Voith Water Tractor

Voith Turbo

Facts and Figures As of 2006-09-30

Sales 3,739 million

Net income 246 million

Number of locations over 250 worldwide

Number of employees over 34,000 worldwide

Our History

The history of Voith begins in a small craftsmans workshop

in 1867. Today, we are one of the largest family-owned

companies in Europe. Our independence as a family-owned

company allows us to pursue our strategies and goals far

into the future.

Voith Our Company.

Voith is the reliable partner for essential industries. We set stand ards around the world in our markets for paper, energy, mobility and service.

Paper

We Are Shaping the Future

People at Voith have written and re-written technical history

with their ideas and developments. Today, our products set

standards around the world. Our engineers will continue to

shape the future actively in our markets, for the benefi t of

our customers and the long-term success of our company.

1995Fish-friendly turbine

1978Itaipu (largest hydroelectric power station)

1952Voith Water Tractor, Voith automatic trans-mission (DIWA)

1960Flow brake,fl otation deinkingprocess

1932 Voith turbo transmission

1927Voith SchneiderPropeller

18811st Voith paper machine

1903Niagara (at that time the worlds largest turbines)

18691st Voith patent (refi ner)

18691st VoithFrancis turbine

Customers

Everything we do is centered around the needs of our

cu s tomers. Our global presence and proximity to our

customers allow us to create a working relationship

based on con fi dence and trust. We want to draw on our

engineering skills, our innovative strength and our solidity

in order to be a reliable partner for generations to come.

Markets

Our equipment, components and services allow us to

make a major contribution towards our customers

success. The global demand for paper, energy, mobility

and services will continue to grow in the coming years.

We will be there to watch these markets of the future

develop, and to play our part in shaping them.

A world without paper? Unthinkable.

More than every third sheet of paper

in the world is produced on a Voith

paper machine. Voith Paper offers

its customers the entire paper-mak-

ing process from one single source.

Energy Mobility Service

2004Curtain Coater

2003Voith Cycloidal Rudder

2002Aquatarder

2001One Platform Concept

2005SeaLencer

Drive and braking systems from

Voith ensure that people and goods

reach their destinations quickly and

safely. In a wide range of indus-

tries, Voith components operate in

all places where energy has to be

converted into controlled motion.

The future belongs to integrated

service concepts and packages.

Voith is one of the largest sup-

pliers of technical services: from

maintenance, technical cleaning,

engineering through to industrial

assembly, process and facility

management.

More than a third of the electric-

ity generated with hydropower

is produced with turbines and

generators made by Voith

Siemens Hydro. Voith compo-

nents ensure energy supplies in

power stations all over the world.

We see ourselves as being

fair, reliable and innovative:

Voith Engineered reliability.2006PTC - PaperTechnologyCenter

Voith Water Tractor (VWT) Best Available Technology

Voith Water Tractor means:

Logical correlation of the main systems

propellers with all-round protection, towing

gear, skeg and integrated control station

for all duties in the wide field of ship handling.

This concept has revolutionised

shiphandling worldwide. More than

800 Voith Water Tractors in more

than 120 ports are the hallmark of

safety today. Reliability, speed and

precision in towing and escorting

service, salvaging, fire-fighting, oil

pollution control and offshore sup-

ply have led to the classification:

Best Available Technology

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Design Criteria

Ship handling is an important link between overland and

waterborne transportation to ensure fast, smooth traffic flows.

The task of the ship handling vessel

is to bring the tow to its destination:

Rapidly and by the shortest route.

With minimum power require-

ments but with optimal utilization

of the installed power.

While ensuring maximum safety

for the tow, the tug, the crew and

the port facilities.

For the successful performance of

this task the ship handling vessel

must satisfy the following require-

ments:

Fast and safe take-over of lines,

even at high speeds outside

protected harbour waters, in

adverse wind conditions, swell

and currents.

Immediate function after taking

over the lines, with active braking

and steering to ensure a smooth

transition from free movement of

the incoming vessel to the towing

operation.

Substitution of the tows own

controls in the event of rudder

and/or engine failure.

Continuous transmission of

forces with no long delays

while the tug changes position

in relation to the tow.

Maximum manoeuvrability, to

facilitate operation in restricted

spaces with very quick and pre-

cise changes in position.

These fundamental criteria

are best satisfied by the Voith

Water Tractor.

The VWT is driven and controlled

by the Voith Schneider Propeller

(VSP), which integrates propulsion

and steering of the Voith Water

Tractor into a single system. The

VSP sets outstanding standards

of propulsion efficiency and pre-

cise manoeuvring at extremely

high safety levels.

Swift, sensitive, stepless thrust

variation in direction and magni-

tude, independent of the VWTs

speed.

Thrust variation according to

Cartesian co-ordinates.

Easily controlled, redundant

steering, logically related to

VWT movement.

Robust, slow-running marine

engineering using top-quality

materials.

High degree of resistance to

external stresses in rough

shiphandling operations and

extremely long service life.4

5

The diagram shows the logical

arrangement of the basic compo-

nents.

1. The VSP is located in the forebody, with free inflow and outflow in all directions. The thrust forces act ahead of the vessel axis of rotation.

2. Fitted underneath the propellers is a protective guard that exerts a nozzle effect and increases propeller thrust. It also pro-tects the propeller blades against running aground and supports the vessel in dock.

3. The hull is an integrated part of the system, creating lift for the indirect steer-ing principle and ensuring low resistance in transit.

4. Located underneath the aft body is an effective skeg for steering and braking as sistance of the tow, shaped to create lifting force. The skeg shifts the centre of lateral resistance aft, thus increasing leverage between propeller thrust and pivot point. It also ensures adequate course sta-bility when running either bow or skeg first.

5. The towing gear (staple and winch) is lo-cated aft of the vessels centre of rotation.

6. The VWT is operated from the control stand in the wheelhouse. One or several synchronised control stands, depending on the size of the vessel, can be installed. The steering system is usually connected mechanically to the propellers, permitting direct control of the system with no risk of steering system failure.

Concept

The Voith Water Tractor is a functional vessel with

integrated Voith Schneider Propellers (VSP).

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4

3

6

2

1

Since the Voith Schneider Propeller

is driven at a constant engine speed

due to its controllable pitch charac-

teristic, it is possible to use the free

flywheels of the main engines to

drive auxiliary units such as firefight-

ing pumps.

The Voith Water Tractor remains

fully operational when fire fighting

Manoeuvrability

Control of the Voith Water Tractor

is direct. The direction of the steer-

ing force coincides with the desired

direction of movement, since the

steering forces act ahead of the

vessels axis of rotation. This form

of control results in the smallest

possible turning circle, i.e. on the

spot.

The direction of the tugs movement

is the same as the movement made

at the control stand. This enables

the tug master to devote undivided

attention to the tow handling opera-

tion.

Changes in position are extremely

quick and precise, due to the unri-

valled steering times of the Voith

Schneider Propeller. This allows

more time for effective work and

keeps the tow under more effective

control.

even with a fire pump capacity of

more than 70% of the rated engine

power.

The Voith Water Tractor can also

be used in a similar way as an oil

pollution control vessel, or in com-

bination.

6

7

Safety

The Voith Water Tractor concept averts

the risk of capsizing, which is a constant

fear with any stern-driven tug when work-

ing with a towline. The steering force (pro-

peller thrust) acts ahead, and the towline

force always astern of the vessels pivot

point.

As soon as the forces deviate from

the VWTs longitudinal direction, they

create a reversing torque about the

vertical axis.

The tractor turns its longitudinal axis

in the direction of the towline before

the vessel reaches a critical heeling

movement. In other words, even with-

out the assistance of thrust, the ves-

sel stabilizes itself.

This eliminates a major risk normal-

ly associated with ship handling.

Thanks to this principle, ship han-

dling manoeuvres can be performed

far more safely, directly and smoothly.

Taking over lines between an

in com ing vessel and a tug involves

considerable risk. The procedure

frequently takes place at a rela-

tively high speed and the tug has

to come very close to the vessel

that is to be handled.

In particular at the bow of the in-

coming vessel, the tugboat passes

through a negative pressure field

which, in addition to other external

forces such as wind and current,

can cause a collision or lead to

the tug being overrun by the tow.

This risk is minimized by the Voith

Water Tractor. Full power is avail-

able instantly for a steering manoeu-

vre thanks to the Voith Schneider

Propeller propulsion at the forward

end of the tug, enables the VWT to

free itself from such critical situa-

tions.

The sensitive thrust control provid-

ed by the Voith Schneider propul-

sion system allows the tractor to

keep close to the vessel being as-

sisted, thus permitting safe and

rapid transfer of the line.

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9

Dynamic ship assistance and escort work

Contemporary ship handling opera-

tions cover the entire speed range

from the vessel at rest to the tugs

free-running speed. In stationary

operation, the direct method of

working is used.

In this mode, engine power gener-

ates the necessary forces through

the propulsion system. In dynamic

operation, the indirect working

method is applied. In this mode

the hydrodynamic force of the hull

is utilized.

There is a smooth transition be-

tween the direct and indirect

methods. The Voith Water Tractor

performs this transition continuously

and without risk.

A further improvement is possi-

ble without undue complexity by

in stalling the Voith Turbo Fin (VTF),

a rotating tube at the leading edge

of the skeg. The VTF exerts a spe-

cific boundary layer influence on the

flow acting on the ships hull and

generates a considerable increase

in lift. With VTF installed, steering

forces can be increased by 18-20%.

Direct ~ 0-5 kn Indirect ~ 3-10 kn

Forces transverse [t]

Forc

es lo

ngitu

dina

l [t]

-160 -120 -80 -40 0 40 80 120 160

100

50

-50

-100

-150

-200

At speed = 0 knAt speed = 2 knAt speed = 4 knAt speed = 5 knAt speed = 6 knAt speed = 8 knAt speed = 10 kn

Butterfly diagram for Voith Water Tractorescort Ajax, Ostensj Reederi A/S, Norway

The Voith Water Tractor with its

unique capabilities can be a key

element of the complex safety

system of any port.

The VWTs superior dynamic ship

handling characteristics reduce

expenditure on shore-side facilities,

such as breakwater extensions

and channel dredging.

The VWT fleet increases and main-

tains the existing traffic density and

permits an approach to harbour in

poor weather conditions at all ports

that serve merchant vessels.

Most damage to vessels occurs

in bad weather conditions. In such

poor operating conditions, it is

essential for effective ship assist-

ance to be available.

Protection of human life, awareness

of environmental protection needs

and ship handling in an emergency

are some of the critical tasks that

must be accomplished by marine

support facilities.

Economy and Environmental Protection

This is possible with the VWT

because precise thrust control is

available from the Voith Schneider

Propeller to counteract external

forces with no delay and minimal

risk.

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Voith Turbo Schneider

Propulsion GmbH & Co. KG

P.O. Box 2011

89510 Heidenheim/Germany

Tel. +49 7321 37-6595

Fax +49 7321 37-7105

vspmarine@voith.com

www.voithturbo.com/marine

www.voithturbo.com

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