# Voith Schneider Controls



## NSA66

Does anyone on here have any experience of Voith propelled tugs. I am considering modelling a water tractor and was wondering about the nature of the wheelhouse propeller controls. 

I know that certain ships (red funnel ferries for example) have simple handwheels (1 for overall pitch and 1 for direction) to control each of the forward and aft units, as well as a series of buttons to select various engine power settings.

It strikes me that this arrangement, although simple, would not be particularly quick in response. Do tugs have a similar system or is there some sort of joystick arrangement to control both pitch and direction which might make manoeuvring easier?


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## howardang

NSA66 said:


> Does anyone on here have any experience of Voith propelled tugs. I am considering modelling a water tractor and was wondering about the nature of the wheelhouse propeller controls.
> 
> I know that certain ships (red funnel ferries for example) have simple handwheels (1 for overall pitch and 1 for direction) to control each of the forward and aft units, as well as a series of buttons to select various engine power settings.
> 
> It strikes me that this arrangement, although simple, would not be particularly quick in response. Do tugs have a similar system or is there some sort of joystick arrangement to control both pitch and direction which might make manoeuvring easier?


You may like to try this Voith simulation which gives some indication of control design as well.

The links for opening or downloading it are at the bottom of the page (VSP programme)

I hope this helps.

http://www.voithturbo.com/vt_en_pua_marine_vspropeller.htm



Howard


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## vincent simmonds

Voith Units work by a constant drive system run at full speed at all times.
The Port unit having an anticlockwise rotation. The Starboard unit with a clockwise rotation.

The wheel is kept in midships the two handles in a central point, this will operate the units in a negative motion.

Tugs have their units positioned in the bow “it’s my opinion this is incorrect the Voith units should be set aft of a tug making the stern the bow and vice versa”. In fact for open sea escorting I would do away with the stern and have two bows, I wonder if time proves me right. 

When you move the wheel to port the bow will move to port the stern will stay in place.
If the tug is lying alongside a wall starboard side to, it will spin 180° and will then lay portside to the wall, keeping the stern in its original position. To go back alongside the wall starboard side just do the reverse. 
This is a very useful manoeuvre in tug boating it’s one of the many manoeuvres which gives a Voith tug its well earned reputation.

If you turn the wheel to starboard then move the port lever forward and the starboard lever aft the tug will go sideways you have to balance the three movements to go sideways to port reverse the movements.
The look of astonishment of on lookers when this manoeuvre is carried out with a barge tied up alongside.

To move ahead in a straight line keep the wheel in midships and move both levers forward, you can be in full speed ahead and then pull the levers straight full astern with out delay and the units will be in full astern motion.

The levers can be split one ahead and one astern moving from ahead to astern and back again with out stopping also spinning the wheel from port to starboard.

The best thing of all is the units operate fine as you move the wheel or levers giving such control you can make a Voith tug do anything in fast or slow motion.
This is why I believe VOITH SCHENIDER are the ultimate in tug boats. 
Colin Laugharne


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## NSA66

Thanks guys. I was aware of the basic theory of the VS drive but Colin's reply has filled in the details I was looking for. 

Just for clarification then, am I right in assuming that the port and starboard levers adjust the total thrust of each unit individually from fully positive to fully negative and that the wheel controls the relative direction of thrust between the two drives? i.e. if both levers are fully forward and the wheel fully starboard, then both drives are pushing the bow to starboard? I take it that with each lever in the centre position pitch is neutral - the props turning but no thrust being developed?

Sorry to labour the point a bit but I'd like to have a good idea of full scale practice.


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## vincent simmonds

glad we can help did you receive the email ?
look up radhwa in model tug section and neptune


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## vincent simmonds

you ask "if both levers are fully forward and the wheel fully starboard, then both drives are pushing the bow to starboard?" yes 
on a voith unit there is a over ride which over rides to much power from the levers when the wheel is hard over to p/s but remeber the bow will pivot from the stern it not at all like a rudder boat


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## cryan

It is beneficial to have Voith tugs in the Tractor configuration as it moves the steering and propulsive forces fwd of the towing point whilst working over the stern which gives far greater manouvering ability also it is usual that the tow is lead through a towing eye quite close to the stern which gives much greater safety while towing as reduces girding risk. It is esential to have the large skeg aft on the hull to efect good lateral stability when towing and also to provide better ahead steerage especially when steaming at speed. If the Tug is operating in passive or active escort mode then it is baneficial to have the skeg forward to aid with course and lateral stability also again more control is achieved when manouvering when the propulsive /steering forces are at opposite end of vessel from the tow lead. For harbour work the skeg aids against girding.
Voith now have active skegs which have powered rollers on their tip which improves skeg performance. On most voiths except newer tugs the controls are direct mechanical from the wheelhouse which greatly improves reliability and robustness the wheel is linked directly to both units on a twin voith and controls them together while each unit has a seperate fore/aft pitch control. on many voiths you can vary the engine speed as well so as there is no need to burn huge amount of fuel for light jobs.
If all controls are at zero then no thrust is applied and the blades have zero attack on the water although the blade carrier disk is still spinning. Incidently Voiths are terrible for moving barges etc in a lash up mode as the thrust acts against the barge etc and cancels itself out. We move a lot of dock gate caissons and bunker barges about and a twin screw conventional tug is better for the job as if a voith is lashed up you need a huge overhang to allow the prop units to be clear of the end of the barge.
Sandown Minesweepers use voiths as well although at the stern and this is becuase of the reduced noise signature of a voith.


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## cryan

I dont think our voiths have a power override but then again they are quite old. we also operate a small single unit voith which is one of the greatest little boats around, extremely handy and capable. Our big twin unit voith is great for ship moves and far superior to either conventional or asd tugs.


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## Andrew Craig-Bennett

Many years ago being in Hamburg on a Sunday I was invited to join a Bugsier water tractor for the port Carnival. Ever been waltzing to a brass band in a tug? Wonderful!


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## tugdoc

Hi,
with regard to the suggestion of Voith props in the stern note that there are a number Voith escort tugs in Norway which can be termed as 'reverse Voith's. See under Bukser & Bergning
Job (TugDoc)


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## cryan

The latest design between Voith and Robert Allan is for a Voith Scneider unit at each end,,, http://www.maritimejournal.com/feat...n-and-voith-introduce-the-rave-by-jack-gaston


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## alba

*Hutton Cross (Tug with Voith Schnider Propulsion)*

Good to see the comments on Voith Schnider. I will be putting something on my web site including some pictures of the Hutton Cross built by Scott & Sons Bowling in 1958. She was built for the Tees Towing Company and was fitted with a Voith Schnider. There is a lot of information including photographs at the National Archive for Scotland, Glasgow University Site.
I would be interested in including some of the comments that have been made on this site, if you guys are ok with that? 
I am curently working on a new version of my web site, which should be up and running within the next couple of weeks, but feel free to visit the existing site at www.scottsofbowling.com

Regards
Alba


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