the double hull issue and oil spill risk on … · and oil spill risk on the pacific west coast...

THE DOUBLE HULL ISSUEAND OIL SPILL RISKON THE PACIFIC WEST COAST

October, 1995

The Double Hull Issueand Oil Spill Risk

On the Pacific West Coast

Prepared byDF Dickins Associates Ltd.

Salt Spring Island, British Columbia

for

Enforcement and Environmental Emergencies BranchMinistry of Environment, Lands and Parks

Victoria, British Columbia,Canada

October, 1995

Canadian Cataloguing in Publication DataMain entry under title:The double hull issue and oil spill risk on the Pacific

west coast

Includes bibliographical references: p.ISBN 0-7726-2472-0

1. Tankers – Safety measures. 2. Tankers –Law andlegislation – British Columbia. 3. Petroleum –Transportation –Envir onmental aspects – Pacific Coast(B.C.) 4. Oil spills –Pacific Coast (B.C.) –Prevention. I. BC Environment. Enforcement andEnvironmental Emergencies Branch.

VM455.D68 1995 363.73'82'0916433 C95-960174-0

Ballast refers to a substance, usually sea water, carried when the vesselhas no cargo in order to load the vessel down and maintain itsstability.

Beam refers to the greatest breadth of a vessel.

Canada Shipping Act governs the design and operation of all commercial ships in(CSA) Canadian waters including issues of pollution prevention. The

Act is administered by the Canadian Coast Guard.

Deadweight tonnage is essentially equal to the carrying capacity of a ship. It is the(Dwt) difference in weight between a ship loaded with stores and fuel

and the same ship empty but with stores and fuel. Deadweighttonnage is a useful measure of the absolute cargo capacity(within 5%). Deadweight tonnage is used to determine theretirement schedule for single-hulled vessels by the Canada.9

Gross Tonnage is a measure of registered tonnage not directly related to cargocapacity. For most tankers and barges, the gross tonnage isapproximately 1/2 the deadweight tonnage. Gross tonnage isused to determine the retirement schedule for single-hulledvessels under the United States Oil Pollution Act of 1990(OPA 90).

HydrostaticallyBalanced Loading refers to the practice of partially filling cargo tanks only to the

point where, at the bottom, the pressure inside (oil) and outside(water) the tank are equal. In the event of a grounding, seawater will flow inward with minimal oil escape. Another termused is partial loading.

InternationalMaritime Organization is a United Nations agency that sets international shipping(IMO) standards for safety and pollution prevention at sea. It is up to

individual countries to adopt the standards set by IMO as theysee fit. For example, the United States has not adopted the recent IMO standards regarding double hulls and the mid-deckconcept. Canada has adopted many of the IMO standardsthrough the Canada Shipping Act.

ABBREVIATIONS AND DEFINITIONS

MARPOL 73/78 refers to the IMO convention governing the installation of segre-gated ballast tanks on all new tankers built after 1982. Regula-tions 13F and 13G to Annex 1 of this convention were adoptedin March 1992 and establish the standards governing the adop-tion of double hulls for member nations.

Oil Pollution Act of 1990 refers to an act passed by the American Congress in 1990 that(OPA ’90) covers a broad range of oil spill prevention and response issues.

Aspects of OPA 90 dealing with vessel safety and design areadministered by theUnited States Coast Guard.

Refined Petroleum refers to products produced from crude oil through a refiningProduct process. Products can range from extremely light and easily(RPP) evaporated substances such as distillate and gasoline to heavy

and persistent oils such as Bunker C used as main engine fuel inmany deep sea vessels.

Segregated Ballast Tanks refers to dedicated tanks, used only for ballast, never for oil.(SBT)

Trans-Alaska refers to the pipeline and tankers that transport crude oil fromPipeline System the Prudhoe oil fields through Alaska to the southern US states.(TAPS)

Oil Volumes: 1 barrel = 35 Canadian gallons = 42 US gallons = 0.159 m3

Dimensions: 1 statute mile = 1.6 kilometre = 0.87 nautical miles3.28 feet = 1metre1 inch = 2.5 centimetres

ContentsABBREVIATIONS AND DEFINITIONS ........................................................................................ 5

SUMMARY ......................................................................................................................................... 9

TIME FOR ACTION ........................................................................................................................ 11

INTRODUCTION ............................................................................................................................ 13

PART 1: EXISTING OIL MOVEMENT PATTERNS & VOLUMES........................................... 15Explanation of Cargo Movement ........................................................................................... 16Per Cent of Annual Oil Volumes Moved

by Tankers and Barges ........................................................................................................ 16

PART 2: TANKER DESIGN ............................................................................................................ 18Single-Hulled Tankers Represent the Status Quo................................................................ 19Variations on Single Hulls ....................................................................................................... 19Interim Protection Measures ................................................................................................... 21Principle of Hydrostatic Balance Loading ............................................................................ 23Mid-Deck ................................................................................................................................... 24Double Hulls ............................................................................................................................. 25Design Comparison.................................................................................................................. 27Scheduling Recommendations ............................................................................................... 31

PART 3: COMPARISON OF UNITED STATES, CANADIANAND INTERNATIONAL REGULATIONS ............................................................................. 31

Scheduling Implementation.................................................................................................... 33The Real Issue ........................................................................................................................... 34

PART 4: EXPECTED FUTURE TRENDS IN MARINE OIL CARGOES................................... 39

PART 5: BENEFITS & COSTS OF SCHEDULE ACCELERATION........................................... 41

CONCLUSION................................................................................................................................. 43

REFERENCES................................................................................................................................... 45

ACKNOWLEDGMENTS ................................................................................................................ 47

APPENDIX A: BACKGROUND - TANKER DESIGN .............................................................. 49

APPENDIX B: BACKGROUND - REGULATORY ISSUES ...................................................... 53

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In the wake of the 1989 Exxon Valdez oilspill disaster, a multitude of governmentstudies, workshops and independent re-views recommended double hulls as thesingle most effective technology to preventmany future oil spills from tankers. Mostship classification societies and legislativebodies accept that total replacement of allexisting tankers with double-hulled vesselswill result in a 50% reduction in the totalamount of oil spilt from tanker casualties.

It is important to realize that double-hulled tankers do not mean the end of oilspills; there will always be exceptionalaccidents such as fires and explosions whichresult in the loss of oil. Since double hullconstruction is a design spill preventionmeasure (not an operational measure), itwill not reduce the likelihood of a vesselaccident (collision or grounding). Neverthe-less, double hulls will result in an appreci-able reduction in risk, simply by having asecond hull within a hull.

Where are we after years of deliberationsabout the urgent need to protect our pristineenvironment? When will we realize thebenefits of new tanker designs?

Some 250 million barrels of crude oil andrefined petroleum products are moved eachyear by tankers and barges in Puget Sound,the Juan de Fuca Strait, and British Colum-bia coastal waterways. Of this total, over200 million barrels, or approximately 80% ofthe total, is still carried in single-hulledvessels.

In essence, “single hull” means that inthe event of a collision or grounding there isa single layer of steel, 20 - 35 mm, or aboutan inch thick, separating the oil cargo andthe marine environment. By far the greatest

risk of a large crude oil spill in our waterscomes from the daily passage of single-hulled tankers into the Strait of Georgia/northern Puget Sound regions deliveringAlaskan and foreign oil to the WashingtonState refineries. These refineries are locatedwithin 15 to 60 kilometres of the Canada/United States border. There are about 380tanker trips annually.

With over 10,000 other transits of majorvessels such as container ships, bulk carri-ers, ferries and cruise ships each yearthrough the Juan de Fuca Strait, there isalways the potential for a collision orgrounding. Most of the risk of small tomoderate spills (less than 10,000 barrels) canbe attributed to these passenger and generalcargo vessels as they often carry more than5,000 barrels of engine and system (bunker)fuel against a single hull.

Another contributor to the risk of ma-rine oil spills comes from the many Ameri-can and Canadian single-hulled bargescarrying refined petroleum products such asbunker fuel oil, diesel, and gasoline todifferent coastal communities and mills.

Canadian tanker movements make asmall contribution to the regional risk: forexample, only three oil tankers carriedcrude oil out of Vancouver in 1994. Canadais an exporter of oil on the west coast fromterminals located in the Port of Vancouver.

Most of the oil destined for the Washing-ton refineries is carried in 19 older shipsbuilt between 1969 and 1974. It is the re-placement of these single-hulled tankersdedicated to the Alaskan trade which drivesthe timing of when new double-hulledtankers will provide any substantial relieffrom the present level of spill risk in ourlocal waters.

SUMMARY

The timing of when older US flag tankersmust be retired is controlled by a scheduleestablished by the United States Coast Guardin their administration of the Oil Pollution Act(OPA ’90) passed by the American Congress in1990. Canada and the rest of the world hasadopted a schedule for large tankers devel-oped by the InternationalMaritimeOrganization (IMO).

Under OPA ’90, approximately 18 of theolder single-hulled tankers carrying 78% ofthe Alaskan oil to Puget Sound will be forcedto retire by 1999. Unfortunately, this manda-tory retirement is unlikely to result in directreplacement with new double-hulled vessels.Industry is delaying placing new orders inview of the depressed state of the worldtanker market, high cost of new construction,and uncertain crude oil supply.

The US Jones Act of 1920 is one of the keyfactors preventing American tanker ownersfrom voluntarily retiring and replacing theirolder vessels. This act prohibits any foreignbuilt vessel from trading between two Ameri-can ports such as between the States of Alaskaand Washington. Without the US Jones Actrestriction, industry would have many moreoptions available to charter or purchase for-eign double-hulled tankers to replace theaging American fleet and still remain USowned and operated.

There are significant benefits for reducingthe risk of a spill. These benefits includeavoided response (clean up) costs, naturalresource damages, and restoration costs. A1995 study comparing the benefits and costsof accelerating the current retirement sched-ules by 15 years to year 2000, revealed that thecost to the Alaska (TAPS) fleet to be $240million ($US) with the US Jones Act, or halfthis cost without construction location restric-tions stipulated by the act. The estimated

benefits to British Columbia and the sharedwaters of the State of Washington for acceler-ating the TAPS oil tanker double hull scheduleis about $147 million. Benefits accrued to otherregions, such as Alaska and California, werenot estimated, but would no doubt besubstantial. The analysis of Canadian-flag oilbarges showed that an accelerated schedule toreplace the single-hulled barges could resultin regional benefits exceeding the cost.

The benefit estimates are both reasonableand conservative when considering that thedamages for one moderate spill, such as thethe Nestucca barge spill in 1988, may rangefrom tens to hundreds of millions of dollars,and the damages from a large spill may reachseveral billions of dollars, as in the case of theExxon Valdez spill in 1989.

It is important to consider the distribu-tional consequences of who loses and whogains for not undertaking (or conversely forundertaking) the expeditious retirement ofaging single-hulled tankers and barges andtheir replacement with double-hulled ones. Ifthe oil industry delays the retiring of theirsingle-hulled vessels, then the risk and cost ofspills are borne locally on the west coast,while the savings of not converting to double-hulls at an earlier date are realized throughout North America and abroad.

The time period before double hulls willsubstantially reduce the number and severityof oil spills is troubling. Economic factors suchas the depressed tanker market, lack of finan-cial incentives for safer vessels, and lawsprotecting shipbuilding interests all act topreserve the status quo for as long as possible.Economic incentives, or if need be, legislativechange are required to expedite the replace-ment of aging, single-hulled oil tankers andbarges before the turn of the century.

The length of time before the west coastis likely to see any substantial benefitsfrom double-hulled vessel construction inreducing the number and severity of oilspills is unacceptable when one weighs thesevere environmental and economic conse-quences of a spill. Current requirementsindicate that it will be another 10 yearsbefore double hulls make a real differencein reducing the risk of oil spills in our localwaters.

The following activities to speed-up theprocess of eliminating single-hulled tank-ers and barges that pose a risk to ourshared waters are recommended:

1. That British Columbians and our neigh-bours in the United States realize theshortcomings of current laws regardingthe retirement of existing single-hulledtankers and barges, the implications of

delayed replacement of these vessels,and the continued risk to our vulner-able Pacific west coast.

2. That the United States and Canadianfederal governments seek meaningfulways to accelerate the single-hulledtanker and barge retirement schedulecurrently established under the US OilPollution Act and the Canada ShippingAct through economic incentives forsafer vessels, changes to the schedulinglegislation, establishing special marineareas, or combinations thereof.

3. That the Canadian government withtheir United States counterparts deter-mine what steps tanker owners andcharterers are taking to expedite theretirement of aging, single-hull tankerson the west coast that pose a risk to ourshared waters, and to ensure there is anet improvement in oil spill protection.

TIME FOR ACTION

Some 250 million barrels* of crude oiland refined products (bunker, gasoline,diesel fuel, jet fuel) are moved each year bytankers and barges in Puget Sound, theJuan de Fuca Strait, and other British Co-lumbia coastal waterways. Following thenow famous Exxon Valdez oil spill (1989), ahost of national and international bodiesdissected every possible safety issue affect-ing tanker transportation. Many of thesestudies recommended some form of doublehull to create an additional shield betweenthe oil and the sea in the event of an acci-dent. These recommendations are only nowbeing implemented as part of new stand-ards developed by the International Mari-time Organization (IMO) and the UnitedStates and Canadian Coast Guards.

Of most concern, and the focus of thisreport, is the timing of when the oldersingle-hulled tankers that pose a risk to ourwaters will be replaced under the newstandards. Questions arise such as: howmuch reduction in environmental risk canbe expected from the latest tanker designs;how long do we have to wait until a suffi-

INTRODUCTION

* Refer to the foreword for common conversions to other units;barrels are used here as a convenient and familiar universal measure.

cient number of vessels are replaced tosubstantially reduce the risk of spills; whatcan be done to speed up the process; whatare the costs compared to the benefits ofacclerating the retirement schedule; andhow can we make people aware of theimplications of recent US, Canadian andinternational regulations on the futuresecurity of our marine environment? Thepurpose of this document is to answerthese questions.

A series of related topics are developedto understand the issue of double hulls –what they can achieve and when:

• the new tanker designs;• comparisons of United States,

Canadian and international regulations;• the timing for double-hulls;• the benefits and costs of an

acclerated retirement schedule;• the tanker and barge industry now

and in the future; and,• actions to speed up the process of

improving tanker standards.

250 Million Barrels of Marine Oil Cargoes Each Year –

The risk of spills can be greatly reduced by using double hulls.

How long do we have to wait before every tanker and oil barge

in local waters is fitted with a double hull?

The map shows the main routes of tankers travelling down the west coast and into theStrait of Georgia/Puget Sound area.

Approximately one tanker each dayenters the Juan de Fuca Strait and threadsit way through narrow passages to oilterminals located 15 to60 kilometres southof the US/Canada border. Each year, thesetankers cross paths with over 2,000 othermajor vessels, such as container ships,ferries, and bulk carriers that make over10,000 trips to or from British Columbiaand Washington State ports. This level oftraffic density leads to the ever presentdanger of collision between a tanker andanother vessel. Hundreds of barges and afew small coastal tankers carrying refinedpetroleum products (RPP) also contributeto the risk of a spill along inside passagesas well as the outer coast.

About 75 per cent of Canada's oil prod-uct barge movements is on the west coast,both in terms of the number of trips andtotal tonnage carried.

The table (below) and pie chart (nextpage) show trading patterns to highlightthe relative contributions of foreign,American and Canadian tankers andbarges to the overall risk of oil spills in ourlocal waters. These oil imports and exportsto and from both countries, lead to a com-bined oil spill risk as we share commonborders between the Strait of Georgia andPuget Sound, in the Juan de Fuca Straitand in Dixon Entrance.

In addition to the local oil vessel trafficshown on the chart below, laden tankers

PART 1: EXISTING OIL MOVEMENT PATTERNS & VOLUMES

Overview of Marine Petroleum Cargo Movements in the Strait ofGeorgia/Puget Sound Basin and Along the British Columbia CoastFrom To Oil Type Total # Vessel Sizes Est. % Total

Trips/year Dwt RegionalVolumePIE CHART

1. Alaska Puget Sound Crude 351 - tankers1 70 - 125,0002 68%

2. Puget Sd. California Crude 33 - tankers1 70 - 125,000 3%Panama (Partial loads)

3. Foreign Puget Sound Crude 17 - tankers1 40 - 90,0003 5%

4. Puget Sd. Washington, Refined 178 - tankers4 20,000 - 40,0005 9%California Products

5. Puget Sd. Washington, Refined 213 - barges 1,300 - 20,000 5%California Products

6. Vancouver Foreign Ports Crude 3-10 - tankers6 65,000 2%

7. Vancouver B.C. Refined 600 - 800 200 - 4,900 8%Destinations Products mostly barges7

Superscript numbers refer to notes on the following page.

from Alaska travel dailyabout 160 kilometres (100miles) off the west coast enroute to Panama andCalifornia.

Of 250 million barrels ofoil moved annually throughcoastal waters in close prox-imity to British Columbia,approximately 190 millionbarrels is crude oil, and 57million barrels is refinedpetroleum products (RPP)covering a wide ranging from

Per Cent of Annual Oil Volumes Movedby Tankers and Barges

Foreign Crude Tankers 5%Washington RPP Barges 5%

Vancouver Tankers 2%Washington RPP Tankers 9%

*Alaska Crude Tankers 71%

B.C. Barges 8%

Explanation of Cargo Movement1 Figures for 1993 provided by Washington State Office of Marine Safety and Tofino traffic Services. A portion of

this Alaska traffic (about 33 tankers according to 1994 figures) is partially unloaded at Puget Sound refineriesthen leave for southern US ports on the west coast.

2 Typical range of sizes from list of American Flag vessels calling at Puget Sound Refineries in 1990.1 Some smallertankers down to 40,000 Dwt make a limited number of trips.

3 Range of sizes derived from 1994 list of foreign flag tankers allowed to operate in Alaska State Waters with ap-proved contingency plans, published in Marine Digest, November 1994.

4 Number of tanker and barge shipments for the transport of refined products (bunker, heavy fuel oil, jet fuel,distillates) - from Table 1 of Reference 2. Not of all these Puget Sound refined product trips pose a direct risk toBritish Columbia waters depending on location and routes. Numbers in the table exclude tanker or bargemovements involving transfers and shipments within Puget Sound and any shipments for bunkering; these areassumed to be small volumes and far enough removed in most cases from British Columbia waters to eliminatemost spill risk.

5 The typical tanker size associated with refined products was derived by converting average shipment volumesfrom barrels to tons, and multiplying by 1.2 to account for trips at less than full capacity. Refined PetroleumProducts (RPP) barge sizes were derived from a separate list of typical oil barges operating in the Puget Soundarea.3

6 Tanker exports out of Vancouver were highly variable in the past few years due to market conditions favouring theexport of oil by pipeline to the US rather than shipment to foreign countries (e.g. fourteen in 1993 down to threein 1994).

7 The estimated annual number of barge trips in British Columbia waters carrying refined products was derived byreducing the number of trips quoted by the States/British Columbia Oil Spill Task Force 2; 200 trips were elimi-nated to account for the reduced volumes of bunker oil being delivered to Vancouver Island pulp mills followingthe completion of the gas pipeline (bunker volumes are down by approximately 75%). The figure shown in thetable includes a small number of exports of refined product from Vancouver to Puget Sound by barge. There issome uncertainty as to the total number of barge trips in British Columbia as many movements cover very shortdistances to provide bunkering to deep sea vessels in Vancouver Harbour and Prince Rupert. A realistic numberof annual trips is probably less than 600.

RPP: Refined Petroleum Products*Includes out-bound partial loads

heavy fuel oil to light distillates.1 The totaloil volume is dominated by the Trans-Alaska Pipeline System (TAPS) crude oiltankers (about 92% of this crude oil move-ment is by American registered tankers).

The majority of the refined petroleumproducts are moved by a mix of Canadianand American barges, while almost all of

American and foreign tanker deliveries of crude oil to Puget Sound Refineries account for

over 75% of the total volume of oil and refined products moved in Washington and British

Columbia coastal waters. One tanker per day brings crude oil into terminals located as close

as 15 kilometres south of the sensitive Fraser River estuary. An accident to any one of these

tankers could result in a spill the size of the Exxon Valdez spill or greater.

the crude oil is transported by American-flag tankers. This mix of products, vol-umes, type of vessel and ownership willbecome important later in the discussion.The sources of local spill risks are interna-tional in nature. Spilled oil, driven bysurface currents and winds, does not rec-ognize international borders.

There are a range of hull designs incurrent use or proposed: single bottom,double bottom, mid-deck, double hull,such as illustrated below. Compared withthe traditional single-hulled tanker, each ofthese designs are more effective in reduc-ing the number of oil spills and/or theamount of oil spilled in certain types of

JAMES MCFARLANE / SEATTLE TIMES

accidents. This section clarifies the relativemerits and drawbacks of each designoption beginning with the status quo, singlehulls, followed by interim protection meas-ures, then double hull design.

It is important to realize that, whiledouble hulls and other designs to protectthe cargo can reduce or eliminate oil spill-

PART 2: TANKER DESIGN

age after a grounding or collision, suchdesigns do not reduce the likelihood of amarine casualty. Measures such as crewtraining, electronic chart navigation sys-tems, vessel traffic systems, and doublepilotage are some of the many other spillprevention measures which need to beintroduced along with safer ship designs.2

Single-Hulled Tankers Represent theStatus QuoMost of the world’s marine oil trade is

still carried out in single-hulled vessels.Locally, the majority of the crude oil andrefined products is still moved in single-hulled tankers and barges: approximately200 out of the 250 million barrels (or about80%).

Only a thin layer of steel, 4 cm (orabout 1 1/2 inches) thick, separates thecargo of oil in a single-hulled tanker fromthe sea water outside. This layer can beeasily torn or punctured during collisions,groundings, and other accidents.

The cut-away view on the next pageshows a single-hulled tanker that is repre-sentative of a tanker carrying oil from

Alaska to Puget Sound.5 For comparison,the tanker is approximately twice thelength of a large British Columbia orWashington State ferry.

Variations on Single HullsSingle-hulled tankers can be divided

into two groups based on their date ofconstruction, conventional and MARPOLtankers.

Conventional single-hulled tankershave some segregated ballast tanks, butthe amount of ballast tankage is often lessthan current international standards and isnot required to meet any minimum per-centage of the hull area. Most of theAlaskan (TAPS) crude oil imported intoPuget Sound is still carried in conventionaltankers built prior to 1974. These single-hulled tankers are most susceptible to oilspills in any kind of accident involvingdamage to the outer hull. Unfortunately,the timing of when these vessels will bereplaced is quite uncertain.6 Please refer toa further discussion of this critical issue inPart 3.

The majority of the world’s tankers are still single-hulled; only one layer of steel less than 4 cm

thick (about one 1 1/2 inches in many cases) separates the oil from the ocean. There are a

number of design options available for new tankers which offer a great deal more protection

and actually prevent any oil from leaking in some situations.

Locally, 80% of crude oil and refined products are still transported in single-hulled tankers or

barges.

MARPOL tankers are so named be-cause they are built to the specifications ofthe International Maritime Organization’sInternational Convention for the Preven-tion of Pollution from Ships, 1973 and itsassociated Protocol of 1978, known asMARPOL 73/78.7 According to this proto-col, tankers completed after May 1982 arerequired to have segregated ballast tanks(SBT) arranged to cover 30% of the side orbottom area of the tanker, thereby provid-ing a measure of protection during a colli-sion or grounding. Depending on theloaded state of the tanker, these ballasttanks are maintained empty, or with seawater, to achieve the required stability. Theprotocol of 1978 also prescribed a maxi-mum size of the cargo tanks to limit thespilled volume of oil should only onetank be damaged.

Estimates are that less than 40% oftankers worldwide currently qualify asMARPOL tankers.8 The majority of tankersstill fail to meet even the minimal protec-tive measures mandated in 1978, highlight-ing the difficulty in making substantialchanges to thousands of tankers in even afew decades. The current situation regard-ing replacement of these older tankers ismade more serious by the steady decline intanker freight rates. Recent estimates showthat the available daily charter incomefrom a new double-hulled tanker is lessthan half that required to break-even on itscapital and operating costs. The result isthat the rate of actual replacement of oldersingle-hulled vessels is likely to fall far

short of theirmandated rate ofretirement. Fur-thermore, thereare few directeconomic incen-tives on the westcoast for employ-ing safer vessels,such as reducedport, pilotage,harbour andother fees/charges. Oneexception is therecent (Novem-ber, 1994) USCoast Guardrequirement fortug escorts of allsingle-hulledtankers in Puget

JAMES MCFARLANE / SEATTLE TIMES

internationally as possible spill preventionimprovements which can be applied toexisting single-hulled tankers:

• protectively located spaces; and,• hydrostatically balanced loading.These interim protection measures are

being put forward as a means of providingsome improvement during the 10-15 yearphase-out of most existing single-hulledvessels. Neither measure provides thedegree of protection afforded by doublehulls.11 After several years of public discus-sions, the United States Coast Guard is notexpected to recommend and approve anyspecific measures until early in 1996.

"Protectively located spaces" is essen-tially a new term to describe segregatedballast tanks as shown below, originallycalled for by the International Maritime

Sound and the Juan de Fuca Strait east ofPort Angeles. The Canadian Council ofMinisters of the Environment report (May1995) strongly recommends that there beeconomic incentives for safer vessels. 9

Suggested incentives are reduced port andmarine service fees for vessels havingadditional spill prevention design or tech-nology measures (e.g. double-hulls, elec-tronic charting).

It is important to note that there are noequivalent requirements for oil barges tohave segregated ballast tanks or protectivespaces.10 Most such barges carry the oildirectly against a single hull.

Interim Protection MeasuresTwo interim measures are being seri-

ously considered in the United States and

Organization in 1978. Protectively locatedspaces provide some measure of protectionby ensuring at least 30% of an oil tanker’shull are either ballast or spaces free of oil.In theory, a random collision has a chanceof damaging a ballast tank instead of an oiltank. In such a case, provided the damagewas limited to the ballast tank, no oilwould be spilled. These protective spacesare much less effective in preventing oilloss in a grounding situation.

On the plus side, the allocation ofprotectively located spaces on existing pre-1982 vessels is relatively inexpensive andcan be quickly implemented; on the nega-tive side, this measure provides only mini-mal protection on a “hit or miss” basis andwill also reduce cargo capacity.

The second interim measure,hydrostatically balanced loading (HBL), isan operational rather than a design measure;on most vessels. It will not require struc-tural modifications, but it will require

different loading procedures. With HBL,the cargo tanks are filled with oil only tothe point where the pressure at the bottomof the cargo tank remains less than the seawater pressure outside the tank. Thisprocedure is also called partial loading. Ifthe tank bottom is ruptured, sea water willflow into the tank to equalize the pressureinstead of oil flowing out as illustrated onthe next page. However, some oil willalways be swept out of the tanker.

A number of shipping companies onthe west coast already use HBL as a matterof convenience when their vessels partiallyunload at Puget Sound refineries and thenproceed onto California with the remain-der of their oil cargo.12 The motivation hereis strictly one of economics rather thanenvironmental concern. In fact, these par-tial shipments pose an additional riskfactor caused by the additional crude oilmovement out of the Juan de Fuca Straiton the Canadian side en route to California.

Single-hulled tankers can’t help but leak oil when there is any structural damage to the outer

hull. Segregated ballast tanks were required on all tankers built after 1982 but over half the

world’s fleet still lacks even this minimal degree of protection.

Fully 70 % of the Alaskan crude oil imported in to Puget Sound is still carried in tankers built

prior to 1974. These single-hulled tankers are most susceptible to oil spills in any kind of

accident involving damage to the outer hull. Most oil barges in local waters are single-hulled.

A depressed tanker market does little to encourage the rapid replacement of older vessels.

In summary, HBL is a potentially effec-tive interim measure for grounding acci-dents. Its success in practice would dependon the diligence of the operators in main-taining the more complicated loadingprocedures and accepting the reduction incargo capacity. Some of the advantageswould be offset by the increased numberof sailings required to achieve the same

volume throughput with an HBL fleetcompared with conventionally loadedtankers. These many uncertainties couldreduce the effectiveness of HBL in day today operations. Any wide-scale adoptionof HBL may prove to be counterproductivewhen applied to the overall risk of a majorspill in local waters.

Interim measures are really just a stop-gap solution which do little to address the overall

problem of too many single-hulled tankers still sailing. It is better to apply all available

resources to replacing the older tankers rather than relying on “bandaid” solutions.

Principle of Hydrostatic Balance Loading

twice as wide as in a normal double hull inorder to meet the ballast space require-ments.

The deck between the lower and uppertanks is water- and oil-tight. Although someoil will always be lost if the bottom is torn,the amount will be considerably less thanfrom a single-hulled tanker for two reasons:first, less oil is available in the lower tankthan in a conventional tanker and second,the oil in the lower tank is at a hydrostaticadvantage such that in the event of a bot-

Mid-Deck Tanker

The mid-deck concept is a new design, developed in Japan, as an alternative to double hulls.

Although theoretically superior in collisions and high speed groundings, the mid-deck design

is unproved in service. The design measure has been accepted by the IMO and the Canadian

Coast Guard, but not the United States Coast Guard. The most significant drawback of the

mid-deck is that it will always spill some oil in a grounding situation which damages the

bottom outer hull.

Mid-DeckThe mid-deck concept is a new design,

developed in Japan, as an alternative todouble hulls. This concept is also known asthe intermediate oil-tight deck. As yet un-proved, it is expected that construction andoperational costs will be comparable to thedouble hull.

The mid-deck tanker has a very highdouble bottom, typically 1/5 – 1/4 of thetanker beam, that is filled with oil anddouble sides with no oil as illustratedbelow. The double sides are approximately

tom rupture, outside water will tend toflow in rather than oil flowing out.

The mid-deck design is potentiallysuperior to the double hull in two situa-tions:

• During Collisions: full penetration ofthe wider side tanks of a mid-decktanker will be less likely; and,

• During High-Speed Groundings(over 15 knots): the mid-deck willtheoretically spill less oil than adouble hull. At such high speeds,the inner bottom hull of a double-hulled tanker would likely be dam-aged anyway, giving the advantageto the mid-deck tanker with itsshallow tanks.

The main difference between the twodesigns, mid-deck versus double hull, isthat in low speed groundings the mid-deckdesign will always spill some oil where adouble hull would spill none. The UnitedStates Coast Guard considers this to be afatal defect of the mid-deck design. Esti-mates are that 65% of oil spilled fromtankers has historically occurred duringgroundings.12 Current United States rules

do not consider mid-deck tankers an ac-ceptable alternative to double hulls.6

The International Maritime Organiza-tion on the other hand, has judged themid-deck design to be comparable to thedouble hull in its potential for reducing thetotal amount of oil spilt in marine acci-dents.14 Canada has adopted the IMOstandards for new construction, meaningthat the Canadian Coast Guard will acceptboth double hulls and suitable mid-deckdesigns for any new ships calling at Cana-dian ports.15 Part 3 deals with the regula-tions in more detail.

In conclusion, although the mid-deckdesign has a number of theoretical advan-tages, its lack of operating experience andlack of acceptance by the United StatesCoast Guard rules against any whole-hearted acceptance of the mid-deck designas a real alternative to double hulls. Theinability of the mid-deck to avoid a smallspill in almost any grounding is a signifi-cant drawback. The mid-deck will neverreduce total number of oil spills to the sameextent as double hulls.

Double HullsDouble hull construc-

tion provides a provensolution to the problem ofhow best to reduce oilleakage after a shipstrikes another object ortouches the bottom. Dou-ble hulls provide a tankwithin a hull, thus pro-viding two steel barriersbetween the oil and theocean as illustrated.

The IMO design standards for double-hulled tanker construction (adopted byUnited States and Canada) will ensure thattankers greater than 65,000 Dwt, such astankers delivering oil to Puget Sound refin-eries, will have a minimum gap of approxi-mately 2 metres between the inner andouter hulls. Only clean ballast water, neveroil, can be carried in the spaces between thehulls. Groundings, collisions, and otheraccidents which only damage the outerhull, will result in no oil spill.

Some idea of the scale of double hullspacing can be gained from the followingsketch of the midships ballast tanks on atypical 130,000 Dwt double-hulled tanker.The insert shows the same vessel as itmight appear in a grounding or collisionsituation.

Double hulls, are the best design im-provement for reducing tanker oil spills:

• IMO and the US Coast Guard placedouble hulls at the top of their list ofpossible designs and use them as ayardstick to evaluate other designs.

• The double hull design was identi-fied as one of the most cost effectivefor all accident scenarios by the USNational Research Council.7 Theyestimated that double hulls wouldeliminate half of the annual spillagefrom vessels in the US.

• IMO estimated in their 1992 studythat the inner hull would not havebeen penetrated in 84% of historicalgroundings worldwide if vesselshad been double hulled.14

• The US Coast Guard has not identi-fied any other design which issuperior to the double hull forprevention of oil outflow due togroundings.16Groundings accountfor 65% of the total volume of oilspilled from tankers in the US.7

• Double hulls will also reduce oilspillage from collisions and situa-tions of structural failure.

The double hull design is a provendesign. In 1989, 18 per cent of the world’stanker fleet was either double-hulled ordouble bottomed.17All ships carryinghazardous chemicals or dangerous prod-ucts such as Liquefied Natural Gas (LNG)are already required to have double hullsto provide protection for their cargo.

None of the tankers carrying oil fromAlaska to Puget Sound are currently dou-ble-hulled, although a few have doublebottoms.

Double-hulled tankers are usually builtas new construction; double hulls can beretrofitted into existing vessels but this israrely done. Estimates are that doublehulls will cost 15-20% more for construc-tion over equivalent single hulled tankers.However, the additional construction andoperating cost of double-hulled tankerswill add a relatively minor cost of less than0.15 cents per litre to the cost of oil. 17, 6

The international requirements fordouble hulls have only been put in placeafter a fifteen year debate between indus-try, regulators, and environmentalists.Three operational concerns were continu-ally raised as reasons not to implementdouble hulls: too difficult to inspect, in-

creased risk of fire and explosion, anddifficult to salvage. Experience with exist-ing double-bottomed and double-hulledtankers, though still quite limited by thefew number of such vessels, has led togeneral agreement that these issues aremanageble. Further discussion of theseissues is provided in Appendix A.

The fears surrounding inspection, fireand explosion, and salvage have beenfurther put to rest by two large independ-ent tanker owner associations who havestated that double hulls, although moredifficult to maintain than single hulls, canstill be operated in a satisfactory manner.14

Considering the dramatic rise in spillliability following the Exxon Valdez oil spillsettlements, the long-term benefits ofdouble hulls will be realized in both eco-nomic and environmental terms. Doublehulls are the preferred design for futuretanker construction; every effort needs tobe made to ensure that the process ofreplacing older single-hulled tankers pro-ceeds as quickly as possible.

Design ComparisonThe double hull offers the dual advan-

tages of halving the oil volumes spilled intanker and barge accidents, and reducingthe number of oil spills. The overall costinvolved in achieving this protectionamounts to approximately 0.15 cents perlitre of oil transported. The double hullwill avoid oil spills in over 80% ofgroundings while the mid-deck tanker, likethe existing single hulled fleet, will alwaysspill some oil as shown in the sketch on thenext page.

The bar graphs on the following pagecompare the different new designs withold single hulled tankers in two ways:

• first, the volume of oil spilled over arange of accidents which match thepattern of historical events in termsof the proportion of groundings andcollisions; and,

• second, the absolute number ofspills prevented in situations where

the ship may be damaged but thenew design prevents any oil fromspilling into the environment.

Not surprisingly given the wide rangeof circumstances surrounding marineaccidents, no one design appears as theonly possible solution. The effectiveness ofany given design solution depends to alarge extent on how we view the problemand the spill location. If our main goal is to

Double Hulls–Half the Pollution: Double-hulled construction provides a solution to reduce

oil leakage after a tanker or barge strikes another object. Double hulls provide a tank within a

hull, thus providing two steel barriers between the oil and the ocean. Double hulls are widely

accepted as the best proven design.The International Maritime Organization estimates that the

inner hull would not have been penetrated in 84% of historical groundings worldwide if

vessels had been double hulled. Additional construction and operating cost of double-hulled

tankers are estimated to add less than 0.15 cents per litre to the cost of oil. The US National

Research Council claims that salvers actually prefer double bottoms, countering the early

arguments that a double-hulled tanker would be more unstable in an accident.

prevent oil spills, then double hulls are thewinner by far (up to an 80% reduction innumbers of spills for groundings). On theother hand, if our main concern is to de-crease the overall volume of oil enteringthe marine environment from large spills,accepting that there will always be una-voidable smaller spills, then double-hullsand mid-decks offer similar theoreticalbenefits. In practice, no interim measurefor existing vessels offers the protection ofdouble hulls. Such measures as protec-tively located spaces (or segregated ballasttanks) and hydrostatically balanced load-ing can only be considered as a minimum

cost approaches as opposed to the bestavailable technology.

In the end, economics and practicalconsiderations of operations and mainte-nance favour double hulls as the preferredand proven solution for new constructionof both tankers and barges.

In extreme accidents, it is impossible topredict whether any design will prevent atotal loss. In order to achieve their fullpotential, the new double-hulled tankerswill still require the highest standards ofcrew training and vessel traffic systems tomaintain safe navigation corridors.

Double hulls are the preferred and proven solution for new construction of both tankers and

barges. We need to remember that even the most advanced tanker design cannot prevent

spills in extreme conditions of weather or negligence. There is no substitute for the highest

standards of crew training and vessel navigation.

Following the Exxon Valdez oil spill in1989, a large number of national and inter-national inquiries, panels and studiesexamined the oil spill problem from theperspectives of both prevention and re-sponse. Prevention ideas took many differ-ent forms including new routes, crewtraining, navigation systems, terminaldesigns and operations, and tanker design.Our concern in this report is with tankerand barge design. Part 3 looks for answersto two questions:

• What recommendations concerningdouble hulls surfaced from themany investigations and hearingsover the past several years?

• What is actually happening now orabout to happen as a result of recentlaws and international agreementsrequiring the replacement of single-hulled tankers still carrying most ofthe oil in British Columbia andWashington State waters?

Scheduling RecommendationsFirst, lets take a look at some of the

federal, provincial and US state recom-

mendations which followed lengthy hear-ings and reports in the aftermath of theExxon Valdez spill:

The Canadian government Public Re-view Panel on Tanker Safety and Marine SpillsResponse Capability , 1990,18 commonlyreferred to as the Brander-Smith report,made the following recommendationspecific to Canada’s west coast:

“All Canadian tankers and bargescarrying oil or petroleum products inBritish Columbia's coastal or inland watersmust be double hulled within seven years.The use of single-skinned tankers and tankbarges between the mainland and Vancou-ver Island should be permitted to continueuntil the new gas pipeline under construc-tion in this area has been completed andpetroleum consumption levels diminished.This waiver must not extend beyond sevenyears, at which time all tankers and bargesmust be double hulled” (Rec. #6-47).

As of 1993 the gas pipeline between themainland and Vancouver Island has beencompleted and oil consumption dimin-ished. Accordingly, there should be nodomestic coastal barges or tankers of sin-

PART 3: COMPARISON OF UNITED STATES, CANADIANAND INTERNATIONAL REGULATIONS

RECOMMENDATION: That all oil barges and tankers in Canada be double hulled by 2000

STATUS: Single hulled barges allowed to operate until 2015, and many tankers being allowed

to operate well into the next century.

gle-hull construction after year 2000. Na-tionally, the Brander-Smith report recom-mended: "Canada should require that in 10years time all tankers and tank bargesentering its water be double hulled(Rec.#3-2). Again, according to this recom-mendation, mandatory retirement of sin-gle-hulled tankers and barges ought tohave occurred by year 2000.

The federal government’s final responseto the panel recommendations (June 1993)agreed in principle to these regional andnational scheduling recommendations.However, in their final response to theBrander-Smith recommendation on fund-ing to expedite replacement of the Cana-dian-flag fleet with doubled-hulled vessels,the final report stated: "... that existingsingle-skinned tankers be retrofitted orphased-out on a schedule that is consistentwith requirements imposed by other coun-tries. Similar requirement will be appliedto oil barges..." (Rec.#2-1) As the follow-ing comparision of double-hull scheduleswill show, the matter of international con-sistency took precedence over the moreexpeditious national and regional recom-mendations.

The Province of British Columbia’sReport to the Premier on Oil Transportationand Oil Spills, November 1989 commonlyreferred to as the “David Anderson Re-port”,19 recommended: “ In the event of theSecretary of Transportation (United States)or the National Academy of Sciences(United States) reporting in favour ofdouble bottoms, greater use of ballastsides, or reduced tank sizes for tankers ortank barges, Canada serve notice thatwithin four years such design features willbe required for tankers and tank bargescalling at Canadian ports”. (Recommenda-tion #20). The National Research Councilin Washington recommended in favour ofsuch designs in 1991.13

The Final Report of the States/BritishColumbia Oil Spill Task Force, 1990 2 recom-mended unanimously that double hulls berequired for all new tank vessels designedto carry oil or other petroleum products ascargo. No time was specified.

By 1992, federal governments on bothsides of the border as well as the govern-ments of individual States and BritishColumbia were all in complete agreementon the need for double hulls.

In terms of reducing the risk of oil spills, the critical question is not the date after which all

new tankers have to have double hulls, or the dates when the existing single-hulled fleet is

forced to retire but the timing when owners are willing to build replacements. Of particular

concern is the continued operation of old single-hulled tankers carrying Alaskan oil, and

aging single-hulled barges carrying refined products within our waters.

Under these rules, the last year inwhich a single-hulled tanker can call atany port in the world where the govern-ment has acceded to the InternationalMaritime Organization’s MARPOL con-vention will be 2007 in the case of a tankerwith no segregated ballast tanks, or 2025 inthe case of tankers which have this addedmeasure of protection. As over half of thelarger tankers were build during the early1970's, most of the world tanker fleet willbe forced to retire by the turn of the cen-tury under the MARPOL, Canada ShippingAct (CSA) and US Oil Pollution Act (OPA’90) schedules.

For tankers calling at US ports, thatcountry has established its own independ-ent schedule under the (OPA ’90) whichdiffers from the world standard (see chartbelow). Canada, through the CSA hasadopted a mix of replacement schedules,

Comparison of New Regulations Requiring Double Hulls or their Equivalentfor New Construction of Oil Tankers or Barges (7,9,14)calling at US Ports calling at Canadian Ports

Relevant Legislation US Oil Pollution Act, 1990 Canada Shipping Act

Affected tanker and barge sizes all all

Designs Allowed double hull only double hull or mid-deckexcept for vessels less than

5,000 gross tons

Interim Standards for not finalized – rule expected as acceptable to IMOExisting Vessels by 1996 (e.g., protectively located

spaces, HBL)

Dates in effect vessels contracted after vessels contracted after July June 30, 1990 and delivered 6, 1993 and completed after

after January 1, 1994 July 6, 1996 (completion(delivery takes precedence) takes precedence)

Scheduling ImplementationIn November 1992, Canada acceded to

the International Convention for the Pre-vention of Pollution from Ships, known asthe MARPOL 73/78 convention of March1992.7 Agreements reached at this meetingare critical, in that, they define the interna-tional standards and schedules to be usedfor the design of new tankers and theretirement of the existing world single-hulled fleet. Under the new IMO rules anytanker older than 25 years as of July 1995,without segregated ballast tanks must bereplaced or have a new double hull. Tank-ers with SBT are allowed to be 30 years oldbefore replacement. Canadian oil bargesless than 10,000 Dwt that are single hull donot have to be retired until year 2015. NoCanadian tank barges on the west coastexceed this size (average size is approxi-mately 2,000 Dwt).

It may take until well into the next century before sufficient number of new double-hulled

tankers are built to provide any substantial reduction in spill risk.

following the IMO standards for tankers over20,000 Dwt, and following the United Statesretirement schedule for smaller tankers andbarges.15,10 In practice, given the size of themarket, the OPA ’90 schedule will dictate themandatory retirement date for many tankerstrading in the world, and for most tankersposing a risk to the west coast.

The OPA ’90 provides the US CoastGuard with the authority to develop theirown standards for new tanker constructionas well as a mandatory retirement sched-ule for existing single-hulleded tankerscalling at US ports.6 The OPA ’90 require-ments and timetables for double hulls havefar reaching implications for a large pro-portion of the world’s tanker fleet. The USCoast Guard has estimated that these ruleswill affect some 3000 tankers worldwide,mostly foreign flag ships.6

The Real IssueIn terms of reducing the risk of oil

spills the critical question is not the dateafter which all new tankers have to havedouble hulls nor the dates when the exist-ing single hull fleet is forced to retire, butwhen and if new double-hulled US flag

tankers will be constructed as replace-ments for the aging single-hulled tankerscarrying Alaskan (TAPS) crude oil. Withthe current low return on investmentassociated with the tanker charter market,very few new tankers will likely be builtover the next ten years. Even with theMARPOL and OPA ’90 requirements formandatory retirement, the natural aging ofthe world’s fleet is of grave concern toshipping organizations like the IMO andthe Coast Guard.

Most foreign flag vessels will have toadhere to whichever regulation is stricterto be able to continue trading worldwideand to North America. In practice, thedifferences between international andUnited States schedules for retiring single-hulled tankers would be important toBritish Columbia only if many more for-eign tankers started to call at Port ofVancouver. This is an unlikely situationsince British Columbia does not generallyimport oil by vessel, and is reducing its oilexport by vessel. Foreign tankers calling atPuget Sound (United States) will have tosatisfy both OPA ’90 and MARPOL which-ever is more stringent.

In an effort to understand this issue, theretirement schedules called for under OPA’90, MARPOL, and CSA were applied tothe actual mix of sizes, ages and numbersof tankers trading on the Alaska oil route,between foreign ports and Puget Sound(via the Juan de Fuca Strait), and tankerswithin British Columbia coastal waters.The objective was to produce a clear andrealistic picture of the earliest dates whenwe could start to see a substantial reduc-tion in spill risk from new double-hulledtankers and barges. An assumption is thatnew double-hulled tankers are introducedat the same time the older single-hulledones are forced to retire. In order to applythe various retirement schedules to actualvessels, six different oil trading categorieswere used (see Part 1 of this report).

Trade 1 US flag tankers deliveringAlaskan (TAPS) crude oil: Thereare over 30 vessels engaged inthis trade in any given year.However, 78% of the oil is car-ried in 18 ships which are nowmore than 20 years old (builtbetween 1969 and 1974). UnderOPA ’90, these 18 tankers will allbe forced to retire between 1996and 1999. Industry has an-nounced no plans for new con-struction and it remains unclearhow the potential capacity short-fall in the US flag TAPS tankerfleet will be met. See Part 4 onexpected future trends regardingexport of Northslope Crude oilfrom Alaska, and the use of

foreign flag vessels (Trade 2) tomeet potential oil supplyshortfall.

Trade 2 Foreign flag tankers deliveringcrude oil to Puget Sound refin-eries: Based on the age of tank-ers on this trade in 1993,replacement with double-hulledvessels may occur between year2003 and 2010 according to OPA’90 schedules. (Note: IMOstandards would allow the samevessels to continue operatinguntil year 2007 for the oldest or2023 for the newest.)

Trade 3 Tankers carrying refined prod-ucts out of Puget Sound: Tank-ers in the refined product tradecalling at Puget Sound tend to beapproximately half the averagesize of crude oil tankers in ourarea (42,000 vs. 88,000 Dwt.). Theexact ages of individual vesselsin this trading category were notavailable. In 1992, it was re-ported that approximately 1/3of the oil refined in WashingtonState goes to foreign countries(mostly in foreign flag ships)and the rest goes to other westcoast states in US flag tankers.1 A1994 list of tankers approved tooperate in the Pacific Northwestshowed that 20% of the tankersengaged in the refined producttrade are already double-hulled.The rest are new enough thatretirement is not mandatory

until after 2005.20 The US NavySealift Command plans to retireits single-hull fleet and beginreplacement with double-hulledtankers in 1995.

Trade 4 US flag barges carrying refinedproducts out of Puget Sound:Most Puget Sound barges are lessthan 5,000 gross tons meaningthat under OPA ’90 they canoperate until 2015 before needingdouble hulls. According to a 1990listing of 44 tank barges in PugetSound,3 there are only two vesselswhich are large enough to fallinto the next size category underOPA ’90 (5 - 15,000 gross tons.

Trade 5 Canadian flag barges carryingrefined products in B.C. waters:Under the recently releasedCanadian Coast Guard Oil BargeStandards,10 all barges usedlocally will be allowed to oper-ate with single hulls until 2015 -another 20 years. This replace-ment schedule is a direct copy ofthat required by the US CoastGuard for American oil bargessuch as those in the states of

Washington and Alaska. Evenwith the reduction in bunker fuelvolumes being moved to Vancou-ver Island, the movement ofrefined oil products by barge inBritish Columbia waters stillaccounts for approximately 8% ofthe total volume of marine oilcargoes on the west coast. Muchof this oil is carried throughnarrow passages adjacent tohighly sensitive areas, particu-larly up the Inside Passage (in-cluding Johnstone Strait,Discovery Passage, ChathamSound).

On the positive side, the westcoast oil barge fleet has a verygood safety record and has greatermechanical redundency than thelarger tankers through the use oftwin-screw (propeller) tugs.

Trade 6 Crude Oil Tankers ExportingAlberta Crude from Vancouver(Westridge Terminals): Due tochanging market conditions andeconomics, the numbers of tank-ers leaving from Vancouver hasfallen far short of what wasprojected in the early 90’s.

The Canadian Coast Guard standards allow all single-hulled oil barges to operate until 2015

before having to be replaced with double-hulled vessels.

According to Trans MountainPipelines Limited, fewer than 10vessels per year are expected inthe future. This level of trafficwould constitute only about 2%of total marine oil cargo move-ments in our region. Tankersused in this trade tend to bemuch newer than the worldaverage; for example, the oldesttanker calling in the past yearwas built in 1980. Strict stand-ards are applied in selectingvessels for charter into Vancou-ver and no tankers are acceptedwithout segregated ballast tanks;most have fully protected cargospaces along the sides (essen-tially double sides). Double-hulled tankers will be phased into this service between 2015 and2020 according to the scheduleset by IMO for tankers withsegregated ballast tanks. Thisphase-in may be sooner as theavailability of double-hulledtankers for charter increases.

The results of the analysis shows thatunless American ship owners begin amassive program of acquiring new double-

hull tankers by 1996 (whether built in theUS or purchased from foreign ship-yards),we will have to wait until well into thenext century before double hulls start tomake substantial contribution to reducingthe risk of spills on the west coast.

Foreign flag tankers leaving from Van-couver carry only 2% or less of the totalregional oil cargo on an annual basis.Consequently, the retirement schedule setby the International Maritime Organiza-tion and adopted by the Canada ShippingAct has little or no impact on the timing ofdouble hull benefits in our waters.

The average age of the US flag oiltankers trading along our coast is now 21years and the newest tanker in regular use,the Kenai, is 15 years old.20 In contrast, fullyhalf of foreign flag tankers, similar in sizeto vessels in the US Alaska (TAPS) fleet,were built since 1980.8 The reasons for thisage difference are primarily economic.

Under the US Jones Act (also known asthe Merchant Marine Act of 1920) onlytankers built in United States shipyards arepermitted to carry cargoes between twoAmerican ports. The cost of tanker con-struction in the United States has tradition-ally been much higher, up to double, thanin many other shipbuilding nations(China, Korea, Japan). The result is that

If double hulls could be depended upon to prevent a spill in half of all accidents on average, then the

simple act of retiring all US flag tankers older than 25 years in 1998 will result in approximately 12%

fewer spills in the future.

new tankers built in the United States willhave great difficulty in operating economi-cally.

Companies are understandably reluc-tant to replace their older single-hulledTAPS tankers until either the vessels be-come too difficult to maintain due to ag-ing, or until called for under the OPA ’90legislation. At the same time, the produc-tion of oil from the Prudhoe Bay oilfield isin steady decline with no future replace-ment clearly projected. The US Jones Actrestrictions forces tanker owners to main-tain their aging tankers for as long aspossible and to delay plans for their re-placement. This economic strategy placesthe environment at risk.

A study on TAPS tanker structurefailures done in 1991 indicated that thesevessels account for 59 per cent of the hullfractures reported to the US Coast Guard,though the TAPS tanker fleet compriseonly 13 per cent of the US tankers. 20 Thehull cracks were generally attributed to:inadequate design of structural details,

poor workmanship and quality control,use of high tensile steel, lack of mainte-nance, harsh marine environment, andcombinations thereof. This 1991 studynoted that "... TAPS operators revealed thatthere are no plans for replacement of thisfleet by new construction." Four yearslater, no plans for replacement tankershave been made public.

It appears that the time is right to con-sider foreign-built double-hulled tankers,but still American owned-and-operated, totravel on the Alaskan (TAPS) route. Thiswill require either a special waiver underthe existing US Jones Act or new legislationin United States.

In conclusion, the timing of the benefits(spill risk reduction) from double-hulldesign is of significant public and environ-mental concern. The gap between whatwas recommended under various publicenquiries and the realities of real-worldeconomics should be reduced by whateverlegislative or incentive means possible.

Unless ship owners elect to replace their older tankers according to the retirement schedule, we may

have to wait another ten years before double hulls start to make substantial contribution to reducing the

risk of spills on the west coast.

The average age of the Alaskan tanker fleet is now 21 years and the newest tanker in regular use is 15

years old. In contrast, fully half of the foreign tankers were built since 1980. The high cost of oil tanker

construction in the United States, compared to Asian ship yards, is a significant deterrent to replacing the

TAPS oil tanker fleet.

Recent changes in market forces, eco-nomics and carriage liability are all havingan effect on both the volume and distribu-tion of marine oil movements in and adja-cent to British Columbia waters, andwhether double-hull construction willoccur:

• The rate of growth in the demand forpetroleum products is expected toremain fairly flat. The effects of theincreasing population and relativelyrobust economy of the Pacific North-west is being offset by such factorsas more efficient motor vehicles andenvironmental regulations favouringalternative energy sources such asnatural gas and cleaner air quality.

• The decline in Alaska North Slope oilreserves will lead to an increasingreliance on foreign oil to supplyPuget Sound refineries. In 1992, theWashington State Energy Officeestimated that this effect wouldbegin to be felt by 1996, and that bythe year 2000, Alaska would supplyonly 60% of regions’ crude supply,down from 90% in 1990. Further-more, new US legislation has beenprepared(Senate Bill 395 - passedMay 15th, 1995) that authorizes theexport of crude oil from Alaska,dropping the requirement that allTAPS crude oil be processed in theUnited States. The difference islikely to be made up by tanker im-ports from Indonesia, and other

countries, and pipeline exports fromCanada, which is already happen-ing. More vessels will be foreign-flag oil tankers which is both goodand bad news for the environment.While many of these ships are muchnewer than the existing Americanflag TAPS tankers, the majority stillonly have single hulls or at best,segregated ballast tanks. Operation-ally, there is the risk of sub-standardforeign-flag tankers transiting thehazardous passages of Puget Sound,such as Rosario strait. For example,the Washington Office of MarineSafety reported that, of the 13 for-eign flag tankers the visited thestate in 1993, six were identified ashigh safety risk by the US CoastGuard. This new legislation essen-tially takes the pressure off of the oilindustry to replace the TAPS fleet.

• Future tanker traffic out of Vancouver(primarily Westridge Terminals) isexpected to be much less than pro-jected four years ago. Only threevessels sailed in 1994, down from the12 to 14 loads more typical of the pastfew years. The trend is towards more“specialty shipments” from Vancou-ver which could lead to between 6and 10 tank vessels per year calling topick-up such cargoes as gas fieldcondensate and synthetic crude.22

These cargoes pose less risk to themarine environment than the morepersistent crude oils.

PART 4: EXPECTED FUTURE TRENDS IN MARINE OILCARGOES

• There is a recent oil transport practiceof parially unloading TAPS crude oiltankers at Puget Sound refineriesand then having them return, viaCanadian waters, to off-load theirremaining oil at southern US portson the west coast. In 1994, therewere 33 such partially loaded ship-ments involving TAPS tankers.23

These outbound vessels essentiallydouble the risk because trafficmovement involves two loadedtransits in local waters.

• Increasing amounts of Alberta crudeoil are being moved via pipelinefrom British Columbia to Washing-ton State. As of November 1994,Canadian crude imports were meet-ing approximately 20% of the PugetSound daily refining needs, up fromaround 1% five years ago. Thissupply situation is highly desirablefrom and environmental standpointas it reduces the overall risk of amarine spill. The pipeline supply isvery dependent on pricing andmarket pressures from other geo-graphic areas.

The rate of growth in the demand for petroleum products is expected to remain fairly flat; in

terms of marine traffic, the overall number of tankers will probably remain about the same or

decrease somewhat, while the proportion of foreign tankers delivering crude oil to Puget

Sound is expected to increase.

• The transport of refined products inBritish Columbia waters by Cana-dian barges has declined by ap-proximately 15% overall since thecompletion of the natural gas pipe-line to Vancouver Island (bunkervolumes were reduced by up to75%). Trends in the Canadian oilbarge industry indicate little or nogrowth in petroleum product deliv-eries and probably a slight declinewith fewer destinations beingserved by sea as a result of newregulations under the Canada Ship-ping Act governing shoreside oilhandling facilities and the require-ment to have adequate oil spillresponse capability. 24

There are significant benefits for reducingthe risk of a spill. These benefits includeavoided response (clean up) costs, naturalresource damages, and restoration costs. A1995 study commissioned by the BC Minis-try of Environment, Lands and Parks com-pared the benefits and costs of acceleratingthe current retirement schedules by 15 yearsto year 2000.25 The estimated cost of acceler-ating the replacement of the Alaska (TAPS)fleet (28 vessels) is $240 million (1995 $US)with the US Jones Act. The US Jones Actdoubles the cost of tanker construction. Theestimated benefits to British Columbia andthe shared waters of the State of Washingtonto is about $147 million. Benefits accrued toother regions, such as Alaska and California,were not estimated in the study, but wouldno doubt be substantial. The analysis of theTAPS fleet indicated that a waiver of the USJones Act, which would allow the use of lesscostly foreign-built vessels on the route,would decrease the cost by 50 percent of theaccelerated replacement, whereby a netbenefit of $27 million (US) or greater wouldbe realized.

The study's benefit-cost analysis ofCanadian-flag oil barges (21 vessels) showedthat the benefits of expediting the currentretirement schedule under and CSA exceedthe costs by $154 million. This outcomelargely reflects that even small spills ofpersistent fuels can be expensive both incleanup and damages. The benefit-costanalysis did not, however, count in regionalspills from deep sea vessels or that mostCanadian barges on the west coast carrylighter and less damaging diesel and gaso-line fuel than crude oils. As such, a full

regional analysis of small spill risks, from allsources, and by all types of fuels will likelyshow that the benefits of accelerating thesingle-hulled barge replacement would bemore towards equating with the cost of sucha program.

For foreign-flag tankers such as fromAsian Pacific and Europian countries (16vessels), the study showed that the cost ofexpediting the retirement schedule exceededthe benefits. This outcome largely reflects thesituation of only a few foreign-flag vesselstransit British Columbia and WashingtonState waters each year. The reduction of theregional risk of a spill is therefore low. How-ever, the increased availability of double-hulltankers for chartering at lower rates, and therise in foreign flag traffic to off-set reduc-tions in Alaskan crude oil production willnarrow this gap. Furthermore, the benefitsworld-wide by using double-hulled tankerswere not fully accounted owing to lack ofrisk values that could be applied to thebenefit-cost analysis.

The benefit estimates of this study areboth reasonable and conservative whenconsidering that the damages for one moder-ate spill, such as the the Nestucca barge spillin 1988, may range from ten to hundreds ofmillions of dollars, and the damages from alarge spill may reach billions of dollars, as inthe case of the Exxon Valdez spill in 1989.There is more latitude for costs to decreaseand benefits to rise based on future changesin tanker chartering and construction prac-tices and rising environmental values.

It is important to consider the distribu-tional consequences of who loses and whogains for not undertaking (or conversely,

PART 5: BENEFITS & COSTS OF SCHEDULE ACCELERATION

for undertaking) the expeditious retire-ment of aging single-hulled tankers andbarges and their replacement with double-hulled ones. If the oil industry delays theretiring of their single-hulled oil vessels,then the risk and cost of spills are bornelocally on the west coast, while the savingsof not converting to double-hulls at anearlier date are realized throughtout NorthAmerica and abroad.

Who bears the cost has significantrelevance to British Columbia. A 1995study on the financial preparedness for amajor marine spill in British Columbiacommissioned by the BC Ministry of Envi-ronment, Lands and Parks looked at twoaspects: 1) funding to pay for response tomarine spills and 2) compensation forenvironmental and property damages.25

The study revealed that:• Though under the Canada Shipping

Act oil tankers and major vessels mustcontract with a Response Organization(RO) to provide response services, there isno legal obligation by the vessel owner tofund or use the RO services in the event ofa spill;

• In Canada, the combined amounts oftwo international compensation schemes,the Canadian Ship-source Oil Pollution Fundand private-sector oil tanker compensationschemes are not sufficient to compensatefor the cost of cleanup of a major marineoil spill, yet alone natural resource dam-ages;

• Though the US level of financialresponsibility for oil pollution damage bya vessel owner is about 10 times that ofCanada, there is no treaty or other legalobligation to compensate for natural re-sources damages or costs incurred byprovincial or federal government; and

• Canada does not have a naturalresource damage assessment requirementor the capability to fully determine eco-nomic and social losses due to impact tothe environment from a marine oil spill.

Based on the above short-comings,British Columbia is particularly vulnerableto bearing the cost of a major marine spill,particularly if it originated out-side ofCanadian waters from a TAPS tanker orother foreign-flag vessels.

How the US oil industry will meetcurrent retirement schedules has not beenexplained. There is indications that thesedecisions are being pushed as far into thefurure as possible or that alternative solu-tions are being sought such as allowingAlaskan North Slope oil to be sold abroad.The consequences of the latter strategymay be more foreign-flag oil tankers serv-icing Puget Sound refineries to off-set thereduced supply of the Alaska crude oiltransported by the TAPS fleet.

The issue of "economic" versus "envi-ronmental" protection is on the horizon.

The Pacific west coast is a rich environ-ment of constantly changing tidal currents,convoluted coastlines, archipelagoes, andan abundance of marine life. There areshared borders, a dynamic maritime com-merce, and vibrant coastal communities.The spectre of a grounding or collisioninvolving an oil tanker or oil barge, raisesthe image of drifting oil that respects nointernational borders, and oil that threat-ens our sensitive shores with their uniquediversity of marine birds, and intertidalorganisms. The public are deeply con-cerned about these consequences of oilspills and the need for spill prevention.Research on environmental issues showedthat in 1994, British Columbia residentsplaced the highest priority on the preven-tion of oil spills (compared to other envi-ronmental concerns); and ranked highestsuch measures as double-hulled tankerconstruction (84% in favour), marine spillprevention plans (89% in favour) and spillprevention funding (82% in favour).26 Spillprevention must not be an afterthought,but a priority in its own right, along withefforts to improve our ability to respondand to recover spilt oil.

Spill prevention can take many differentforms. Some prevention measures focus onhuman performance, such as crew training:others on technology, such as electronicnavigation charts. Each approach contrib-utes to reducing the risk of a marine vesselcasualty and the possibility of a cata-strophic spill. A proven measure to reduceoil spills in the event of grounding or colli-sion involves double hulls for oil tankersand barges – a structural design measure.

CONCLUSION

The pros and cons of double-hulledconstruction of oil tankers and barges havebeen debated for over 20 years by scien-tists, engineers, industry, governments,and concerned citizens. By 1992, there wasa general consensus that double-hulledconstruction provides a substantial meas-ure of environmental protection in theevent that an oil tank vessel is involved ina grounding or collision. Furthermore,various panel inquries and task forces ontanker safety and spill prevention heldbetween 1989 and 1990 recommended thatthe year 2000 be the target date for man-datory retirement of all single-hulled oiltankers and barges. These recommenda-tions reflected a strong public desire formarine spill prevention.

The requirement for new constructionand the phasing-out of aging tankers andbarges is now embedded in our nationalshipping laws and international conven-tions. Although double hulls are requiredfor all new tankers and barges built world-wide from 1995 on, the time period foractual replacement of existing single-hulledvessels that pose a risk to our shores couldextend well into the next century.

The issue of double-hulled constructionis complex, revolving around the need forinternational consistency and the protec-tion of maritime commerce. Knowing thevalue of our coast and its vulnerability tooil spills, one must question this narrowperspective. The findings of this studyclearly demonstrate that the time periodpresently set for achieving safer tankersand barges is too long, especially when oneweighs the severe environmental and

economic consequences of a spill.Comprehensive regional analysis of the

benefits of acclerating the retirementschedules by 15 years to the year 2000 hasshown that the avoided response costs,natural resource damages and restorationcosts conferred by double-hulls exceed thecost of replacement of our domestic dou-ble-hulled tankers and barges. The currentoil industry silence and their history ofprocrastination on double hulls under-scores our concern that we will continue tobear the regional risk of a major spillwhereas the oil industry and consumersthroughout North American benefit fromthe savings of inaction. Furthermore,Canada, and British Columbia in particu-lar, is financially vulnerable to being inad-equately compensated for damagesincurred. A major oil spill within ourshared waters will demonstrate the falseeconomy of any delaying strategies.

Incentives for new construction have tobe pursued immediately and all impedi-ments fully addressed in order to encour-age industry to phase out its agingsingle-hulled tankers and barges ahead ofschedule and replace them with new, saferdouble-hulled vessels. The time to achievethis goal should be well ahead of thatstipulated by laws and conventions, pref-erably before the turn of the century. Weknow that double-hulled tankers andbarges will reduce oil spills and the risk toour valuable coastal resources and envi-ronment. Now is the time to re-examineway in which owners and operators can beencouraged to not simply retire their oldertankers or barges, but replace or charterwith new double-hulled ones. The goalmust be one of seeking more timely andmeaningful environmental protectionthrough best available technology.

REFERENCES

1 Lagerberg, B. and M. Anderson. January 1992. Washington State Petroleum MarketsData Book. published by the Washington State Energy Office, Olympia.

2 States/British Columbia Oil Spill Task Force Final Report. October 16, 1990. Govern-ment of British Columbia, Victoria

3 DF Dickins Associates Ltd. 1990. Marine Oil Transportation Systems: Evaluations ofRisk & Alternatives for Risk Reduction - Vols. I, II. prepared for the States/B.C. OilSpill Task Force, Victoria.

4 Nalder, E. November 1989. Tankers Full of Trouble. a series of articles published in theSeattle Times.

5 Nalder, E. 1994. Tankers Full of Trouble. Grove Press, New York.

6 United States Coast Guard, Double Hull Standards for Vessels Carrying Oil in Bulk;Interim Final Rule. Federal Register Vol. 57, No. 156: Vol. 33 Parts 155, 157: Vol. 36Parts 30, 32, 70, 90 and 172. Wed. Aug. 12, 1992, adopted as the final changes onMarch 10, 1995. Retirement dates are specified separately in USCG Navigation andVessel Inspection Circular No. 10-94, December 1994.

7 International Convention for the Prevention of Pollution from Ships including Regu-lations 13F and 13G to Annex 1 of the MARPOL 73/78 convention adopted in March1992 at the 32nd session of the marine environmental protection committee of theInternational Maritime Organization.

8 Clarksons’ Tanker Registry, 1994

9 Marine Pollution Prevention Work Group, May 1995, The Report to the CanadianCouncil of Ministers of the Environment.

10 Canadian Coast Guard Ship Safety Branch. 1994. Oil Barge Standards: Part VII.,Ottawa.

11 Structural and Operational Measures to Reduce Oil Spills From Existing Tank Ves-sels Without Double Hulls; Proposed Rules. Federal Register, Vol. 58, No. 203, Fri.Oct. 22 1993, pp. 54870-54887.

12 Office of Marine Safety. Dec. 1993. Draft comments on proposed Coast GuardRulemaking on measures to reduce risk from single-hulled tankers. State of Wash-ington, Olympia, WA.

13 National Research Council. Feb. 1991. Tanker Spills: Prevention by Design. Washing-ton, DC., NTIS No. PB 91-205427, 332 p.

14 International Maritime Organization. 1992 Report on IMO Comparative Study onOil Tanker Design. Marine Environmental Protection Committee, Session 32, Agendaitem 7 (MEPC/32/7/15), London, UK.

15 Canadian Coast Guard Ship Safety Branch. 1993. Standards for the Double HullConstruction of Oil Tankers. Ottawa (also summarized in CCG NewsletterBackgrounder , January 6, 1993.)

16 Secretary, Dept. of Transportation. Dec. 1992. Alternativesto Double Hull Tank VesselDesign, Report to Congress, Oil Pollution Act of 1990. Washington, DC. NTIS No. PB93-128874, pp. 86

17 McKenzie, A. 1990. Double Hulls and the Prevention of Oil Spills. presented at IMAS90, 23-35 May 1990.

18 Public Review Panel on Tanker Safety and Marine Spills Response Capability. Sep-tember 1990. Final Report: Protecting Our Waters. Ottawa.

19 Anderson, D. November 1989. Report to the Premier on Oil Transportation and OilSpills, Victoria.

20 Office of Marine Safety, Security and Environmental Protection, United States CoastGuard, May 1991. Trans-Alaska Pipeline Service (TAPS) Tanker Structural FailureStudy, Follow-up Report, 45 p.

21 Marine Digest, November 1994, Seattle.

22 Personal communication, Richard Ballantyne, Manager Marine Oil Movements,Trans Mountain Pipelines Limited.

23 Canadian Coast Guard, February 1995. Internal memorandum to W. Wolferstan on1994 vessel traffic reports at Amphritite Point, Vancouver Island.

24 Canadian Coast Guard, June, 1994. Standards for Oil Handling Facility Oil PollutionEmergency Plans.

24 Aengus RM Fogarty, June 1995 (draft), Financial Preparedness for a Major MarineSpill in British Columbia. Prepared for the BC Ministry of Environment, Lands andParks, Victoria, B.C.

26 RCG/Hagler Bailly, September, 1995. Benefit-Cost Analysis of Expediting the Sched-ule for Double-Hulling Oil Tankers and Barges Operating in and Near British Co-lumbia Waters. Prepared for the BC Ministry of Environment, Lands and Parks,Victoria, B.C.

27 Environmental Issues in British Columbia, Report on Quantitative Research, August26, 1994.

ACKNOWLEDGMENTSThe following organizations provided invaluable assistance and recent data needed to

develop this report: International Maritime Organization, London, England; InternationalTanker Owners Pollution Federation Limited, London, England; the United States CoastGuard, Washington, D.C.; Trans Mountain Pipelines Limited, Vancouver, B.C.; SeaspanLtd., Vancouver, B.C.; Washington State Office of Marine Safety, Olympia, Washington;Canadian Coast Guard, Ottawa, Ontario; and British Petroleum, Port of Valdez, Alaska.

This report was produced by DF Dickins Associates Ltd., Salt Spring Island, BritishColumbia with the assistance of Ann Godon who prepared Part 2 dealing with TankerDesign.

Appendix A:Background – Tanker Design

APPENDIX A: BACKGROUND - TANKER DESIGN

Hydrostatically Balanced Loading(HBL) provides more protection thanprotectively located spaces. Based onidealized theoretical accidents, the US CoastGuard estimates that HBL could reduce oilspillage by 96% during groundings and15% in collisions.10 Actual performance inpractice under the effects of wind, waves,and currents will likely be lower. Forexample, a tanker grounded at high tidewill lose some or all of its advantage as thewater level falls to the low tide mark. HBLprovides little protection in collisions: oilspills from collisions near the water linewill only be slightly reduced as oil belowthe collision rupture will still flow out.Also the measure cannot be applied tocargoes which are heavier than sea watersuch as asphalt and bitumen (most oils arelighter than water).

While the outlay cost of HBL is low forthe majority of tankers, it is estimated thatthe reduction in cargo capacity of tankerswill cause the measure to be three timesmore expensive than protectively locatedspaces.10 The US Coast Guard estimatesthat partial loading will reduce cargocapacity on existing tankers by 36-50%.10

If tanker traffic increases to move the samevolumes of oil, previous experience pre-dicts that there will be an increase in thenumber of accidents, partly defeating theobject of this interim protective measure.

HBL cannot be implemented on about15% of existing tankers whose cargo tanksare not strong enough to withstand thesloshing of cargo back and forth.12 Nor-mally when a cargo tank is filled almost tothe top, there is very little room for slosh-

ing; cargo sloshing can also adverselyaffect the ability of the tanker to recoverfrom wave action or other forces whichcause the tanker to roll.

HBL would be difficult to implementon barges. Barges handle a variety ofcargoes and the partial loading levels willvary widely depending on the density ofthe petroleum product. As HBL is entirelydependent on accurate loading, any errorsin tank levels will largely cancel the ben-efits of this spill prevention measure.

Mid-deck designs: Without any realexperience base to draw on, there arereservations as to how the mid-deck vesselwill perform in actual service. Operation-ally, the mid-deck design has been metwith many of the same reservations as thedouble hull. Although some tanker own-ers feel that it presents more risks to per-sonnel, there is general agreement that theconcerns are manageable.13 A mid-deckvessel is more complex than a double hulldesign because of the extra piping andventing required for the lower tanks. De-termining oil levels in these tanks duringloading and unloading and cleaning oftanks will require extra vigilance on thepart of the crew, because of the lack ofdirect physical access from the maindeck.12,13 Inspecting the side tanks will beless onerous than inspecting both sidesand bottom of a double hull. Because areduced steel area is open to corrosion incomparison to a double hull, the risk ofundetected corrosion may be somewhatlower in the mid-deck tanker.

The mid-deck design may not be suit-

able for barges as the vessel must be care-fully loaded and unloaded to insure thatthe lower tanks have sufficient cargo toprevent capsizing. Barges, such as thosere-supplying fuel depots along VancouverIsland, often travel with partial loads andmake multiple stops to unload cargo onthe same trip.

Double-Hulls: Tankers and bargesrequire periodic inspection of the hull andcargo tanks to check for corrosion andcracks. Double bottoms make inspectionmuch more time consuming and expensivebecause in addition to the cargo tanks, allthe spaces between the inner and outerhull must be visually inspected. For exam-ple, in a very large tanker (over twice thesize of tankers carrying Alaskan crude), adouble hull has close to three times moreballast areas, all requiring inspection, thanan equivalent MARPOL tanker.12 Inspec-tors run the risk of becoming lost or over-come by fumes in the maze of spacesbetween the hulls (typically only 2 m highin the tanker bottom). Inspection difficul-ties can be overcome by design and plan-ning: the expert committee assembled bythe National Research Council to studydouble hull design concluded that the risksto inspectors were an important concern,but were not unmanageable.12

Claims of increased risk of fire andexplosion (as a result of undetected leaksof highly combustible oil and vapour intothe between-hull spaces) are not backed upby accident statistics. The National Re-search Council’s 1991 study concluded thatthere was no reliable evidence for in-

creased risk to fire and explosion on dou-ble-hulled tankers.12 Lloyd’s Register ofShipping found, after reviewing 11 years ofaccident data from single and doublestructured tankers, that double bottoms orhulls were not responsible for any of thefires and explosions which damaged theintegrity of tankers.

The third argument against double-hulled tankers claims that the vessels aremore difficult to salvage after an accidentbecause the between-hull spaces fill up,making the tanker heavier and unwieldy.In fact, this characteristic can reduce fur-ther damage in a grounding by insuringthe vessel remains firmly grounded ratherthan continuing to move under the effectof wind and waves. It has been claimedthat salvors prefer double bottomed ves-sels.12 The National Research Council’sreport states that “there are no salvage-related concerns that should limit the useof properly designed double hulls”.

The question of the spacing betweenthe hulls in double-hulled vessels provedto be very contentious with many groups(particularly environmental lobbyists)demanding larger protective spaces. Thefinal US Coast Guard specifications matchthe dimensions called for by IMO.7 Thedimensions are considered a reasonablecompromise between economics, practi-calities of inspection, environmental pro-tection and proven shipbuildingtechnology. Interestingly, the double-hullrequirements for oil barges in Canada arenot completely compatible with the US interms of the bottom spacing; the CanadaShipping Act adopts the MARPOL specifi-

cations which make the double bottomspace equal to the side tank breadth (end-ing up with ~ 1 metre minimum for mostbarges). The USCG regulations call for arelatively deeper bottom.

Under a grandfather clause, any exist-ing double-hulled tankers will be allowedto continue operating indefinitely even iftheir hull spacing falls short of the newrequirements; in practice, this clauseaffects a small percentage of the worldsfleet as of 1994.

Interim Protective Measures: Themost complex issue related to double hulls,concerns acceptable interim measureswhich will be required in the interveningperiod, before vessels are forced to retire orbe double-hulleded. The IMO lists anumber of design features which are con-

sidered acceptable and is considering othermeasures. At present, the United Stateshas not taken a final position with respectto interim measures; the Interim Notice ofRulemaking issued by the US Coast Guardin October 1993 was highly controversialand any final Notice of Rulemaking underOPA ’90 is not expected until January 1996at the earliest.

One interim step which could provide asignificant reduction in spill risk at minimalcost would involve legislating smaller indi-vidual cargo tank sizes. However the eco-nomics of making costly interimconversions of existing vessels are highlyquestionable. It seems highly unlikely thatvoluntary compliance with interim protec-tive measures requiring expensive structuralmodifications will appeal to many ownersalready hit hard by falling revenues.

Appendix B:Background – Regulatory Issues

APPENDIX B: BACKGROUND - REGULATORY ISSUES

Under the OPA ’90 requirements, alltankers and oil barges completed buildingafter January 1, 1994 will have to be dou-ble-hulled. Existing single-hulled tankerscalling at US ports will have to be eitherretired or converted to double hulls by2015 at the latest. Under a complex multi-tiered schedule based on the gross weightof the vessel, single-hulled tankers largerthan 30,000 gross tons older than 28 years,33 years if the vessel already has either adouble bottom (DB) or double side (DS),will not be allowed into a US port afterJanuary 1, 1995. The equivalent maximumages for smaller vessels between 5,000 and30,000 gross tons are 40 to 45 years as ofJanuary 1995. Most barges are less than5,000 gross tons and can operate withsingle-hulls under OPA ’90 until 2015.Under the Canada Shipping Act CanadianCoast Guard has adopted the same stand-ards for barges as the United States.9

It is important to realize that althoughthere are close parallels between the USregulations and IMO standards, there arealso important differences in terms ofwhich designs are acceptable and in termsof when older vessels will have to be takenout of service, as follows:

• The retirement schedules called forunder MARPOL and OPA ’90 arevery simlar for tankers built prior to1982. For newer tankers creditedwith segregated ballast tanks,MARPOL tends to allow later retire-ments dates than OPA ’90. Inextreme example, MARPOL allowsa single-hulled tanker completed in1994 to operate as late as the year

2024, while OPA ’90 sets 2010 as thelast year of operation for any tankernot having either a double hull orside.Most foreign flag vessels will have

to adhere to whichever regulation isstricter at any given time in order tobe able to continue trading world-wide and to North America. Inpractice, the differences in retire-ment schedules between the UnitedStates and the MARPOL would onlybe important to British Columbia ifmany more foreign tankers started tocall at Vancouver, an unlikely situa-tion. Foreign flag tankers calling atPuget Sound will have to satisfy OPA’90 as being more stringent. With thepresent distribution of oil move-ments, most of the oil spill risk inlocal waters is linked directly to theUS flag tankers which do not tradeworldwide and only have to followthe OPA ’90 replacement schedule.

• The United States Coast Guard doesnot accept the mid-deck design as analternative to double hulls for newconstruction. The US Coast Guarddoes have the authority to consideralternatives to double hulls forvessels under 5,000 gross tons.

• The United States has not adoptedeither the retirement schedule or therecommended interim protectionmeasures for existing vessels devel-oped by the International MaritimeOrganization. Equivalent standardsfor acceptable interim protectionmeasures have not been established

in the United States.• The double-hull rules under OPA ’90

also apply to vessels carrying ani-mal or vegetable oils in bulk; incontrast the IMO defines oil ascrude oil and petroleum products.

• OPA ’90 applies ultimately to allvessels regardless of size;MARPOL, administered by theIMO, applies only to tankers andbarges larger than 5,000 Dwt(~ 2,500 gross tons). For smallervessels the IMO requirements callfor either double bottoms to befitted or individual cargo tanks tobe limited to 4,400 barrels or less,but no double hulls. The CanadianCoast Guard has elected to followOPA ’90 rules for all tankers andbarges less than 20,000 deadweighttonnes.9 Still, these rules will allowmost single-hulled barges to operateuntil 2015.

In their 1993 Standards for the DoubleHull Construction of Oil Tankers the Cana-dian Coast Guard follows a mix of interna-tional and US regulations:

• for new oil tankers and existingcrude oil tankers of 20,000 tonnesdeadweight (Dwt) or greater andexisting product (gasolines, bunker,diesel, distillates etc.) carriers of30,000 Dwt or greater: the IMOProtocol of 1978 as amended in 1992

as already discussed;• for existing crude tankers less than

20,000 Dwt and existing productcarriers less than 30,000 Dwt: OPA’90 with reference to the US CoastGuard Interim Final Rule issuedAugust 12, 1992 and adopted inMarch 10, 1995. 6

• for tanker barges less than 5,000gross tons (~10,000 Dwt): OPA ’90calling for double hulling by Janu-ary 1, 2015; and

• for tanker barges over 5,000 grosstons (applying to only to two bargesin Canada – none on the west coast):the time schedule for single-hulledtankers of applicable tonnage(meaning essentially as per OPA ’90,as no oil barges exceed the 20,000Dwt needed to place them in theMARPOL replacement schedule).

the double hull issue and oil spill risk on … · and oil spill risk on the pacific west coast...

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