SteerpropAZIMUTH PROPULSION

TECHNOLOGY INFO

STEERPROP

BASIC

FEATURES

Some of the basic features included in the design and

engineering of all Steerprop propulsors are presented in this

leaflet. Some of the shown elements are optional, but most

are belong to the basic characteristics.

Fabricated

Steel

Structure

High

Performance

Nozzle

Triple

Steeringtube

Seals

Electric

Steering

Motors

The Steerprop Propulsor housing is made

of fabricated steel. Utilising the properties

of the steel a precise strength control as

well as a constant quality is achieved.

It also allows for faster delivery times and

size flexibility. Fabricated steel is easy to

and , in case of an accident

to the unit.

maintain repair

Steerprop uses its own in-house designed

high-performance nozzle, the HJ3. The

nozzle is designed to provide an 8-10%

increase in bollard pull, but also an increase

in maximum efficiency of 10-15%

compared to standard type nozzles.

The propeller is situated in the diffusor part

of the nozzle, comparably far aft, enabling

the nozzle to be installed close to the

pivoting axis of the propulsor, thus,

minimizing steering torque.

The steering tube is sealed using triple lip

seals, installed with stainless steel liners to

minimize wear. The outermost seal is

turned downwards to minimize collection of

dirt that may wear out the seals. The triple

seal assembly enables the facility to flush

the seal chamber of propeller shaft seals

Steerprop propulsors are equipped with

motors - hydraulic motors are

available as an option.

The use of electric motors offer the

following advantages:

- constant steering speed

- less power required

- less power loss / better efficiency

- less heat generation -> less cooling

- less piping

- less noise

- less maintenance

a

modern frequency converter controlled

steering system, comprising direct electric

steering

Pressurised

Lubrication

System

The gears and bearings in the upper

gearbox are pressure lubricated, combined

with an ejector based oil level control,

keeping the oil level constant irrespective

of oil temeprature. This enables a better

control of the lubrication as well as

improves the efficency of the unit thanks to

smaller friction, resulting in less power loss

and heat generation.

FlushFluid

Shaft

Seals

The propeller shaft is sealed using either

triple or quadruple ring-type, seals. The

space between the seals is filled with a seal

fluid under pressure against sea water /

lubrication oil . The pressure is provided

with either a header tank or a pressurized

tank. The sealing fluid can be monitored

and flushed.

Keyless

Shrink-fit

Joints

All joints in the power train are either

conical or cylindrical shrink fit joints. There

are no keyways to deteriorate the integrity

of the shafts, nor keys that may wear and

break.

Speed

Control

Clutch

Compact

Propulsor

Size

Number

of Parts

Minimized

Few

Proprietary

Parts

Sequential

Strength

Principle

Steerprop propulsors are equipped with a

multi-disc clutch with slipping facility. As an

option this facility may be utilised by

electronic control and increased cooling to

provide a controlled propeller speed

between zero and prime mover idle speed.

The Steerprop propulsors have been

designed to be as compact as possible. This

enables azimuth propulsors also to be used

on vessel designs with low main decks, with

little space beneath.

The Steerprop R&D engineers have

succeeded to minimize the amount of parts

in the construction of Steerprop

propulsors. This simplified and more

reliable construction leads to easier

maintenance and less spare parts.

One of the corner stones in the Steerprop

basic design is to use commercially

available parts in the assembly to a

maximum extent. The number of

proprietary parts is kept as small as

possible. Using standard parts of well-

known manufacturers, reliability is

improved and spare parts are available

anywhere to facilitate maintenance and

possible repair.

Steerprop propulsors are engineered with

an in-built security in both the housing and

the power train. This comprises a

sequential strength principle, where the

weakest parts are either cheap or easily

replaced - important in case of an accident.

In the power transmission

protecting valuable and hard to access

components of the power train.

Within the overall strength of the housing

structures attention is also paid to safety:

the bolted flange in the steering tube above

the propeller is dimensioned to break in a

controlled manner in case of an

overwhelming impact, e.g. grounding

the weakest

component is a blade of the propeller, thus

200 300 400 500 600 700 800 900 1000

Percentage of nominal torque

PROPELLER

CLUTCH

SHRINK-FIT JOINTS

INTERNAL SHAFT COUPLINGS

GEAR WHEELS

SHAFTS

STEERPROP

CONTRA-ROTATING

PROPELLERS

The new dual-end CRP - developed by Steerprop - combines the well-recognized benefits of CRP with

those of a pulling propulsion unit.

There are basically two physical features behind the efficiency gain offered by a propulsion unit with

contra-rotating propellers:

A propulsion unit with a pulling propeller offers an undisturbed flow to the propeller. This means:

� First, and most well known, is the aft propeller recovering the swirl energy left behind by the forward propeller

Second is the splitting of the power not only between two propellers but also between two gear-sets. This

makes it possible to reduce the propeller RPM and have two large propellers with light load and low speed of

rotation. A combination that yields a very high propeller efficiency. Additionally, also the frictional losses are

reduced because of the low RPM.

Less noise and vibrations due to better cavitation behaviour and lower pressure pulses

Tip clearance can be reduced enabling a larger propeller to be used and thus higher efficiency

The presence of the pod behind the propeller offers an additional gain: The pod geometry may be designed to

create a pressure wave in front of it, which acts like an additional wake for the forward propeller. The increase

in propeller thrust due to this unique interaction between pod and pulling propeller practically cancels the pod

drag.

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Dual

End

CRP

Pulling propeller for high efficiency and

smooth wake

Optimal power split: 60% forward - 40% aft

Optimal aft propeller diameter 80% of

forward propeller diameter

Efficiency gain offered by CRP

Pulling propeller - pod interaction overcomes

pod drag

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Aft propeller clear of forward propeller tip

vortices

Larger tip clearance for aft propeller

Contra-rotating aft propeller - Swirl recovery

Large, slow propellers - Increased ideal

efficiency

Low RPM - Reduced frictional losses

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Features

Advantages Cavitation-free operation in free running

conditions

Low noise and vibrations due to clean inflow

to the pulling forward propeller

3-5% higher than pushing CRP

12-15% higher than tandem propellers

20-25% higher than single propeller

Higher efficiency than any other

propulsor

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STEERPROP

CONTROL

SYSTEM

Instead of designing and manufacturing a control system containing proprietary components and

software, Steerprop has chosen to use contemporary industrial automation system technology and

standard components and software.

This solution enables fast and flexible local procurement of spare parts as well as service and

maintenance by any local automation expert.

The flexibility in the system structure and application software makes it possible to tailor-make the

azimuth propulsor control system for

One great advantage is remote service assistance. The basic system provide the possibility to

connect a remote expert via a mobile phone directly to the control system. Of course it is also

possible to send software updates and records via email - or snailmail as memory units - from

experts to local service and vice versa.

The control system comprises a data log for a lot of different data in order to e.g. help building and

following a preventive maintenance programme. Amongst logged data is running hours, load

distribution, steering and clutch operation. All alarms and last alarms with time labels are also

continuously recorded.

The operator interface is the main source of information in both normal and abnormal situations.

Steerprop has thus put a lot of emphasis to make it as easy and informative as possible. The

different indications are simple and easy to enable the operator as well as service and maintenance

personnel to maintain the system.

- According to Vessel Type and Operation Profile

- According to Prime Mover Type

different kind of applications and operating profiles.

The Steerprop control system can easily be connected to different types of prime movers, e.g. direct

diesel drive with either wide or narrow rpm control area, electric drive or speed modulating clutch.

Advanced Service and Maintenance Technology

Advanced System Monitoring

Simple and Informative Operator Interface

Equipped with Several Levels of

Redundancy

Hydraulic Steering

Electric Steering

The Steerprop control system is provided with

back-up on several levels, ensuring that the

control of the vessel is never lost. In case of

failure in the main control system, an indicator

shows the failure and the back-up system is

manually switched on.

The control system for a vessel with direct

driven diesel engines the redundancy is

provided on up to five levels:

1. Wheelhouse main control

2. Wheelhouse back-up control

3. Close-by control

4. Direct hydraulic control

5. Handpump for maintenance steering

The control system for a vessel with diesel-

electric drive and an electric motor prime

mover the redundancy is provided on up to

four levels:

1. Wheelhouse main control

2. Wheelhouse back-up control

3. Close-by control

4. Direct electric control

5. Manual device

Taylored

System

Structure

Modern

Automation

System

Sequential

Strength

Principle

L

FC

SCU

Steerprop Azimuth Propulsor Prime Mover

R

B

Brake

ON

S

Steering Gear

F I

MM

Wheelhouse Instruments

S = Steering setting potentiometer

R = Prime mover rpm setting

B = Back-up selection (off)

L = Local / Remote selection

FC = Follow-up Control

InvertersD = Inverter

Built-on Instruments

M = Steering motor

F = Feedback potentiometer

I = Secondary feedback potentiometer

N = Input rpm

O = Propeller rpm

Steerpop Control Unit - SCU

D D

FACTORY

ACCEPTANCE

TEST

Running

Test

Full

Torque

Test

Control

System

Test

The prior-to-dispatch factory acceptance tests FAT - are done in the specific

Steerprop test facility that functions also as a laboratory for the R&D. Every

propulsion unit is subjected to test program before departing the factory.

The full torque test is comprehensive method

to reveal and eliminate the flaws and faults in

the structure, bearing assemblies and the

gearing. The prime factors to make the test

effective on Steerprop Azimuth Propulsors are

Precise roller bearings

Welded body structures having accurately

calculable deflection pattern under load

In the full torque test the power train is

submitted to torque against the brake

corresponding to that of full power. Every

teeth in the gear sets are tested.

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The propulsors are run at full speed whereupon times, pressures, temperatures, leaks, noise and

vibrations are observed and measured on the following functions:

Lubrication

Seals

Steering speed

The steering and clutch functions are adjusted and tested by connecting the control system to

propulsors.

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All the controls, main controls, back-up controls and local

controls are connected according to relevant cable diagrams

and tested together with the propulsors. During these tests

the software and hardware are

made. Reaction times, ramps, temperatures etc. are

measured and monitored.

The through tests ensures that the total control system and

all it's components is working faultlessly and that custom-

made cabling diagrams are correct.

tuning and adjustments of

The alarms are checked and

tested as are possible actuators, inverters and motors.

INSTALLATION

OPTIONS

POWER RANGE

3500

500

1000

1500

2000

2500

3000

4000

4500

5000

5500

6000

SP

10

SP

10

SP

14

SP

14

SP

18

SP

18

SP

20

SP

20

SP

25

SP

25

SP

30

SP

30

SP

50

SP

50

SP

35

SP

35

SP

60

SP

60

SP

40

SP

40

SP

70

SP

70

SP

45

SP

45

SP

80

SP

80

Ma

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Inp

ut

Po

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r[k

W]

Steerprop Type

SteerpropSteerprop

NOTE: The power shown in this graph is maximum continuous input power. However, the maximum input power recommended and

accepted by Steerprop Ltd. may be lower, depending on thruster type, application, classification (e.g. ice class), vessel operational profile etc.

Please contact Steerprop Ltd. or the nearest representative for actual project data.

The data given above is for information only. Steerprop reserves the right to make changes and alterations to all or any of above give data

without prior notice

Small mounting adapter Weld-in Large mounting adapter

The Steerprop propulsors are available with three basic installation modes: with small mounting adapter for easy bolt-in

installation in two parts or in one part from below; with a large mounting adapter for installation as one complete lift-in unit

and as a weld-in installation, where special care has bee taken to prevent possible heat distortions due to welding. Other -

custom made - installation modes are also available if required.

SteerpropSteerprop Ltd.P.O. Box 217

FIN-26101 RAUMA

Finland

e-mail: steerprop@steerprop.com

phone: +358 2 8387 7900

fax: +358 2 8387 7910

w w w . s t e e r p r o p . c o m

Steerprop Ltd. is a company dedicated to producingsuperior quality azimuth propulsors. The company isconcentrating on one single product line only, to beable to offer the customer the quality and lifetimeeconomy he expects and deserves.

No nonsense, hocus-pocus or extra packaging - justazimuth propulsors.For the maritime industry and for the offshore oil andgas industries.

Ste

erp

rop

Technolo

gy

Info

v.

1.0

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ovem

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2002

-©Ste

erp

rop

Ltd

.2002