that for such a step-up to be successful a dedicated training programme, aiming at a significant rise in the level of expertise of the sector, is likely to be necessary. And even so the level of specialisation that is becoming the norm in the automotive world will never be possible in the marine world. Where automotive dealers can afford to specialise on one or a few car makes, the marine firm necessarily has to remain a generalist. The market is simply too small for any specialisation. And as to specialised maintenance facilities and equipment: where in the automotive sector the vehicle can always be brought to the equipment, in the marine world at least in the case of inboard engines the equipment will always have be brought to the engine, which in many cases has a very restricted accessibility as well. This will seriously either limit the possibilities to use specialised sophisticated equipment, or have significant price consequences. See also the last part of subsection 9.6. It should be pointed out, however, that on the other hand some firms that specialised in engines for the recreational market were more confident, stating that the problems with lack of expertise on the part of the dealers are primarily those of the small commercial sector (such as local fishermen in southern Europe). They stated that a yacht does represent a significant investment, and that the boat owner as a rule is prepared to spend money on its maintenance. They do fully agree that intensive training will be needed, but are confident that this will be achieved for their own dealers. Nevertheless they agreed that the technology applied should allow diagnosis by no more than a laptop computer, which would still make it more basic than some advanced automotive technology, and dependant on the degree of electronic control. See further subsection 9.7, especially the last paragraph.

10.2 Potential risks

Representatives of the engine manufacturers pointed out that concerning a possible Stage 2 in the environmental legislation for recreational craft propulsion engines, a number of aspects should be taken in consideration that must be regarded as risks to the success of such a step. They feel that a comprehensive community policy should take them into account, and should include ways to deal with them. Fuel quality in harbour facilities was repeatedly reported as severely deficient, especially in certain Member States. The fuel supplied was described as a ‘dumping’ of surpluses from elsewhere. The turnover speeds are low, leading to quality loss, and the presence of water in the fuel was stated to be quite common. Such phenomena concern primarily the commercial sector (small fishing boats) rather than the marinas, but since the engine manufacturer has no control over the destination of his product (recreational or commercial), his engines must be capable of running reliably in both fields of application.


These fuel quality problems were mentioned as especially relevant in the case of outboard engines, which are sold as separate units, rather than as already mounted in a boat; they cannot be separated into commercial engines and engines for recreational purpose, since they are removable. But these infrastructural problems in relation to the commercial sector, especially in southern Europe, in their opinion might seriously influence the durability of sophisticated emission abatement solutions, such as aftertreatment. They pointed out that, even though the RCD requirements aim at recreational use, they still have to design the durability of their engines, and of the emission performance of their engines, for the use that will be made of these engines in the commercial sector.

10.3 Conditions for implementation

A successful implementation of a possible Stage 2 would require the following facilitating requirements concerning the operation of such engines.

10.3.1 Fuel specification If catalytic aftertreatment systems would be introduced, in the case of petrol engines leadfree petrol would of course have to be widely available. But more than in the automotive sector sufficient guarantees would be needed that unleaded fuel supplied by the oil company would not get contaminated with leaded fuel anywhere along the supply line. According to the manufacturers, the sometimes much more elementary or even primitive fuel supply chain should be regarded as a greater risk in this sector than in the automotive one. Similar considerations would concern the sulphur content of diesel fuel if diesel engines would have to be fitted with EGR or aftertreatment systems. The industry stated that for sensible EGR or aftertreatment a fuel with no more than 500 ppm sulphur would be required (in fact the contractor is of the opinion that this is an already high content), whereas e.g. in the US for non-road applications 3000 ppm is the current standard. For comparison: for on-road applications the general perception is that for aftertreatment systems a maximum of 50 ppm should not be exceeded, and 10 ppm is the really preferred figure. Cooled EGR would also be excluded with fuels containing more than 500 ppm sulphur.

10.3.2 The supporting trade sector As already pointed out above (subsection 7.1.9) a dramatic increase in the level of sophistication would necessarily have to be accompanied by a corresponding upgrading of the level of expertise and competence of the supporting trade sector (dealers and maintenance firms). This would require intensive training by the manufacturers of the engines, the purchase of more sophisticated maintenance facilities and a general upgrading of the level of ‘doing business’. See further subsection 7.1.9.

10.4 Economic considerations

According to the industry concerned the following considerations should be regarded as conditional for a cost-effective introduction of a possible further legislation.


10.4.1 A clear long-term strategy Considering the extremely limited overall size of the market, and the resulting slow development and renewal rate of engine designs, the industry will need to know its long-term goals. This is already true for the relatively small PTW (powered two-wheeler) market, but much more so for the marine engine market, which is an order of magnitude smaller again (see e.g. table 3.1 in subsection 3.2.2). In this field any new engine design will not only be tomorrow’s engine, but to a large extent also that of the generation after that. The manufacturers will urgently need to plan ahead, not only for the design that has to comply with the final level of legislation, but also for the route leading there. They should not be exposed to the risk that the technology introduced for tomorrow’s engine will have to be discarded again for the stage after that. The possibility to plan a sensible intermediary route is as important as the final goal itself. In fact the same point was made by the PTW manufacturers in a similar study concerning emission reductions in that market [Rijkeboer 2002]. The contractor fully supports this point of view.

10.4.2 A considerate timing The question what the cost would be of the introduction of a certain abatement technology is decisively dependant on the time available to develop and introduce it. The total cost is always a combination of development cost and production cost. Production costs are reasonably fixed and therefore relatively easy to estimate. Development cost, however, may figure quite prominently in the total, especially in the case of a small series. But development cost is dramatically dependent on secondary variables. If the technology needs to be on the market on short notice, its development requires a dedicated effort that should be fully accounted to its introduction. On the other hand, if its introduction is foreseen on a longer term basis, it can be incorporated in a technology update that would take place anyway, in which case it may to a large extent be part of that update, causing much less extra cost, or maybe even very little at all. So the general rule is always that the further in advance a necessary technology step is known by the manufacturer, the less expensive it will come. And the smaller the series, the more relevant this will be. This point was also made by the contractor in his report about PTWs, and is all the more relevant in the market for recreational marine engines, given the even smaller sizes of the production series.

10.4.3 Introduction from the top end of the market Given the complete lack of experience with stringent emission abatement technologies (especially aftertreatment technologies) in this market, it would make sense not to introduce a legislation requiring such technology as a blanket requirement for the whole market. The manufacturers would prefer a stepwise introduction, starting from the ‘top end’ of the market, i.e. from the highest power engine classes downwards. The contractor likes to stress that this would make sense for the following reasons: • Introduction of stringent requirements in one particular section of the market only,

would give both the manufacturers and the authorities the chance to gain experience.

• In the European context the top end of the market would on the one hand involve a smaller number of engines but on the other hand the engines with the largest contribution per engine.


• Economic consequences would be less severe in the case of more expensive engines that in the case of low cost engines (in the automotive world for that reason new developments are always introduced at the top end, to filter down with time).

It may be added that the experience with the introduction of ‘clean’ cars on the Dutch market, stimulated in the eighties by means of a tax incentive scheme led to the following experience. Although most of the car models on the market were quickly adapted and successfully typetested, complete lack of experience with the solutions adopted resulted in many of them failing in durability and/or customer acceptance of the consequences in terms of operational aspects. And that lack of customer acceptance in turn led to a high rate of tampering, rendering the adaptations inoperative. Since this was quickly becoming clear, because the approach included the set-up of an in-use compliance monitoring system (operated by the contractor), the tax incentive scheme could rapidly be adapted to exclude the solutions that had shown themselves to be insufficiently durable in practice. Not surprisingly such solutions had been more frequent on cheaper vehicles, whereas the more expensive sector of the market had turned to more durable, but usually also more expensive solutions. Because of this possibility to effectively monitor the performance and durability of the various solutions adopted, the introduction could be regarded as successful in the end, notwithstanding the early ‘teething troubles’. Without such a possibility of rapid monitoring it would inevitably have taken much longer to gain the necessary practical experience, and a large number of inadequate systems would have flooded the market before the situation would have been sufficiently sorted out. In that case careful limited introduction would have been the only sensible alternative.

10.4.4 No market disturbance The manufacturers of outboard engines pointed out that a successful introduction policy should avoid that engines complying with different emission levels can be placed on the market side by side, even for a time, when such different levels would result in significant price differences or other customer benefits, and when the products with the lesser level of compliance (and hence the greater level of customer attraction) can be made available in sufficient numbers to satisfy a large part of the total demand. In the automotive world it happens (under certain conditions) that such side by side availability does occur, to allow the possibility of a run-out of existing older products. But the overall size of the market effectively prevents a large-scale shift. Furthermore the total automotive product consists of much more than just the engine, thereby significantly limiting the attractiveness of a run-out product complying with a previous legislative level for one of its main components. In the current case we are talking of an engine only, and a product with much less ‘latest edition’ appeal than a complete car, in a small market where even minor shifts in absolute numbers may have large relative consequences. In such a case side by side availability has the serious potential to create severe market disturbances. Consequently, where one of the major benefits of the US legislative practices in the automotive world is the phase-in procedure that is very often applied there, such a practice is generally feared by the manufacturers of outboard marine engines, or at least the non-US ones, as a potential threat to market stability. On the other hand a manufacturer of sterndrive engines stated that his ability to continue to operate on the US market was effectively due to the fact that he could make use of the FEL (family emission limit) clause in the US legislation, which allowed him to average the emission results of his engines over his total production.


10.5 Special views of the industry

In the interviews with representatives of various engine manufacturers a number of special views and wishes were presented. The major items of these interviews are given here under this heading.

10.5.1 Harmonisation It was pointed out that effectively there are only two sets of legislation, representative for two different markets: the European one and the North American one. But even on one particular side of the ocean, manufacturers are faced with different sets of legislation. For Europe the builders of engines for marine propulsion are faced with certification according to the IMO (for seagoing ships), the CCNR (for inland waters, notably the river Rhine), the BSO regulations (for engines to be used on the Bodensee), the NRMM Directive concerning inland waterways and the RCD. On the other side of the Atlantic manufacturers are faced with the California and the US-federal legislations for commercial and for recreational craft. Manufacturers operating on all of these markets obviously have a preference for full harmonisation of the relevant sets of legislation. This would include: • Harmonised engine categories and emission categories.

This would greatly streamline the certification procedures, even in the case of different standards. In fact this would already be true for the ‘Europe-only’ situation, as outlined above.

• Harmonisation of the measurement protocols. If the same test would be acceptable for different certifications, even if the emission requirements are different, that would save manufacturers much effort. Emphatically this would need to include the use of the same test fuel.

• Streamlining of the certification procedures. It was stated that running multiple tests was perhaps still the least of their problems. The extensive paperwork that had to be repeated for each individual certification constituted at least as much of a barrier, if not more.

• Harmonised limit values. This seems obvious for manufacturers operating on both markets.

Over against the standpoints of the large manufacturers, operating world-wide, there is the situation of the SMEs. Many of those will operate on one market only, so they fear a situation that would mean higher production costs to comply with more stringent requirements of the ‘other’ market, and no benefits from a more streamlined production. In so far as they are obliged to certify for different bodies within their own market (in this case the European one) they might benefit from the items listed under the first three bullet points above or, if these are worked out in a sufficiently sensible way, they would at least not be affected negatively by them, but they have no interest in the fourth one. They would, of course, be interested in an ‘internal’ European harmonisation. For the contractor this would seem to mean that there should be a strong emphasis on the first three points, and that the fourth should be dealt with keeping an open eye for the interests of the SME, whether by keeping his interests in thought during a harmonisation process, or by exempting him from certain obligations resulting from that process.


10.5.2 No technology dependant limits Manufacturers strongly feel that the basic principle should be that engines manufactured for the same type of application ought to be subject to the same requirements. It would be acceptable if these requirements would vary per application (such as e.g. inboard or outboard), especially if the certification procedure could be streamlined, but for a given application there should be no difference in requirement between technologies (such as e.g. 2-stroke or 4-stroke). On the other hand, in a comment on this statement the US-EPA pointed out that it does make sense to differentiate between petrol engines and diesel engines. For this field of application the contractor would agree with that, given the different characteristics of both engine types, and hence the different use made of them. In other fields of application, such as the automotive market, where both engine types result in much more equivalent drive options, it is generally wiser to adapt the drive option to the environmental necessities than the other way round, so as to avoid unwanted developments, as indeed actually practised by the US-EPA.

10.5.3 Similarity in approach What manufacturers fear, even if the legislation will continue to differ on different markets, is that there will be different priorities. By way of example one could imagine a situation where e.g. for diesel engines in the one case there would be a strong emphasis on the emission of NOx (e.g. in the interest of ground level ozone formation abatement) whereas in the other case there would be a strong emphasis on PM (e.g. in the interest of water quality). This would inevitably result in a multiplication of development costs. In actual fact there seems to be little necessity for such emphasis, however, as indicated in Section 8.


11 User related issues

NOTE TO THE READER: The majority of this chapter is based on an interview with the Dutch ‘Watersport Verbond’, a national users’ organisation. Subsections 11.9 and 11.10 are additions based on information received from elsewhere or on available expertise of the contractor.

Since no systematic answers were received from the questionnaires with which the contractor tried to get into contact with the national users organisations, the fact finding for this Section was mainly limited to the Dutch national users organisation. What follows are the answers received during an interview with that organisation. In addition to these answers, two reports were received describing some relevant issues [Watersportberaad, 1991, and van den Hout and de Vries, 1991]. It seems reasonable to assume that the answers are fairly typical for the behaviour of users in Northern Europe; to what extent they would also hold for Southern Europe is not fully sure.

11.1 Environmental awareness of the users

The general behaviour of the users of recreational boats was described as significantly environmentally conscious, at least as far as ‘visible’ aspects were concerned. Among boat owners and users it is ‘not done’ to behave in a way that obviously harms the environment. Primarily this concerns their behaviour on the water during use of the boat. But it also includes the handling of wastes of all kinds. Spilling of oil or fuel in the marina, even if only accidentally, was described as absolutely unacceptable in the eyes of fellow users. And since spilled oil and fuel shows very clearly on the water surface near the offender’s boat, great care is taken not to make such mistakes. Marinas were reported to be equipped with intake facilities for various kinds of wastes (apart from domestic solid wastes: domestic waste water, contents of chemical toilets, bilge water, replaced lubricating oil, etc.), which were stated to be conscientiously used. In fact an extensive report on the influences on water quality by recreational boating in the Netherlands [Van de Hout and de Vries], dated 1991, concludes that already at that time boat users dumped very little, if anything at all, into the water. This situation was emphatically declared by the Dutch users organisation to apply to all of Europe, although the EBA (European Boating Association) later expressed the view that they disagree with this statement. On the other hand the environmental problem is largely approached by assuming that it mainly requires careful behaviour rather than the application of facilities that cost money. Some expense is acceptable, provided the relation with the environment is sufficiently obvious, but the use of equipment that has to be bought and paid for, but of which the environmental benefit is less immediately obvious, at the very least needs sufficiently convincing publicity. Furthermore it appeared from some reports that, although users may generally act in good faith, their actual behaviour may, in some cases, be less desirable than they themselves assume it to be.

11.2 Maintenance

Maintenance of boat engines was stated to be less good than that of car engines. For cars an annual inspection is obligatory, but for boat engines no obligatory check on maintenance exists. And since boat engines in most cases will do a limited number of operating hours per year, maintenance of the engines is often infrequent. Boats


themselves are seen as an investment and are usually meticulously maintained, but this is not habitually extended to their engines. Since most boats in the Netherlands are used on small inland lakes, owners do not perceive a great risk here. For boats used on bigger and more open waters or at sea this situation will be different (but see the box in subsection 10.1.7). An increasing number of owners, especially of bigger boats, have the maintenance done by professional people like dealers or specialised maintenance firms. The others still do their own maintenance, although as in other sectors this is becoming increasingly impossible for modern engines. Older engines are largely maintained on a DIY basis. Obvious things like filters and lubrication oil are changed on a kind of regular, although often infrequent, basis. For most road vehicles the change intervals are based on a kilometrage that is regularly reached in most cases. And for those cases where it is not, the usual alternative is a time interval (such as: ‘or at least annually’). In the case of boats the owners usually base their intervals on the number of operating hours, even if this means that oil is e.g. only changed every three years. It was stated that engine parts are likely to be used until they break or otherwise stop functioning. For inboard engines, especially in small boats, the inaccessibility of the engine often prevents owners to give the engine a thorough check at regular intervals. Taking the engine out in such cases usually means dismantling some of the boat interior. Boats have long lives and their engines are used for a large number of years. A car that does 20,000 km per year will have done up to 5000 hours of running after 10 years. A boat engine that does 35 hours per year will have done around 1000 hours after 30 years. Given the way inboard engines are tucked away in ‘left-over’ spaces, especially in small boats or in cases where they are only used for auxiliary purposes (such as in sailing boats), owners would be reluctant to replace them by another one without very good reasons. Outboard engines are renewed more readily, since they are more removable. Generally speaking engines are more often renewed for reasons of operating costs or technological updating than for wear.

11.3 Lubrication oil

Lubricating oil of 4-stroke engines is often changed by the owners on a DIY basis. The old oil was stated to be conscientiously delivered to the depot of the marina. Dumping in the water would be heavily opposed by fellow yachtsmen. Oil for 2-stroke engines is usually bought in general stores. Synthetic oil, and hence biodegradable oil, is not used to any great extent. Two causes were mentioned: - Boat owners are very conservative. They tend to use what they know to be good

(based on personal experience) and are not readily prepared to experiment with new products. Their purchase is based on trust in a known product, even more than on price.

- As far as finance is concerned boat owners tend to react to immediate out of pocket money more than to overall cost. For that reason they tend to go for a cheaper product, even if a more expensive one might actually reduce the overall cost, e.g. for reasons of prolonged service intervals or leaner lubrication rates.

For those reasons the impact of a possible publicity campaign to use biodegradable lubricating oil is expected to have a limited impact, although a well set up campaign might convince a certain percentage of owners to switch.


11.4 Refuelling

Refuelling was described as worrying. The total throughput of fuel for recreational boats in the Netherlands is extremely low compared with the throughput of fuel stations for road transport. In the past diesel engine owners relied on fuelling stations that served commercial shipping and petrol engine owners often used fuelling facilities in marinas. Since then the use of low-tax diesel fuel as used in commercial shipping has been banned for recreational boats and many bigger fuelling stations serving commercial shipping have not been willing to install a special facility for the sale of a small quantity of high tax diesel fuel as used in road transport. At the same time increasing environmental legislation concerning fuelling facilities has necessitated operators of small service points (both diesel and petrol) either to invest considerably in upgrading or to close down. Upgrading would inevitably mean: asking a higher price per litre, but the boat owners as a rule are not prepared to pay that. So any marinas still offering fuelling facilities do so more out of a desire to offer a complete service than for a commercial break-even. The result has been that many owners of boats with smaller engines are used to fill jerrycans at highway stations and fill their fuel tank at the marina from those jerrycans. This practice of filling from jerrycans plays a role in the frequency of spilling, as outlined in subsection 6.2.

11.5 Fuel quality problems

The use of fuel meant for road use was stated to cause certain problems in the case of use in boats. As a rule fuel in road vehicles is used at a much greater rate than that used in boats. As a consequence this fuel is not optimised for long storage times in tanks. The density may be different, resulting in more evaporation, and the resistance against bacterial growth is considerably less, leading to the development of organic organisms in tanks and fuel systems. This situation is aggravated by the custom of boat owners to put their boats in winter storage with full fuel tanks so as to prevent or to minimise the formation of water condensate and the rusting of metal tanks.

11.6 Evaporation

The Dutch users’ organisation could not offer any information on the evaporation or leakage of fuel from tanks or fuel lines. Their estimate was that any leakage would either be detected by smell or by sight, in which case the owner would take action (fuel is expensive and additionally, in the case of petrol, it might cause a safety concern). If it leaks into the bilge water it would be pumped out into the shore side bilge water receiving tank. Nowadays bilge water is no longer allowed to be dumped overboard. About evaporation there was no information. But the vapours are known to be heavier than air, so in the case of inboard engines they would collect low in the hull, where they are likely to be detected if there is a gas/vapour detection system.

11.7 Registration

Concerning registration the general rule is that boats are not registered. In the Netherlands, registration is compulsory for ‘fast boats’, but the data base is not kept up to date like it is e.g. in the case of cars, and the register is therefore heavily ‘contaminated’. Apart from that there does exist a voluntary registration for those who take a mortgage on their boat, but that is obviously another kind of registration. And the Dutch users’ organisation issues a kind of boat passport for owners who need one for visiting countries outside the EU.


11.8 Summary

For the current study the information received may be outlined as follows: ● The owner’s environmental awareness is generally good, and so far good

publicity campaigns have worked. In certain cases the authorities have preferred legislation, but if this involves modifications to the boat, this can only be checked by random onboard inspection, since there is no registration of a kind that can be used for such a purpose.

● Historically maintenance of engines used for inland waters has usually been limited to the level needed to keep the boat operational. More recently an increasing proportion of owners has the maintenance done by a professional firm, either a dealer or a general maintenance firm. Inevitably these are the more affluent owners, and for that reason they may operate the bigger (more expensive) boats and engines. Furthermore modern engines do increasingly require professional maintenance.

● The replacement rate of engines is low, and is more driven by a desired technology update than by engine wear. This may mean that if the technology update is not perceived as desirable (or as in fact undesirable) the owner is likely to continue with his older engine. The introduction of new engines would then be limited to their installation in new boats, which is likely to exclude outboard engines (see for the possible consequences subsection 8.2).

● A wide-scale use of biodegradable lubricating oil will need a very convincing publicity campaign to convince the owners to use it.

● For a variety of reasons the fuelling of smaller engines is very often performed through the use of jerrycans filled at automotive fuel stations. This involves multiple handling of the fuel, which is likely to lead to increased refuelling evaporative losses. This would negate any attempt to catch refuelling evaporative losses of such engines, either by the installation of onboard facilities, or by facilities on the side of the fuelling station. The practice was not regarded as giving rise to increased spilling losses into the water (but see subsection 11.9).

● The discrepancy between the desired fuel characteristics of boat fuel and the actual characteristics of fuel produced and sold for road vehicles (when used for boats) does not seem to be an immediate concern with respect to air and water pollution aspects, although it ultimately may be a concern for the boat owner for various reasons, including the safety of operation. Nevertheless, in the case of exhaust gas aftertreatment possible negative influences might be expected from contaminated onboard fuelling systems.

● Leakage from fuel lines was not seen as a serious problem in the case of inboard engines. Concerning evaporation from onboard fuelling systems no information was available.

● Registration of engine driven boats, or of marine engines, is either non-existent, or is so incomplete and/or out of date that it cannot possibly be used for any legislative system that would require such a registration for its enforcement. This means that some typical approaches that are used in the field of road vehicles are simply not possible for marine engines.

11.9 Comments

A few comments need to be made to some statements made above. First of all a report about fuel spillage pointed to the use of jerrycans (see subsection 11.4 above) as the main source of such spilling. In that context it reported that if fuel is spilled on the water, owners tend to clear it away by using household detergents, which is


supposed to solve the problem, but which in reality only removes the visibility of the spill, whereas in actual fact it rather hampers the degrading processes. The same source stated that if spilled fuel ended up in the bilge, in half the number of cases this was simply pumped overboard. This contradicts the statement made in this interview that bilgewater is conscientiously deposited at intake points of marinas. The EBA, in a comment on this Section, complained that in far too many European marinas no such facilities are present. This contradicts the suggestion made in the interview that intake points for various kinds of waste intake points are available in most of Europe. On the other hand the suggestion was supported by a report as mentioned in subsection 11.1.

11.10 Biodegradable lubricants

The major aspect of the lubricant in the context of the current study is the water pollution aspect. Early studies, quoted in the 1991 TNO report [Rijkeboer 1991] indicated that biodegradable lubricants disappear much quicker from the water body than mineral lubricants (see also subsection 4.3.3). For this reason local authorities have sometimes tried to promote, with the aid of local users organisations, the use of biodegradable synthetic lubricants. It should be pointed out here, by the way, that biodegradability is a possible characteristic of synthetic lubricants, but not all synthetic lubricants are necessarily also ‘biodegradable’. From subsection 11.3 it follows that in the current situation boat owners are reluctant to change their use of lubricating oil, including a switch-over to biodegradable lubricants. The main reasons were cited as conservatism and the perception of out-of-pocket money at the moment of purchase. On the other hand recent history has shown that a well set-up publicity campaign, organised in joint effort by the trade, the owners organisation(s) and the authorities, sufficiently supported by the relevant press, may succeed to obtain a change in behaviour, if the environmental need for such a change can be communicated sufficiently well. In this context the following should be considered, however.

11.10.1 The water pollution aspects The literature survey presented in subsection 4.3.3 quotes a study by Kelly, that maintains that “the fuel is the major cause of VOC-emissions” and that “the lubricant has little effect on the overall emission rates of PAHs and VOCs”. It should be pointed out that this conclusion has to be related to the very high scavenge losses of conventional 2-stroke engines; in the case of DI 2-stroke engines the fuel-derived VOC emission is considerably lower, which would make the lubricant share correspondingly higher, although it should be expected to be lower also in absolute terms. That DI 2-stroke engines emit very low lubricant derived HC is borne out by test results of such engines as e.g. for road transport use. The study quoted in subsection 6.3 indicates that generally the use of synthetic lubricants for two-stroke engines is steadily increasing, especially for higher tuned engines. Furthermore it is to be expected that in the case of a Stage 2 of the emission legislation for recreational marine engines the conventional 2-stroke engine is largely, or even completely, going to disappear from the market. These combined effects will mean that the problem of water contamination by 2-stroke lubricants is a disappearing problem anyway. Nevertheless it may be felt that in certain local


situations (e.g. when the surface water is also used as a source for the production of drinking water) the progress made is insufficient, and that a more active promotion of the use of synthetic lubricants is desirable.

11.10.2 Active promotion of the use of synthetic lubricants In subsection 6.2 it was concluded that the major aspect of the current trend towards greater use of synthetic lubricants is that it cannot be controlled by the manufacturer but is left to the client/operator. For that reason, when greater use of synthetic lubricants is desired, other or additional policy instruments are needed than type approval requirements. The main disadvantage of a synthetic lubricant is its price, but the vehicle manufacturers expect that they can convince their customers to use it nevertheless. This is especially true for Northern Europe where customers are more quality conscious, but is noticeable even in Southern Europe where customers are more cost conscious. In subsection 11.3 the Dutch owners organisation stated, however, that boat owners are more conservative, and may be less easy to convince. On the other hand, in the past boat owners have reacted positively to well set up campaigns that made them sufficiently aware of the need for certain changes in behaviour for the benefit of the environment. So if, in a specific local situation, there is a clear problem, a concentrated effort by joint forces of all concerned (as outlined in the opening paragraph of this subsection 11.10) has a good chance of success. Efforts of a more general kind, aiming at a more global improvement of the general situation, where the average boat owner may have a much more reduced perception of the necessity, are correspondingly less likely to succeed.


12 Economic consequences of RCD stage 2 options

12.1 Introduction

This chapter will present the economic, social and industrial consequences of the proposed stage 2 scenarios for the recreational craft directive with respect to exhaust gas emissions and noise. Scenario based approached In order to develop the right information and to explore likely options, a scenario based assessment has been chosen. Two scenarios have been developed together with the industry. They describe the possible second stage legislation with respect to the gas emissions. The differences between scenarios will be resulting from ‘engine-technology steps’. This implies that we distinguish the level of technical sophistication of engines with respect to exhaust gas emissions and noise. In this way the scenarios are driven by technological possibilities, rather than by harmonisation arguments (e.g. harmonisation with EPA regulations in the USA). Societal benefits The big benefit for the society shall be the environmental gain due to less damaging pollutants in the water and in the air and less noise disturbance. Furthermore also new jobs can be created (e.g. for installation, repair and maintenance of 2nd stage engines). On the other hand is it also possible that jobs are lost due to reduced turnover by manufacturers. Finding the right balance The following trade-off effects have been identified: • Environmental benefit of emission reduction vs cost for industry. Societal benefits due to less exhaust gas emissions and noise versus investments to be made by the industry to comply with the legislation. It can be expected that the stricter the regulation is, the more savings there will be for the society but the bigger the cost will be for the industry for research, development, training and production of new types of engines (e.g. due to the requirement of sophisticated electronic engine management systems). • Environmental benefit of emission reduction vs loss of turnover and jobs in the

manufacturing industry. Societal benefits due to less exhaust gas emissions but more expensive engines causing possibly a reduction in the sales could lead to reduced turnover by manufacturers and supplies and loss of jobs , a negative impact for society. On the other hand the new engines could require more maintenance and servicing. This could create jobs at the dealers of boats and marine engines.

• Environmental benefit of emission reduction vs cost for certification and

enforcement. If strict regulations are introduced it is likely that the costs to enforce the legislation will be higher. Legislative requirements should not lead to very difficult and expensive enforcement and in this way cause more costs than benefits.


• Engine replacement with modern clean engines vs going on with more polluting old engines. New engines could become so expensive that boat owners will use for an indefinitely extended period their old and more polluting engines. This will then lead to a reduced rate of replacement of polluting engines and thus to higher environmental costs. This will mainly concern outboard engines. Inboard engines will as a rule not be exchanged but stay with the boat.

By means of the scenario assessment we will present the size of effects as mentioned above. We have used the contacts established with the industry to get figures on the cost estimates for technology needed to comply with certain (maximum) emission values. The costs and impacts have been investigated for different scenario’s (hereafter called ‘options’) and different engine types (e.g.: 2-stroke/4-stroke, inboard/outboard, diesel/petrol, power range). We have developed a questionnaire for the manufacturers in order to get information from experts active in the industry. Issues taken into account by means of this questionnaire are the additional costs for research and development for stage 2, effects on production costs and purchasing prices of engines and operational costs, and expected possible reduction of sales. The outcome of these questionnaires were analysed and we have performed an economic assessment of the impact of each scenario on the manufacturing industry. In the first approach the responses were limited, and the outcome led to unanswered questions. On request of the Commission a further inquiry was made into the reasons for unexpected high cost increases that were reported by some manufacturers and not by others. This led to an adjusted evaluation and a further ‘option’.

12.2 Scenario description

In our first approach two basic options for the possible Stage 2 were formulated, with a further variant of option 2 for petrol engines (option 2A). The assumed year of implementation is 2012. For reasons outlined below (subsection 12.5) on request of the Commission a further option (indicated as 2B) was subsequently added for the diesel engines, as a result of the first cost analysis of the options 1 and 2. Petrol engines Option 1: The current 4-stroke limits become valid for all engines, independent of technology.

Assumed technology: the conventional 2-stroke will disappear; 4-stroke and DI 2-stroke only. Option 2: HC+NOx would be limited to 75 % of the current 4-stroke limits; this would bring it at the level of the CARB 2008 outboard rule in the USA.

Assumed technology: for 4-stroke secondary air injection and oxidation catalyst, for DI 2-stroke engine optimisation and possibly an oxidation catalyst. Option 2A: The same as above but for engines > 30 kW only; for engines < 30 kW and for PWC option 1 would apply.


Diesel engines Option 1: The limits for the NRMM (non-road mobile machinery) stage IIIA for engines meant for the propulsion of inland waterway vessels would apply. Note that in that case there are no limits for engines < 37 kW, so they would stay with the RCD Stage 1 limits. Option 2: The limits for the NRMM (non-road mobile machinery) stage IIIA for general use would apply. Note that engines in the range 18-37 kW do stay with the NRMM II limits and engines < 18 kW are not included, so they would stay with the RCD Stage 1 limits. Option 2B: The limits for the NRMM (non-road mobile machinery) stage II would apply.

12.3 Qualitative description of the impacts on the industry

The consequences of the originally proposed options were discussed with the industry concerned by means of a questionnaire, followed by further correspondence where questions arose or situations needed further clarification. The evaluation was primarily based on the technologies required to fulfil the emission requirements, and secondarily on the price consequences indicated by the manufacturers. In the case of petrol engines there was sufficient harmony between the first responses to base our calculations on. The situation concerning diesel engines turned out to be more complicated. The first answers received showed significant variance, and in some cases differed significantly from our own automotive experience. On further investigation the differences could be attributed to significantly different positions of the manufacturers concerning the technologies needed. This is discussed in more detail below.

12.3.1 Petrol engines RCD Stage 1 Already for the compliance with the Recreational Craft Directive Stage 1 changes and investments will be needed by the industry. Conventional 2-stroke (outboard) engines will not be able to comply with the emission limits of Stage 1. Therefore, this engine type will no longer be produced and sold at the European market. European customers will have to purchase more expensive 4-stroke engines or modern DI 2-stroke engines. For inboard engines and 4-stroke engines there will not be a significant change due to Stage 1. Investments needed for RCD Stage 2 To comply with the possible new requirements due to the RCD Stage 2 additional research and development activities will be required. The size of the required investment depends on the scenario and engine type; see Table 12.1 below.


Table 12.1: Overview of the technologies needed under the defined options for different petrol engine types.

Type / fuel Option 1 Option 2 Option 2A Outboard DI 2-stroke petrol Partly redesign to 4

stroke limits DI 2-stroke engine optimisation

Ditto for > 30 kW

4-stroke petrol No changes needed Precise carbureti-on or electronic fuel injection

Ditto for > 30 kW

4-stroke petrol No changes needed Precise carbureti-on or electronic fuel injection

Ditto for > 30 kW

12.3.2 Diesel engines For the diesel engine manufacturers the situation is more complicated. Basically there are three main factors that appeared to determine the additional technology needed, and hence the costs, to comply with a possible Stage 2 legislation: − Is the manufacturer concerned active on the automotive market as well, or not? − In what power range are his engines? − For what power density are his engines designed? These three questions will be discussed first. Is the manufacturer concerned active on the automotive market Some manufacturers of marine engines are active on the automotive market as well as on the non-road market, whereas others are not. And of the latter category some are using their basic engines both for marine use and for other non-road applications, whereas others stated that some of their engines were exclusively used for marine applications. Marine engines that are based on automotive engines are generally of more advanced design (due to the more ‘advanced’ state of the automotive legislation), and consequently have lower ‘natural’ emissions. This will permit the manufacturer to meet Stage 2 limits without (or at least without major) engine redesign and with less sophisticated add-on equipment. Engines that are not based on automotive designs are usually of more robust but also more traditional designs, and consequently are less easy to adapt to more stringent emission requirements. Likewise engines that are also used for non-marine NRMM purposes will have to meet future NRMM legislation in other applications than marine use anyway, whereas engines dedicated to marine applications do not have such synergy opportunities. This reflected in the answers we received from the industry about the financial consequences of a Stage 2 legislation. The power range of the engine From the answers we received on our questionnaire to the industry it was clear that smaller engines (lower power levels) are more easily to adapt than bigger engines (higher power levels). This means that the additional cost will be higher for bigger engines than for smaller engines. But since bigger engines are also more expensive as they are, this tends to level out the relative cost increase. The power density of the engine Engines designed for high power density (such as used for planing boats) are more difficult to adapt to more stringent emission requirements than engines with a lower power density. Measures like EGR tend to reduce the air excess ratio to unacceptable levels, necessitating either an increase in cylinder displacement or 2-stage turbocharging. This will sooner be the case for high power density engines than for low power density engines. Increased cylinder capacity will mean engine redesign,


unless a higher capacity engine happens to be available already. Two-stage turbocharging will mean significant added cost plus testbed time for system matching. The considerations outlined above mean that there were basically two sets of answers to the question which technologies would be needed for the options we had proposed: those from manufacturers that use basically automotive engines, and those from manufacturers that do not. These answers are outlined in Table 12.2 below. After due consideration of this situation we decided that it would not be meaningful to mix these answers. It is true that such mixing would result in an ‘average’ market effect, but the consequences for an individual manufacturer would not be average: they would be either of the one kind, or of the other. So we decided to present these two situations as two different cases. Table 12.2: Overview of the technologies needed under the defined options for

different diesel engine types. Option 1 Option 2

Engines based on automotive design Mechanical injection still possible

On modern designs only readjustments needed (such as timing control)

On older designs possibly increase of cylinder capacity or rematching of turbo-charging activity/charge cooling

More adaptations on high power density engines than on low power density engines

Full electronic injection

Either more EGR or multiple injections

On high power density engines either 2-stage turbocharging or more cylinder capacity

On low power density engines higher degree of turbocharging or more cylinder capacity

Possibly charge cooling and cooled EGR

Cost: 0 to a few % for modern designs up to 10 % for older designs

Cost: up to 30 %

Extra for engines not based on automotive design

Increased injection pressures (PM control)

Electronic fuel injection: < 130 kW: partial electronic control

> 130 kW: full electronic control

Optimisation of combustion chamber design

Optimisation of NOx-PM balance

(full electronic control of injection)

Further increase of injection pressures relative to option 1 (for PM control)

Certainly charge cooling

Certainly cooled EGR (for NOx control)

Combustion chamber redesign for multiple valves

Cost: up to 33 % for the total package Cost: up to 60 % for the total package

The following additional remarks were made: − Increased injection pressures are best obtained with common rail injection.

Although by now common on automotive engines, at the moment such systems for marine engines are produced in extremely small quantities and are therefore disproportionately expensive.

− The marine test cycles of ISO 8178 are more high output orientated than the non-road cycle, which means that the same numerical NOx emission requirements require stronger measures, such as even higher EGR rates for marine engines. This in turn calls for higher air delivery, either by a further increase of cylinder capacity, or by higher turbocharging activity (2-stage turbocharging and/or charge cooling).


− The necessity to use water cooled exhaust manifolds reduces turbo efficiency, also meaning that measures like increase of cylinder capacity, inlet charge cooling and 2-stage turbocharging are necessary sooner than on non-marine engines.

− The difficult part of the NRMM stage IIIA for commercial marine engines is not primarily the reduction of NOx (9.8 to ~ 7 g/kWh), but the fact that this has to be obtained simultaneously with a reduction in PM (from 1.0 to 0.4/0.3 g/kWh), and even more so for the stage IIIA for general use, where NOx has to be reduced still further (to 4.7/4.0 g/kWh) at similar PM levels (in some cases even going down to 0.2 g/kWh). It is especially this aspect which calls for (advanced) electronic fuel injection and multiple injection strategies.

− The fact that on engines not based on automotive designs electronic injection control is needed sooner, and to a greater degree, than on automotive design based engines, is also caused by the fact that such engines are sooner reaching the limits of either the possibilities for further NOx-reduction or of further PM-reduction, thereby seriously limiting the possibilities to solve the problem by re-optimisation. Manufacturers of such engines need electronic control especially since it allows them the necessary flexibility.

Generally speaking larger manufacturers expressed the opinion that option 1 was to be preferred, since it could be met by marinisation and rating development only, and would furthermore provide full harmonisation with the US legislation, allowing manufacturers to develop a common engine specification for both markets. This was stated to provide the best cost/benefit solution towards ‘challenging’ emission limits, without disadvantaging European engine manufacturers. Concerning option 2 it was stated that for manufacturers who only produce non-road engines this needs structural redesign of the engine, which is not justified by the low production volumes involved, rendering this option only economically feasible for engines based on designs developed for automotive application. On request of the client a further option (option 2B) was added, which means that diesel engines for recreational marine use will have to comply with stage II of the NRMM. As outlined in subsection 7.2.5 and calculated in subsection 8.1.2 this stage involves a reduction in NOx, relative to the RCD Stage 1, but virtually without a simultaneous reduction in PM. Hence such an option might be attainable with engine recalibration without necessitating engine redesign or the use of expensive electronic injection strategies. Due to the contract running out, the contractor was not in a position to verify this option with the industry concerned, so we have tried to approach it with intelligent guesses based on the information that had been provided in combination with our general expertise. This led to the following evaluation. Table 12.3: The overview of technologies needed for option 2B. Engines based on automotive design Not based on automotive design Mechanical injection still possible On low power density engines only

readjustments needed (such as timing control)

On high power density engines possibly rematching of turbo-charging activity/charge cooling

Mechanical injection still possible On modern designs only readjustments

needed (such as timing control) On older designs possibly increase of

cylinder capacity or rematching of turbo-charging activity/charge cooling

More adaptations on high power density than on low power density engines

Cost: 0 to a few % Cost: 0 to a few % for modern designs up to 10 % for older designs


12.4 Determination of the economic consequences

For the manufacturer there are two kinds of cost involved: R&D costs and additional production costs. The R&D costs are a fixed amount that needs to be amortised over a number of products sold, determined by the amortisation time needed (in years) multiplied by the annual production; the resulting cost per unit of product depends on the number of engines sold over that period. The additional production costs are, as a rule, a fixed amount per engine, and hence not dependant on series volume. Big versus small manufacturers There can also be big differences between the price consequences for different manufacturers and types of engines. The following table presents a fictive example for the cost calculation for investments in new engines for the manufacturers. Table 12.4: Example of a cost calculation for the investment in new engines.

Aspect Calculation Result (1) Output power of engine 100 kW (2) Sales volume in Europe a) 500 units

b) 1000 units c) 2000 units

(3) Capital costs for engine family € 2,500,000 (4) Variable cost per engine unit € 100 (5) Amortised capital cost to be recovered over engine sales in this model year

(3) * 0.14 = this year’s payment on a loan used to cover the increased capital cost where the annual interest rate is 7% and the production period of the engine family is 10 years

€ 350,000

(6) Total annual increase in variable engine costs

(4) * (2) a) € 50,000 b) € 100,000 c) € 200,000

(7) Manufacturer’s total annualised cost for this engine family

(5) + (6) a) € 400,000 b) € 450,000 c) € 550,000

(8) Total costs to the manufacturer per engine

(7) / (2) a) € 800 b) € 450 c) € 275

From the table above it becomes clear that the size of the sales volume is an important aspect in the determination of the additional costs and price increase per engine. The fixed costs for the research and development on a new engine family are rather similar for different manufacturers whether they produce 1,000 or 10,000 engines. For bigger manufacturers it is therefore easier to re-earn the investment. As a consequence prices don’t have to be increased as much as compared to the engines produced in smaller series by smaller manufacturers. Harmonisation For reasons of ‘scale advantage’ large manufacturers favour international harmonisation. They then don’t have to do separate research and development efforts for different markets (e.g. Europe and USA). And they are able to create scale advantages by producing the same engine type for a world-wide market. It is even acceptable for them to have more stringent emission restrictions which cause more R&D needs to comply with them, as long as there is a harmonisation between USA en Europe. Due to the scale advantage they expect that the cost for the user and industry are smaller compared to separate and different legislation between the EU


and USA. For this reason the big manufacturers favour a full alignment with the rules in the USA set by EPA and CARB. On the other hand small marine engine manufacturers with a local market (e.g. only a national country or limited to the EU) don’t have this argument since their scale of production is limited. These smaller manufacturers clearly are in favour of less strict emission standards to reduce the costs of Research and Development. Their scale of production is limited and therefore they have fewer possibilities to offset the costs for R&D. Furthermore manufacturers only selling in the EU don’t have any benefit from harmonisation with the emission regulations in the USA. On the contrary, harmonisation of RCD Stage 2 with the USA regulations will weaken their competitive position because the bigger manufacturers will be able to create scale advantages. In this way the big brands will be able to offer a lower price for their engines to the consumers compared to the ability of smaller manufacturers. The position of SMEs operating in the European market only can therefore be seriously threatened. Price elasticity Due to a high price elasticity of marine engines it is likely that the sales will decline as result of the price increase. The elasticity of demand for boats has been modelled by US economists by running regression calculations on historical price/sales data and is estimated at -2 % per % price increase:

Elasticity of demand for boats = -2 % / 1 %

In other words, when the price of a boat goes up one percent, sales go down two percent. A real-life example of this demand/price relationship was borne out by the experience of the luxury tax on boats in the US in the early 1990s. The imposition of a 10% tax on boats caused a unit sales drop of between 18 and 30% across various boat categories. During the duration of this luxury tax, small companies (both manufacturers and dealers) were unable to sustain such a dramatic shift in demand, forcing many into bankruptcy and permanently out of the industry. Even though the luxury tax was effective during only two years, the high number of bankruptcies and facility closures it caused had a long-lasting impact on the US boating industry. This high elasticity implies that for example a price increase of 5 % will result in a reduction of the number of engines sold of 10 %. This elasticity also applies for purchases by consumers. In case of a price increase on an outboard engine customers can decide to postpone the investment in a new engine and to keep the old engine for a longer period. Furthermore the newcomers on the market will easily fall back to purchasing second hand engines or boats if the prices for new engines and boats increase. It should be noted as well that the marine industry for recreational craft has significant competition coming from other luxury and vacation industries. Therefore it can be expected that significant price increases will result in a loss of revenues and perhaps also jobs in the manufacturing industry. More service needed On the other hand the engines will become more complex and sensitive since sophisticated engine management systems and even catalysts might be required. It can be expected that more intensive repair and maintenance will be necessary. This


leads to increased operational costs for the industry (warranty cases) and user. Cost for warranty cases could go from 0.5 % to 5 % according to the industry, leading to an increase of servicing costs of 15 % on a European scale under option 2. This will, however, imply that the business for maintenance and repair will grow. The dealers could therefore face a decline of new engine sales but an increase in the repair and maintenance revenues.

12.5 Quantification of effects for the manufacturers

Approach and methodology Based on the results of the interviews and questionnaire send out to the manufactures and information concerning the market (sales volume and prices), the effects for the industry have been quantified to the extent possible. Unfortunately it was not possible to analyse the PWC market due to a lack of information and input from the manufacturers concerned. The analyses are therefore split into outboard engines and inboard petrol and diesel engines. Outboard engines represent some 80% of the market. The remaining 20% are inboard engines. Outboard engines The outboard engines are all petrol engines in 2-stroke or 4-stroke configuration. As result of the RCD stage 1 the sales of conventional 2-strokes will already be replaced by DI 2-strokes and 4-strokes. New DI 2-stroke models will therefore be developed to replace the conventional 2-strokes in the engine programme of manufacturers. However, DI 2-strokes and 4-strokes will be more expensive than the conventional ones. Due to this change as result of RCD Stage 1 the average price of outboard engines is expected in increase by 9 %. Due to the high price elasticity it is expected that the sales volume (in units) will drop by 14 %. As a result the total turnover of outboard engine sales in Europe is expected to drop by 6 %. For the first option of the RCD Stage 2 additional investments are needed for the DI 2-stroke models. No additional R&D is needed for 4 stroke models. As a result of the first option it is therefore expected that only DI 2-stroke engines will become more expensive. The estimated price increase of this engine type is 6 %. The impact on the total sales volume in Europe is estimated to be a decrease of 0.2 %. Consequently the revenues are expected to decrease with 0.25 %. This may be considered to be a rather limited impact. By the time of the implementation of the RCD Stage 2 it is likely that consumers will buy a 4-stroke engine instead of a DI 2-stroke. The market of the DI 2-strokes is not expected to become very big. The DI 2-strokes will be competitive mainly in the market for the bigger engines (> 100 kW). As a result of the limited market size the impact of a price increase of DI 2-strokes on the overall market is limited as well. For the second option of the RCD Stage 2, investments will also be needed for the further development of 4-stroke outboard engines. These engines need more precise carburetion or electronic fuel injection to provide the same power at lower emission levels. Also the DI 2-strokes need further attention to comply with the limits. Cost related to option 2 of RCD Stage 2 for outboard engines is estimated to increase with 3 % resulting in an increase of 3 % on the retail price for the consumer. The


estimated impact on the European sales volume is a relative decrease of 6 %. The impact on revenues is a decrease of 3.2 %. For option 2A the impact is only relevant for engines > 30 kW. The expected impact is a sales volume reduction of 1.5 % and a reduction in revenues by 1.9 % Inboard engines Inboard engines running on petrol have a market share of about 15 % of all inboard engines. The remaining 85 % of the inboard engines are running on diesel fuel. These engines are being sold to boat builders (business to business). Since the final customer buys a boat (including the engine) it is necessary for the analysis to make an estimate on the cost share of the engine. The cost share of an inboard engine with respect to the overall price of the boat differs and is strongly dependant on the type of boat. For large, heavy displacement craft and sailing yachts the cost share of the engine is 10 %. For yachts with high power engines calculations present a cost share of 25 %. For powerboats used near the coast and on larger lakes the engine plays an even more important role. For these powerboats the cost share of the engine can run up to 50 % of the total retail price of the boat. Therefore there is a large bandwidth in the actual cost share of the engine. Observing the market we see that the number of powerboats is rather limited. Moreover the majority of the sales volume is determined by the smaller motorboats with inboard engines in the range of 30-50 kW. Therefore it is justified to use for the further calculations an estimated average cost share of 15 %. The bandwidth needs to be kept in mind by the reader, however, when interpreting the results. Inboard petrol engines Petrol fuelled inboard engines will have to comply with the same regulations as the outboard engines. Inboard engines are all 4-stroke engines. For RCD Stage 2 option 1 there is no effort needed to improve the engines. For the second option a range of extra measures is needed. The cost increase is estimated by the industry to be 3 %. These engines are being sold to boat builders. The cost share of an engine can differ but on average is estimated to be 15 %. A 3 % increase on this cost component will therefore have an impact on the price of the boat of +0.45 %. As a result of this price increase there is a reduction of demand of 0.9 % and consequently the revenues of the engine manufacturer increase with 2.1 %. For option 2A the impact is smaller than for option 2 since for engines with a power below 30 kW option 1 applies. So in option 2A the price increases will only occur for engines over 30 kW. The impact is therefore expected to be half that of option 2: a reduction in demand by 0.45 % and an increase of revenues by 1.05 %. Inboard diesel engines In our first approach the diesel fuelled inboard engines had to comply with proposed limits for commercial vessels in option 1. We received input specifically concerning the diesel inboard engines from manufacturers regarding the necessary technology, investment and expected price increases.


For diesel engines it is more difficult to comply with the required limits and drastic changes are needed compared to RCD stage 1. The engines either need to be equipped with more expensive and more sophisticated components and techniques available on the market, or have to be partly redesigned concerning their combustion chambers. For the second option additional R&D is necessary and even more sophisticated techniques and systems are required. It was found that the cost effects differ between manufacturers. Especially manufacturers that are not active on the automotive market have high research and development costs and need to redesign the engines. For this reason the quantitative effects are split into 2 groups: 1. Manufacturers dedicated to the production of marine engines: Option 1 As a result the price of a marine diesel engine will increase with 33 %. Given the average share of 15 % on the total price of a boat, the price of the boat would increase with 5 %. As a result of price elasticity of 2 the number of boats and their inboard diesel engines are expected to drop by 10 %. However, given the small (average) impact on the price the total revenues of the diesel inboard engine manufacturers are expected to increase by 20 %. Option 2 As a result the price of a new marine diesel engine will increase with 60 %. Given the average share of 15 % on the total price of a boat, the price of the boat would increase with 9 % and the volume of inboard diesel engines sold to boat builders is therefore expected to drop by 18 %. The impact on the revenues for the manufacturers of marine diesel engines is estimated to be +31 %. 2.) Manufacturers active as well in the automotive industry: Option 1 The expected price increase under option 1 is between 0 and 10 %. Given the average share of 15 % on the total price of a boat, the price of the boat would increase between 0 and 1.5 %. As a result of price elasticity of 2 the number of boats and their engines are expected to drop with a maximum of 3 %. The total revenues of the diesel inboard engine manufacturers are expected to increase with 0 - 7 %.

Option 2 The expected price increase under scenario 2 is 30 %. Given the average share of 15 % on the total price of a boat, the price of the boat would increase with 4.5 %. As a result of price elasticity of 2 the number of boats and their engines are expected to drop with 9 %. The total revenues of the diesel inboard engine manufacturers are expected to increase with 18 %.

12.6 Option 2B

Option 2B for diesel engines was introduced when it became clear that the price consequences of even option 1 could be very high for one class of manufacturers: those that built engines that were not based on automotive base engines. Consequently this option was introduced at a late stage. It would have the following consequences, when we base ourselves on the assumptions of Table 12.2. For engines not based on automotive designs the expected price increase is between 0


and 10 %. Given the average share of 15 % on the total price of a boat, the price of the boat would increase between 0 and 1.5 %. As a result of price elasticity of 2 the number of boats and their engines are expected to drop with a maximum of 3 %. The total revenues of the diesel inboard engine manufacturers are expected to increase with 0 - 7 %. The consequences for engines based on automotive designs are likely to range from 0 to a fraction of the maximum effects given for engines not based on automotive designs (for the calculation we based ourselves on 50 % maximum). What this is going to mean for individual manufacturers is not easy to indicate on the basis of the current information. Of the large manufacturers some do use automotive based designs and hence would be minimally affected by an NRMM stage II harmonisation, and not even very seriously by an NRMM stage IIIA harmonisation with commercial marine engines. Other large manufacturers produce for the non-road market only or, in the case of some of their engines, even for the marine market only, but sell world-wide and hence would still welcome a harmonisation with stage IIIA of the NRMM for commercial marine engines, since this would provide harmonisation with the US legislation. Small OEMs, on the other hand, are likely to be hit harder by anything exceeding a harmonisation with the NRMM stage II, because on the one hand they are more likely to need to redesign their engines and on the other hand this will have more serious consequences for their production costs because of their small series volumes. And they will not be in a position to offset this by any internal harmonisation of their production, since they are likely to operate on a limited market only rather than world-wide. In the case of marinisers, however, the likelihood of automotive based engines being used for such marinisation, especially in the case of smaller engines, is rather large. In such cases the manufacturers should not have much difficulty in meeting the standards for commercial marine engines. But for marinisers that base themselves on small industrial engines, who are known to exist as well, clearly the opposite will be the case. RECOMMENDATION Although the survey reported in this Section brought these various aspects to light, the extent of the contract did not allow an extensive further investigation of the full extent of the market in this respect. So the considerations given in this subsection can only lead to the recommendation to make this the subject of a separate dedicated investigation that should shed more light on the exact dimensions of the problem.

12.7 Secondary effects

There will, of course, not only be effects for the engine manufacturers. As already shown in the previous subsections, there are also decreases to be expected in the number of new boats sold. As a result there will be an impact on other places in the maritime/yachting cluster, such as the boat building industry, the equipment and service providers, and the maintenance and repair facilities. Based on a report “Economic Impact of Maritime Industries in Europe” the turnover of the yachting industry was already 3 billion Euro in 1997. Countries dominating this industry are France, United Kingdom and Italy, while Germany, the Netherlands and Sweden form the sub-top. The direct added value of this sector in the EU was 1 billion Euro and the indirect added value was 1.6 billion Euro. Direct employment in 1997 was 33.000 and indirect employment another 32.000 persons. Therefore it can


be concluded that there is a multiplier effect of 1.6 when looking at the indirect effects of the yachting industry. The water recreation industry is much bigger than the yachting industry alone. Already in the Netherlands1 the production value of the water recreation industry is estimated to be 1.2 billion Euro, with an export value of 47 %. The direct added value is 600 million Euro (figures year 1999). Figure 12.1 shows the relevance of each sub-sector. Figure 12.1 Relative shares of sub-sectors in the direct economic significance of the

Dutch water recreation industry

The water recreation industry does also make a further contribution to other sectors of the economy. The indirect effect of the production value is estimated at another 600 million Euro (1999). The total value of the water recreation industry in the Netherlands is therefore estimated on 1.8 billion Euro. The consumer plays an important role since near 50 % of the revenues is generated directly by consumer expenditures. Moreover due to the high price elasticity the water recreation industry can be marked as being very sensitive to price changes. This has also been shown by the study in the USA on the introduction of luxury tax, referred to in subsection 12.2 (under the heading ‘price elasticity’). It was also found that the biggest trading volume within the water recreation industry is the supply of ship parts to the yacht building industry. Given the cost share of the engine, in this supply chain the procurement of marine engines is rather significant. Based on the above mentioned facts, which are based again on studies on the European maritime cluster and on the Dutch water recreation industry, it is clear that price increases of engines and boats will result in significant impacts in other sub clusters and have an impact as well on other parts of the economy (e.g. hotel and catering). Studies show that there will be a multiplier effect of 1.6.

1 The Netherlands is number 5 in Europe with respect to yachting with a turnover of 250 million Euro (1997)


12.8 Conclusions regarding economic impacts of RCD Stage 2

Given the impacts on the prices and volumes as discussed, the following table presents the overview of market impacts. Table 12.5: Impacts on retail price, volume and revenues for the various options.

Retail price Volume Revenues Option 1 Outboard +2 % for DI 2-stroke -0.2 % -0.25 % Inboard petrol - - - Inboard diesel based on automotive design

0 to +10 % 0 to -3 % 0 to +7 %

Inboard diesel not based on automotive design

+33 % -10 % +20 %

Option 2 Outboard +3% -6% -3.2% Inboard petrol +3% -0.9% +2.1 Inboard diesel based on automotive design

+30 % -9 % +18 %


+60 % -18 % +31 %

Option 2A Outboard > 30 kW +1 % -1.5 % -1.9 % Inboard petrol > 30 kW +3 % -0.45 % +1.05 % Option 2B (estimated effects) Inboard diesel based on automotive design

< 5 % < 1.5 % < 3.5 %


0 to +10 % 0 to -3 % 0 to +7 %

For the inboard engine market the number of units sold on the market is expected to reduce but the revenues of these manufacturers will increase. The biggest impact is expected on the inboard diesel engine manufacturers as the price increases are significant (33 % for option 1 and 60 % for option 2). However due to the fact that this is a business-to-business market (B2B) the impact on the actual sales volume is limited. From the tables above it becomes clear that the revenues are expected to fall for manufacturers active in the outboard market. The outboard market is clearly more sensitive because of the fact that this is a business-to-consumer market (B2C). The total effect on the revenues in Europe is expected to be:

• 1.9 million Euro in the Stage 2 option 1 • 24.6 million Euro in the Stage 2 option 2 • 14.4 million Euro in the Stage 2 option 2A.

Secondary effects Based on studies on the maritime and water recreation industry it was shown that there are significant relations. Price increases of engines and boats will therefore result in significant impacts in other subclusters. They will even have an impact as well on other parts of the economy (e.g. hotel and catering). Studies show that there will be a multiplier effect regarding the secondary effects of 1.6.


12.9 References to this Section:

U.S. Environmental Protection Agency (EPA), Regulatory Impact Analysis; Control of Air Pollution; Emission Standard for New Nonroad Spark-Ignition Marine Engines, June 1996 Charles Komanoff & Howard Shaw, Ph.D., Drowning in Noise; Noise costs of Jet Skis in America, April 2000 TNO Automotive / European Commission DG Enterprise, Emission Regulation of PTW’s, Delft/ Brussels, February 2002 Policy Research Corporation and Institute of Shipping Economics and Logistics / European Commission DG Enterprise, Economic Impact of Maritime Industries in Europe, Brussels, 2001 Foundation Dutch Maritime Network, European Maritme Clusters, Rotterdam, November 2003 NEI & MERC / Foundation Dutch Maritime Network, Economic importance of Dutch watersport industry, Rotterdam, Rotterdam 1999


13 The possibilities for international harmonisation

13.1 The existing legislation

This subsection gives an overview of the existing exhaust gas legislation that is regarded to be relevant for the current study. For practical reasons this overview is divided into legislation concerning petrol engines (spark ignition or SI engines) and legislation concerning diesel engines (compression ignition or CI engines). In Europe two kinds of regulations exist. On the one hand there are EU-Directives, which are binding for all relevant situations in all EU Member States, and on the other hand there are requirements which are valid for a certain local area or a certain body of water, declared binding by national or even local governments for the area or body of water concerned, on the basis of mutual agreements. On the US side there is the national (federal) legislation, issued by the EPA (Environmental Protection Agency) and there is a Californian State legislation, issued by the CARB (Californian Air Resources Board). In view of the technological possibilities not only the legislation concerning marine engines has been selected, but also some legislation that was regarded as concerning sufficiently comparable classes of engines.

13.1.1 Petrol engines The following legislation was regarded to be relevant for the current study: EUROPEAN UNION Concerning marine use: • The EU Recreational Craft Directive (RCD) 94/25/EC as amended by 2003/44/EC Concerning general use: • The Non-Road Mobile Machinery Directive (NRMM) 97/68/EC as last amended

by 2004/26/EC (stages 1 and 2) LOCAL EUROPEAN • The Bodensee Schiffahrts Ordnung (BSO) Stage I (1993) and stage II (1996),

valid for the Bodensee (Lake Constance) only, and issued by the local authorities of the Länder and Kantons bordering on that lake.

USA Concerning marine use: • US 40 CFR Part 91: Control of emissions from marine SI engines (EPA outboard

rule) • EPA evaporation emission rule (currently a Notice of Proposed Rulemaking -

NPRM) • California CCR 13 Article 4.7: SI marine engines (CARB outboard rule) • Ditto (CARB sterndrive/inboard rule) Concerning general use: • US 40 CFR Part 90: Control of emissions from non-road SI engines at or below 19

kW.


The EU-RCD differentiates between 2-stroke and 4-stroke engines. The components addressed are CO, HC and NOx.

The EU-NRMM differentiates between ‘handheld equipment’ (SH) and ‘non-handheld equipment’ (SN). Both categories are subdivided into classes based on engine capacity (swept volume). The components addressed are CO, HC and NOx for SH stage 1 and CO and HC+NOx for SH stage 2 and for SN stages 1 and 2. Due to the late date of publication of the amendment, for SN the introduction period of stage 2 was already relevant at the entry into force of the amendment.

The BSO is a local regulation, specially conceived for application on the Bodensee (Lake Constance). It is applied by the local Austrian, German and Swiss Länder and Kantons bordering on that lake. The components addressed are CO, HC and NOx. Switzerland currently uses the BSO stage 1 for its national legislation, but considers adopting the RCD procedures, although with lower limits. Austria and Germany, as Member States of the European Union, will have to transpose the emission requirements of Directive 2003/44/EC into their national legislation and to amend their existing legislation on the Bodensee to bring it in line with this EU legislation.

On the US side the EPA legislation is federal and applies to the ‘49 States’ (i.e. other than California). It concerns outboard engines only (but including PWC). The components addressed are HC+NOx. For future legislation the EPA is considering the inclusion of CO, however (see subsection 13.2).

California is allowed to have its own legislation. There are different regulations for outboard engines (but including PWC) and sterndrive/inboard engines. The components addressed are HC and NOx for outboard engines and HC+NOx for sterndrive/inboard engines. Table 13.1: Scope and test method.

area/region scope test method

loca

l

BS

O all new diesel and SI

propulsion engines in craft used on the Bodensee

ISO 8178 test cycle E4

EU

R

CD

all new diesel and SI propulsion engines intended for recreational craft

between 2.5 and 24m

ISO 8178 test cycle E4

EUR

OPE

Euro

pean

Uni

on

EU

N

RM

M

SI engines

intended for non-road machinery with a power of ≤19 kW

ISO 8178 test cycles C1 and D2

CA

RB

R

ule SI engines for recreational craft

(excluding sterndrive and inboard engines) intended to be sold in California

same as ISO 8178

test cycle E4

outb

oard

/ P

WC

EP

A

Rul

e SI engines for recreational craft (excluding sterndrive and inboard engines)

same as ISO 8178

test cycle E4 USA

ster

ndriv

e in

boar

d en

gine

s

CA

RB

S

D/I

Rul

e Sterndrive and inboard engines for recreational craft

intended to be sold in California

same as ISO 8178

test cycle E4


General details concerning scope and test method are shown in table 13.1 above. It shows that the BSO is a local regulation for one particular lake, but currently relevant for users both from EU Member States and non-EU Member States using their boats on that lake. Its coming about was described in subsection 1.1. The other legislation is general legislation, covering all legal territory of the governmental body concerned. That is either the EU on this side of the Atlantic, or the US Federal territory or California on the other side of the Atlantic. The test methods are universally based on ISO 8178, even that of the BSO, which originally had its own test procedure. Apart from these regulations some local authorities may have adopted the BSO for local circumstances, or a national legislative body (such as Japan) may accept one of the other regulations shown in these two tables. This effectively means that there are only two legislative areas involved (reflecting a similar picture of the market, see section 3), with the North-American legislation further divided into Californian and US Federal. This in turn means that any attempt towards international harmonisation can effectively be approached as a bilateral transatlantic problem, rather than in a world-wide forum like the UN-ECE. Table 13.2 shows additional requirements to the basic legislation. With the exception of the EU-NRMM Directive all regulations refer to “in-use compliance” (but see Section 9). For the EU-NRMM Directive an approach of ‘averaging’, ‘banking’ and ‘trading’ was proposed, but not adopted, although there is a ‘flexibility scheme’ that allows a certain degree of exeedance of members within a family. The EPA Rule allows for all of this, whereas the CARB Rules only refer to ‘averaging’. Such ‘averaging’ allows for a phase-in, which is by now accepted custom in the US, but still new for the EU. This aspect is further discussed in Section 10.4.4. Figure 13.1 shows the implementation dates for the various legislations. As can be seen, all this legislation is of current date, either from the recent past, or to be implemented in the near future. Tables 13.3-13.5 list the formulae and parameters that determine the limit values. The general approach is to make the limit values dependant on the nominal power of the engine in the case of CO (where applicable) and HC or HC+NOx in the case of boat engines, or at least outboard engines. This approach was chosen since early investigation into the emission behaviour of such engines showed this to be the ‘natural’ behaviour of outboard engines. For the limitation of NOx the tendency is to set a fixed limit; the fact that it is still expressed in the form of a formula (of which the variable part is then set at 0) has to do with an internal harmonisation of the shape of the presentation. The BSO and the RCD apply this approach to all boat engines, whereas the Californian legislation only applies it to outboard engines, and treats sterndrive and inboard engines similar to other non-road applications. The EPA Rule applies only to outboard engines anyway.


Table 13.2: Additional requirements.

BSO

(s

tage

2)

EU

RC

D

EU

NR

MM

CA

RB

ou

tboa

rd R

ule

EPA

ou

tboa

rd R

ule

CA

RB

S

D/I

Rul

e

Averaging 1 - - - 6 yes yes yes

Banking 2 - - - - yes -

Trading 3 - - - - yes -

In-use compliance testing yes Yes 5 - yes yes yes

NTE 4 - - - - - -

Notes: 1: Averaging means the exchange of emission credits between families within a given manufacturer’s

product line 2: Banking means that within the banking system a manufacturer may save credits from one year to

another to meet the average 3: Trading means that a manufacturer may buy or sell credits from or to another manufacturer 4: NTE (not-to-exceed zone) is a zone under the engine’s power curve where the engine may not

exceed a specified emission standard 5: EU-RCD: In its current stage the RCD requires a durability test as part of the conformity

assessment procedure. Two years after the entry into force of the Directive, the Commission shall submit a report on the possible benefits of an in-use compliance system (Article 2a)

6: EU-NRMM: there is a ‘flexibility scheme’, see text Figure 13.1: The dates of entry of the emission legislations in force or considered for spark

ignition (SI) engines. BSO EU-RC EU-NRMM CARB

outboard CARB

sterndrive/ inboard

EPA outboard

EPA evaporation

Rule 1993

1994

1995

1996

1997

phase-in stage 2 from stage 1 during period 2007-2008

phase-in, starting 1998 MY until 2006 MY with a 8.3% reduction each year

1998

introduction of stage 2 for different classes in the periods 2004-2007 and 2007-2008

1999

2000

2001

2002

2003

2004

2005 4-S

2006 2-S

2007

2008

2009

2010

Stage 1 Stage 2 Stage 3

≥30 kW only

all engines

SN SH


Table 13.3: Exhaust limit requirements BSO BSO

Stage 1 Stage 2

kWhginPACO m

N !"=

kWhginPACO m

N !"=

P [kW] A m P [kW] A m P<4 600 0.5

4<P<100 600 0.5 30<P<100 400 0.6505 P>100 60 0 P>100 20 0 C

O [

g/kW

h]

Mass emission: 4500 g/h Mass emission: 1500 g/h

kWhginPAHC m

N !"=

kWhginPAHC m

N !"=

P [kW] A m P [kW] A m P<4 60 0.7747

4<P<100 39.39 0.4711 30<P<100 30 0.6505 P>100 10.13 0.1761 P>100 3.375 0.1761 H

C [

g/kW

h]


kWhginPANO m

NX !"=

kWhginPANO m

NX !"=

P [kW] A m P [kW] A m P<4 15 0

4<P<100 15 0 30<P<100 10 0 P>100 15 0 P>100 10 0 N

Ox

[g/k

Wh]


Table 13.4: Exhaust limit requirements EU.

EU EU-RCD EU-NRMM

kWhginPBACO n

N !"+=

Cate- gory 1

stage

1

stage

2 A B n SH 1,2 805 805

2-str. 150 600 1 SH 3 603 603

CO

[g

/kW

h]

4-str. 150 600 1 SN 1-4 519 610

kWhginPBAHC n

N !"+=

Cate- gory 1

stage

1

stage

2

A B n SH 1 295 2-str. 30 100 0.75 SH 2 241 4-str. 6 50 0.75 SH 3 161

HC

[g

/kW

h]

SH 1-3 5.36

Lim

its a

re fo

r H

C+N

Ox

(see

bel

ow)

all figures below are for HC+NOx

kWhginPBANOx n

N !"+=

SH 1,2 - 50 A B n SH 3 - 72

2-str. 10 0 0 SN1 50 50 4-str. 15 0 0 SN2 40 40

SN3 16.1 16.1 SN4 13.4 12.1

NO

x

[g/k

Wh]

NOx < 10 for stage 2 1 SH1: Handheld machinery < 20 cm3

SH2: Handheld machinery 20 –50 cm3

SH3: Handheld machinery >50 cm3

SN1: Non handheld machinery <66 cm3

SN2: Non handheld machinery 66 - 100 cm3

SN3: Non handheld machinery 100 - 224 cm3

SN4: Non handheld machinery >224 cm3


Table 13.5: Exhaust limit requirements US. US

CARB outboard EPA outboard CARB

sterndrive/inboard

MY Limit P> 4.3 kW

B)557151( 9.0 ++!P

A B)557151( 9.0 ++!P

A

or C, whichever is lower 2003 16

MY A B MY A B C >2006 5

2001 0.25 6 1998 0.917 2.44 278

2004 0.20 4.8 1999 0.833 2.89 253 Small volume manufacturer

2008 0.09 2.1 2000 0.750 3.33 228 >2008 5

P< 4.3 kW 2001 0.667 3.78 204 MY Limit 2002 0.583 4.22 179

2001 81 2003 0.500 4.67 155

2004 64.8 2004 0.417 5.11 130

2008 30 2005 0.333 5.56 105

>2005 0.250 6 81

HC

+NO

x [g

/kW

h]

Family emission level: 2004: 80 g/kWh 2008: 44 g/kWh

Since the formulae and parameters in table 13.3-13.5 do not allow for an easy comparison of the degrees of legislation, the limit values are graphically represented in Figures 13.2 and 13.3 below. The emission of CO is generally regarded as of little importance, and for small petrol engines the emission of NOx is generally low. Hence only the emission limits for HC are shown where possible, or those of HC+NOx wherever these are specified instead. Figure 13.2 shows the HC limits for the EU-RCD, compared to the limits according to the BSO and those of the EU Directive for handheld equipment > 50 cm3 and non-handheld equipment > 224 cm3.

When comparing stringencies, the BSO 1 lies at the RCD 4-stroke level for low power output, but is more than 40 % lower for high power outputs. The BSO 2 is much more stringent than that, but there are actually no outboard engines certified for that level at the time of writing (see subsection 7.2.5).

Figure 13.2: Graphical representation of the limit values of Tables 13.3 and 13.4 for various European Regulations (NB: NRMM = HC+NOx).

1

10

100

1000

1 10 100 1000

nominal power [kW]

HC

[g

/kW

h] EU NRMM SH3 stage 2

EU RCD 2-Str

EU RCD 4-Str

BSO stage 2

BSO stage 1

EU NRMM SN4stage 2


The NRMM stage 2 limits for HC+NOx in the case of petrol engines vary from 72 g/kWh for small engines for handheld equipment (usually 2-stroke engines) to 12.1 g/kWh for bigger non-handheld equipment (usually 4-stroke engines). Both extremes are shown in Figure 14.2. In the interest of comparability an estimate was made for the applicable power ranges of these classes. Figure 13.3 shows a comparison between the limit values for HC+NOx for EU and US regulations for recreational boating. The upper graph shows a comparison between the HC+NOx limits according to the CARB outboard rule and according to the EPA outboard rule. The lower graph compares the EPA HC+NOx values with the sum of the values for HC and NOx of the EU-RCD.

When comparing stringencies, it shows that EPA >2005 is equivalent to CARB 2001, whereas CARB 2008 is set at 35 % of that. When comparing EU and US legislation it appears that the final level of the US-federal legislation for outboard engines for 2006 and beyond practically coincides with the RCD 2-stroke level. For 4-stroke engines the EU-RCD limits are ~50 % lower, but have been set about a third higher than those of CARB 2008.

Figure 13.3: Graphical representation of the limit values of Tables 14.4 and 14.5 for

EU, CARB and US federal Regulations (NB: HC+NOx).

1

10

100

1000

1 10 100 1000

nominal power [kW]

HC

+NO

x [

g/kW

h]

CARB outboard 2001

CARB outboard 2008

EPA outboard 2001

EPA outboard >2005

1

10

100

1000

1 10 100 1000

nominal power [kW]

HC

+NO

x [

kW]

EPA 2001

EPA >2005EU RCD 2-Str

EU RCD 4-StrCARB outboard 2008


13.1.2 Diesel engines The following legislation was regarded as relevant for the current study: EUROPEAN UNION Concerning marine use: • The Recreational Craft Directive (RCD) 94/25/EC as amended by 2003/44/EC • The Non-Road Mobile Machinery Directive (NRMM) 97/68/EC, as set out in

document PE-CONS 3686/03 of the European Parliament and the Council, concerning engines for propulsion of inland waterway vessels

Concerning general use: • The Non-Road Mobile Machinery Directive (NRMM) 97/68/EC as last amended by

2004/26/EC (stages I, II, IIIA, IIIB and IV), including engines for the propulsion of inland waterway vessels.

LOCAL EUROPEAN • The relevant resolutions of the Central Commission for the Navigation of the Rhine

(CCNR) NOTES TO FIGURE 13.4: General: The rows in the lower half of the table indicate levels of stringency, not official stages in the legislation. Only the limits for NOx or HC+NOx and for PM are shown. Limits for CO (where applicable)

have been omitted, since they are not considered to be of relevance for the actual design of diesel engines.

Since the legislative documents concerned know many different classes and situations, often not fully mutually comparable, the table below should be regarded as no more than a rough, quick reference, summary.

1. The levels are valid for Tier 1, Tier 2 and Tier 3. Sets of limits are applicable for different power ranges. The power ranges shown are: 19-37 kW, 37-130 kW and >130 kW for Tier 1. The HC limit is only valid for >130 kW. The power ranges shown are: 19-37 kW, 37-75 kW, 75-130 kW and 130-225 kW for Tier 2. The power ranges shown are: (19-37 kW), 37-75 kW, 75-130 kW and 130-560 kW for Tier 3.

2. The levels are valid for the official stages I, II, IIIA, IIIB and IV. Sets of limits are applicable for different power ranges. The power ranges for the stages up to IIIA are: 18-37 kW (not yet in stage I), 37-75 kW, 75-130 kW and 130-560 kW. The power ranges for the stage IIIB are: 37-56 kW, 56-75 kW, 75-130 kW and 130-560 kW. The power ranges for the stage IV are: 56-130 kW and 130-560 kW, but there is no difference in limits for HC, NOx and PM. The dates of entry into force differ per power range; hence the large overlap between the periods for the different stages.

3. For ‘marine CI-engines for commercial use’ (US), and the ‘engines for propulsion of inland waterway vessels’ (EU) the current US legislation and the current proposal for amending the EU NRMM Directive only specify limits for Tier 2 and stage IIIA, respectively. They are shown here as ‘level 2’ since generally they do have that level of stringency. Sets of limits are applicable for different swept volume per cylinder (< 0.9, 0.9-1.2, 1.2-2.5 and 2.5-5 litres/cylinder), and in the case of for engines of more than 37 kW only. This is the V1 category of the Directive. Category V2 concerns engines with bigger cylinders, but they are considered not to be relevant for this summary. The dates of entry into force differ per power range.

4. CCNR = Central Commission for the Navigation of the Rhine. The limits for stages I and II are equivalent to those of the EU Directive for Non-Road Mobile Machinery (NRMM). The limits for ‘engines for propulsion of inland waterway vessels’ of the NRMM stage IIIA are supposed to be equivalent to stage II of the CCNR, but this equivalence has yet to be recognised by the CCNR.


Figure 13.4: The dates of entry of the emission legislations considered for compression ignition (CI) engines.

Nonroad

US 1 Nonroad

EU 2

Marine Commercial

US 3 CCNR 4

Marine Commercial

EU 3 4

Marine Recreational

US 3

Marine Recreational

EU 1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009

2010 ?* 2011

2012

2013

2014

Level Emission limits in g/kWh for NOx (or HC+NOx, indicated by *) and PM respectively

9.5* - 0.8 9.2 – (--)

9.2 – 0.54 (HC: 1.3)

9.2 – 0.85 9.2 – 0.70 9.2 – 0.54 (HC: 1.3)

9.2 – 0.85 9.2 – 0.70 9.2 – 0.54 (HC: 1.3)

9.8 – 1.0

7.5* – 0.6 7.5* – 0.4 6.6* – 0.3 6.6* – 0.2

8.0 – 0.8 7.0 – 0.4 6.0 – 0.3 6.0 – 0.2

(HC: 1.5-1.0)

7.5* - 0.40 7.2* - 0.30 7.2* - 0.20 7.2* - 0.20

8.0 – 0.8 7.0 – 0.4 6.0 – 0.3 6.0 – 0.2

(HC: 1.5-1.0)

7.5* - 0.40 7.2* - 0.30 7.2* - 0.20 7.2* - 0.20

7.5* - 0.40 7.2* - 0.30 7.2* - 0.20 7.2* - 0.20

* possible requirements and a date of

entry into force are under discussion

(7.5* – 0.6) 4.7* – 0.4 4.0* – 0.3 4.0* – 0.2

7.5* – 0.6 4.7* – 0.4 4.0* – 0.3 4.0* – 0.2

Under

discussion

Under

discussion

Under

discussion

4.7* - 0.025 3.3 – 0.025 2.0 – 0.025 (HC: 0.19)

Under

discussion

Under discussion

0.4 – 0.025 (HC: 0.19)

For footnotes: see previous page

1

18- 37 kW

2

3

5

4


USA Concerning marine use: • US 40 CFR Part 94: Control of emissions from marine CI engines. Concerning general use: • US 40 CFR Part 89: Control of emissions from new and in-use non-road CI engines. The next stage EU legislation concerning engines for non-road applications has been brought fully in line with the equivalent US legislation. Likewise the proposed EU legislation for commercial marine use has been brought fully in line with the US legislation for commercial and recreational marine use. This also means that the EU legislation has adopted the current US practice to legislate HC+NOx rather than HC and NOx separately.

Figure 13.4 shows the major aspects of the legislation outlined above.

These values are graphically represented in Figure 13.5. In that figure the non-road legislations of the US and the EU are divided into power classes. The class divisions do vary (as indicated in the notes to Figure 13.4), and some power classes have the same NOx-limits, although other limits, like those for PM may differ. Since Figure 13.5 only shows the NOx-limits power classes sharing the same limit have been grouped together. The US and EU legislation for marine engines is divided into engine swept volume classes rather than into power classes. The RCD contains a single limit value for NOx.

Figure 13.5: Graphical representation of the NOx-data given in Fig. 13.4.

* For the RCD stage 1 there is a floating scale for the HC limit

The corresponding values for the particulate emissions are graphically represented on Figure 13.6 below. Since the PM limits are divided over the power classes in a slightly different way from the NOx-emissions, the power classes have been grouped in a slightly different way as well.

19-37 kW or < 0.9 litre/cil

US

Tie

r 1

US

Tie

r 2

US

Tier

3

EU

NR

MM

II

EU N

RM

M II

IA

Mar

ine

US/

EU

EU-R

CD

*

0

2

4

6

8

10

12

stage of legislation

g/kW

h

HCNOxHC+NOx

37-56 kW or 0.9-1.2 litre/cil

US

Tie

r 1

US

Tie

r 2

US

Tier

3 EU

NR

MM

I

EU

NR

MM

II

Mar

ine

US/

EU

EU N

RM

M II

IB

EU N

RM

M II

IA EU-R

CD

*0

2

4

6

8

10

12


g/kW

h

HCNOxHC+NOx


US

Tie

r 1

US

Tie

r 2

US

Tier

3 EU

NR

MM

I

EU

NR

MM

II

Mar

ine

US/

EU

EU

NR

MM

IIIB

EU

NR

MM

IIIA EU

-RC

D *

0

2

4

6

8

10

12


g/kW

h

HCNOxHC+NOx

EU N

RM

M IV

>75 kW or 2.5-5 litre/cil

US

Tie

r 1

US

Tie

r 2

US

Tier

3 EU

NR

MM

I

EU

NR

MM

II

Mar

ine

US/

EU

EU-R

CD

*

0

2

4

6

8

10

12


g/kW

h

HCNOxHC+NOx

EU N

RM

M IVEU

NR

MM

IIIB

EU N

RM

M II

IA


Figure 13.6: Graphical representation of the PM-data given in Fig. 13.4.

13.2 Engines certified for the BSO

The question may be asked what possibilities have been demonstrated to comply with the BSO Regulation. For this reason an analysis was made of the number of different engine types certified for this Regulation. The List of certified engines was kindly supplied by the Swiss EMPA [EMPA]. For the BSO some 250 basic engine types have been certified. Of these about 40 % are petrol engines and about 60 % are diesel engines. One half of the petrol engines are outboard engines, which are all certified to the Stage 1 requirements. The great majority of these engines fall in the category 3-12 kW. For relatively low powered engines BSO 1 is not much more stringent than the RCD Stage 1, 4-stroke (see Section 14). No outboard engine is certified for the Stage 2 requirements, which is only required for engines >30 kW. Petrol fuelled inboard engines are mostly certified to the Stage 1 requirements, but a few types (less than 2 % of all certified engine types) are certified to the Stage 2 requirements. The great majority of the certified petrol fuelled inboard engines fall in the power range 150-300 kW. So they are bigger engines on which probably much automotive emission abatement technology could be applied. Of the certified diesel engines two low power engines are outboards, both certified to Stage 1 requirements. All others are inboard engines. They all fall in the category beyond 10 kW, with nearly half of them in the category beyond 100 kW (up to 1300 plus kW). The great majority has been certified for the Stage 2 requirements. This is hardly surprising, since the requirements of the BSO for diesel engines are at the level of current non-road engines for other applications. Many of these engines are used in commercial vessels, and are likely to be identical to those installed in vessels elsewhere. A summarised picture is presented in Figure 7.2.

19-37 kW or < 0.9 litre/cil

US

Tie

r 1

US

Tie

r 2

US

Tier

3

EU

NR

MM

II

EU N

RM

M II

IA

EU N

RM

M II

IB

EU N

RM

M IV

EU-R

CD

0

0.2

0.4

0.6

0.8

1

1.2


g/kW

h

Mar

ine

US/

EU


US

Tie

r 2

US

Tier

3 EU

NR

MM

I

EU

NR

MM

II EU-R

CD

EU N

RM

M II

IA

0

0.2

0.4

0.6

0.8

1

1.2


g/kW

h

37-56 kW

Mar

ine

US/

EU

EU

NR

MM

IIIB

EU N

RM

M IV


EU

NR

MM

I

US

Tie

r 2

EU-R

CD

0

0.2

0.4

0.6

0.8

1

1.2


g/kW

h

US

Tie

r 3

EU

NR

MM

II

EU

NR

MM

IIIA

EU N

RM

M II

IB

EU N

RM

M IV

Mar

ine

US/

EU

>130 kW or 2.5-5 litre/cil

US

Tie

r 1

EU

NR

MM

I

US

Tie

r 2

EU-R

CD

0

0.2

0.4

0.6

0.8

1

1.2


g/kW

h

Mar

ine

US/

EU

EU N

RM

M IV

EU N

RM

M II

IB

EU N

RM

M II

IA

EU

NR

MM

II

US

Tie

r 3


Figure 13.7: The percentage of engines certified for the BSO Stage 1 and Stage 2 requirements per category (fuel and engine type).

13.3 Legislative aims and tendencies

When considering the legislation concerning non-road engines in Europe and the US, a few aspects appear, that should be made more explicit before a new stage (if any) is formulated. In the automotive field US legislation started with HC, since this was perceived as the major contributor to photochemical smog, which at the time was the main environmental problem, especially in California, where such legislation started. CO was added since its abatement combines conveniently with that of HC, and it is a potential health problem. NOx came somewhat later, when it appeared that the initial abatement strategies adopted by the automotive industry for HC and CO were causing NOx to increase, and NOx was known to play a part in the photochemical smog phenomenon next to HC. European automotive legislation originally focussed on CO, since this was perceived as the major health problem affecting pedestrians in congested European inner cities. HC was added at the same time, again since it combined very well with CO, and NOx was added later, originally to prevent it from increasing, and later primarily as the component causing acidification. Ground level ozone formation was recognised as a potential health problem much later than in the US, but by now is the main driver for NOx-reduction. With the introduction of a diesel legislation, PM (particulate matter) was introduced as a special diesel-related component. The limitation of total-HC is by now a proxy for the abatement of specific components such as benzene and PAH, and the abatement of CO is generally regarded as completed and CO is usually no longer regarded as a problem component.

0%

25%

petro

lou

tboa

rd 1

petro

lou

tboa

rd 2

petro

lin

boar

d 1

petro

lin

boar

d 2

dies

elou

tboa

rd 1

dies

elou

tboa

rd 2

dies

elin

boar

d 1

dies

elin

boar

d 2

Category

perc

enta

ge c

ertif

ied

< 10 kW10-100 kW> 100 kW


When considering the European legislation for non-road engines it is clear that the by then usual range of components has been addressed from the beginning: CO, HC, NOx and in the case of diesel engines PM. The US legislation in the first approach limited itself to HC+NOx as a combined issue, and PM for diesel engines; CO was not included, since it was not regarded as an issue. The combination HC+NOx originates from early truck engine legislation, and was introduced since both components contribute to photochemical smog (now usually indicated as: ground level ozone formation). Given the usual emission behaviour of diesel engines the limit for HC+NOx mainly sets a limit for NOx (whereas in the case of 2-stroke petrol engines it mainly sets a limit for HC) and the fact that HC is included, in practice gives the manufacturer a little more room for NOx. In Europe the HC+NOx approach was introduced in the early eighties for passenger cars, at a time when it was unclear in which direction technology would move and the ECE (who first adopted it) wanted to give rival technologies, that would either focus on HC or on NOx, equal chances. Scientifically there was hardly any reason for such a combination, but once introduced such practices are very hard to abandon again, and it took until Euro 3 in 2000 before this marriage of convenience was dissolved again. Concerning non-road engines the EU started with separate limits for HC and NOx, but more recently tends to combine them for reasons of harmonisation with US. In view of the policy adopted so far, it may seem somewhat surprising that the US now considers to introduce CO in the marine engine legislation after all. The background to this is, however, a number fatal accidents which were traced to CO-poisoning of people swimming or otherwise being active very close to boat exhausts. According to some sources the underlying cause of such accidents is that car exhausts by now have become so clean that the current generation of American citizens insufficiently regards engine exhausts as something to stay away from. Significantly such fatal accidents concerned boats with inboard engines, and more specifically sterndrive petrol engines; outboard engines apparently, by their overall behaviour, still induce sufficient respect to cause people to keep their distance. Boat builders have tried to solve the problem by placing the engine exhaust at a less ‘risky’ location on the boat (such as sufficiently removed from swimming platforms), but the EPA has decided that there is still a need for CO-legislation as well. In the PTW case (where 2-strokes still play an important role) the original tendency was to set different standards for 2-stroke and 4-stroke engines. The background to this practice was that, due to so-called scavenge losses, conventional 2-stroke engines are characterised by very high HC-emissions and an HC-limit that would be even halfway sensible for 4-strokes would immediately have driven 2-strokes completely off the market. In fact this was what happened in the case of cars, but in the case of PTWs this was regarded as an unwanted effect. By the time DI 2-strokes began to be introduced it became clear, however, that emission-wise these behaved more like 4-strokes: much lower HC but somewhat higher CO and NOx. An early proposal to require DI 2-strokes to comply with 4-stroke limits was sensibly ignored and in the current legislation there are no longer any technology dependant limits. After all, the final goal should be to build environmentally acceptable engines, with the technology that should best fit the requirements. In the case of cars something similar happened for diesel engines. By the time they came to be included in the European emission legislation their position on the European market had already become so strong that a set of requirements that would have driven them off the market (as had happened in California) was already completely


unacceptable from an economic point of view, which resulted in a considerable allowance for NOx-emission relative to that for petrol engines. The question for how long this should remain to be the case is now discussed in the context of the Euro 5/6 standards.

13.4 Aspects of harmonisation

13.4.1 Harmonisation so far As is clear from Figure 14.4 there is already a high degree of harmonisation going on between the EU and US legislation concerning diesel engines for non-road mobile machinery. Given the strong relationship between engines used for NRMM and those for marine use, it seems logical to align the diesel engines for marine use with some stage of the NRMM Directive, even if this is not the latest stage for engines used for other applications. Table 14.4 suggests that the US is considering a similar approach. For petrol outboard engines neither the EU nor the US has adopted a direct link with the NRMM legislation. But mutually the EPA HC+NOx limits for 2005 and beyond are largely similar in effect to the RCD stage 1 limits for 2-stroke engines. Any discussion would concern the possible alignment of an RCD stage 2 with the intended next step of the US legislation. Concerning petrol inboard engines, the CARB has a more stringent requirement for those engines, that the US Federal legislation does not (yet) have, whereas the EU legislation does not classify these engines as a separate category at all.

13.4.2 The relative stringency of the requirements The US-EPA is now considering a further step for petrol outboard engines, aligning the requirements with the CARB 2008 limits, and the introduction of a legislation for petrol inboard engines, aligning with the CARB sterndrive/inboard rule. Furthermore the EPA considers the introduction of a CO requirement. The intention to further tighten the requirements may stem from the consideration that the limits are expressed in g/kWh, meaning that the bigger engines, which power a large part of the US-fleet, may still have a rather high emission level. Furthermore an alignment with the Californian legislation would create more unity within the overall American situation. The intention to introduce a CO-requirement has a background of health and safety, rather than an environmental background. As discussed in Section 8, the CARB 2008 level more or less coincides with a 75 % level of the RCD stage 1 4-stroke limits for HC+NOx. The RCD stage 1 limit for CO has a floating scale, as for the other components. The relative stringency cannot be judged against the US level, however, since so far no CO-level for the US has been indicated.


13.4.3 Components Since the RCD restricts the emissions of CO, HC and NOx (and PM for diesel engines), and since the US-EPA considers to limit the emission of CO next to HC+NOx, no conflict needs to be expected concerning the components to be regulated. There will be the question, though, whether to limit HC and NOx separately (as currently in the EU) or as HC+NOx (as currently in the US). Technologically there is no justification for a combination, but it does give the manufacturers somewhat more freedom. Concerning CO: according to industry sources who discussed this with representatives of the EPA, the intention is to have a CO-cap, i.e. a uniform requirement for all power classes. When the objective is to prevent negative health effects and fatal accidents, a maximum CO-concentration would be closer to that objective than an engine-size dependant mass emission limitation as in the case of HC. A fixed CO mass-emission, independent of the engine size, would have a similar effect: it would prevent the carburation to be adjusted unnecessarily rich, without subjecting the manufacturer to further restrictions. For the EU this would need a reformulation of the CO-approach, but this would not be a bad thing in itself: it would shift the emphasis from general air quality (where CO is generally regarded as no longer a problem) to possible local health effects, which might still be an issue.

13.4.4 Categories of engines Both sides of the ocean tend to address petrol engines and diesel engines separately, so in that respect there needs to be no difference. There is a difference though, in the fact that the US differentiates between petrol engines for outboard installation or for PWC, and petrol engines for inboard use (sterndrive and shaftdrive). In Europe no differentiation between those two categories exists. In Europe only an estimated 3 % of the marine engines are petrol inboard engines, against 80 % for outboards (see Figures 3.1 and 3.2). Introducing a separate legislation for petrol inboard engines, with more stringent requirements than for petrol outboard engines, would not result in significant environmental benefit as shown in subsection 8.1.3. If such introduction would nevertheless be considered for harmonisation purposes one might bear in mind that such inboard petrol engines are exclusively delivered by marinisers, who as a rule are only operating on local or regional markets, and not both in the EU and in the US. So harmonisation would not seem to have much purpose here.

13.4.5 Threats and opportunities Harmonisation would be a great benefit for manufacturers who operate on both markets. These include six of the eight outboard manufacturers and all four manufacturers of PWCs (three of which also operate on the outboard market). One outboard manufacturer is operating on the European market only and one is not operating on the European outboard market at all. The diesel OEMs are operating world-wide, both with their marine engines and with their non-marine engines. Marinisers are, as far as we could establish, not operating on both markets simultaneously. For the manufacturers and marinisers that only operate on the European market harmonisation might be a threat, since they might have to comply with more stringent requirements than otherwise would have been the case, without the benefit of more unity in their production. An approach as in scenario 2A (Section 8) would at least


partly solve this since it would exclude the smallest engines from the tightened requirements. An exemption for engines produced in small series, of for small volume manufacturers, might provide a further solution. It may be noted that, in the case of petrol inboard engines, the CARB approach is to grant SMEs a 2 year delay in the introduction, but this would seem an rather limited solution.


14 Review of RCD boat design categories

(by Mr. Handley, consultant)

14.1 Introduction

The Review clause (Article 2) of Directive 2003/44/EC requires the Commission to submit a report by 31st December 2006 that considers the need to revise the boat design categories. This section of the report considers the RCD boat design categories in respect of this requirement. An interim report of the boat design categories dated 5th July 2004 was circulated prior to the 2nd Stakeholders meeting in Brussels on the 27th July 2004 and stakeholders were invited to comment. Some views were expressed at the meeting and subsequently written comments were received from the EBA, the European boat user's association, and Icomia, the international marine industry association. There was a divergence of views in this correspondence. The EBA raised concerns about the current design categories that they had previously put to the Commission and suggested that increasing the number of boat design categories would resolve some of these issues. Icomia reported that their Technical Committee had considered the interim report of 5th July and supported the conclusion to remain with the four current categories and seek to define them better. Points made for and against increasing and/or redefining the design categories in this and other correspondence have been included in this report and some of the comments and recommendations revised accordingly.

14.2 Background to RCD Boat design categories

When the RCD was introduced in 1996 it included a requirement that all boats must be assigned to one of four ‘Boat design categories’. These design categories were given the titles of A ‘Ocean’, B ‘Offshore’, C ‘Inshore’ and D ‘Sheltered waters’. Each category was defined by: • the title description, e.g. Ocean, offshore • limits for wind force, using the Beaufort Scale • limits for wave height, expressed as significant wave height for highest one-third of

waves • description of typical areas of use, e.g. rivers, small lakes Upper limits were given for wind force and wave height for each category except for Category A which had only lower limits but included a requirement for boats to be 'largely self-sufficient'. The amendments of Directive 2003/44/EC slightly amend the definitions for Category A and D and wave height for Category D, as described below, but otherwise the design category definitions remain the same. These design categories were included in the RCD in recognition of the fact that satisfactory levels of safety in respect of a boat’s strength, stability, watertight integrity and some other factors vary depending on the design type of the craft. For example, a boat that is designed for cruising in sheltered inland waters need not be built to the same level of strength, stability, etc, as a boat designed for making offshore sea passages.


Other criteria for the design categories were considered, such as distance from shore when in use. As very severe conditions can exist close to the shore this factor was not considered acceptable. The important criteria were considered to be the sea and weather conditions that the boat was designed for rather than factors related to location when used.

14.3 Interpretation of the Design Categories

When the Directive came into force and the harmonised standards were being prepared, particularly the stability standard (EN ISO 12217), questions were raised about the interpretation of design categories. Some concerns related to possible links to navigation and usage rules that were being applied in some nations, including limits on the distance that a boat may go from the shore. It was suggested that such links were contrary to the objectives of the Directive and likely to harm the European tourist trade. It was also suggested that the category definitions could be misleading and possibly dangerous in their suggestion of suitability of purpose, e.g. it may be possible that a boat user assumes from the title 'offshore' that a Category B boat is suitable for any offshore conditions, which is not the case. There were also concerns about the understanding of the wave height limits. The height used in the Directive is ‘significant wave height, H1/3’ which is derived from the average of the highest one-third of the waves. Some waves will therefore be higher - up to twice the H1/3 height according to EN ISO 12217, although this assumption is probably based on statistics from ocean waves. This led to concern that some small boats might be excluded from Category D by the wave height limit of 0.5m H1/3, as waves of greater height than 0.5m would not normally be encountered in sheltered waters. In response some involved proposed a fifth design category for 'flat water' boats for use in areas where waves are smaller, such as narrow canals. For Category A there was concern that it was open ended due to the absence of upper limits and hence needed further clarification. It was not possible to change the RCD at that time so these questions were dealt with by issuing interpretations of the requirements for Category D and A in the Commission Comments on the RCD (the CC Guide). The interpretation for Category D proposed that the 0.5m wave height should be taken as an allowance for waves from passing vessels, the CC Guide text stating “For Category D, allowance should be made for waves of passing vessels up to a maximum wave height of 0.5m”. This was considered appropriate as such waves may occasionally occur even in ‘flat water’ cruising areas. For Category A, the guide clarified the intention that this category excludes abnormal conditions, the text stating “For category A, extreme conditions apply as they reflect that a vessel engaged on a long voyage might incur any conditions and should be designed accordingly, excluding abnormal weather conditions e.g. ‘hurricane’.” The exclusion of hurricanes effectively provided an upper limit to category A. On the question of any possible links between the design categories and usage rules the CC Guide states “The directive does not include any navigation or usage rules and there


is no link between the design categories and any such rules; taking into account construction safety, the user is only clearly informed of what the boat was designed and built for in relation to certain parameters of significant wave heights and wind speed.” This clearly specifies that there is no intention to link the Directive’s categories to any navigation or use rules.

14.4 Amendments to the Design Categories

When the RCD was under consideration for amendment to add the emission and PWC requirements the opportunity arose to amend the text of the design categories to align them with the interpretations given in the CC Guide and used by the harmonised standards. The Commission established a Task Force to consider possible amendments to the design categories and this group met twice in 2001/2. It proposed amendments to the wording of both Category A and D and for Category D proposed that the wave height should be reduced from 0.5m H1/3 to 0.3m H1/3 with an allowance for 0.5m maximum height for waves from, for example, passing vessels. These amendments are now in Directive 2003/44/EC which will amend the RCD from January 2005. The amendments will formalise and improve the interpretations that have already been issued in the CC Guide and accordingly there will be no need to amend the harmonised standards following implementation of 2003/44/EC, as these standards already approximately follow the CC Guide. As a result of the amendments it is anticipated that no type of recreational craft will be excluded from RCD compliance, as small boats designed for sheltered waters will be able to meet the lower wave criteria defined in revised Category D. Accordingly there should be no need for an additional 'flat water' category. The gap between Category D and C is now slightly larger than before for wave height. Some suggestions have been made for a new category(ies) between D and C. A Dutch/Austrian proposal was made for 4 inshore categories, based on the EC Directive for inland waterways, with limits of 0.3m, 0.6m, 1.2m and 2.0m significant wave height. When comparing the requirements of the two directives it should be noted that the wave heights for the inland waterways Directive are based on the average of the highest 1/10th of the waves, whereas the RCD use the average of the highest 1/3rd. Also, no wind speeds are given for the inland water categories, but are important for the RCD for assessment of sailing boats and some motor boats, as discussed in subsection 14.7 below. Wind speed is not important for the inland waterways Directive as it covers commercial craft operating under power. Another concern has been that boats are sometime assigned to 'higher' categories than appropriate. This may be for marketing reasons, e.g. a Category A boat may be perceived as better than a similar Category B boat. It has been suggested that if there were more categories with smaller increments of wind/wave limits this practice would change, but others believe that this would continue. Rather than amending the Directive to address this issue the problem may be resolved by ensuring that the RCD's standards have provisions such that a boat cannot reach a higher category unless it is suitable for that category. Currently work is underway to


prevent inland/inshore boats from being assigned to Category B or A by establishing new requirements in the stability standard for the handling of motor boats in wind and waves at sea. As a separate exercise a standard is being drafted to link more boat features to the design category, such as fuel capacity and number of berths. The standard for inflatable boats now sets special requirements for Category B RIBs to ensure that they are suitable for offshore use.

14.5 Development of the harmonised standards

Several aspects of a boat’s design are affected by design category, including stability and buoyancy, prevention of falling overboard, structural requirements and watertight integrity. Accordingly the harmonised standards that have been developed to support these areas of design refer to the design categories when setting safety requirements that are relevant to sea conditions that will be encountered. For example, certain types of opening window are permitted for Category D boats, but not in the higher categories to ensure a higher level of watertight integrity. The stability and buoyancy standard, EN ISO 12217, is most closely affected by design categories. This standard, and several of the other important standards, were drafted at the same time as the interpretation of the design categories was being discussed. To ensure alignment between these standards and the RCD the working groups developing the standards were encouraged to follow the interpretations issue in the CC guide and, when eventually known, the proposed text for the amendments to the Directive. EN ISO 12217 adopted similar wording to that used in the in the CC Guide to describe its four categories. For Category D the standard states “A boat given design category D is considered to be designed for occasional waves of 0.5m height and a typical steady wind force of Beaufort force 4 or less.” This wave height is further described in a table below the descriptions as wave height up to “0.5 m maximum”. A full explanation of the meaning of design categories in EN ISO 12217 is given in the standard. Although these descriptions align closely with the categories defined in the RCD there are some differences and to address this a note was added to the Annex ZA appended to each part of EN ISO 12217 stating that “Design categories A, B, C and D defined in the standard are considered to correspond to design categories A, B, C and D of the Directive.” As the Annex ZA is the official link for a harmonised standard to the relevant part of the Directive there should be no concern about the slight difference in wording, which does not affect any of the specific requirements of the standard. Other standards have also used similar text to describe the categories and more recently several have been published using the same text as the category definitions amended according to 2003/44/EC. Some standards address safety issues that are not related to design category - e.g. fire, electric's, gas, and accordingly do not refer to the RCD boat design categories.

14.6 The RCD and other regulations

When considering the need, if any, for further amendment to the RCD design categories, it is of value to review other regulations, rules and codes of practice that also set categories for small craft. From available literature twelve such regulations (national


and international) were identified. All differed slightly in their approach, criteria and values used for categories. There was no indication of a common approach to boat categorisation that has been followed to date or could be followed in future, although the criteria used most is distance or time from shore. From these other rules, 15 different criteria (e.g., wind strength, wave height, water depth, daylight, distance from shore, time to rescue, etc) can be identified. However, of these only a few can be used as design criteria or for writing standards. These include wind strength, wave height, length, number of persons and descriptions such as 'self-sufficient'. The other criteria are more relevant to the ability to avoid bad weather by returning to a safe haven or to be rescued from an incident, e.g. distance/time from shore, availability of rescue facility etc. Length and number of persons are generally too design restrictive for recreational boats, although the RCD does set one specific length requirement - boats under 6.0m length are required to have flotation if they are susceptible to swamping. In general large boats tend to belong to higher categories, but there are some small boats that are designed for operation in waves (e.g. many types of sailing dinghy) and some large boats that are for inland use only (e.g. canal ‘narrow’ boats). If length and number of persons are therefore not considered to be suitable criteria, we are left with the same design criteria that are already used for the RCD categories - wind strength, wave height and self-sufficiency (for Category A). Accordingly there is nothing to suggest that the RCD currently uses the wrong criteria for its design categories, or should consider other additional criteria for categories. For example, distance from shore is not a factor that can be designed to, as the sea conditions close to the shore are not known. One possible additional requirement for the inshore categories could be 'daylight use only', but again this is difficult to allow for from a design perspective apart from a requirement for navigation lights. Some regulations with categories are being aligned with the current RCD design categories and other regulations provide a link between their categories and the RCD design categories. The Canadian Coast Guard have stated that they are working towards aligning their categories with the four RCD Categories and the UK Inland Waters Small Passenger Boat Code links its categories 'A' and 'B' to RCD Category D and its categories 'C' and 'D' to RCD category C. The ORC/ISAF Special Regulations for offshore racing sailing boats have more than four categories, but include a table to link their categories to the RCD categories for stability assessment. RCD Category A covers SR Categories 1 and 2 (long offshore races), Category B covers SR Category 3 and Category C covers SR Category 4. The Special Regulations also include a Category 0 which is for trans-oceanic races in cold water and heavy storms. This category is considered to exceed RCD Category A, but is only used by specialist racing yachts that are exempt from the RCD (and could be assigned to Category A if later used as cruising yachts). At a recent meeting, ORC and ISAF representatives stated that they were happy with this link to the RCD categories.


14.7 Use of wind strength and wave height as design parameters

Wind strength is important for sailing boats and its influence on heel angle and potential to capsize may be calculated for design evaluation. This is done in EN ISO 12217 for specified wind speeds corresponding to each category and gives an indication of the risk of capsizes or swamping. For certain types of sailing boat this is important for determining the design category. Wind strength is also relevant for some motor boats because the heeling moment from the wind may combine with wave induced heel to create a potential capsize hazard. The effect of the wind on some motor boats is therefore assessed in EN ISO 12217 for specified wind speeds corresponding to the category. The combined effect of the wind strength and assumed roll due to waves is also assessed for Category A and B motor boats, but wave height is not used directly in these calculations or any other stability calculations. Strong wind at sea implies large waves, but for recreational boats the shape and characteristics of a wave are of more concern than the wave height, e.g. a high but long ocean swell is of little concern, but a steep wave with a breaking crest can cause damage or capsize even if it is much smaller than the smooth wave that is harmless. Wave height is sometimes used without reference to wind speed for categorisation of ships and inland commercial vessels, but although there is considerable literature on seaworthiness and strength of recreational boats the concept of designing a leisure boat for a maximum design wave height is rarely mentioned, except for structural assessment of large boats. There are several reasons why wave height may be more relevant for commercial vessels than recreational craft, the most obvious being the larger size of ships. The shape and configuration of the craft is also relevant, e.g. longitudinal strength is relevant for ships in waves but not short craft. Some commercial inland craft may be very sensitive to wave height, but not wind, e.g. commercial barges heavily loaded with low freeboard. For recreational boats wave height alone is relevant mainly for small tenders/rowing boats that may swamp if operated at full load, usually when full of people, in anything but small waves. EN ISO 12217 sets requirements for freeboard of open boats (downflooding height) linked to design category. However this requirement increases only from 20cm to 30cm from Category D to C for typical small boats, as it is recognised that larger and longer waves are not a much greater swamping hazard for these boats than small short waves. Also, the main stability hazard for small non-sailing boats is probably capsize from crew weight offset, possibly in combination with turning, and this is a flat water hazard that is largely independent of wave height and design category. Stability and buoyancy requirements for recreational boats tend to vary more according to the boat configuration (e.g. decked, partially decked, open) than wave height. Accordingly EN ISO 12217 identifies 24 groups of stability tests/requirements that are options depending on the boat type, deck configuration, presence of flotation, length and category. Within any one option the requirements for adjacent design categories are often quite close.


When considering construction of recreational craft, wind strength is not very relevant except for the strength of sailing boat rigs and attachments, but boats that are designed to operate in waves must be built more strongly than boats designed for smooth water operation. Most existing scantling rules for recreational craft give strength requirements that are sufficient to ensure that any boat built to them will be strong enough for sea-going operation in waves, and accordingly a little overbuilt for flat water use. As the draft hull construction standard prEN ISO 12215 is intended to support the RCD which has design categories, the standard's strength requirements for sea-going boats are slightly reduced for the lower wave size categories. This reduction is not linked to the wave height by direct calculation, but simply a reduction intended to reflect the fact that the loads will be less in smaller waves. In general, when considering the influence of waves on recreational craft, it can be said that recreational boats tend to be designed either for use in waves (sea boats), or not for use in waves (inland boats), with little if any reference to a maximum design wave height when designing the boats.

14.8 Natural Categories for recreational boats

A common distinction made for sea boats is 'inshore' and 'offshore', the former being mainly smaller 'day' boats designed for fair weather coastal use and the latter being mainly cruisers designed with offshore capability in mind, i.e. more strength, stability, safety equipment, and some self-sufficiency if caught in bad weather. Offshore cruisers intended for long distance 'blue water' passages are designed with an even greater degree of self-sufficiency and strength. These commonly used groupings for sea boats, plus the ‘inland’ boats, create four natural categories of recreational boat - inland boats, inshore boats, offshore boats and long-distance offshore ‘blue water’ cruisers. These natural categories coincide approximately with the current RCD categories. The wind/wave limits specified for the RCD categories also correspond to the typical weather/sea condition that might be associated with using a boat of each type, although it is clear that opinions on the most appropriate wind strength/wave height and descriptions for each category may vary. Any change to the number of categories would move away from these natural categories, and it may be more difficult for builders and boat users to understand the meaning of the new categories. It should also be noted that some boats are assigned to 2 or even 3 current design categories, with different loads/number of people for each category. The fact that some boats already span several categories suggests that the current number of categories is adequate.

14.9 Conclusions and recommendations

As a result of discussions that commenced shortly after the RCD’s introduction, Directive 2003/44/EC will amend both Category D and A from January 2005. Taking into consideration these forthcoming amendments and the fact that they address the original concerns relating to small boats in Category D and the open-ended nature of Category A, the following conclusions can be drawn:


1 In future no recreational craft type should be excluded from an appropriate RCD

design category, as the revised categories cover the full range of conditions suitable for recreational craft from near calm water to severe ocean conditions.

2 The design of boats need not be compromised to fit one of the four design categories,

as the categories only cover conditions in which recreational craft operate, not other design characteristics or boat type.

3 The design categories link well to common groups that are understood in the marine

industry and by boat users, i.e. inland, inshore, offshore, blue water/ocean. The limits for wind strength or wave height between the categories could perhaps be discussed, but this has already been addressed in the discussion on Category D and A and covered by the amendments of 2003/44/EC.

4 Abnormally extreme ocean conditions, e.g. hurricanes, are excluded by the revision

to Category A. Some trans-oceanic racing sailing boats are intended to operate in such conditions and it has been suggested that a new category higher than A should be added for such boats. However, these racing boats are excluded from the RCD, so it should not be necessary to add a category for them even if such a category exists in yacht racing regulations.

5 Boats are sometimes assigned to 'higher' categories than appropriate. It has been

suggested that if there were more categories with smaller increments of wind/wave limits this practice would change, but others believe this would not help. Work is currently underway to develop standards so that boats cannot reach a higher category unless suitable for that category, and it is hoped that this work will resolve this problem.

6 From the above observations on stability requirements and wind speed/wave height,

it is difficult to see how the stability standard could be improved by the introduction of new inshore categories or why this would have any added value for safety. The stability standard considers boat type, deck configuration, flotation, length and other factors as well as design category. The requirements for Category D and C for similar boat types are often quite close.

7 From the above observations on hull construction, there is no reason to believe that

the construction standards would be improved by increasing the number of design categories, and there have been no requests for this within the ISO working group developing the standard.

8 The Commission’s comments on the RCD clearly state that there is no intention to

link the design categories to any navigation or usage rules. Any increase in the number of RCD categories to align with other navigation/usage rules might encourage this practice.

9 Any significant change to the design categories, including the addition of new ones or

sub-categories, will create a need to revise several of the important harmonised standards. These standards are revised periodically anyway, but as they are ISO standards as well as ENs, amendments specifically to align with an EC Directive may not be possible. At present the categories defined in the relevant EN ISO harmonised


standards all follow the RCD categories. This is a status with potential benefits for the marine industry and boat users that should be preserved if at all possible.

10 Any significant changes to the design categories, including the addition of new ones

or sub-categories, will create a situation where the new categories have different titles and/or meanings from the current categories. This could be misleading for boat users, as the design categories for existing boats and new boats will then differ.

Taking all these points into consideration there does not appear to be any strong evidence to suggest that safety of using boats covered by the RCD could be improved by significantly changing the current design categories, or by adding new categories. Minor amendment to the definitions may be worthwhile, such as amending the descriptions of categories C, B and A based on the new wording adopted for Category D, i.e. use 'when conditions' rather than ‘where conditions’. There is some evidence to suggest that boat owner’s, and some builders, are not fully aware of the meaning of the boat design categories and their implications with respect to safety. One way to address this may be to add more information on categories to the Builder's plates, e.g. the category title, maximum wind strength and maximum wave height, or alternatively a "Read Owner's Manual" sign to encourage users to read the full description of the category in the manual. This could be part of a separate exercise to try to educate boat users and builders on the meaning of the design categories and their safety significance.


15 Approval under the ‘New Approach’

15.1 Introduction

Under the ‘New Approach’ the procedures for type approval and monitoring of the conformity of production have been replaced by a modular approach. An outline of the new procedure as applying to recreational craft is shown in subsections 15.2 and 15.3 and in the figures 15.1 and 15.2. A specific question in the context of the current study was: is this modular system as described in 94/25/EC and amended by 2003/44/EC a satisfactory solution, or should it be simplified, either in general, or in the case of e.g. SMEs? In this Section this question will be discussed. The representation in Figure 15.1 actually does not represent the way the modular system is presented in the Directive, but rather as an attempt to show the basic underlying philosophy, which is as such not explained in the Directive. In the Directive the modules are described in detail in the Annexes V – XII (modules A to H inclusive, with the exception of module E) and Annex XVI (module E), which was added in the amendment 2003/44/EC. The requirements to the ‘Technical Documentation’, and the requirements to the ‘Written Declaration of Conformity’, which play a part in the procedure, are given in Annexes XIII and XV respectively. Annex XIV describes the requirements for a Notified Body. In 2003/44/EC, for the assessment of the conformity with the exhaust emission requirements clauses are added to Annex VIII (module C) that go a long way into the direction of requiring either module D or E as a basis or, if the results are deemed unsatisfactory by the Notified Body, something approaching the procedure of module F. A possible simplification of the modular system may be looked at from two different angles. On the one hand one might look at the possibilities for a simpler and more transparent description of the system, perhaps represented in a smaller number of different basic modules, if necessary with some further specified options within those modules. And on the other hand one might look at a possible reduction in the overall number of options, whether or not contained in different modules. The contractor feels that a combination of these two approaches should be aimed at.

15.2 General description

In the ‘New Approach’ there is no longer a direct involvement of the national authorities in the approval. There is a larger responsibility of the manufacturer, with a supervising role for so-called ‘Notified Bodies’ that perform checks on the obligations of the manufacturers. Furthermore there is not one single route to follow, but a number of options from which the manufacturer can choose. The Notified Bodies are appointed by the national governments, but the manufacturer has the freedom of choice as to which Notified Body he chooses for the task.


Figure 15.1: The general set-up of the modular approval system of the RCD, including the exhaust emissions.

Figure 15.2: The set-up for the modular approval system of the noise emission.

15.3 The procedure in the case of the RCD

Since the RCD primarily concerns the construction of recreational craft, of which the engine is only a component, most of the system is only relevant for the vessel itself. Figure 15.1 shows a simplified scheme of the total system (with the exception of the noise aspects). Figure 15.2 shows separately the procedure for the noise emission. The basic division of Figure 15.1 (first column) is into category of boat, or of piece of equipment produced or item to be approved (such as exhaust emissions). The basic division of Figure 15.2 (first column) is into boats equipped with engines for which the


engine manufacturer has supplied the exhaust as an integral part of the package (PWC, outboard engine or sterndrive engine with integral exhaust), and boats equipped with engines for which the boat builder has supplied and installed the engine exhaust(s) (sterndrive engines without integral exhaust and inboard engines). The further division concerns the exact way in which for the second case the approval was obtained. In the original Directive 94/25/EC the choice of available modules differed per item, and was limited in each case. With the amendment of 2003/44/EC becoming effective, in each case most of the modules, or combination of modules, is available. In order to show somewhat more clearly the general approach of this system of modular choices, the representation in Figure 15.1 has been subdivided into three groups.

• Generally speaking group 1 modules describe a self-certification procedure by the manufacturer, without testing (module A) or with testing (module Aa). In the case of module Aa the tests have to be performed under the responsibility of a Notified Body.

• Group 2 modules describe a procedure where a larger role is played by the Notified Body. This procedure contains the checking of a representative product (module B, a form of type approval) and a system for checking the conformity of the production (one of the modules C-F) in the case of series produced products.

• Group 3 modules (G and H) describe a procedure that is especially relevant for limited series or one-off products.

In several modules an approved quality system replaces actual testing for the evaluation of the production conformity. Approval and periodical checking of this quality assurance system is performed by the Notified Body. Subsection 15.4 gives a short summary of the most relevant aspects of the various modules and groups of modules.

15.4 Short description of the modules

Group 1 modules Module A: Internal production control This module contains the following essential elements: 1. A written declaration of conformity by, or on behalf of, the manufacturer. 2. Technical documentation that allows the conformity of the product to be assessed. 3. An obligation for the manufacturer to ensure compliance of the manufactured

product. Module Aa: Ditto plus tests This module contains the elements of module A, plus the following supplementary requirement: 4. A test, or an equivalent calculation or check, carried out by, or on behalf of, the

manufacturer, concerning: − the stability of the vessel, in accordance with point 3.2 − the buoyancy characteristics, in accordance with point 3.3 of the ‘Essential Requirements’ as described in Annex I of the Directive. These tests, or their equivalent checks, shall be performed under the responsibility of the Notified Body.


Group 2 modules Module B: EC type-examination This module replaces the ‘Type Approval’ of series produced products in Directives previous to the ‘New Approach’. It contains the following essential elements: 1. Technical documentation as in module A, to be provided by the manufacturer. 2. Ascertaining and attesting by a ‘Notified Body’ of the compliance of a

representative specimen of the product with the provisions of the Directive. The Notified Body does so on the basis of examination (inter alia of the technical documentation) and tests.

3. An obligation on the part of the manufacturer to inform the Notified Body of any subsequent modifications of the product specification. Where deemed necessary, such subsequent modifications need additional approval.

A procedure that includes module B always contains a further additional module concerning the conformity of production (one of the modules C-F). Module C: Conformity to type This module concerns the conformity of the products for which a type-examination according to module B has taken place. It contains the following essential elements: 1. A written declaration of conformity by, or on behalf of, the manufacturer, as in

module A. 2. An obligation for the manufacturer to ensure compliance of the manufactured

product, as in module A. A procedure using modules B+C contains the elements 2 and 3 of module B additional over module A. Module D: Production quality assurance Like module C, this module concerns the conformity of the products for which a type-examination according to module B has taken place. It contains the following essential elements: 1. A written declaration of conformity by, or on behalf of, the manufacturer, as in

module A. 2. An obligation for the manufacturer to operate an approved quality system for

production, final inspection and testing. The requirements for this quality system are specified in the module. It will be assessed by the Notified Body.

3. Periodical audits by the Notified Body to check the continued appliance of the quality system.

A procedure using modules B+D replaces the simple obligation for the manufacturer of point 2 in module C by a specified production quality system. Module E: Product quality assurance Like module C, this module concerns the conformity of the products for which a type-examination according to module B has taken place. It contains the following essential elements: 1. A written declaration of conformity by, or on behalf of, the manufacturer, as in

module A. 2. An obligation for the manufacturer to operate an approved quality system for final

product inspection and testing. The requirements for this quality system are specified in the module. It will be assessed by the Notified Body.



A procedure using modules B+E replaces the production quality system of module D by a product quality system. Module F: Product verification Like module C, this module concerns the conformity of the products for which a type-examination according to module B has taken place. It contains the following essential elements: 1. A written declaration of conformity by, or on behalf of, the manufacturer, as in

modules A and C. 2. An obligation for the manufacturer to ensure compliance of the manufactured

product, as in modules A and C. 3. Examinations and tests by the Notified Body, either of every product, or of a sample

of products on a statistical basis which is described in the Directive. A procedure using modules B+F contains product testing by the Notified Body as an additional element over the combination of modules B+C. Group 3 modules Module G: Unit verification This module contains the following essential elements: 1. Technical documentation that allows the conformity of the product to be assessed. 2. Examination and tests by the Notified Body of the individual product. To this

purpose the Notified Body will make use of the technical documentation specified under point 1.

This module differs from module Aa in particular in the fact that the verification of conformity is carried out by a Notified Body rather than by the manufacturer himself. The procedure aims at individual products rather than at a series of products, and would be appropriate for one-off products. Module H: Full quality assurance This module contains the following essential elements: 1. A written declaration of conformity by, or on behalf of, the manufacturer, as in

module A. 2. An obligation for the manufacturer to operate an approved quality system for

design, manufacture, final product inspection and testing. The requirements for this quality system are specified in the module. It will be assessed by the Notified Body.


This module differs from module D in that it includes the design stage in the quality assurance programme. This module would be especially appropriate in the case of manufacturing of one-off products. It differs from module G in that it specifies a quality assurance system instead of a system of examination and testing of the finished product.

15.5 Summary of the approach

In summary it can be said that, depending on the item to be approved, either group 1 or group 2 modules are specified as a minimum approach. For vessels below 12 m in length of the categories A-C, as a rule group 1b (i.e. module Aa) is specified as the minimum. For PWCs, vessels of category D (all lengths) and vessels of category C less than 12 m in length and complying with paragraphs 3.2 and 3.3 of the Essential requirements, group 1a (i.e. module A) is sufficient. For vessels of the categories A-C


longer than 12 m, and for components, including engines, the modules of group 2 are specified as a minimum. And in all cases the modules of a ‘higher’ group may be applied instead.

15.6 Concerning exhaust emissions and noise

The procedure concerning exhaust emissions specifies as a minimum approach the modules of group 2, which means a form of type approval in combination with a system that has to ascertain the conformity of the production. Since as a rule engines will be produced in series, this seems to make sense. But the relevant clause in the Directive allows the modules of group 3 to be applied instead. These aspects are further discussed in subsections 15.7 and 15.8. In contrast to the general approach, the procedure concerning noise does not specify the full range of modules (see Figure 15.2). It basically specifies the modules of group 1, but also allows the modules of group 3. Whether the approach of 1a (module A) is sufficient, or if the approach of 1b (module Aa, meaning tests) is required, depends basically on whether or not the exhaust is part of the engine as delivered by the engine manufacturer, and if not, which test procedure forms the basis of the approval.

15.7 Proposal for a simplified structure

The proposal following is based on the aspects discussed above: − It reduces the eight modules to three main possibilities, with a maximum of two

options each. − It takes together a few sub-variants that do not differ sufficiently to warrant

presentation as fully separate variants. − It describes the intention of each of the three main possibilities so as to make clear

for what purpose it is intended, thereby making the whole procedure more transparent.

Even so the restructured presentation basically still contains all of the options of the eight original modules. Any limitation of those options is a political choice, which falls outside the scope of this study, but would, on the other hand, only require the relevant adaptation of the wording. The proposal starts hereafter. The wording of the proposal only aims at making clear its intentions and should not be regarded as a proposal for the actual text.

ANNEX ‘XX’: THE APPROVAL PROCEDURE This Annex describes the approval procedure. There are three possibilities: 1. The standard procedure 2. A simplified procedure 3. An extensive procedure without type examination


XX.1. Module 1: The standard procedure The standard procedure contains an EC type-examination and a conformity assessment system. It is meant to represent the standard situation. XX.1.1: Basic requirements For this procedure there are the following basic requirements: a. Technical documentation describing the product, according to Appendix 1 to

this Annex (as in Annex XIII of the current Directive). This documentation shall enable the conformity of the products with the requirements of the Directive to be assessed (as in Annex VI of the current Directive).

b. A written declaration of conformity (as in Annex XV of the current Directive). Its requirements are further specified in Appendix 2 to this Annex.

c. Selection of a Notified Body by the manufacturer, and the acceptance by the manufacturer to allow the Notified Body the necessary access to the information he needs to establish the conformity of the product, including the access to tests or the availability of products for testing. Appendix 3 to this Annex specifies the minimum criteria to such Notified Bodies.

XX.1.2: EC type-examination (description as in module B of the current Directive) XX.1.3: Conformity assessment The manufacturer has an obligation to assure the conformity of his production. The assessment of the conformity of manufactured products shall be performed under the supervision of the Notified Body. (to be described as in module C, Annex VIII of the current Directive) The assessment may either be made by the manufacturer who has to report the results of this assessment to the Notified Body at its request and to its satisfaction, or it may be made by the Notified Body itself. For this assessment there are two options. One is based on a quality assurance system operated by the manufacturer, and the other on a verification of the finished products by the Notified Body. XX.1.3.1: Option 1: Production quality assurance This option contains monitoring by the Notified Body of an approved quality system that the manufacturer operates to assure the quality of his products. This system must concern the final product inspection and testing, and may or may not include the production process. It is up to the discretion of the Notified Body to decide if the extent of the quality assurance programme is sufficient to assure the conformity of the final product. If the Notified Body does decide that this is not the case, either the manufacturer will have to adapt his quality assurance system, or he will have to adopt the other option. (text as in modules D and E, Annexes IX and XVII of the current Directive, with adaptations where necessary)


If needed, guidelines may be included to indicate to the Notified Body in which cases a quality assurance of the production needs or needs not to be part of the quality assurance programme. XX.1.3.2: Option 2: Product verification (text as in module F, Annex X of the current Directive) XX.2. Module 2: A simplified procedure The simplified procedure may be applied in special circumstances where the standard procedure is deemed to cause an undesired financial burden for the manufacturer, because of the limited extent of the production and/or because it concerns product characteristics for which a guarantee of full compliance with the requirements is less critical. It concerns the following cases:

Here a listing of the conditions needs to be given under which the simplified procedure is acceptable. These will be limited to manufacturers for whom a more involved and costly procedure would be unacceptable (SMEs) and product characteristics for which full compliance with the requirements is less critical.

The simplified procedure may or may not include a type-examination. In the first case the simplified procedure only concerns a simplification of the conformity assessment; in the second case it offers a simplification of the complete approval procedure. XX.2.1: The simplified procedure without type-examination. XX.2.1.1 The simplified procedure without type-examination contains the following elements: − The basic requirements as set out in paragraph XX.1.1 − A general assessment of the compliance by the Notified Body. XX.2.1.2 The assessment of the compliance by the Notified Body may be based on the following information: − The technical documentation as supplied by the manufacturer. − Internal reports of the manufacturer concerning adjustments and/or checks of

equipment made during production or on the final product in cases where this is relevant.

− Checks on the final product by the Notified Body, or under his supervision, whether by test or by calculation, or by examination.

This procedure does not contain a type-examination. It is meant to represent the modules A and Aa, Annexes V and VI of the current Directive. The actual text may be largely copied from the texts of these Annexes. If needed guidelines may be included to indicate to the Notified Body in which cases actual checks on the final product are necessary. It exceeds the requirements of module A in that it states that in any case at least some way of assessment, by whichever means,


needs to be performed by the Notified Body, which does not seem to be specified by the current text of module A.

XX.2.2: The simplified procedure with type-examination. The simplified procedure with type-examination contains the following elements: − The basic requirements as set out in paragraph XX.1.1. − A type-examination as set out in paragraph XX.1.2. − A general assessment of the compliance by the Notified Body, as set out in

paragraph XX.2.1.2.

This requirement covers the current combination of modules B+C. XX.3. Module 3: An extensive procedure without type examination The extensive procedure without type examination is limited to the assessment of the conformity of the finished product. It is especially applicable to products that are not produced in (large) series. There are two options. One is based on a full quality assurance system operated by the manufacturer, including the design stage, and the other of an acceptance test of each individual product by the Notified Body. XX.3.1: Option 1: Full quality assurance. (text as in module H, Annex XII of the current Directive) XX.3.2: Option 2: Full product verification. (text as in module G, Annex XI of the current Directive)

NB: the reason for placing ‘full quality assurance’ before ‘full product verification’ is that in the description of the basic procedure the quality assurance also is placed before the product verification. This gives more consistency in approach.

Appendix 1 to Annex XX: Technical documentation to be supplied by the manufacturer (text as in Annex XIII of the current Directive) Appendix 2 to Annex XX: Written declaration of Conformity (text as in Annex XV of the current Directive) Appendix 3 to Annex XX: Minimum criteria to be taken into account by Member States for the notification of bodies (text as in Annex XIV of the current Directive)


A schematic overview of the system is shown in Figure 15.3. It should be noted that the ‘quality assurance system’ and the ‘product testing’ of modules 1 and 3 are parallel but not identical. Figure 15.3: Schematic overview of the proposed simplified modular procedure


References

1975/440/EC, Directive on surface water quality, 1975 94/25/EC, Directive on recreational craft, 1994 97/68/EC, Directive on non-road mobile machinery, the emission of gaseous and particulate pollutants from internal combustion engines to be installed in non-road mobile machinery, 1997. Amendment directive 97/68/EC, Non-road Mobile Machinery, Brussels, March 15, 2004. 2002/49/EC, Directive on environmental noise, 2002. 2002/88/EC, Directive on non-road mobile machinery, the emission of gaseous and particulate pollutants from internal combustion engines to be installed in non-road mobile machinery, 2002. 2003/44/EC, Directive on recreational craft, 2003. Aanwijzing 13 van de Centrale Commissie voor de Rijnvaart, bedoeld in artikel 43 van de Herziene Rijnvaartakte (in Dutch), Staatsblad 1976. Adriaanse, P.I. (1996): Fate of pesticides in field ditches: the TOXSWA simulation model. Winand Staring Centre, Report 90, Wageningen. Asplund T.R., The effects of motorized watercraft on aquatic ecosystems, Wisconsin Department of Natural Resources, Publ. SS-948-00, 2000. Balk, L., G. Eriscon, E. Lindesjöö, I. Petterson, U. Tjärnlund and G. Åkerman (1994), Effects of exhaust from two-stroke outboard engines on fish – Studies of genotoxic, enzymatic, physiological and histological disorders at the individual level, Institute of Applied Environmental Research, Laboratory for Aquatic Ecotoxicology, Stockholm University Nyköping, Sweden Benchmark-research, Regulatory Impact Assessment, UPDATE, Amended Recreational Craft Directive, September 2003 Besluit luchtkussenvoertuigen Wet geluidhinder (in Dutch), Stb. 1989, 393 19 september 1989. Blankendaal, V.G., C.C. Karman, L.P. Simons & E.W.J.T. Nijhuis (2002): Emissieloos schip in de recreatievaart. TNO rapport R2002/203. Brandes, L.J., H. den Hollander & D. van de Meent (1996): SimpleBox 2.0: a nested multimedia fate model for evaluating the environmental fate of chemicals. RIVM report 719101029.


Buiten, J. & M.J.A.M. de Regt, Water traffic (in Dutch), Guideline on Noise abatement, 1994 Buro Maas (1984) CARB (California Air Resources Board), Staff report, Public Hearing to consider adoption of emission standards and test procedures for new 2003 and later spark-ignition inboard and sterndrive marine engines, 8 June 2001. CARB, California exhaust emission standards and test procedures for 2001 model year and later spartk-ignition marine engines. CARB, California Code of Regulations. Title 13; Motor vehicles. Article 4.7; Spark-Ignition Marine Engines. CARB letter, July 6 1999. Caroll, James N., White Jeff J., SwRI (South West Research Institute), Marine Gasoline Engine Testing, Final report, September 2001. Caroll, James N., SwRI, Marine Gasoline Engine and Boat Testing, Final report, September 2002. Charles Komanoff & Howard Shaw, Ph.D., Drowning in Noise; Noise costs of Jet Skis in America, April 2000 CIW (2000), Normen voor het Waterbeheer, Achtergronddocument NW4, CIW, Den Haag, The Netherlands, 2000 COM(2000) 639 definitief, 12 November 2000. COM(2001) 636 definitief, 31 October 2001. Egashira, H., Kiziwa, T, Iida, K., Furukawa, N., Study of the Impact to the Water Quality by Marine Engine Exhaust Emissions, SAE paper 2002-32-1810. EPA (US Environmental Protection Agency), Regulatory Impact Analysis: Control of Air Pollution Emission Standards for New Nonroad Spark-Ignition Marine Engines, June 1996. EPA, Nonroad engine and vehicle emission study, November 1991. EPA, Draft Regulatory Support Document: Control of Emissions from Unregulated NonRoad Engines, EPA report EPA420-D-02-003, July 2002. EPA, Code of Federal regulations, 40CFR part 89, 90 and 91, Air Pollution Control; Gasoline Spark-Ignition Marine Engines; New Nonroad Compression-Ignition and Spark-Ignition Engines, Exemptions; Rule, October 4, 1996.


EPA, Code of Federal regulations, 40CFR part 92 and 94, Control of Emissions of Air Pollution From New Locomotive Engines and New Marine Compression-Ignition Engines Less than 30 Liters per Cylinder; proposed rule, June 29, 2004 EPA, Code of Federal regulations, 40CFR parts 86, 90, 1045, 1051, 1068 Control of Emissions from Spark-Ignition Marinne Vessels and Highway Motorcycles; proposed rule; proposed rule, August 14, 2002. Erneborn, D. Wet Exhaust from a Marine Leisure Craft Diesel Engine - Environmental Aspects -, February 2000. Foundation Dutch Maritime Network, European Maritime Clusters, Rotterdam, November 2003. Gerretsen, E., Environmental noise descriptors in Europe – comparison of definitions and prediction methods, TNO-report 960059, 1996 Gerretsen, E., Calculation methods for noise (in Dutch), TNO-report 99-039, 1999. Icomia Marine Engine Committee, Personal Watercraft sound test report, Jet Ski Village, France, September 2003. Icomia, Falcao, F., Impact of the use of outboard motors on the aquatic environment, 2004. Icomia, Boating Industry Statistics 2002. InfoMil (2000), Nederlandse Emissie Richtlijn Lucht, InfoMil, Den Haag, The Netherlands 2000. ISO 14509 ‘Small craft – Measurement of sound pressure level of airborne sound emitted by powered recreational craft’, 2000. IWSF Environmental Handbook. Jet Skis Position Paper, internet http://www.earthisland.org/bw/jetskipos.shtml#jet ski Jetski issues – a summary of studies (2001), The Port Hacking Protection Society Inc. Jüttner, F., D. Backhaus, U. Matthias, U. Essers, R. Greiner and B. Mahr (1995) Emissions of two- and four-stroke outboard engines-I. Quantification of gases and VOC, Wat. Res. Vol. 29, No. 8, pp. 1976-1982. Jüttner, F., D. Backhaus, U. Matthias, U. Essers, R. Greiner and B. Mahr (1995) Emission of two- and four-stroke outboard engines-II. Impact on water quality, Wat. Res. Vol. 29, No. 8, pp. 1983-1987. Jong, R.G. de e.a., Assessment method for the noise in conservation areas (in Dutch), TNO-report, 1998.


Kastelein, R.A., Verboom, W.C., Muijsers, M., Van der Heul, S. and Vaughan, N. (Marine Environment Research, in press) The influence of underwater acoustic data communication sounds on the behaviour of harbour porpoises (Phocoena phocoena) in a floating pen. Kastelein, R.A., Van der Heul, S., Verboom, W.C., Triesscheijn, R. and Vaughan, N. (Marine Environment Research, in prep.) The influence of underwater data transmission sounds on the behaviour of harbour seals (Phoca vitulina) in a pool.

Kelly, C.A., G.A. Ayoko and R.J. Brown (In prep.), Can environmentally adapted lubricants reduce water-borne two-stroke outboard engine emission. Lambrecht, U., Helms H., Kullmer K., Knörr, W., IFEU, Entwicklung eines Modells zur berechnung der Luftschadstoffemissionen und des Kraftstofverbrauchs von Verbrennungsmotoren in mobilen Geräten und Maschinen, Endbericht, Im Auftrag des Umweltbundesamtes, January 2004. Lanpheer, R.A., Standard boat concept sound level test report, Sterndrives with integral exhaust systems, August 1999. Lanpheer, R.A., Motor cruisers & Sailboats sound level test report, Phase 1, IMEC, June 1998. Lanpheer, R.A., Lassanske, G.G., Powered recreational craft sound level test report Lake X Florida, IMEC, 1994. Malcolm J. Crocker, Encyclopedia of Acoustics, John Wiley & Sons, Inc, 1997. Lepper, P. (2002): Towards the derivation of quality standards for Priority Substances in the context of the water Framework Directive, Final Report, Fraunhofer Institute. Miedema, H.M.E. & Henk Vos, Exposure-response relationships for transportation noise, JASA 104, 1998. NEI&MERC / Foundation Dutch Maritime Network, Economic importance of Dutch watersport industry, Rotterdam, 1999. New Jersey State Police, Boat noise tests using static and full-throttle measurement methods, 1995 Nordic Ecolabelling, Ecolabelling of Marine Engines, Criteria document, 8 December 1995- 7 December 2002, version 3.4. Ntziachristos L., A. Mamakos, A. Xanthopoulos, E. Iakovou: Impact assessment / Package of new requirements relating to the emissions from two and three-wheel motor vehicles. University of Thessaloniki, Lab. Of applied thermodynamics. June 2004. PE-CONS 3686/03, 2002/0304 (COD) Directive of the European Parliament and of the Council amending Directive 97/68/EC, Brussels, 15 March 2004.


Policy Research Corporation and Institute of Shipping Economics and Logistics / European Commission DG Enterprise, Economic Impact of Maritime Industries in Europe, Brussels, 2001. PWC Task force, Personal watercraft sound test report, IMEC, September 2003. Rijkeboer R.C., Study on exhaust regulations for pleasure boat propulsion engines, TNO report 733160022/ES, December 1991. Rijkeboer R.C., D.A.C.M. Bremmers, Z. Samaras, L. Ntziachristos: Emission Regulation of PTW, TNO report 03.OR.VM.004.1/RR, February 2002. RIVM (1999) Environmental Risk Limits in the Netherlands (Part I Procedure / Part II Risk Limits), RIVM, Bilthoven, The Netherlands. SAE J34, Exterior sound level measurement procedure for pleasure motorboats, SAE Recommended Practice, Technical report J34 of Society of Automotive Engineers, Inc., New York, 1973. San Juan Islands (Washington state), carried out by the Woods Hole Oceanographic Institute. Seamarco B.V. Harderwijk and TNO TPD/FEL (The Netherlands). SFT (1988), Exhaust emissions from boats, SFT-Report No. 89/88, State Pollution Control (SFT), Oslo, Norway. Smit, M.G.D., C.C. Karman and G.B.J. Rijs (1999), Milieumeetlat voor biocidehoudende aangroeiwerende verven in de recreatievaart, Fase 1 Beschrijving van de methodiek, RIZA-werkdocument 99.008x, RIZA, Lelystad, The Netherlands (In Dutch). STOWA-Waterpakt (1999), Watervervuiling door motoren van pleziervaartuigen, Een studie naar de omvang van de verontreinigng en de effectiviteit van reducerende maatregelen, STOWA, Utrecht, The Netherlands (in Dutch). The Port Hacking Protection Society Inc, Jetski issues – a summary of studies, 2001. Tjärnlund, U., G. Ericson, E. Lindesöö, I. Petterson & L. Balk (1995): Investigation of the biological effects of 2-cycle outboard engines’ exhaust on fish. Marine Environmental Research 39: 313-316. US-EPA, Regulatory Impact Analysis; Control of Air Pollution; Emission Standard for New Nonroad Spark-Ignition Marine Engines, June 1996. Van Donkelaar, P. (1990): Environmental effects of crankcase- and mixed-lubrication. The Science of the Total Environment 92: 165-179. Van den Hout, M., P. de Vries (1991): De verontreiniging van oppervlaktewater door de pleziervaart (The pollution of surface water by recreational boating). KNWV, Bunnik, the Netherlands (in Dutch), September 1991.


Van Holst & Koppies, NEI/MERC, The Situtaion and Perspectives of the Recreational Craft Sector in the Applicant Countries (Bulgaria, Estonia, Lithuania, Poland, Romania, Slovenia), Capelle aan den IJssel/Rotterdam, October 2001. Van Vlaardingen, P. T. Traas and T. Aldenberg (2003): ETX-2000. Veldt, C. and P.F.J. van der Most (1993), Emissiefactoren, Vluchtige organische stoffen uit verbrandingmotoren, Publikatiereeks Emissieregistratie rapport nr. 10, Ministerie van VROM, Directoraat-Generaal Milieuhygiëne, Den Haag, The Netherlands (in Dutch). Verbeek, R.P. (2001): Verfahren zur Messung von Abgasemissionen an Bord von Binnenschiffen. TNO report 01.OR.VM.054.1/RV, October 2001. Wachs, B., H. Wagner & P. van Donkelaar (1991): Two-stroke engine lubricant emissions in a body of water subjected to intensive outboard motor operation. The Science of the Total Environment 116: 59-81. Warrington, P. (1999): Impacts of Outboard Motors on the Aquatic Environment. www.nalms.or/bclss/impactsoutboard.htm. WHO (World Health Organisation), Guidelines for Community Noise, 1999, Geneva. Yumly, S.V. (1994) Estimates of Emissions from Pleasure Craft in Canada, Environmental Protection Series, Report EPS 5/AP/5, March 1994, Environment Canada, Ottawa, Ontario, Canada.


Abbreviations

2s 2-stroke 4s 4-stroke BSO Bodensee Schiffahrts Ordnung CARB California Air Resources Board CCNR Central Commission for the Navigation of the Rhine CI Compression ignition (diesel engine) CO Carbon monoxide (emission component) CoP Conformity of production DI Direct Injection DIY Do it yourself DOC Diesel oxidation catalyst DPF Diesel particulate filter EBA European boating association (federation of European users organisations) ECE Economic Commission for Europe (a UN regional organisation) EEA European Environmental Agency EFI Electronic fuel injection EGR Exhaust gas recirculation EPA United States Environmental Protection Agency EQC Environmental quality criterion EQO Environmental quality objective EQS Environmental quality standard HC Hydrocarbons (emission component) ISO International Standardisation Organisation IuC In-use compliance KNWV Koninklijk Nederlands watersportverbond (Dutch users’ organisation) MAC Maximum allowable concentration (short duration criterion) MPC Maximum permissible concentration (average long duration concentration) NOx Oxides of nitrogen (emission component) NRMM Non-Road Mobile Machinery OBD Onboard diagnostics (onboard electronic monitoring system) OEM Original equipment manufacturer PAH Polycyclic Aromatic Hydrocarbon (emission component) PM Particulate matter (emission component) PTS Permanent threshold shift (hearing defect) PTW Powered two-wheeler (moped or motorcycle) PWC Personal watercraft RCD Recreational Craft Directive, 94/25/EC RW Road worthiness test (periodical inspection for road vehicles) SAE Society of Automotive Engineers SAI Secondary air injection SCR Selective catalytic reduction SI Spark Ignition (petrol engine) SME Small and medium enterprises SOx Oxides of sulphur (emission component) TA Type approval TAA Type approval authority TTS Temporary threshold shift (hearing defect) UN-ECE Economic Commission for Europe of the United nations


VOC Volatile organic compound (emission component) WHO World Health Organisation

A.1/1

TNO report | 04.OR.VM.057.1/RR

A Answers to the questionnaire

The following responses were received to the questionnaire (summarised):

Data Details of use Legislation Norway Est. 650,000 total ~ 500,000 in actual use ~ 70 % SI outboard ~ 30 % inboard (most CI) ~ 60 % < 25 hp ~ 20 % 25-50 hp

Coastal waters and fjords (salt waters) May-September, with a peak in summer months

Restricted use of PWC Noise regulations Environmental problems observed

Sweden 640,000 with engine: sailing boats 16 % open boats 68 % motorboats 16 %

~ 40 % on lakes ~ 45 % on the Baltic sea ~ 15 % on the west coast Short season mid-June to mid-August

Regulation concerning pleasure craft generated waste Directive 94/25/EC Environmental problems observed

Germany No registration, so no data Maintenance estimated to be frequent and good

Outboards on sailing boats only used for manoeuvring in or out of harbours 1 min/time, for ~ 40 days per year

Restrictions of use on reservoirs for drinking water Engine requirements on Bodensee

Denmark ~ 45,000 in 1997

~ 10 % on inland waters most on coastal waters

Restrictions on use of PWC

Lithuania ~ 3,700 in total ~ 65 % motorboats ~ 25 % powerboats ~ 10 % yachts

Curonean lagoon Baltic coastal waters Lakes and rivers

Legislation concerning safety Directive 94/25/EC to be implemented

Poland No specific data, but no significant numbers yet Significant growth expected for the future

Switzerland About 101,000 boats (majority is recreational) About 60,000 with engine

Nearly 100 % of boating on lakes, hardly on rivers Large lakes ‘shared’ with other countries.

Current BSO on Lake Constance BSO stage 1 elsewhere Modified ISO 2922 for sound; sound is no longer regarded as a problem May adopt procedure of RCD, but with lower limits

B.1/7


B Emission factors

A study into the current exhaust emission levels of engines for recreational craft resulted in the following. Emission data of marine engines, and special emission data of engines used in recreational craft were found in several studies carried out in the US. These studies were mostly performed under contract for or by the EPA or CARB. Some data was found in a study carried out for the Lake Tahoe case (situated partly in California and partly in Nevada, US). In-use data as well as some data of new engines is available for SI 2-stroke and 4-stroke engines, CI engines and some DI 2-stroke engines. EU data for outboard engines was collected by Icomia and stems from several manufacturers in the field. Most of the data concerns the specific emission of carbon monoxide, and nitrogen oxides and total hydrocarbons plus some data available on particulate matter emissions from CI engines. All figures are expressed in g/kWh. An overview of the data collected for this study can be found in the next figures. In order to gain a first insight into the emission performance of recreational craft engines in the field, the emissions are plotted together with the stage 1 limits from 2003/44/EC, the Directive that recently amended 94/25/EC. Warning It should be noted that the 4-stroke data stem partially from an older generation of engines, whereas in the case of 2-strokes the conventional 2-stroke mostly represents the older generation and the DI 2-stroke data refer to modern engines. Hence the data of the conventional 2-stroke should be compared with those of the older 4-strokes, and those of the 2-stroke DI to those of the newer 4-strokes. Furthermore it should e.g. be borne in mind that, as pointed out in Section 3, the DI 2-stroke engines and the 4-stroke engines are representative for different power categories, and the limit values in g/kWh do decrease with increasing nominal power.

B.2/7


Figure B.1: The CO and HC emission from some 2-stroke SI engines (dots) and the stage 1 emission limits from 2003/44/EC (lines).

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emission limits from 2003/44/EC (lines).


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B.3/7


Figure B.3: The CO and HC emission from some 4-stroke SI engines (dots) and the stage 1 emission limits from 2003/44/EC (lines).


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B.4/7


Figure B.5: The CO and HC emission from some DI 2-stroke engines (dots) and the stage 1 emission limits from 2003/44/EC (lines).

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Figure B.6: The NOx emission from some DI 2-stroke (dots) and the stage 1 emission

limits from 2003/44/EC (lines).

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B.5/7


Figure B.7:The CO and HC emission from some 4-stroke CI engines (dots) and the stage 1 emission limits from 2003/44/EC (lines)..

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B.6/7


Figure B.9: The PM emission from some 4-stroke CI engines.


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The various data of the previous figures is shown for quick reference in Figure B.10. For the calculations made in this report Icomia provided a dataset measured on 60 outboard engines, 24 2-strokes, 4 DI 2-strokes and 32 4-strokes. This dataset is shown in a quick-reference format as well in Figure B.11. General conclusions Looking at the emission figures the following can be said: • The conventional 2-stroke engines generally have a very high level of specific HC

and CO emission, with individual levels ranging from 200 up to 750 g/kWh for CO and 100 up to 800 g/kWh for HC.

• A large share of the conventional 2-stroke engines emit significantly more CO and HC than the 2003/44/EC limits. This for almost the complete power range, with exception of the CO emission of some small engines. Altogether this suggests that implementation of the stage 1 limits would already bring about a substantial reduction in the emission of hydrocarbons and carbon monoxide by 2-stroke engines.

• The 4-stroke engines perform much better than the 2-strokes on HC and CO. • Concerning the NOx emissions of the 2-stroke engines, they are well below the limit,

whereas the 4-stroke engines as a group emit substantially more, but still below the limit. Furthermore it should be noted that the NOx-emissions are very low in any case (note the increased scale for NOx in Figure B.10!).

• For DI 2-stroke engines the emission levels of HC as well as CO are much lower than for the conventional 2-strokes. They are at or well below the EU stage 1 limits. The specific NOx levels of DI 2-stroke and conventional 2-stroke do not seem to differ substantially.

• For the CI engines (not in Figure B.10) the HC and CO emissions are very low compared to the SI engines. The specific NOx levels of 4-stroke SI and 4-stroke CI do not seem to differ substantially for the larger capacity engines. For the lower capacity engines this comparison can not be made because data for diesel engines are not available in this range.

B.7/7


Figure B.10:‘Quick-reference’ overall impression of characteristic emission levels (average, minimum and maximum are given) found in literature of the different engine technologies. Note the different scale for the NOx-emissions.

Figure B.11:‘Quick-reference’ overall impression of characteristic emission levels (minimum and maximum of range) provided by Icomia for the different engine technologies. Recent measurements on 24 2s engines, 4 DI-2s engines and 32 4s engines. Note the different scale for the NOx-emissions.

Data from literature

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[g

/kW

h]

0

20

40

60

80

100CO left axisHC left axisNOx right axis

CO, HC NOx

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C Scenario studies concerning various environmental

aspects

C.1 Introduction

For the purpose of this study a number of scenarios were defined and calculated, so as to establish the impact of the baseline and stage 1 situations, or to estimate the impact of further legislation. The following aspects have been investigated in this way: • The total emissions to air. • The contribution to the local air quality aspects on a virtual big lake. • The water quality in a virtual local small lake. • The sound aspects on three typical locations: a waterway (river, canal), a marina

and a lake. Since in all cases a less favourable situation (c.q. a ‘worst case’ situation) was aimed at, the descriptions of the scenarios differ.

C.2 The total emissions to air

For the calculation of the total exhaust emissions to air only an overall European fleet had to be assumed. This was done for the baseline (reference year 1995), for stage 1 (reference year 2005), and for three different options for stage 2 (reference year 2015). The technologies for the reference years were derived from Icomia sales data concerning outboards engines of 1996, 2006 (projected) and 2010 (projected). For 2015 no later projections than 2010 were available. It was assumed that in a stage 2 situation no conventional 2-stroke engines would be sold anymore. The reader should be aware that for the purpose of this calculation it is assumed that in the reference years ALL engines of the fleet comply with baseline emissions or stage 1 or 2 emissions respectively. In actual life this will of course not be the case, but this is the only way to show the final impact of the legislation. The reference years only serve to supply a set of technology shares and a fleet size. The proportions between outboard engines, inboard petrol engines and diesel engines were derived from the data presented in Section 3, and were maintained for the three reference years. The fleet size was very difficult to establish. From known data concerning certain fleets it was deducted that a fleet equal to 17x the sales in the final year might present the best estimate. In fact the fleet sizes of the reference years are linked by the assumption that from 1995 to 2005 the increase was a cumulative 1.5 % per year, and from 2005 to 2015 1.0 % per year. So if the 1995 fleet size is wrong that would only mean that the whole spectrum would move up or down, whereas the mutual differences would remain intact. The assumptions resulted in the following data: Table C.1: Shares of the main engine types

Type of engine outboard 85 % inboard petrol 4 % Inboard diesel 11 %

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The shares in the technologies are: Table C.2: shares of the engine technologies for 1995 Power class

kW ave power

kW 2-stroke DI 2-stroke 4-stroke diesel

< 3 2 0.242 0 0.021 0 3-12 7.5 0.241 0 0.047 0

12-20 16 0.069 0 0.003 0.0055 20-30 25 0.079 0 0.007 0.011 30-45 37.5 0.050 0 0.022 0.0198 45-75 60 0.039 0.011 0.011 0.022 75-110 92.5 0.017 0.009 0.007 0.0385

110-150 130 0.003 0.008 0.001 0.0077 > 150 170 0 0.003 0.001 0.0055

Sum per technology 0.739 0.031 0.120 0.110 Table C.3: shares of the engine technologies for 2005 Power class

kW ave power


< 3 2 0.055 0 0.151 0 3-12 7.5 0.134 0 0.164 0

12-20 16 0.019 0 0.033 0.0055 20-30 25 0.025 0 0.057 0.0110 30-45 37.5 0.011 0.010 0.062 0.0198 45-75 60 0.009 0.013 0.049 0.0220 75-110 92.5 0.001 0.015 0.047 0.0385

110-150 130 0.004 0.009 0.007 0.0077 > 150 170 0.002 0.004 0.007 0.0055

Sum per technology 0.260 0.053 0.578 0.110 Table C.4: shares of the engine technologies for 2015 Power class

kW ave power


< 3 2 0 0.206 0 3-12 7.5 0 0.298 0

12-20 16 0 0.052 0.0055 20-30 25 0.002 0.080 0.0110 30-45 37.5 0.012 0.070 0.0198 45-75 60 0.016 0.056 0.0220 75-110 92.5 0.015 0.049 0.0385

110-150 130 0.013 0.007 0.0077 > 150 170 0.005 0.008 0.0055

Sum per technology 0 0.063 0.827 0.110 The fleet sizes finally assumed are: Table C.5: overall number of relevant fleet in Europe (engine equipped boats only) Reference year 1995 2000 2005 2015 Total size European fleet 3.20 million 3.45 million 3.72 million 4.10 million

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For the emissions measured data from Icomia have been used. When, for later reference years, these emissions are still lower that those required by legislation, these figures have been maintained. If the relevant stage of the legislation requires lower emissions, an emission of 80 % of the legal limit has been assumed. This percentage is based on experience with emission legislation and actual emissions in other fields of application, mainly automotive. In some cases it has been assumed that recalibration of the engine may lead to an increase, as far as the emission limits do allow this. These assumptions result in the following emission factors: Table C.6: emission factors in g/kWh. Conventional 2-s engines; stage 0 and stage 1 Power class CO HC NOx

kW stage 0 stage 1 stage 0 stage 1 stage 0 stage 1 < 3 220 176 149 72 0.48 1.0

3-12 267 147 195 42 0.61 1.2 12-20 312 120 226 34 0.80 1.6 20-30 351 111 247 31 1.01 2.0 30-45 400 106 268 29 1.30 2.6 45-75 481 102 295 28 1.81 3.6 75-110 592 100 321 27 2.56 5.1

110-150 258 99 135 26 3.42 6.8 > 150 238 98 115 26 4.34 8.7

Table C.7: emission factors in g/kWh. DI 2-s engines; stage 0 and stage 1 Power class CO HC NOx

kW stage 0 stage 1 stage 0 stage 1 stage 0 stage 1 < 3 45 45 46 46 2.2 2.2

3-12 48 48 45 45 2.3 2.3 12-20 53 53 44 44 2.5 2.5 20-30 58 58 43 43 2.7 2.7 30-45 66 66 41 41 3.0 3.0 45-75 79 79 38 38 3.6 3.6 75-110 97 97 33 33 4.3 4.3

110-150 119 99 28 28 5.2 5.2 > 150 142 98 22 22 6.2 6.2

Table C.8: emission factors in g/kWh. 4-s engines; stage 0 and stage 1 Power class CO HC NOx

kW stage 0 stage 1 stage 0 stage 1 stage 0 stage 1 < 3 297 288 29.8 28.6 3.7 4.0

3-12 211 147 14.8 13.6 4.0 4.8 12-20 183 120 11.0 9.8 4.6 5.6 20-30 170 111 9.6 8.4 5.1 6.0 30-45 161 106 8.6 7.4 6.0 7.2 45-75 152 102 7.9 6.7 7.4 8.8 75-110 146 100 7.3 6.1 9.5 11.2

110-150 142 99 7.0 5.8 12.0 12.0 > 150 139 98 6.8 5.6 14.6 12.0

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Table C.9: emission factors in g/kWh. diesel engines; stage 0 and stage 1 Power class CO HC NOx PM

kW stage 0 stage 1 stage 0 stage 1 stage 0 stage 1 stage 0 stage 1 < 3 2.25 1.25 1.25 0.4 18.0 8.0 0.4 0.25

3-12 2.25 1.25 1.25 0.4 18.0 8.0 0.4 0.25 12-20 2.25 1.25 1.25 0.4 18.0 8.0 0.4 0.25 20-30 2.25 1.25 1.25 0.4 18.0 8.0 0.4 0.25 30-45 2.25 1.25 1.25 0.4 18.0 8.0 0.4 0.25 45-75 2.25 1.25 1.25 0.4 18.0 8.0 0.4 0.25 75-110 2.25 1.25 1.25 0.4 18.0 8.0 0.4 0.25

110-150 2.25 1.25 1.25 0.4 18.0 8.0 0.4 0.25 > 150 2.25 1.25 1.25 0.4 18.0 8.0 0.4 0.25

For the different options of stage 2 scenarios the following emission factors were used (in option 2A the engines < 30 kW have the values of option 1): Table C.10: emission factors in g/kWh. DI 2-s engines; stage 2, options 1 and 2 (2A) Power class CO HC NOx

kW option 1 * 2A

option 2 option 1 * 2A


option 2

< 3 * 48 48 28.6 21.4 1.7 2.3 3-12 * 52 52 13.6 10.2 1.8 2.5

12-20 * 56 56 9.8 7.4 2.0 2.6 20-30 * 62 62 8.4 6.3 2.2 2.9 30-45 72 72 7.4 5.6 2.4 3.2 45-75 84 77 6.7 5.0 2.8 3.8 75-110 100 75 6.1 4.6 3.5 5.1

110-150 99 74 5.8 4.4 4.2 5.5 > 150 98 74 5.6 4.2 5.0 6.6

Table C.11: emission factors in g/kWh. 4-s engines; stage 2, options 1 and 2 (2A) Power class CO HC NOx

kW option 1 * 2A



option 2

< 3 * 288 216 28.6 21.4 6.0 4.0 3-12 * 147 110 13.6 10.2 7.2 4.8

12-20 * 120 90 9.8 7.4 8.0 5.6 20-30 * 111 84 8.4 6.3 9.6 6.4 30-45 106 80 7.4 5.6 12.0 8.0 45-75 102 77 6.7 5.0 12.0 8.0 75-110 100 75 6.1 4.6 12.0 8.0

110-150 99 74 5.8 4.4 12.0 8.0 > 150 98 74 5.6 4.2 12.0 8.0

For the diesel engines the stage 2 emission limits have only a limited impact. In the case of option 1 in practice only the engines > 30 kW are affected. For engines > 30 kW there will be a limit for HC+NOx. This has been shared over the emission factors of HC and NOx on the basis of engineering judgement, which in turn is based on the knowledge and experience with engines in other fields of application, especially road transport. In the case of option 2 only the engines > 20 kW are affected. For the engines

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of 20-30 kW the NOx-limit will reduce the NOx-emission by 20 %; it has been assumed that this will lead to a calibration that will increase the emissions of HC and PM somewhat. For engines > 30 kW the limit for PM will actually reduce the PM-emission. In the case of engines of 30-45 kW there will be a limit for HC+NOx. In this case the same approach applies as for all engines > 30 kW in option 1. For engines > 45 kW there are separate limits for HC and NOx, that will effect both emission factors. It is assumed that neither in the case of option 1, nor in the case of option 2 the CO-emission will actually be affected by the CO-limit in force. So in both cases the CO-emission factor is identical to that of the stage 1 legislation. This results in the following emission factors: Table C.12: emission factors in g/kWh. diesel engines; stage 2 options 1 and 2

Power class CO HC NOx PM kW opt. 1 opt. 2 opt. 1 opt. 2 opt. 1 opt. 2 opt. 1 opt. 2 < 3 1.25 1.25 0.40 0.40 8.0 8.0 0.25 0.25

3-12 1.25 1.25 0.40 0.40 8.0 8.0 0.25 0.25 12-20 1.25 1.25 0.40 0.40 8.0 8.0 0.25 0.25 20-30 1.25 1.25 0.40 0.50 8.0 6.4 0.25 0.30 30-45 1.25 1.25 0.40 0.56 5.6 3.2 0.32 0.16 45-75 1.25 1.25 0.40 0.15 5.6 2.65 0.32 0.16 75-110 1.25 1.25 0.32 0.15 5.45 2.65 0.24 0.12

110-150 1.25 1.25 0.32 0.15 5.45 1.6 0.24 0.12 > 150 1.25 1.25 0.32 0.15 5.45 1.6 0.24 0.12

The calculations result in the following overall emissions for the European fleet:

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Table C.13: Emissions for recreational craft in the EU, for the various stages, as calculated in this study. Baseline and stage 1 CO

t/y NMHC

t/y NOx t/y

PM t/y

Rec. craft SI baseline 123 526 69 917 1 246 - Rec. craft CI baseline 679 377 5 431 121

Total baseline (fleet 1995) 124 200 70 300 6 680 121

Rec. craft SI stage 1 69 200 10 426 4 573 - Rec. craft CI stage 1 438 140 2 802 88

Total stage 1 (fleet 2005) 90 600 10 570 7 380 88

Total stage 2 (fleet 2015)

option 1 petrol diesel TOTAL

76 812 391 77 200

5 459 133 5 590

6 502 2 166 8 670

101 101

option 2 petrol diesel TOTAL

58 260 391 58 700

4 094 79 4 170

4 757 1 017 5 770

53 53

option 2A petrol diesel TOTAL

63 988 391 64 400

4 596 79 4 680

5 190 1 017 6 210

53 53

C.3 The contribution to the local air quality aspects on a virtual big

lake

Apart from the overall contribution, there is the contribution to local air quality. The impact of a particular source (in this case recreational boating) on the actual local air quality is dependant on a number of purely local factors that determine the relation between emissions and immissions (pollutant concentrations in air). These factors include, inter alia, the geographical and meteorological aspects of the locality and the presence and strength of other contributing sources. Since these factors vary from place to place, no hard overall statements are possible. For that reason it was decided to compare the numerical contribution of recreational boating on a hypothetical locality with the situation of three known urban situations. These urban situations were selected from the Auto-Oil II study, since their air quality aspects had been extensively analysed in the context of the further necessity of exhaust gas legislation for automotive sources. See further subsection 4.2. For the hypothetical locality a ‘virtual’ lake was defined. Since for the purpose of local water quality calculations, already a virtual lake had been defined (’Lake Fun’, see subsection C.4), for which the overall emissions had been calculated, for the current evaluation a ‘Lake Fun Plus’ was defined that simply consisted of a lake five times as large, with five times as many boats. A quick investigation of the relevant localities in Europe had shown that the majority of European lakes has a surface area of roughly between 5 and 50 km2. Since Lake Fun has a surface area of 7 km2, a multiplication by a factor of five brings it at 35 km2, and hence near the upper limit of that range. Only a few European lakes have surface areas of considerably larger size (in the range 300-500 km2), but they have considerably lower boat densities. So the overall emission on Lake Fun Plus may be regarded as a worst case situation. Since for local air quality only the emission of organic compounds would be of interest (see subsection 4.2), only the overall HC-emission was selected for comparison.

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The characteristics of Lake Fun Plus, as entered into the comparison, are shown in the following table: Table C.14: The characteristics of ‘Lake Fun Plus’ and the overall emissions on a busy

summer weekend day. Characteristic unit magnitude Total surface area km2 35 Total number of boats - 16000 Total HC-emission

baseline t/day 0.95 stage 1 t/day 0.12

For further details, such as fleet composition: see subsection C.4, below.

C.4 The water quality in a virtual local small lake

C.4.1 General approach For similar reasons as in the case of the local air quality, local water quality has been judged on the basis of calculations for a ‘virtual’ lake, ‘Lake Fun’. Again these calculations may be considered as realistic (although mostly worst case) for different local situations encountered in Europe (see subsection 4.1). Environmental concentrations of the contaminants were calculated for a number of constituents of exhaust gases from recreational craft. The total amount emitted was calculated and then partitioned across air, water, suspended solids, sediment etc. For the longer term, degradation (e.g. by microbes or under the influence of light) was also taken into account, as was evaporation of the substances from the water column to the atmosphere. For the calculations an existing model SimpleBox 2.0 [Brandes et al., 1996] has been used. The documentation for this model also describes the default values for all other model parameters.

C.4.2 Description of the lake Lake Fun is modelled on the Dutch lake “Nieuwkoopse Plassen”. This is typical for a shallow and relatively small lake, which is not constantly refreshed, although it is part of the Dutch water system that eventually discharges its water to the sea. It has been used in earlier studies [STOWA/Waterpakt, 1999] on the same subject. Hence the major characteristics of Lake Fun are: • overall area of 7 km2 • average depth of 2.3 m • suspended matter concentration of 22 mg/l • water temperature of 12 ºC The water temperature selected is the default value of the model; it represents a broad overall average. Since Lake Fun is a virtual lake the selection of an actual temperature was not possible. Instead, the influence of the temperature was investigated by a small sensitivity analysis. In the majority of the scenarios the other parameters are also set to their default values. These default values are representative for the Netherlands and other European countries with a moderate Atlantic climate. In several of its aspects Lake Fun may be regarded as a worst case situation, however.

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For the number of craft Buro Maas (1984) gives a count of 2000 craft on lake “Nieuwkoopse Plassen” for 1982. Since then the average annual growth of the fleet is estimated at 2 %. From this the number of vessels for Lake Fun has been extrapolated (and rounded to the nearest hundred) as shown in table C.15. Table C.15: Number of recreational craft on Lake Fun for two different years.

Year Number of recreational craft 1995 2600 2005 3200

It should be noted that, although these boat densities are realistic for the actual location for which they were established, in fact they represent a very high boat density. From data taken from STOWA/Waterpakt (1999) it is estimated that on a peak day each vessel would be used for about 0.9 h. In actual fact some vessels will remain in the marina and others will be used more intensively. However for the current purpose this estimate is adequate. Table C.16: Technology mixes for two years (expressed in percentage of total).

Technology 1995 2005 Boats PWC Boats PWC 2-s 60.4 0.2 27 0.2 DI 2-s 1 0.2 6.4 0.2 4-s 9 0.2 37 0.2 diesel 29 0 29 0

For this calculation a technology mix for the current fleet was reconstructed from data with regard to outboard engines as supplied by Icomia, and completed by the data concerning inboard engines as presented in Section 3. Since, as will become clear later, diesel engines contribute more than average to the emission of naphthalene, the diesel share has been set at a high value; this does not have a large effect on the other components. This data is most relevant for the present situation and used in conjunction with the modelling year 2005. For 1995 a different technology mix has been derived by adjusting the categories DI 2-s and 4-s downward and a higher share of 2-s. The technology mixes are given in table C.16. Sales data for outboard engines for the years 1996 through 2002 by Icomia have been used to estimate an average engine size per technology type (this data is presented in more detail in Section 3). For the estimates of environmental concentrations two sets of engine sizes have been used. First the estimate for the Netherlands, as a situation with many small inland waters, where typically relatively small boats and engines are used, and another set which is arrived at by taking the average engine size across all available European countries (where in fact a certain share of the fleet will be used at sea). This second set is referred to as the EU-engines. Since this set has larger engines in each category (except for the PWCs) it generally results in higher emissions than the NL-set. As diesel engines were not present in the Icomia-sales data this category was estimated by assuming their power to be roughly double that of 4-stroke engines. The rationale being that the average size of the 4-stroke category is low as it is numerically dominated by small outboards, which will not be the case for inboard mounted diesel engines. For PWCs a tour was made along websites of manufacturers of such craft. From this an

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engine size of about 65 kW, was taken as a reasonable, though somewhat conservative, value. Both sets of engine sizes per technology are presented in table C.17. Table C.17: Average engine power levels [kW] per technology for the Netherlands and

for the aggregated European set. Technology NL set EU set Boats PWC Boats PWC 2-stroke 12 65 30 65 DI 2-stroke 126 65 140 65 4-stroke 12 65 32 65 diesel 25 60 An engine load factor per engine type (2-stroke, DI 2-stroke, 4-stroke, diesel, as well as for PWCs) was taken from the test procedure for marine engines: ISO 8178-4 (0.207 for petrol engines and 0.340 for diesel engines). For the calculation of the emissions the data as discussed and presented in subsection C.2 have been used. In combination with ‘emission profiles’ that give the fraction of a compound in relation to the total HC-emissions for each technology an estimated total emission per compound is calculated. A final conversion of the unit then yields an emission-intensity expressed as t/day (table C.22).

C.4.3 The scenarios The scenarios have been laid out as follows. • Scenario 3 should be regarded as the base case. • Scenarios 1-4 describe the influence of the changes in fleet composition and the

technology improvement for the ‘Dutch fleet’ situation. • Scenarios 5-8 describe the influence of the changes in fleet composition and the

technology improvement for the ‘EU fleet’ situation. • Scenarios 9 and 10 describe the influence of the water temperature (± 4 ºC, relative to

the 12 ºC of scenario 3). Thus ‘warmer’ has been defined as a temperature of 16°C (instead of the default value of 12 °C). This would roughly be an average temperature over the summer half-year in the Netherlands.

• Scenarios 11 and 12 describe the influence of the amount of particles suspended in the water (5 and 30 mg of suspended matter per litre of water respectively, relative to the 22 mg of scenario 3).

• Scenario 13 was added to understand the influence of stratification. This scenario was not actually calculated, as the model is not suited to this kind of problem. A qualitative approach was taken to address such a situation adequately.

The scenarios are detailed in Table C.18.

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Table C.18: Listing of the scenarios.

fleet year

techn. mix emission engines lake approach compounds



Scenario 3 2005 2005 Stage 1 NL Standaard Quant. All

Scenario 4 2015 2005 Stage 1 NL Standard Quant. Two





Scenario 9 2005 2005 Stage 1 NL Warmer Quant. Two

Scenario 10 2005 2005 Stage 1 NL Colder Quant. Two

Scenario 11 2005 2005 Stage 1 NL Less particles Quant. Two

Scenario 12 2005 2005 Stage 1 NL More particles Quant. Two

Scenario 13 2005 2005 Stage 1 NL Deeper/Strat. Qual. #N/A

C.4.4 The compounds selected for the evaluation In this scenario study five compounds of the exhaust emission were selected based on findings in literature, relatively high known concentrations in water or sediment, and high toxicity (low ‘environmental quality objectives’). They have been chosen from the numerous constituents of engine exhaust based on their relatively large share in the exhaust. Also further analysis is possible for these compounds as other data is available on e.g. environmental quality standards. These compounds are: • benzene • naphthalene • toluene • xylene • formaldehyde Although other compounds may be relevant as well, they could not be assessed due to a lack of information on the characteristics of such compounds. The results for the five selected compounds will give a fairly representative picture, however. Of these five compounds only two (benzene and naphthalene) have been calculated for all scenarios; the other three have only been calculated for the scenarios 1-3. In table C.19 an overview is given of the chemical specific parameters that are relevant for this calculation.

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Table C.19: Chemical specific parameters used in the calculation of selected environmental pollutant concentrations.

Compound CAS MW Solu-bility mg/l

Melt. point

°C

Boil. point

°C

Flash point

°C

Vapour Press. mmHg

log Pow

Kp l/kg d.m.

pKa Phys. State

Benzene 71-43-2 78 1790 6 80 -11 94.8 2.13 0.97 l

Naphthalene 91-20-3 128 31 81 218 78 0.085 3.3 2.37 s

Toluene 108-88-3 92 526 -93 111 4 28.4 2.73 1.15 l

Xylene 1330-20-7 319 106 -50 140 25 7.99 3.16 1.87 l

Formaldehyde 50-00-0 30 g/l 550 -118 -20 60 3890 0.35 13.3 g

CAS = chemical abstracts service number MW = molecular weight log Pow = logaritm (octanol - water partition coefficient) Kp = solids - water partition coefficient pKa = dissociation constant physical state: gaseous, liquid or solid

Table C.20: The fractions of the five compounds in the overall HC-emission, used for

the current calculation technology benzene naphthalene toluene xylene formaldehyde petrol 2-s 0.045 0.00019 0.120 0.081 0.017 petrol DI 2-s 0.045 0.00019 0.120 0.081 0.017 petrol 4-s 0.045 0.00118 0.120 0.081 0.017 diesel 0.020 0.00923 0.015 0.020 0.060 The emissions have been calculated by calculating the overall HC-emissions and multiplying these with the average fraction of that compound in these overall HC-emissions, as found in literature. The fractions used are shown in Table C.20. The resultant emissions, as valid for a busy weekend day on Lake Fun, and used as input for the model, are shown in Table C.21:

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Table C.21: The emissions of the five compounds per scenario in kg/day, as used for the model input

Emissions benzene naphthalene toluene xylenes formaldehyde

Scenario 1 35.5 0.37 94 64 14.6

Scenario 2 43.7 0.46 116 78 18.0

Scenario 3 13.1 0.22 34 23 5.7

Scenario 4 15.5 0.26 41 28 6.7

Scenario 5 92 0.79 244 165 36.9

Scenario 6 113 0.97 300 203 45.5

Scenario 7 23 0.49 60 41 10.4

Scenario 8 27 0.58 71 48 12.3

Scenario 9 13.1 0.22 34 23 5.7

Scenario 10 13.1 0.22 34 23 5.7

Scenario 11 13.1 0.22 34 23 5.7

Scenario 12 13.1 0.22 34 23 5.7

Scenario 13 0nly qualitative

C.4.5 Modelling results The modelling exercise led to the following results: Table C.22: Modelled concentrations, process half life and the associated dominant

process for benzene. benzene concentration process half life water sediment water sediment

µg/l µg/kg(wet) d

dominant

process d

dominant

process

Scenario 1 10.5 0.002 5.0967 volatilisation 0.0014 degradation












Only qualitative

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Table C.23: Modelled concentrations, process half life and the associated dominant process for naphthalene. naphthalene concentration Process half life water sediment water dominant sediment dominant µg/l µg/kg(wet) d process d process













only qualitative evaluation Table C.24: Modelled concentrations, process half life and the associated dominant

process for toluene. toluene concentration Process half life water sediment water dominant sediment dominant µg/l µg/kg(wet) d process d process

Scenario 1 47 9 5.4806 volatilisation 0.9616 degradation




Table C.25: Modelled concentrations, process half life and the associated dominant

process for xylenes (combined o-, m- and p-). xylenes concentration Process half life water sediment water dominant sediment dominant

µg/l µg/kg(wet) d process d process

Scenario 1 34 0.2 5.8077 volatilisation 0.0769 degradation




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Table C.26: Modelled concentrations, process half life and the associated dominant

process for formaldehyde. form- concentration Process half life aldehyde water sediment water dominant sediment dominant µg/l µg/kg(wet) d process d process




Scenario 4 1.6 0.01 3.4582 volatilisation 0.0579 degradation Table C.27: Estimated emissions (kg/day) for benzene, naphthalene, toluene, xylenes,

and formaldehyde with an indication of the stage and option of the emission legislation for which these are valid. EU-fleet, 2005 size.

Stage and option

Benzene kg/day

naphthalene kg/day

toluene kg/day

xylenes kg/day

formaldehyde kg/day

Stage 0 12.3 0.11 32.5 4.9 22.0

Stage 1 3.1 0.07 8.0 1.4 5.4

Stage 2 (1) 0.9 0.03 2.4 0.4 1.7

Stage 2 (2) 0.7 0.03 1.8 0.4 1.2

Stage 2 (2A) 0.7 0.03 1.8 0.4 1.2 Table C.28: The modelled concentrations for benzene and naphthalene. Stage and option

benzene concentrations

naphthalene concentrations

water sediment water sediment µg/l µg/kg (wet) µg/l µg/kg (wet)

Stage 0 27.2 0.004 0.44 0.7

Stage 1 6.8 0.001 0.27 0.4

Stage 2 (1) 2.1 0.000 0.12 0.2

Stage 2 (2) 1.6 0.000 0.11 0.2

Stage 2 (2A) 1.6 0.000 0.11 0.2

C.5 The sound aspects on three typical locations: a waterway (canal), a lake and a marina

C.5.1 General approach

The sound impact of recreational boating depends on the number and duration of activities (passing craft, circling craft), the sound emission per craft during that activity and the propagation to the observer. To give some estimate, the following situations were considered: A waterway (canal), of which the sound impact on the shore was calculated A small lake, of which both the sound impact on the shore and the sound impact on

other boat users were calculated A marina, of which the sound impact on the surroundings was calculated

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For the number and use of the boats estimates were used for an average day in the summer season and a peak day in that season. Other situations could be estimated from these results.

C.5.2 The modelling used The propagation of sound from recreational craft is likely to be estimated best by models for road traffic or industrial sites, since the spectra of the sound emission for such sources are comparable. However, the variation in frequency effect in the sound propagation of various sources is only moderate so the influence of this choice is not very important. Though large differences have been found between the estimates by different models within Europe [Gerretsen, 1996], some have shown to be comparable enough for global estimates. Such models could consider areas with random traffic of craft (lake) as well as flowing traffic of craft along a line (canal, river). Such models take into account the sound reduction due to distance, air absorption, ground effects and screening and scattering by objects. For a global approach, as is intended in this study, the predictions will be based on A-weighted levels; hence also the sound reduction will be treated on A-weighted levels. Since the spectrum shape of the considered sources influences the actual reduction effects, it is likely that a road traffic approach would best fit the situation with recreational craft. For water traffic in general this has also been the conclusion of a partly European study into the modelling of urban impact [Gerretsen, 1999], hence the model as described for URBIS will be used also for recreational craft. The model will be used to estimate the sound impact expressed as Lden at a receiver height of 4 m taking into account a long-term averaging over weather conditions (primarily wind direction). See the box on page 71 for an explanation of Lden. This is in accordance with the European Directive and the interim models as prescribed for road traffic, rail traffic and industrial activities [2002/49/EC, 2002].

C.5.3 Description of the localities Canal, river It is assumed that the canal or river has a width of 50 tot 100 m and that the observers are living along the shores; the average distance between the passing craft and the observers is assumed to be 50 m. Since the use of PWCs is more restricted to a certain area and not so much passing, these craft will be neglected here. Furthermore it is assumed that the craft are used for 80 % during the daytime (7:00h to 19:00 h) and for 20 % during the evening (19:00 to 23:00h) and are not used during the night period; this division does not prove to be critical though. Open water In case of open water the craft will not so much pass the observer but will be distributed over (a large part of) the water, so partly at larger distance from the observer at the shore. As a representative average a distance of 200 m is chosen. The same distribution over day and evening is used as for the canal; in this case PWCs are considered as well, with a use of 1 h per day, equally divided over day and evening time. Outboard engines in this case are considered to be used only part of the time, leading to an engine use varying from 1/2 h (sailing boat) to 3 h (motor boat).

C.16/18


Another aspect in this case could be the disturbance of people in one craft by another craft. For this situation a typical minimum passing distance of 25 m is chosen; all other assumptions are taken as identical. Marina For a marina also a distance of 200 m is arbitrarily chosen, but the global effect of other distances is indicated. It is assumed that engines are used for 1/3 h for each boat to leave and enter a marina. Other activities in the marina are neglected, as well as sound reduction through screening by buildings and other obstacles.

C.5.4 The fleet The largest group of craft concerns craft with outboard engines. It is assumed that this represents 88 % of the total fleet, another 10 % being craft with inboard engines and 2 % personal watercraft. This assumption of only 10 % inboard engines is again a kind of worst case situation, since the European average for inboard engines is closer to 15 %. For outboard engines a distribution over installed power is available from a German study [TÜV], with the nominal power and the power while in use (= 22 % of nominal power). For other engines types typical values for the nominal power are assumed on the bases of various reported measurement data (see subsection 5.2.2). The power for normal use in these cases is assumed to be also 22 % of the nominal power for inboard engines and 33 % for PWCs. This distribution is presented in table C.29, with some additional data. Table C.29: Distribution of recreational watercraft over types as used for the sound

impact estimates, with indications of nominal power, power and speed in normal use and the A-weighted sound power level for full nominal power, duty cycle and average use.

Type P nom [kW]

P use [kW]

speed [km/h]

% fleet LWA-nom

[dB] LWA-DC

[dB] LWA-use

[dB] Outboard 5,5 1,2 12 52% 104 95 97 21,5 4,5 21 14% 108 99 101 40,5 8,5 27 12% 109 101 103 80,5 16,9 36 10% 111 103 105 Inboard 160 33,6 25 10% 101 (93) 94 PWC-min 65 22 40 1% 113 103 108 PWC-max 65 22 40 1% 116 108 111

Inboard 160 33,6 25 10% 101 (93) 94 Outboard 8 24 88% 107 99 100 PWC 22 40 2% 115 106 110 The indicated average speed is based on the average power in use, using a relation derived from the mentioned measurement studies for outboard engines (v ≈ 11,5P0,4 [km/h]). The indicated A-weighted sound power levels are deduced from the nominal power Pnom and the power in use P, by applying the relations presented below (subsection C.5.6), see table C.31 below, applying the relation that the sound power varies with the used power as 10 lg P/Pnom. This follows globally from the available data as can also be seen in the table from the good comparison between this sound power level and that measured for duty cycle. The results in the table are also grouped in the two categories outboard engine and personal watercraft. These two groups will be

C.17/18


used for further estimation of the sound impact; the inboard engines will further be disregarded due to the scarce data for these engines in combination with the estimated small contribution to the impact.

C.5.5 Intensity of use For the intensity of use two different situations were modelled: an average season day, and a typical peak day. The resulting intensities are shown in Table C.30. Table C.30: Intensities of use per type of craft for two different situations as used for the

different localities modelled situation Type of craft Average

season day Typical

peak day nr./h nr./h canal d = 50 m boats 15 45 lake d = 200 m 3) boats/PWCs 10/0.2 40/0.8 marina d = 200 m 3) boats 1 7 passing d = 25 m boat/PWCs 2/2 20/20

C.5.6 Sound power levels

For predictions the sound emission is best expressed in terms of the sound power level instead of sound pressure levels at a given distance. Sound power levels can simply be calculated by the following formula: 2lg10 !+= SLL pW dB

where LW = sound power level in dB(A) re 1 pW; Lp = measured sound pressure level in dB(A) re 20 µPa; S = area of hemisphere with radius r (measurement distance) (= 4πr2) in m2.

This is used to express the relations for the sound pressure levels as derived from the measurements, mostly in accordance with ISO 14091, also in sound power levels; see Table C.31. The derived relations for the sound pressure level at 25 m, second column, are also presented in the figures 5.4 and 5.5.

C.18/18


Table C.31:Global A-weighted sound pressure levels and corresponding sound power levels of (recreational) craft. The formulae are best fit lines from measurements results conducted by IMEC (Lanpheer). The measurement procedure is according to 14509-1.

Craft/Source LAmaxS, 25m [dB(A) re 20µPa]

LWAmaxS

[dB(A) re 1pW]

Remark

Outboard engine 62+6.5lgP [kW]

53+6.9lgP[kW]

99+6.5lgP [kW]

90+6.9lgP[kW]

Full throttle

Duty Cycle

Inboard engine 33+14.2 lg P [kW] 70+14.2 lg P [kW]

Sterndrive engine - -

Personal watercraft 64/67+6.5lgP [kW]

53/58+6.9lgP[kW]

101/104+6.5lgP [kW]

90/95+6.9lgP [kW]

Full throttle

Duty Cycle

towing sound by

boats (v ≈ 11,5 P0,4)

53+9.2lg P [kW] 90+9.1lg P [kW]

(66+22.7lg v [km/h])

references: [Icomia 2003, IMEC]

C.5.7 Results The modelling results are shown in Table C.32. Table C.32: Sound impact Lden in dB(A) for the two modelled situations and the three

different localities. situation average season

day typical

peak day sound impact

Lden in dB(A) 1) sound impact Lden in dB(A) 1)

canal d = 50 m 43 47 lake d = 200 m 2) boats PWCs

50 42

56 48

marina d = 200 m 2) boats

40

49

passing d = 25 m boat PWC

38 (55-65) 3) 45 (68-80) 3)

48 55

1 since A-weighting is applied in the determination of Lden the unit dB(A) is used here for clarity, though the directive calls the unit dB

2 at 100 m the levels are 7 dB higher than at 200 m. 3 in brackets: the maximum level LpA,Smax, excluding exceptional situations as planing and exhaust

above water level

D.1/4


D Sound: Animal hearing

D.1 Introduction

Hearing abilities of some 180 vertebrate species have been studied [Crocker, 1997]]. One of the aspects is the determination of the so-called ‘audiogram’. An audiogram is a sound level hearing threshold, plotted as a function of frequency – for examples see figures D.2 and D.4. Audiograms are U-shaped with an area of lowest threshold (highest hearing sensitivity) and an upper and lower cut-off slope. However, audiograms for relatively few animal species have been determined, so there is a large lack of information in this respect. Other important factors to determine are the so-called ‘critical bandwidth/ratio’ and the ‘receiving directivity index’, influencing the detectability of sound signals in a noisy environment. In hearing, detectability of (man-made) noises depends on a combination of the species audiogram, its critical bandwidth/ratio, the background noise and its directivity index.

D.2 Bird and bat hearing in air

For approximately 20 bird species an audiogram (in air) is known, rather homogeneous in sensitivity and frequency range and rather similar to the human audiogram. Best hearing of birds is between 1 and 6 kHz. For instance the barn owl is very sensitive and has best hearing between 2 and 9 kHz [Crocker, 1997]. Figure D.1 gives a rough impression of the audiogram limits for birds. The spreading is relatively small and the most sensitive threshold area of birds is quite similar to that of humans.

Figure D.1: Guideline audiogram limits for birds and amphibians/reptiles (in air) – derived by TNO TPD.

Audiogram limits (in air)

-20

0

20

40

60

80

100

50 80 125

200

315

500

800

1.25

k 2k

3.15

k 5k 8k

12.5

k

Freq. [Hz]

SPL

dB r

e 20

mic

roPa

Birds (upper)

Birds (lower)

Amphibians/Reptiles(upper)Amphibians/Reptiles(lower)human in air

Bats are a special order, because they use a high-frequency echolocation system (in air). Hearing of bats is very good. However, in general their sensitivity is optimum above 10 kHz, although there are species being more sensitive at lower frequencies. Consequently airborne noise radiated by ships is not very relevant for bats.

D.2/4


D.3 Pinniped hearing in air

With respect to pinnipeds, and possibly also for amphibians and birds, airborne sound from boats is relevant. Figure D.2 shows guideline audiograms for two seal families, measured in air. At the lowest thresholds seals are almost as sensitive as humans, but in a higher frequency range (around 8 kHz). Figure D.2: Guideline audiogram (in air) for two seal families, Hair seals (Phocidae)

and Eared seals (Otarioidae) – derived by TNO TPD.

Guideline Audiograms In Air

0

20

40

60

80

100

120

100

160

250

400

630 1k

1.6k

2.5k 4k

6.3k 10

k

16k

25k

40k

Freq. [Hz]

SPL

dB re

20

mic

roPa

- R

MS guideline Eared seals

guideline Hair seals

D.4 Fish, amphibian and reptile hearing in water

Within the bony fishes, many species produce sounds, although it is not clear what part of the 25,000 extant species do so. It means, however, that for this group hearing is an important means for communication etc. The question is how many fish species (if not all) are able to detect sound. Certain fishes do not produce sound, but have an excellent hearing system. The hearing system of relatively few fish species has been studied and the results show a large spread, as can be seen in figure D.3. Certain species have good hearing capabilities; others are relatively ‘insensitive’. In general the hearing range of fishes covers the range up to 3 kHz, although there are certain species (herring for instance) that seem to have hearing properties up to even above 100 kHz. Audiograms of 49 fish species have been determined, showing a very large spread in threshold levels and frequency range. In general best sensitivity is between 100 Hz and 1 kHz [Crocker, 1997] (Figure D.3). Certain sensitive fish species have a sensitivity equal to the most sensitive cetaceans. Also amphibians have good hearing capabilities, such as frogs for instance. In general their hearing range is below 5 kHz. Only few hearing data are available for amphibians and reptiles. Figure D.1 gives audiogram limits for airborne noise, Figure D.3 shows the same data converted to underwater noise reference levels. In water amphibians seem to

D.3/4


be relatively insensitive; in air, however, their lowest threshold is almost equal to humans. Figure D.3: Guideline audiogram limits for amphibians/reptiles and fish (in water) –

derived by TNO TPD.

Audiogram limits (in water)

405060708090

100110120130140150160

50 100

200

400

800

1.6k

3.15

k

6.3k

12.5

kFreq. [Hz]

SPL

dB re

1 m

icro

Pa

Amphibians/Reptiles(upper)Amphibians/Reptiles(lower)Fish (lower)

Fish (upper)

D.5 Marine mammal hearing in water

Marine mammals can be roughly divided into cetaceans (whales, dolphins, etc.) and pinnipeds (seals, sea lions, etc.). In principle all marine mammals produce sounds, a large group also makes use of echolocation, to detect prey. The hearing range of pinnipeds is below 60 kHz. Cetaceans can have a range up to 200 kHz. Figure D.4 shows guideline audiograms for two pinniped families (Hair and Eared seals) and for the Harbour porpoise. The audiogram of other cetaceans does not differ very much from that of this porpoise. From this figure it can be concluded that cetaceans are 20 dB more sensitive (in the range of best hearing) than seals. However, in the low-frequency range seals have a lower hearing threshold and are therefore more sensitive for man-made noise. Also between the two pinniped families there are differences, as can be seen in figure D.2.

D.4/4


Figure D.4: Guideline audiogram (in water) for two seal families, Hair seals (Phocidae) and Eared seals (Otarioidae) and the Harbour porpoise (Phocoena phocoena) – derived by TNO TPD.

Guideline Audiograms

405060708090

100110120130140150160

50 100

200

400

800

1.6k

3.15

k

6.3k

12.5

k

25k

50k

100k

200k

Freq. [Hz]

SPL

dB re

1 m

icro

Pa -

RM

S

guideline Hair seals

guideline Eared seals

guideline Harbour porpoise

E.1/9


E Water quality: comparison between the TNO and TÜV studies

E.1 Comparison of the TNO and TÜV models

In subsection 4.6 a modelling exercise is presented that estimates the concentrations of certain organic compounds in the water of a virtual lake, Lake Fun, with intensive boating. The original model input used is presented in more detail in Appendix C. A similar study was done by the German TÜV on behalf of the German Umwelt Bundes Amt (UBA). Although at the time of writing the TÜV-report is not yet final, the UBA kindly presented us with the relevant chapter, allowing a comparison, which is presented here. For easy reference the virtual lake used by the TÜV is indicated here as the “TÜV-See”. The relevant parameters are brought together in Table E.1. They represent the situation for the existing fleet, which is the baseline case of the TÜV study, and more or less scenario 2 of the TNO study. Table E.1: The relevant parameters used and calculated in the TNO study and the

comparable TÜV study. Lake unit TNO Lake-Fun TÜV-See surface depth water volume

km2

m 106 m3

7 2.3

16.1

0.6 1.5 0.9

Operational parameters nr. of boats average power boats per area

[-] kW

nr./ km2

3200 ~ 14 457

75 ~ 17.5

125

operational time/boat total for fleet ditto per surface area

ditto per water volume

h/day h/day

h/ km2

h/106 m3

0.9 2880 411 179

2 150 250 167

Emission data * HC - total fleet ditto per water volume benzene toluene xylene

kg/day kg/106 m3

kg/106 m3 kg/106 m3 kg/106 m3

908 56

2.53 6.71 4.54

105 70

3.85 7.35 5.95

* The unit kg/106 m3, used for the relative emission intensity, is actually identical to the unit µg/l, used for the resulting concentrations in the water body. The TÜV-See turned out to be much smaller than Lake-Fun, and also even shallower. The boat density, corrected for surface area, is lower, however. The average power of the engines used, which can be approximately determined from the fleet composition, is comparable, but the number of operational hours per boat is bigger for the TÜV fleet. The boat density of the TNO case, although modelled on an existing lake, represents a

E.2/9


very high boat density, but this is moderated again by a low engine operating time per boat. This reflects the fact that on the actual lake used for the density figure a high proportion of sailing boats is present, which only use their engines for exit from and entry into the marina. In the TÜV case a lower number of boats is combined with a longer operating time per engine, typical for a larger share of motorboats. In the comparison the aggregated engine operational time per unit of water volume (the ultimate measure for the environmental load) is therefore not very different: approximately 180 versus 170 hour per million cubic meter of water. The emissions for the fleets are derived from the same Icomia dataset. The calculated overall emission levels for HC are therefore reasonably comparable when set in relation to the overall volume of the water body. The differences can be fully attributed to some minor differences in fleet composition (conventional 2-strokes have a much higher HC-emission than other technologies, so that relatively minor differences in their share will result in disproportionately larger differences in HC-emission). In both studies the emissions of benzene, toluene and xylene have been calculated by assuming a fixed percentage of the total-HC to consist of the compound concerned. The percentages were derived from a literature survey in the case of the TNO study, and from the German ‘Handbook’ for automotive emission factors in the case of the TÜV study. The percentages used do not differ very much, however, and the resulting emissions of the three compounds are again reasonably comparable when set in relation to the total water body volume. The emissions per unit of water body volume, as shown in the row ‘emission data’, would actually also represent an average concentration if all emissions were retained in the water, and homogeneously distributed over the water body.

E.2 Comparison of the TNO and TÜV modelling results

The TÜV study then used a fraction of the emissions of the three compounds that remains in the water body, whereas the remainder does escape directly from the water body in a gaseous state. This escape is due to aeration as a consequence of the water being ‘stirred’ by the propeller (see subsection 4.4.2). The actual fraction was determined by running a sample of five different outboard engines in a 500 litre water tank and determining the concentrations in the water before and after the test. So as to obtain a maximum level for the possible water pollution, the fractions eventually taken were not the averages over these five engines, but the highest for each compound over the range of engines: they are 4.3 % for benzene, 4.4 % for toluene and 18.8 % for xylene (this means that more than 95 % of the benzene and toluene, and more than 80 % of the xylene did escape from the tank straightaway). The study assumed that the ‘worst case’ concentrations would result immediately after the emission phase, if the compounds concerned would be homogeneously distributed over the total water body. The resulting concentrations are shown in Table E.2.

Table E.2: Comparison of the first results of the TNO modelling with the TÜV results.

Lake unit TNO Lake-Fun TÜV-See Calculated concentrations * benzene toluene xylene

µg/l µg/l µg/l

12.9 57 42

0.17 0.32 1.12

* The unit kg/106 m3, used for the relative emission intensity in Table E.1, is actually identical to the unit µg/l, used here for the resulting concentrations in the water body.

E.3/9


The study states that the concentrations go down very rapidly in time, so that the rest concentrations remaining the following day may be reasonably assumed to be zero, and that no accumulation over time needs to be expected. The TNO study used a calculation model that takes into account the various removal mechanisms, as set out in subsection 4.6. In the first approach no loss due to aeration was included. These concentrations are also shown in Table E.2. When these concentrations are compared, there appear large differences in the results. These differences will be discussed hereafter.

E.3 Discussion of the modelled concentrations

The relation between the input of emission components and the resulting concentrations in water is not a very straightforward one. It is influenced, inter alia, by the following aspects: • The percentage of the input that escapes directly back into the atmosphere due to

aeration, as indicated in subsection 4.4.2. • The adsorption/desorption rates to/from particles suspended in the water. This is very

dependant on the concentration of suspended matter. In clear water the retention of hydrocarbons will be much less than in more turbid water.

• The water temperature, which influences the rate of evaporation. The model selected by TNO for the calculations can deal with these aspects, but needs values to be specified for its operational parameters. Obviously these values will vary from location to location. It was nevertheless expected that by assuming either average or ‘worst case’ values, the results could be taken as an indication of a typical order of magnitude, possibly as of a worst case, depending on the exact input parameters chosen. They should indicate if a local water quality problem on a typical European locality is likely, possible or unlikely.

E.3.1 Aspects of the TNO modelling Because of the nature of the model used (SimpleBox), the input in the TNO modelling had to be made as a steady state input that is constant over time. This means that, since a season top-day had been selected as the basis for modelling, the input for the model had to assume 365 identical top days. It had been expected that, in agreement with understood practical experience, the water concentrations would be approaching zero when the next day would start, as actually assumed in the TÜV approach. On further analysis, however, the results showed that in fact a significant accumulation effect took place, where the stable condition represented the input of approximately 5-9 days. In view of these long retention times it became clear that a significant causal effect might be attributed to the assumed ‘daily’ input of the top-day emission level (whereas in actual fact boat emissions would mainly take place over the weekend days only) and to the continuous character of that input (whereas the actual input would take place over e.g. a 10-hour day, followed by a 14 hour recovery, as in the TÜV model). This was subsequently investigated. In the second place it was realised that the high rate of accumulation was also caused by the fact that the model assumed the emission to be an undisturbed input without any aeration. In reality, in the case of outboard engines the action of the propeller would cause a large degree of aeration, causing a significant percentage of the emission to

E.4/9


escape to the air straightaway; in the case of inboard engines (in this calculation mainly the diesel engines) such aeration effect might be largely absent. The model calculation would in reality only be valid for the remaining emissions. The main problem here, however, is the fact that no reliable information about the percentage ‘escape’ is available from literature.

E.3.2 Aspects of the TÜV modelling The TÜV modelling assumed only outboard engines. And it was based on measured escape rates for the three compounds considered. These escape rates are in the order of 95 % for benzene and toluene, and 80 % for xylene. However, the following aspects should be considered: • The measurements were made by running an outboard engine in a rather small tank.

This means that the water was constantly stirred, whereas in a real-life situation the boat moves away from the place of emission. This is likely to have led to too high measured escape rates.

• The temperature of the water in the tank is likely to have been at ambient laboratory level (say 22 ºC) at the start of the test, and to have increased over the duration of the test. This again will have led to increased escape rates.

In the TNO calculations by means of the SimpleBox model the influences of the water temperature on the concentrations of benzene (and also for naphthalene) was established. It amounted to about 10 % per 4°C for benzene (and zero of naphthalene). The TÜV approach assumed that only one day’s emission would be relevant for the determination of the concentrations in water, since the half-life values are stated to be in the order of 1 hour or less, so that after a night without any boating activity no relevant residual concentrations would be left. Although the original understanding of TNO was similar, the model used by TNO suggested otherwise. This assumption was therefore subsequently checked in a further investigation with another model used by TNO, as set out below.

E.3.3 Further evaluation of the pollutant behaviour Since the large differences in final concentrations between the TNO-study and the TÜV-study were rather disturbing TNO decided to go much deeper into the mechanisms involved. These further investigations were made with the aid of another model, called Toxswa [Adriaanse 1996]. The first experiments revealed that indeed a significant accumulation of the compounds emitted takes place, under all simulated circumstances; this is further elaborated below. Furthermore a variation of the input parameters, carried out for benzene, by way of example, showed significant influences of parameters like temperature and water depth. An increase of water temperature from 12 ºC to the 26 ºC that was tentatively assumed for the average during the tests at TÜV, would reduce the equilibrium concentrations by about 40 %. A variation of the water depth from the 1.5 m of the TÜV-See to 0.75 m resulted in a decrease of 36 %, whereas an increase to 2 m resulted in an increase of 24 %. The depth of Lake Fun (2.3 m) could not be modelled by this model since 2 m is the maximum that this model allows. The next range of experiments concerned the fact that the input of the emissions does not take place in a continuous stream, but over a limited period of daytime hours

E.5/9


(assumed to be 10 hours in the TÜV calculations), after which an overnight period without boating would cause a certain degree of recuperation. Figure E.1 shows the concentration resulting from a ‘pulsed’ daily benzene input. Figure E.1: Input/output of the model Toxswa: ‘pulsed’ daily benzene input of 3.85

kg/106 m3 for a duration of 9 days and resulting residual water content.

Figure E.2: Output of the model Toxswa: for pulsed daily benzene input of 3.85 kg/106

m3 for a duration of 9 days. Water concentration.

For the input value the TÜV input of 3.85 kg/106 m3 was assumed, although without any escape due to aeration. The resulting benzene concentrations in water are shown more clearly in Figure E.2. As can be seen there is a clear accumulation effect, which reaches its equilibrium after about 4 days. It is true that immediately after the first day’s input a decrease takes place to about 47 % of the original input, but the next day’s input starts

E.6/9


from that 47 %, increasing the concentration from about 1.8 to about 5.3 µg/l. The final equilibrium concentration is about 6.0 µg/l. This is equivalent to about 1.6 times the daily input, whereas in the continuous input situation as used in the SimpleBox model the equilibrium amounted to about 5 times the daily input. A simulation with an input in two separate pulses of about 1.9 kg/106 m3 each, adding up to the same overall daily input, resulted in an equilibrium concentration of about 5.1 µg/l, so about 20 % lower. This further illustrates the influence of the input rhythm. Analysis of the concentration in sediment shows that of the total input over a period of 9 days the concentration in the sediment is still increasing, although it has nearly reached its equilibrium value (Figure E.3). By that time something close to 18 % of the overall cumulative input is still present in the water body and something close to 9 % is still present in the sediment. The remainder has eventually mostly evaporated into the atmosphere at a more or less constant rate. When the input is stopped it takes about 5-6 days before the water concentration is back to zero again. In the situation calculated, the equilibrium concentration is about a third higher than the input concentration. Figure E.3: Output of the model Toxswa for pulsed daily benzene input of 3.85 kg/106

m3 for a duration of 9 days. Sediment concentration.

It should be noted that these mechanisms would still be active if at the time of emission a certain percentage of these emissions would immediately escape to the atmosphere by aeration; only the levels would be lower. Simulations with a 95 % escape rate showed a roughly proportional decrease in output.

Similar runs of the model for toluene and xylene resulted in the following observations. A daily pulsed input of toluene of 7.35 kg/106 m3 (see Table E.1) in a lake like the TÜV-See results in an equilibrium concentration of just over 11 µg/l in water, reached after 4-5 days. A daily pulsed input of xylene of 5.95 kg/106 m3 (Table E.1) results in an equilibrium concentration of about 9 µg/l in water, again reached after 4-5 days.

E.7/9


E.3.4 Conclusion

In conclusion it can be said that the water concentration is caused by the ‘buffer’ of benzene between the input and the output (eventually by evaporation). In the calculated situation, this buffer contains between 15 and 20 % of the cumulative overall input. If the temperature rises, or if the water depth decreases, the rate of evaporation will increase and the buffer will decrease, but given the relative magnitudes a relatively minor change in the rate of evaporation (or, for that matter, in the exchange rates with the sediment) will result in disproportionately higher changes in the size of the buffer and hence the water concentration.

E.4 Corrected comparison

In an attempt to correct for the effects outlined in subsection E.2 the following ‘corrections’ were made: The TNO values were corrected for pulsed input. This was done by comparing the

equilibrium concentration for continuous input, with that of the pulsed input as calculated by ‘Toxswa’ for a water depth of 1.5 m. These differed by about a factor of 3.3 for benzene, 5.6 for toluene and 6 for xylene.

No correction was made in the TNO case for the weekend effect, since Figure E.2 shows that even when starting from zero, already after two days the equilibrium concentration is almost reached. And in practice there will also be some boating during the week, so that the situation will not start with absolutely clean water.

The TÜV values were corrected for the accumulation effect, as established in the further investigation reported in E.3.3.

The TÜV values were also corrected for temperature, by tentatively assuming that the temperature would increase from 22 ºC at the start of the test and reach an equilibrium at 26 ºC. This would have resulted in a 40 % lower equilibrium value in the case of benzene than at 12 ºC; a similar correction was assumed for toluene and xylene.

Table E.3: The calculated maximum water concentrations as determined by TNO and

TÜV, ‘corrected’ for known influences, with the exception of escape rates due to aeration.

TNO Lake-Fun TÜV-See Uncorrected values benzene toluene xylene

12.9 57 42

0.17 0.32 1.12

Corrected values (1st correction) benzene toluene xylene

3.95 10.2 6.85

0.28 0.53 1.87

What then remains is the fact that in the TNO case no escape due to aeration was assumed, whereas in the TÜV case the effects of such aeration were taken into account through measured values of approximately 95 and 80 %, but based on measurements that are likely to have resulted in too high escape rates. Consequently the true rates must be somewhere in between. On the basis of the scarce literature data it was tentatively

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assumed that the ‘true’ aeration rates would be 90 % for benzene and toluene and 60 % for xylene. Furthermore a spread was investigated from 80 % to 95 % in the case of benzene and toluene (i.e. a factor of 2 on the remaining concentrations both ways from the assumed average), and from 40 % to 73 % in the case of xylene (i.e. a factor of 1.5 on the remaining concentrations both ways from the assumed average). In that case the comparison would look as shown in Table E.4 below.

Table E.4: The maximum water concentrations as determined by TNO and TÜV, ‘corrected’ for known influences, as in Table E.2, and with assumed escape rates due to aeration of 90% for benzene and toluene and 60 % for xylene, with sprads as given in the text.

TNO Lake-Fun TÜV-See Corrected values as in Table E3 benzene toluene xylene

3.95 10.2 6.85

0.28 0.53 1.87

Ditto with assumed escape rates benzene toluene xylene

0.40 (0.20-0.79) 1.02 (0.51-2.04) 2.74 (1.85-4.11)

0.65 (0.33-1.30) 1.21 (0.60-2.41) 3.98 (2.69-5.97)

It may be concluded that the final results do broadly speaking lie in the same range. Furthermore it should be noted that the figures given above ought still to be corrected for the effect of water depth, which was different for the two virtual lakes. The models available to TNO were not capable, however, of fully establishing this influence.

Unfortunately it was not possible to establish the influence of the pulsed input on the concentrations in the sediment, since the Toxswa model expresses this in other units than the SimpleBox model (µg/l of the water adsorbed to the sediment versus µg/kg of wet sediment). Hence the sediment concentrations were only corrected for the aeration effect. This was judged acceptable though, since the response rates for the sediment are much slower than for water (see e.g. Fig. E.3). The results of the modelling study reported in Appendix C were subsequently adapted to these further insights when reported in subsection 4.6 and 4.7.

Conclusion The conclusion from the considerations given above is that the initial large differences observed between the water concentrations calculated by TNO and TÜV respectively, can be attributed to the following effects: The unknown actual escape rates due to aeration by the propeller, which was not

taken into account by TNO, but which may have been set too high by TÜV. The initial neglect by TNO of the effect of a ‘pulsed’ input, as a consequence of the

use of a model that did not take this effect into account. Differences in water temperature and water depth. A significant accumulation effect that is borne out by the model approach used by

TNO, which was not taken into account in the simpler approach by TÜV. Of these influences the exact escape rates have by far the biggest influence. The next biggest influence turned out to be the exact rhythm of the emission input.

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In general terms this comparison clearly shows that a global evaluation is only possible in very broad terms, and that actual water concentrations are to a very large extent dependant on the exact circumstances of the water body concerned.

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