[HN Gopher] Voith Schneider Propeller
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Voith Schneider Propeller
Author : Luc
Score : 113 points
Date : 2026-02-15 20:22 UTC (4 days ago)
(HTM) web link (en.wikipedia.org)
(TXT) w3m dump (en.wikipedia.org)
| yccs27 wrote:
| This reads a lot like an advertisement. The linked page
| [[Cyclorotor]] is more neutral and has more information on the
| design and applications outside of marine vessels:
|
| https://en.wikipedia.org/wiki/Cyclorotor
| adolph wrote:
| This is conceptually significant because the article links the
| mechanisms used in watercraft and aircraft.
| mkreis wrote:
| See a tug showing off here:
| https://www.youtube.com/watch?v=u6uNECa_X8Q Voith is the only
| company producing those, even though the patent has expired.
| dylan604 wrote:
| Please excuse me while I rock your boat up against the pier
| unnecessarily as I show how to do burnouts and donuts with my
| boat for some viral content.
| javiramos wrote:
| The coolest recent development in marine propellers is toroidal
| propellers which are now commercially available and seem to
| perform significantly better than standard propellers:
| https://www.sharrowmarine.com/
| LoganDark wrote:
| That website seems to no useful information; only marketing
| speak about how great it is... Do you know of a good source on
| how toroidal propellers work and the engineering behind them?
| LysPJ wrote:
| Here you are:
| https://en.wikipedia.org/wiki/Toroidal_propeller
| reedciccio wrote:
| Uhm... The article lacks quite a few citations.
| AftHurrahWinch wrote:
| Really enjoyed this:
|
| > In the centuries after Archimedes invented the
| Archimedes' screw, developments of propeller design led to
| the torus marine propeller... it was invented in the early
| 1890s
|
| "the centuries" indeed. :)
| HoldOnAMinute wrote:
| I didn't even see a picture of the propeller, if there was
| one. There was a giant, white, blank space.
| LoganDark wrote:
| That space is blank for me too.
|
| This page seems to have one halfway-functional photo for
| me: https://www.sharrowmarine.com/store/p/sharrow-by-veem-
| ds9sw
|
| This URL may work: https://images.squarespace-
| cdn.com/content/v1/560055b1e4b017...
| dylan604 wrote:
| If that's machined, that's impressive. I've seen some
| crazy 5-axis CNC examples, and it's usually some bladed
| turbine fan. Not sure how many axis (axii??) this would
| require, but it looks cool nonetheless.
| LoganDark wrote:
| It looks bent to me, or potentially stamped.
| stackghost wrote:
| Propellers (both marine and aero) are just spinning wings. If
| you picture a 2D airfoil like you might see in one of those
| "intro to lift" diagrams, all the flow is in what we call the
| _chordwise_ direction, that is the flow is entirely along the
| axis of the wing 's chord (leading edge to trailing edge).
|
| A real 3D aircraft, however, has a fuselage. Similarly, a
| prop has a hub and the tips of each blade are spinning faster
| than the roots. The tl;dr of this is that real 3D lifting
| surfaces typically exhibit a mixture of chordwise and
| _spanwise_ flow, which causes wingtip vortices to form[0],
| resulting in induced drag /induced power loss.
|
| For a given amount of thrust the total amount of momentum
| that the prop transfers to the fluid is fixed. The tip of a
| conventional prop ends abruptly which causes a large pressure
| gradient and a strong vortex. A toroidal prop's shape causes
| the pressure gradient to be broader and less concentrated,
| therefore the wake vorticity is distributed over a larger
| region, reducing peak swirl velocities and lowering the
| kinetic energy lost to vortex formation (and to cavitation).
|
| [0] https://www.youtube.com/watch?v=duSZ1hyK7sY
| brk wrote:
| For the most part the Sharrow props have not proven to be much
| of an improvement, particularly for the high price.
|
| The tests that have shown "significant" improvements have
| frequently compared the Sharrow to a sub-optimal prop. Feedback
| from many actual users is that the gains are moderate over a
| narrow RPM range.
| closewith wrote:
| And much harder to repair.
| HPsquared wrote:
| That's pretty cool, but I wonder if they can get stuff tangled
| in there.
| martinclayton wrote:
| See also https://news.ycombinator.com/item?id=26339421
| xpe wrote:
| I recommend this video with animations :
| https://www.youtube.com/watch?v=QrBF9BWYAZY
| xpe wrote:
| From a resilience POV, my guess would be that failure of any one
| blade would botch the system overall. Maybe that is why many
| diagrams show them installed in pairs. (I would guess each
| operates in a different direction for angular momentum reasons.)
| I have no idea about overall reliability.
| brk wrote:
| For marine applications dual drives are common as it enables
| better rotational control for maneuvering. The redundancy
| aspect is also a factor, but moreso for applications where you
| are going to be far from shore. For tugboat and ferry type
| applications, where these drives are most common, that is less
| of a concern.
| w4der wrote:
| They are installed in pairs and work together with bow
| thrusters to allow for dynamic positioning, the RV Falkor (too)
| has them for this reason.
| somat wrote:
| I think you are right, One only provides directional thrust, a
| pair would be needed for rotational thrust.
|
| Most traditional tugs have a pair of screws for just this
| reason. Not so much to turn but by applying differential thrust
| they can pull sideways. A vector drive like this will vastly
| increase the envelope of possible pull conditions.
| oliwary wrote:
| Cool, similar to helicopters which can also control direction
| indepentendent of thrust, which leads to RC helicopters being
| able to pull of crazy, physics-defying moves like here:
| https://www.youtube.com/watch?v=QSiwyoQldfo
| ted_dunning wrote:
| That is bizarre and amazing. I have never seen any kind of
| aircraft that resembled a dragonfly as much as that.
|
| The maneuvers are so extreme and come so fast that I would not
| have been able to say for certain that this wasn't just a very
| nasty crash in progress. But they were, in fact, completely
| controlled and intentional.
|
| Incredible.
| dylan604 wrote:
| That's the worst lawnmower I've ever seen. It didn't even cut
| the grass as much as it just bothered the blades of grass. 0
| out of 5 stars. What's that? It's not a mower. Oh, well then,
| that thing is cool as hell, but not as cool as the pilot that
| looks like he's just casually standing there.
| _aavaa_ wrote:
| Thanks! I'll keep this on hand for next time I hear that a UFO
| proof video comes out saying that an object can't move the way
| it does on screen.
| xpe wrote:
| See also:
| https://en.wikipedia.org/wiki/Swashplate_(aeronautics)
| manyturtles wrote:
| These were used on three car ferries in Scotland, mostly between
| Gourock and Dunoon but the same vessels were sometimes used on
| other routes. The Saturn, Juno and Jupiter which were quite fast
| and incredibly maneuverable: "...service speed was around 15
| knots (although she could also achieve 13 knots astern and 3
| knots sideways" with just those drives. No separate screws, bow
| or stern thrusters. Same drive was used on a few smaller local
| ferries, too.
|
| If I remember right what they didn't do was go exactly straight.
| You could see a (very modest) s-shape in the wake over distance.
|
| ref: https://www.shipsofcalmac.co.uk/fleet-features/the-streakers
| silveira wrote:
| The same article in german has some nice animations:
| https://de.wikipedia.org/wiki/Voith-Schneider-Antrieb
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(page generated 2026-02-19 23:01 UTC)