Voith-Schneider Propeller

[Jets]

A few years back we were tearing them down every 4 years. Because I was spending all my time on warships I wasn't looking after them well enough. After contacting VS we were told to top off the header tank, haul them out and watch for blade seal leaks. Change the seals every 10 years. Flex the the bottom back and forth to check bearing play. Twist the blades back and forth to check play in the arms. Finally use oil analysis to watch for salt water. In 25 years we have never replaced a blade. However the other end of the arm is attached to casting that looks like an open hand. This we broke and the hydraulics managed to really #^&%$ the guts - about $125KUS worth. Still cheap. I once ran across a web page were a guy had built a 2 - 3 inch diameter VS drive and put it in a model. Impressive.

[jimbo611]

Originally Posted by Jets

A few years back we were tearing them down every 4 years. Because I was spending all my time on warships I wasn't looking after them well enough. After contacting VS we were told to top off the header tank, haul them out and watch for blade seal leaks. Change the seals every 10 years. Flex the the bottom back and forth to check bearing play. Twist the blades back and forth to check play in the arms. Finally use oil analysis to watch for salt water. In 25 years we have never replaced a blade. However the other end of the arm is attached to casting that looks like an open hand. This we broke and the hydraulics managed to really #^&%$ the guts - about $125KUS worth. Still cheap. I once ran across a web page were a guy had built a 2 - 3 inch diameter VS drive and put it in a model. Impressive.

The size model we work on is a 21. Mike from vsp in Germany says they make a small unit that you can carry around, it's a size 8. Changing the blade seal is about it, axel cleareance and we put a strap around the set of blades and put 200 lbs of pressure to check for seal leaks. The one that broke an arm had caught something in the blade while under way, made a mess of the hyd. too. We managed to change out these systems with the blades still on the unit but the cost to transport was high so now we pull the blades again. Ounce the oil is out we drop 10 blades in one day and put 10 blades back the next. It's the big ass torque wrench thats the most fun. ha ha

[paul210480]

hello,

i am very new to this forum, and wondering if anyone would be able to help me. I am starting my final year of BEng yacht and powercraft design degree, and trying to research for my dissertaion.

I have recently been shown of the Voith-Schneider Propeller, and i`m very interested in the possible use for small craft (20 - 30ft). The possiblities for a highly manouverably harbour tug. I`m looking for any reseach or technical information on the lateral resistance characteristics of hull forms i.e ideal lines for minimal resistance.

I understand the technical information is normally highly guarded. But if anyone could help I would be very apprieciated. I have already looked through the past 20 years of RINA Transactions, and 10 years of SNAME Transations, but there is nothing on Lateral hull resistance.

Thank you.

Paul.

[jimbo611]

Originally Posted by paul210480

hello,

i am very new to this forum, and wondering if anyone would be able to help me. I am starting my final year of BEng yacht and powercraft design degree, and trying to research for my dissertaion.

I have recently been shown of the Voith-Schneider Propeller, and i`m very interested in the possible use for small craft (20 - 30ft). The possiblities for a highly manouverably harbour tug. I`m looking for any reseach or technical information on the lateral resistance characteristics of hull forms i.e ideal lines for minimal resistance.

I understand the technical information is normally highly guarded. But if anyone could help I would be very apprieciated. I have already looked through the past 20 years of RINA Transactions, and 10 years of SNAME Transations, but there is nothing on Lateral hull resistance.

Thank you.

Paul.

I see them up front and in the rear, no thec on it, here is a pict.

[Jets]

Paul,
1. What you are looking for probably doesn't exist because a vessel with low lateral resistance would be very unstable and undesirable. Like a personal waterjet craft, it would be very hard to maintain a steady course as it would tend to spin out. I have a 10 ft flat bottom rowboat with a 20 HP motor. It is fast - 35 MPH but it slides in corners so much that I have to stay well away from other boats.
2. V-S drives have specific uses. The Germans invented them and used them on minesweepers during WWII as the entire drive could be made out of non-magnetic materials and put in a wooden hull. The drives are heavy, expensive and intended for slower moving vessels such as harbour tugs, minesweepers and passenger ferries. They are also suprisingly trouble free. The city of Halifax has a passenger ferry made like a flying saucer with a V-S fore and a V-S aft. Its trip is short but it has to be agile as it crosses the traffic path in the harbour. In that same harbour the Canadian Navy has some tugs with side by side V-S drives. While the tugs can go sideways, they generally go ahead or astern because it is much faster and they can pull harder.
There are plans for model V-S drives on the net and a yacht has been proposed with a rudder built as a V-S drive to provide get-home capability.
3. If you really want something fast with no lateral resistance, it has already been done. Buy a hovercraft. Narrow displacement hulls just don't like to go sideways so calculating lateral resistance is not high on the Nav Arc's list and I doubt that many customers would care to pay to find out how fast their boat van go sideways.
Jets

[Joel]

I get it, Props can be made with plastic, a metal or w/e...

Thanks for the fact!

[coolblizz]

Hi all.....

I am working on the hydrodynamics of the tugboat using the Voith Schneider propeller. Can anyone please help enlighten me on the question below?

"For a Voith Schneider control, the X-pitch changes the ship's Fwd and Aft speeds, while the Y-pitch changes the amount of Port and Starboard turnings. Could anyone please tell me how are the X-pitch and Y-pitch calculated?"

Coolblizz