mjp designers guide low uppd130618

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Designer’s Guide



Designer’s Guide

32

The Company, the guide and jet principles

Selecting jet size and engine powerExample perormance diagram

Gearbox

Intake, material and designIntake grid

Shat arrangement

Denition o jet position

Hydraulic and lubrication system

Control system

Steering optionsRules and classication

Shipyard installation requirementsExpert level

MJP Questionaire

Version 82013-06-18

NM

Designer’s Guide



Designer’s Guide

54

Introduction

• Superior waterjet pump performance, thrust and cavitation margin.

• Waterjet propulsion eciency is traditionally high at inter-mediate and superior at high ship speeds. By choosing a su-ciently large MJP Waterjet high eciency can be achievedalso at low ship speeds.

• In order to urther enhance the course-keeping ability andmaintain high thrust when operating in a seaway, headingcontrol rudders can be integrated and oered in t heMJP system

• Steering at high ships speeds can be made more ecient whenintegrated with interceptor system steering and MJP splitsteering unction.

• Protected Propulsion keeps the propulsion equipment una-ected even ater groundings and is actually cost-saving.

• The MJP design is made to withstand operation in ex-tremely dirty conditions in very shallow waters.

• Low Vibrations both in orward and reverse operation as wellas at high ship speeds greatly improve comort on board.

• Superior Manoeuvrability allows excellent harbour manoeuv-ring and shortens turn around times. At maximum ship speed,the crash stop can eectively be used to avoid collision andthereby improve saety and control.

• At constant consumed power the jet unit rpm is little aectedby ship speed and allows the engine to always operate inavourable conditions independent o loading o the vessel.This smooth engine load extends the service lie o the dieselengine and oers lower engine service costs compared totraditional propeller installations. The jet unit can be usedon vessels with extremely varying loads and ship speeds,rom light ship to ull load conditions without aectingor compromising the diesel engine.

• An interesting aspect o water jet propulsion is low waterbornenoise, which is important or military applications or wherethe environment is concerned.

Marn Jt Powr AB is a world leading supplier o jets.

Several products are marketed by the company. This designers

guide is or the CSU and DRB series suitable or vessels rom

15 meters in length and powers rom 500 kW per shat.

Marine Jet Power CSU and DRB generates more thrust rom

installed power leading to higher ship speed and better

acceleration as well as lower uel consumption.

The product is very strong, made o duplex stainless steel and

can be used in shallow and dirty waters without compromis-

ing the product or vessel. The steering and reversing units

oer very good manoeuvring at high and low ship speeds.

Supported by a number o patents, design and engineer-

ing solutions a unique product has been created targeting

low operational costs and easy maintenance and service.

Among the many MJP customers around the world are Coast

Guards, Yacht Builders and Commercial Operators.

The scope o supply includes one or several water jets and

control system. Depending on hull design and material the

intakes are made locally by shipyard or by MJP. Combining

the MJP duplex stainless steel product with FRP intakes

provides a very strong, ecient, corrosionree product

with a minimum o maintenance requirements. The control

system comprises o hydraulics and mechanical or electronic

controls and can include options or easier manoeuvring,

additional steering stations, integration o rudders and/or

interceptors (trim tabs) etc.

The Purpose o the MJP CSU and DRB Designer’s Guide

The aim o the MJP Designer’s Guide is to support operators, shipyards,consultants, project engineers and sales personnel:

• to bttr unrstan th prncps o a jt prop vss

•

to hp n th pannng o th aout o th vss• to sgn to th prormancs st up or th vss

• to prov guns or th scton o approprat jt unt

• to succssu ntgrat th propuson sstm nto th vss

• to crat awarnss o th varous possbts an optons n th MJP sstm

Why Marine Jet Power?

The design and application concept o MJP is based on a global approach to the reduc-tion o operating costs. The main advantages o MJP are:



Designer’s Guide

76

Selecting jet size and engine power

P4

P3

P2

P1

P*

P4

P3

P2

P1

P*

300

400

500

600

700

800

900

1000

1100

1200

1300

0

50

100

150

200

250

300

350

4

0 10 20 30 40 50 60

S h a f t S p e e d , r p m

Vessel's Speed, knV*

RPM*

T*

Shaft Speed

Net Thrust

Power Levels

Power Levels

P5

P5

The perormance diagram calculated or a water jet

propulsion system establishes a relation between water

jet thrust, impeller shat rpm (or engine output shat

rpm when the gearbox is selected and the gear ratio

is xed), engine power and vessel speed. The diagram

presents two sets o curves: thrust curves in the lower

section and shat rpm curves in the upper. The curves

are plotted or a number o dierent engine power

values P1…P5 (P5 is the maximum value) in unction

o the vessel speed.

Superimposing a hull resistance curve onto the thrust

curves will allow, using the intersection points o this

system o curves, a variation o shat rpm with vessel speed

(‘shat rpm curve’) that corresponds to given resistance.

Let us consider an example o t he use o this diagram.

Let the vessel speed be V*. When in steady motion,

the value o the waterjet thrust, T*, is equal to that

o the resistance corresponding to the speed V* on the

perormance diagram. The impeller shat revolutions,

RPM*, are obtained rom the shat rpm curve or the

same speed V*. The power, P*, engine to the waterjet is

obtained by interpolating the values between the neigh-

bouring curves (either thrust curves or shat rpm curves

can be used).

The maximum attainable speed is determined by the

intersection point between the hull resistance curve and

the thrust curve corresponding to the maximum power

level P5.

Example perormance diagram

Normally the resistance data is provided by the customers’

ship designer. The best accuracy is achieved i the data

is based on experienced values or bare hull resistance

model tests.

It is noted that a larger jet will provide better cavitation

margin and can be a better choice at lower ship speeds.

In principle a larger jet will give b etter eciency and

acceleration. However or a very ast vessel a smaller jet

with less weight is more advantageous.

Dierent characteristics can be achieved by var ying

the jet nozzle diameter. One nozzle gives less thrust but

a better cavitation margin, etc. Thereore please always

involve MJP in your perormance predictions and power

estimates.

Specic Perormance Diagram with engine power,

jet size, resistance dat a, selected nozzle diameter and

gearbox ratio is made or each delivery. For enquiries a

questionnaire is enclosed in the end o this guide.

The jet range is presented in CSU and DRB product

data sheets enclosed at the end o this Guide.

The correct jet size is based on:

•Vessel’s design speed

•Vessel characteristics such as hull type,resistance data and curve shape.

• Jet pump cavitation margin.

•Engine power.

•Special requirements such as operation on singleor reduced number o jets

•The MJP Perormance Diagramcalculates 3% transmission losses as standard.

Resistance curve

Shaft Speed at Resistance curve

Cavitation limit



Designer’s Guide

98

Gearbox

Functon

The unction o the gearbox is to match the optimum

jet speed (rpm) to the engine speed (rpm) and power,

please reer to the engine manuacturer’s power/rpm

diagram or data. The gearbox is also a clutch that enables

disengaging o the jet.

Rato

The MJP pump absorbs certain power at certain speed

(rpm). The engine speed (rpm) is equal to the jet

speed (rpm) times the gearbox ratio (i). The gear-

box ratio (i) must be selected to match the jet power

absorption to the engine power, see enclosed example

graph. The ratio, i, is normally selected or 100% MCR

(Maximum Continuous Rating) as ollows: lowest

allowed engine speed (rpm) corresponding to 100%

MCR / jet shat speed <= i <= highest allowed engine

speed corresponding to 100% MCR / jet shat speed.

Transmsson osss

The MJP perormance diagram estimates 3% transmis-

sion losses as experienced well proven standard value.

The gearbox losses are normally 2 – 3% depending on

type and size o gear.

Backfush

Optionally the reduction gearbox can be equipped with

a reverse so called backfush gearbox. A gearbox runningin reverse can clear debris stuck in the jet and intake.

Typically losses in a backfushing gearbox are ~ 0.5%

higher than in a non-reversing gear.

As an alternative to backfush, the vessel canreverse with one jet in back up mode to clearthe other jet.

Gearbox ratio shall be selected to reach ideal designpoints. Too low or too high gearbox ratio will lead toengine overload or overspeed.

120

100

80

60

40

20

030 50 70 90 110100%

B r e a k P o w e r P

B

i n ( % ) R a t e d P o w e r

Speed in (%) Rated Speed

MCR Curve

Idealdesignpoints

Engineoverload

Engine

overspeed

Jet RPM Curves

upperlimit

lowerlimit



Designer’s Guide

1110

Intake material and design

Optionally complete GRP or FRP intakes can be selected. The major advantage is reedom o design and

shape, giving perormance as well as corrosion resistance-reducing maintenance. The options are:

Hu matra Opton 1 Opton 2 Opton 3

Metal GRP intake complete romMJP bolted to structure.

MJP provide intake patternor yard-produced intake inFRP bolted to structure.

Yard-produced pattern andintake in FRP bolted tostructure.

Composite GRP intake completerom MJP laminated tostructure.

MJP provide intake patternor yard-produced intakein FRP integral with hullstructure

Yard-produced pattern andintake in FRP integral withhull structure.

Not 1: The complete intake and surrounding structure is subject to scantling and approval ensured by yard.

Not 2: The surrounding intake structure must be made uninterrupted load carrying and integral with the

ship’s structure.

Intake grid

MJP do not generally recommend intake grids or DRB and

CSU series. However each vessel operates in dierent condi-

tions and grids may be required due to extreme conditions

such as in shallow waters, beaches or rivers. It is noted that

smaller jets are more liable to be aected by debris. The MJP

CSU and DRB jet unit is designed in duplex stainless steel

and stands even extreme operating conditions in, or example,

sandy and muddy waters. For vessels equipped with optional

grids, MJP will make a specic intake grid drawing.

The jet intake shape is an integral part o the jet pump

design and a very important actor or the total peror-

mance and successul jet installation. MJP support the use

o GRP/FRP in the intake structures since it reduces the

maintenance requirements o intake and corrosion load

on metallic hulls.

The DRB jet range is equipped with a GRP intake as

standard supplied by MJP and bolted or laminated to

the hull structure. As an option, special intakes can beprovided as agreed with yard designer’s and to a shape

designed by MJP experts. The yard may well produce

the intake. Especially in FRP hulls, local yard-supplied

integrated intake is strongly recommended since supe-

rior shape and structural strength can be achieved in a

seamless installation.

The CSU jet range is made to meet ree jet positioning.

The designer’s can optimize the design and perormance o

the vessel. The intake shape is designed by MJP to ensure

jet pump perormance. As a standard the at section o in-

take is a MJP supplied GRP bend and the orward part

o intake is made by t he yard. As an option complete

intakes can be provided by MJP. The purpose o the stand-

ard GRP bend is to insulate the jet unit rom the intake

structure, thus reducing the corrosion load. Hence the

GRP bend cannot be replaced by, or example, steel or

aluminum. The material and scantlings o the orward

part o the intake shall correspond to the surrounding

structures and lines to a shape designed by MJP experts.

Scantlings are subject to global structural loads. Henceclassication approval o intake scantlings are sought

and secured by yard.

The area surrounding and orward o the intake must

be made fush without any items protruding that can

cause turbulence and disturbed fow into the jet intake

thus aecting the perormance. It is recommended that

anodes be positioned on the stern as well as recessed

and to the side o the intake. It is also preerred that the

engine cooling intakes are positioned at side, at, or well

orward o the intakes. MJP experts can provide specic

recommendations or each individual case.



Designer’s Guide

1312

Shat arrangement

First o all it is to be noted that al the thrust is taken in the

MJP CSU and DRB jet unit. Hence no thrust block is required

inside the hull or gearbox. Another great advantage o

the MJP system is the “foating” drive shat. It allows as

standard the MJP Waterjet drive shat to run all the way up

to the gearbox fange without the need o additional sup-

port bearings, couplings or intermediate shats. The limiting

actors are the unsupported MJP drive shat length and the

distance rom the stern to the gearbox fange. The unsupported

MJP drive shat length can be maximum 25 times its diameter.

The distance rom outside stern to gearbox fange, including

jet shat, coupling and spacer, can be up to 30 times the shat

diameter. The nal shat arrangement is subject MJP and o

course classication approvals.

Larger jets upon request.

•Transom•Impeller housing•Intake•MJP Drive Shat•MJP Drive Shat Seal

•Coupling and spacer with fange to gearbox fange

•Transom•Impeller housing•Intake•MJP Drive Shat•MJP Drive Shat Seal•Support bearing (split type)•Coupling•Intermediate shat•Coupling and spacer adapted to gearbox fange

•Transom•Impeller housing•Intake•MJP Drive Shat•MJP Drive Shat Seal•Combined Support bearing and bulkhead seal•Composite intermediate shat arrangement with coupling and spacer adapted to gearbox fange.

Alternative intermediate shat arrangement with composite shat

Standard intermediate shat arrangement

Standard shat arrangement with drive shat up to gearbox ange

A standard delivery consists o:

• Jet drive shat (foating)

• Shat seal (foating)

• Coupling and spacer adapted to the gearbox fange.

I the distance rom outside stern to the gearbox fange

exceeds 30 times the jet drive shat diameter an optional

intermediate shat is needed.

The ollowing items are added to the above arrangement:

• Support bearing on the jet drive shat

• Additional coupling or intermediate drive shat

As an option, hollow bore shats are available that improve

weight and strength o the jet and intermediate steel drive

shats.

Alternative and individual arrangements including composite

solutions are oered separately. For each project or design

MJP makes an individual shat arrangement drawing.

MJP need the gearbox fange drawing or designing the spacer.

Mo Jt shat Ø 25 tms 30 tms jt shat Ø jt shat Ø

MJP 350 Ø 65 1625 1950

MJP 400 Ø 75 1875 2250

MJP 450 Ø 85 2125 2550

MJP 500 Ø 95 2375 2850

MJP 550 Ø 105 2625 3150

MJP 650 Ø 120 3000 3600

MJP 750 Ø 130 3250 3900

MJP 850 Ø 160 4000 4800MP 950 Ø 180 4500 5400



Designer’s Guide

14 15

Defnition o jet position

In MJP CSU and DRB series the position o the jet shat

is relatively ree, but it is strongly recommended to keep

the height o the water jet intake as small as possible toreduce power lost in liting water and to reduce the weight

o water in the duct, which is included in the overall

weight and aects the vessel perormance. In addition,

careul consideration must be taken in priming the jet

pump, the reversing jet stream and service access.

PrmngIt is important to select a jet drive shat position to ensure

priming o the jet pump when the clutch is engaged.

When the jet shat is high in the water the priming rpm

is also higher as shown in enclosed graph. The general

recommendation is to position the jet unit drive shat

in the waterline at light ship orward trim condition.

Rvrsng jt stramTo ensure reversing perormance the jet stream must

not touch the hull. The general recommendation is t oposition the centre o the shat no higher than 0.9 times

the intake diameter above hull measured at centre o

jet. For exact measurement please reer to drawing o

each jet size and/or consult MJP.

0

100

200

300

400

500

600

700

800

- 400 - 300 -200 -1 00 0 1 00 2 00

Reference Priming Shaft Speed

J450

J450

J550

J550

J650

J650

J750

J750

J850

J850

J950

J950

J1100

J1100

Above Water LineBelow Water Line

J1350

J1350

J500

J500

J1550

J1550

Shaft Submergence, mm

: Ex: Intake Dia.750 x 0.9 = 675



Designer’s Guide

1716

Hydraulic and lubrication system

Each jet unit has its own hydraulic and lubrication cir-

cuits. The purpose o the hydraulic circuit is to oer

steering and reversing control o the jet unit. The pur-

pose o the lubrication circulation tank unit is to oer

head and to monitor the level and quality o the hub

unit oil. According to classication rules, tank units

must not be combined on vessels with two jets to avoid

comprimising redundancy.

The hydraulic system is designed and delivered indi-

vidually to each project. Tank units can be customised

to customer requirements or example, trim faps or

interceptors as well as rudders can be ully integrated

in both hydraulic and electric controls. Tank units

can be made separated or compact in combined tanks

and in stainless steel material to suit, or example,

yacht applications.

In MJP CSU and DRB series the hydraulic and hub unit

tank circuits. The main reason is easy operation and

service. The hydraulic system is driven by a load-sensing

pump tted on a gearbox or engine PTO. The hub unit

lubrication oil is circulated by a gear pump. As standard

the MJP hydraulic system is made all mechanical, no

other power on board than 24V DC is needed to operate

the complete MJP system. Electrical back up pumps can

be provided as an option.

The hydraulic tank unit should be positioned

above and close to the PTO pump in order to

minimize the wear o the PTO pump and

diameter o the suction pipe diameter.

The lubrication tank unit should be posi-

tioned above the jet unit to oer head to

the hub unit and allow operation even i

the circulation pump is down.

The all mechanical system with PTO hydraulic pump and piggy backtted lubrication circulation pump

Mechanical hydraulic system with PTO pump and electrical drivenlubrication circulation unit

Mechanical system with PTO hydraulic pump and electrical back up pumpand piggy back tted mechanical lubrication circulation pump

Hydraulic PTO drive LubOil Electric drive

Hydraulic PTO drive

LubOil Piggyback drive

with electric standby

LubOil Piggyback drive

Hydraulic PTO drive

Example o combined lubrication and hydraulic tank unit.



Designer’s Guide

1918

Control system

The MJP Electronic Control System oers complete control o the

jet position and engine rpm control, thereby controlling all vessel

motions in steering, reversing, side movements, rotation or crash

stop, that is all the manoeuvring that makes a jet boat so ecient

compared to propeller-driven vessels. As each customer or group

o applications have dierent preerences, we have developed

three main alternatives that cover a wide range o applications and

requirements.

ACSAzmuth contro sstm

Two Azimuth levers and one second steer tiller. EachAzimuth lever controls its dedicated jet. The system can

operate in Separate or Common mode, with Autopilot or

with the second steer tiller conveniently positioned in

the armrest. This system requires more o the captain

to eciently operate the vessel.

CSW Combnator an strng whCSW includes combinator with two levers, steering wheel

and a VCS joystick. The combinator levers controls the

jet buckets and engine rpm, the steering wheel controls

steering just like on a traditional boat.

Especially on ast vessels it is appreciated to steer with

a steering wheel and control the rpm with the combinator

levers. The VCS joystick oers ull and computerised

control o the vessel in a harbour or at slow speed

operation. Clutch control is most oten included as

well as Autopilot.

VCS Vctor Contro Sstm

This system oers operation with a joystick and steeringtiller (or wheel). The computer translates the steering

commands, optimises the jet positioning and rpm to make

the boat move as requested by the captain or convenient

and easy control. The VCS system helps the Captain

quickly become an expert in controlling the vessel.

The system accepts Autopilot steering signal.

All SySTeMS HAVe THe NeCeSSARy COMMANd,

AlARM ANd iNdiCATiON PANelS.

For all types o control systems the ollowing

options can be considered:

•Clutch Control Panel with or without“backfush” (reversing gearbox).

•Additional steering stations, indoors or outdoors

•Interceptor or trim tab control panels

•Integration o external trim tab system

•

Rudder control panel and indicator•Split steering

•Bow thruster integration

•Interace to shipboard ship alarm system

•Interace to so called “Black Box”

Voyage Data Recorder, VDR

The control system is set via a terminal or with

a standard lap top connected to the system.



Designer’s Guide

2120

Rules and classifcation

The MJP are designed to international standards.

Each delivery is individually approved by the Classication Society.

To match the approval to the actual vessel, the yard application

identication number should be given to MJP. Where no Classication

Approval is required, jet systems are delivered with Inspection Cer-

ticate type 3.1 per EN10204. Please however note that a classication

approval or a jet cannot be obtained ater delivery (post actum).

The intake structure approval is sought by the shipyard. The hydraulic

system is approved ater installation on board.

Lackoffulfilmentof conditions assetout intheCertificationAgreementmayrenderthisCertificateinvalid.

DET NORSKEVERITAS,BOX 6046,17106SOLNA,SWEDEN.T EL:+46858794000FAX:+4686517043

DET NORSKE VERITAS

MANAGEMENT SYSTEM CERTIFICATECertificate No. 2006-SKM-AQ-2395

This is to certify that

Marine Jet Power ABat

ÖSTERBYBRUK, SWEDEN

has been found to conform to the Management System Standard:

ISO 9001:2008

This Certificate is valid for:

Design, manufacture, repair and service of water jet propulsion systems

InitialCertification date:

1995-07-06

Placeanddate:

Stockholm, 2010-12-03

ThisCertificateis validuntil:

2014-03-31

for theAccredite dUnit:

DNVCERTIFICATIONAB,SWEDEN

Theaudithasbeenperformed underthesupervisionof:

Wilhelm Sabelström Ann-Louise Pått LeadAuditor ManagementRepresen tative

Steering options

The ollowing items can be deliveredwith classication certicates:

a Jet unit(s) with Hydraulic Actuatorsb Drive shat(s)c Coupling(s)d PTO pump(s)e Control System.

It is important to note that the high-speed heading control rudders in this example do not increase the vessel draught.

The steering perormance o a water-jet-driven vessel can

be improved by split steering and interceptors (trim faps).

A signicant innovation oered by MJP is the use o

balanced-type rudders o comparatively small area

intended to control the vessel’s heading ater reaching

a certain speed. These rudders improve the vessel’s

maneuverability and course keeping at high-speed

operation, especially in heavy ollowing seas without

compromising the thrust capability.

Spt strngWhen a vessel is making course-keeping steering cor-

rections, ship speed is only higher i the inner jet is

steering. The outer jet is kept standing still. The result

is higher ship speed during steering. I a ull steering

command is made both jets will automatically steer nor-mally. The Split steering unction is a standard eature

in the MJP Electronic Controls System. The parameters

are set individually on each vessel during start up.

intrcptorsDierent loading conditions o a vessel can be compensated

by an interceptor or trim fap systems. An interceptor/

fap system can also be used to enhance steering i it is

integrated with the MJP Control System. Parameters or

the automatic steering commands are set in the MJP

sotware at sea trials. MJP can also integrate hydrauli-

cally yard or externally supplied systems.

The MJP electronic control system is set to t the inter-

ceptor/fap system and the helmsman will automatically

appreciate enhanced steering command and higher ship

speed. MJP can supply interceptor systems as an option,

or more details please contact MJP.

RursRudders improve steering as well as course s tability.

In the MJP system, rudders can b e ully integrated in

the MJP hydraulic and electronic controls.

The electronic control system is set individually or

every vessel to the best perormance. The captain is using

his normal controls and will experience improved steering

perormance and course keeping.

The design o the rudders is customised to each appli-

cation, designed ship speed, drat requirements etc. Forinstance, in a high speed application the rudder area can

be made small and in slow speed application the area can

be made larger.

This permits to completely renounce using the waterjet

steering nozzles as means o heading control during

high-speed operation, which substantially increases

operating eciency o the waterjet units since steering

nozzles remain in the neutral position and no thrust is

lost due to their defection. At ull s teering commands

both rudders and steering nozzles are used to provide the

superior maneuvering typical or a MJP equipped vessel.



Designer’s Guide

2322

Shipyard installation requirements

The impeller housing is tted on the stern so that its centreline is aligned

with that o the gearbox output shat. The alignment can be made either

by machining the stern ace or by the use o Chockast resin. Method o

installation must be selected when making drive shat arrangement drawing

dening drive shat length. The installation alignment requirement o the jet

pump and drive shat is +/- 0.05 degrees. During operation the MJP jet shat

is allowed to foat up to +/- 0.25 degrees without aecting the installation.

The impeller play is set rom actory and is not changed during operation

ollowing or instance hull fexibility and or resiliently mounted gearbox.

For each and individual project a detailed installation instructions procedure

is provided.

Expert level

The water jet thrust is generated by the reaction orce o the discharged jet

o water. The thrust value can be determined rom the momentum equation

using the parameters o water entering the water intake and that discharged

through the water jet nozzle.

The water jet thrust thus increases with volume fow rate Q and water jet

discharge velocity Vj.

When a ship moves through the water, a fow retardation zone due to viscosity

orces arises on its bottom. This zone is called the boundary layer. Because

o that zone, the average fow velocity in the water intake is less than the

ship’s speed. When determining the water jet thrust, this circumstance is

accounted or by introducing the wake actor w into the equation.

The fow is accelerated by the water jet pump using the mechanical powersupplied by the propulsion engine. Besides this, the mechanical power

supplied by the engine has to overcome unavoidable hydraulic losses in the

water jet, inlet duct and to lit the fow through the duct.

As a precaution MJP calculates the so called thrust deduction actor t as zero.

The eect o thrust deduction (or negative thrust deduction actor) is hull-

related and cannot generally b e accounted or.

Average intake velosity Vi

Vessel's speed Vs

Pump Jet Intake duct

Nozzle Guide Impeller

Duct bendPump s ta to r Rotor

Shaft

Ship hull

Jet velosity Vj

Height above water line

vanes

Streamline

.

.

.

.

T =ρQ V j - ρQ Vi = ρ Q (V j - Vi) =ρ Q (V j – (1-w) Vs)

Q - volume fow rateρ - mass density o water

T - waterjet thrustw - wake actor



Designer’s Guide

2524

Propulsion Application Checklist or MJP CSU and DRB

Inquiry date:

Customr Company

Contact

Address

Telephone Email

input dataHull resistance attached Yes No

Lines Drawing attached Yes No

Classication required Yes No

G. A. Drawing attached Yes No

Shat position details attached Yes No

Architect/Designer

Page 1 of 2

Jets with CSU, Compact Steering Units, are avail-

able in sizes rom the MJP 450 up to the 1550.

Our foating drive shat acilitates installation

and is one reason behind the excellent pump

perormance that oers lower uel consumption,

a longer range and higher top speeds. From

the MJP 550 and up, the hub unit is accessible

rom the at, greatly improving the ease o

service o the large jets. Our duplex stainless

steel design oers superior resistance to wear

and corrosion.

Your choice o Waterjets

* Maximum power or continous operation.** Weight per unit [kg] including hydraulics, excluding shating and intake.

*** Approximate volume [litres] depending on adaptation to hull lines.

The DRB, Double Reverse Bucket jet series is avail-

able in our sizes, rom the M JP 350 to t he MJP

500 and powers up to 2000 kW per shat. This

creates a very attractive and unique product that

combines our amous high perormance MJP pump

technology with the heavy-duty, all stainless steeldesign and maintenance-ree composite intake.

.

***rtil

tnI

.,

****rtlrt

.

.

***rtil

tnI

.,

****rtlrt

.

Customr xpct prormanc

M ax sp eed at light ship dis placem ent [kno ts] Max speed at laden disp lacement [knots ]

C ru is ing spe ed a t l ight sh ip d ispl ac ement [ knots] C ru is ing spe ed a t l aden di sp la ce me nt [knots ]

engn an gar spccaton ( avaab)

Engine make and model (ull designation)

Rated power

Gearbox make and model (ull designation), gear ratio (i available)

Number o steerable jets One Two Three Four

Number o booster jets One Two Three Four

______________________ kW at ______________________ rpm

Number o jet in

Trailing modeShat locked mode

Intake grid No (standard) Yes (optional)

input or MJP Prormanc dagram (Pd)(*) mandatory inormation

(*) Number o engines/jets (*) Engine power [kW]

(*) Target ship speed [knots] (*) Vessel length [m]

Engine speed [rpm] Wetted length at target speed [m]

Reduction gear ratio Waterjet size

Vessel resistance data

Not available (will not be shown in diagram)

As per attachment File name: ______________________

As per table example below (please complete table with several displacements, conditions, ship speeds and resistance data)

Resistance curve 1 Resistance curve 2

Identication label Identication label

Vessel speed [knots] Resistance [kN] Vessel speed [knots] Resistance [kN]

A E B

D

F

G

C

SIZE kW A B C D* E* F* G* Steerable Booster Intake (Kg) (Kg) V Litres*

350 1000 800 800 480 315 1690 2200 720 310 170 140

400 1250 1110 800 440 360 1950 2500 820 590 300 250

450 1500 1020 1000 600 405 2210 2800 920 740 350 300

500 2000 1130 1100 550 450 2470 3100 1020 850 460 350

550 2500 1550 1100 600 495 2730 3400 1120 1200 650 400

*Dimensions may vary in each project

SIZE kW A B C D E F G HSteerable Booster Intake

(Kg) (Kg) V Litres

450 1500 428 1247 708 450 1850 3100 570 470 540 350 300

550 2500 560 1412 866 550 2250 3790 630 505 1100 650 400

650 3000 665 1680 1020 650 2675 4510 750 600 1600 1050 750

750 4000 765 1900 1133 750 3075 5180 860 690 2300 1450 1200

850 6000 880 2100 1370 870 3540 5890 990 765 3700 2200 1900

950 8000 1010 2460 1480 970 4070 6590 1100 915 4350 2800 2700

1100 10000 1370 3200 1890 1180 4820 7630 1350 1090 7000 5400 4700

1350 12000 1540 3650 2300 1360 5560 8000 1650 1250 12000 8300 7000

1550 15000 1825 4080 2460 1550 6800 9700 1970 1460 17700 9700 8300



Designer’s Guide

2726

Prrr strng unt (tck approprat box) CSU, Compact Steering Unit

(available in models 450, 550, 650, 750, 850, 950, 1100, 1350 ,1550)

DRB, Double Reverse Bucket(available in models 350, 400, 450 and 500)

intak (tck approprat box) GRP bend + drawing or intake made by yard in the same

material as hull (Standard CSU)

Complete intake rom MJP made o GRP (Standard DRD)

Drawing or yard (local) manuacturing o intake in FRP (Option)

Pattern or yard (local) manuacturing o intake in FRP (Option)

Shat arrangmnt (tck approprat box) Distance rom transom to gear fange < 30 x jet shat

diameter = MJP standard drive shat arrangement.

Distance rom transom to gear fange > 30 x shat diameter,intermediate shat arrangement is required: (Optional)

By yard, please speciy preerred shat interace

Steel by MJP

Composite by MJP

Shat arrangement drawing is included and the ollowing itemsare requested in MJP supply e.g. (Optional)

shat split support bearing

bulkhead seal

combined support bearing and bulkhead seal

Hrauc an o crcuaton sstm (tck approprat box) Separate tanks

Main PTO driven hydraulic pump with piggy back mounted lubeoil circulation pump. (Standard)

Main PTO driven hydraulic pump with electric driven lube oilcirculation pump, start and control box. (Option)

Main PTO driven hydraulic pump with electric driven backup and piggy back mounted lube oil circulation pump,start and control box.(Option)

Combined tank

Main PTO driven hydraulic pump with piggy back mounted lubeoil circulation pump. (Option)

Main PTO driven hydraulic pump with electric driven lube oilcirculation and back up pump, start and control box. (Option)

Contro sstm (tck approprat box) CSW, combinator and steering wheel with VCS Joystick. Basic system

with single CU, cabled in wheel house, acombined alarm and commandpanel with clutch, terminal, dial type indicator, back up panel pushbutton control, autopilot interace, split steering. (Standard)

VCS, Vector Control System with one VCS joystick and a steeringtiller. Basic system with double CU, cabled in wheelhouse, terminal,led bar indicator, back up with joy stick, autopilot interace,split steering. (Option)

ACS, Azimuth control system with two Azimuths and a second steertiller. Basic system with double CU, cabled in wheelhouse, terminal,led type indicator, back up with joy stick, autopilot interace,split steering. (Option)

Contro sstm optons Cabled rom wheelhouse to engine room

Clutch panel (Note: standard or CSW) (tick appropriate box):

without backfush (Standard)

with backfush

Interceptor / Trim tab to provide steering assistance and trim androll control (tick appropriate box):

Hydraulic and electric integration o yard supplied arrangement,giving steering assistance, trim and roll control.

MJP supply o electric inteceptor system integrated with MJPcontrol system giving steering assistance.

Integration o external system, please speciy:

Rudder (tick appropriate box)

Hydraulic and electric integration o yard supplied rudder

Design assistance or yard manuactured rudder arrangement

Active rudder control (supplied by MJP, incl. rudder assembly)

Steering indicator engine room

Steering wheel replacing second steering tiller (ACS) orsteering tiller (VCS) (tick appropriate box)

Bridge wing station (tick appropriate box)

Wing stations with controls, transer and command panel

(tick appropriate box):

Indoors, 2 ixed wing stations

Outdoors, 2 ixed wing stations

Fly bridge, 1 ixed ly bridge station

Portable, 1 portable station

Optional xed bridge wing station equipment (tick appropriate box)

Clutch

Indicator

Additional stations please speciy:

Casscaton: Works certicate

Classication certicate

Society:

Classication notation:

Page 2 of 2

Input data or MJP CSU and DRB quote



Marn Jt Powr lmt Uppereld Rd, Cheltenham, Glos, GL51 9NY, EnglandTel: +44 (0)1242 707 900

E-mail: [email protected]

Marn Jt Powr inc. 1110A Claycrat Rd Columbus, Ohio 43230, U.S.A.Tel: +1 (614) 759 90 00


Marn Jt Powr ABSE 748 01 Österbybruk, SwedenTel: +46 (0)295 244 250


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