Voith Schneider Propeller | Hacker News Reader

Voith Schneider Propeller

en.wikipedia.org

169 pointsluu30 comments

The company that manufactures these is interesting in itself: an archetypal family-owned German business that has managed to survive for almost 200 years [1]

There's quite a few of those type of companies left in Germany, I wonder if there are similar examples in the US.

[1] https://en.wikipedia.org/wiki/Voith

An example that stuck with me is this US company founded in 1623 (ok, it was initially founded in Constantinople and relocated to the US via Romania at the beginning of the 20th century, but still impressive):

https://en.wikipedia.org/wiki/Avedis_Zildjian_Company

Found this informative video: https://www.youtube.com/watch?v=QrBF9BWYAZY

This video shows the thrust and motion vectors: https://m.youtube.com/watch?v=HyJHX6MZOWg

Fascinating, seems kind of like a water-bound analogue to the omni-directional wheels used on forklifts and such ( e.g. https://www.youtube.com/watch?v=0DBXuZv38l8 )

This was definitely required to help me figure out what the heck is going on. Basically it's a water wheel on its side, where the angle of attack for your paddles varies, which allows you to direct thrust in a particular direction.

In my childhood I always wanted a model tugboat with a Voith Schneider Propeller, but never could afford one.

They are still around, in modernized versions with brushless motors. See for example https://www.hobbydirekt.de/Alte-Kategorien/sonstiges/VOITH-S....

Nice, but that's not a brushless motor. Brushed motors are still being used in RC boats because they can get to lower RPMs.

Permanent magnet motors are used because they can get to lower RPMs.

It's not necessarily an attribute of all brushless motors.

In a sense a Voith Schneider propeller looks and seems to work somewhat like a helicopter's rotor, but with the blades point down instead of outwards.

The reverse, a vertical axis wind turbine, example being the McDonnell Aircraft Giromill. http://www.wind-works.org/cms/index.php?id=503

I was able to observe in a tugboat in a major harbor once -- amazing technology. Not just the propulsion -- they have displays that show where the ships are and where they are headed.

That’s AIS which is standard on all commercial ships and optional, AIS-B, on pleasure craft. It’s transmitted on channel 70 VHF. You can get the same information from a site lie MarineTraffic.com or build your own receiver from rtlsdr library and a cheap tv receiver.

The Staten Island Ferry (from SI to Manhattan) uses these. I had always wondered how the ferry does some of the maneuvers it does, without having all sorts of maneuvering thrusters. The Voith Schneider was the answer.

The downside of these is that repair times are a bit longer. But I always thought they were cool because they work basically the same as helicopter rotors.

The first non-experimental ship ever outfitted with one of these was the MS Kempten on Lake Constance, here seen (in the back) at Lindau: http://www.bodenseeschiffahrt.de/Bilder/Motor-Li/deutschland...

The Augsburg seen in the front right was also outfitted with Voith-Schneider propellers.

The original MS Kempten propeller is exhibited at the Swiss Museum of Transport in Lucerne: https://res.cloudinary.com/hnwlmxxdz/image/upload/w_660,c_sc...

The German Wikipedia article has some very nice animations to demonstrate the principle: https://de.wikipedia.org/wiki/Voith-Schneider-Antrieb

I found these animations the most helpful to understand what's going on!

That's cool. I never knew about these.

I suspect that efficiency, and probably speed, are sacrificed for maneuverability.

It would certainly require a great deal of maintenance. Anyone that has ever dealt with marine, knows that anything that touches seawater needs a lot of TLC, and it looks fairly complicated (compared to screws).

They're actually highly efficient. More efficient than screw propellers. They have very large surface areas, and move at uniform speed through the water. Screws spin very quickly at their tips, very slowly at their base, and the sweet spot in the middle is the only prime area for converting energy to propulsion. The fast moving parts generate significant drag, the slow moving parts generate insufficient forward propulsion for the drag they generate. VSPs do not have this disadvantage.

They are, of course, as you pointed out, a goddamned nightmare for maintenance. Lots of moving parts. Lots of seals. Lots of mechanical parts in contact with saltwater.

They're generally only used on tugboats, because tugboats must be able to point in one direction, but apply force in a different direction. And they must be able to change which direction they're applying force on a dime. And if and when tugboats break down -- they're already in a port. If a tugboat breaks down they've by definition not stranded in the middle of nowhere. Which mitigates the maintenance nightmare significantly.

Many short-distance (< 30 km) ferries in the UK that sail in busy waters (i.e. harbours, ports) have them, and generally they're very reliable and low-maintenance.

One of the disadvantages are the draft required, and it is a concern for grounding, so many have plates underneath for protection.

I hadn't heard before about ferries using Voith Schneider propellers. I did know that many ferries use (somewhat more traditional) azimuth thrusters for good maneuverability.

My local ferries use them: https://www.doverferryphotosforums.co.uk/new-mv-wight-light-...

Also used by the short-range ferries in Stockholm's Hammarby Sjöstad. Source: have travelled on these many times and observed the weird wake.

These are used on tugs for the most part, which has the requirement to apply thrust immediately to any direction so you can control the motion of a larger vessel easily. I'm not sure about efficiency, but they're fun to drive.

They seem to be the mecanum wheel of the sea, another high maintenance, low durability locomotion method.

That's inconsistent with the increasing usage described in the article.

I was thinking the same thing, and it’s certainly true functionally, but the mode of operation is quite different. It’s not about combining force vectors from different wheels, instead each blade rotates to always be thrusting in the desired direction.

The „Deutsches Museum“ in Munich has one of these on display, it is interactive and you can see the dynamic motion of the paddles as you change the movement direction via joystick.

Any small non commercial craft use these? They look awesome and I'd imagine they are a lot tougher than a typical fan bladed motor.

Is this safer for wildlife? It looks like the blade path is more pushing along than slicing through.

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