7 ms·

Cycloidal marine propellers: Efficient thrust in any direction

100 points by Zobat 2y ago

kayodelycaon 2y ago
This isn't exactly a new concept: https://en.wikipedia.org/wiki/Voith_Schneider_Propeller https://en.wikipedia.org/wiki/Voith_Schneider_Propeller Tugboats use them.
- agos 2y ago
  individual blade control seems like a pretty big difference
  - wtallis 2y ago
    It's a big difference in implementation, but I'm not seeing where they state whether it achieves any significant improvement in performance over existing cyclorotor designs like Voith Schneider. I think when they compare against "conventional shaftline configurations" they are talking about ordinary screw props.
    - mlhpdx 2y ago
      I can see the potential for dramatic improvements in efficiency and control using individual blade tuning, particularly during maneuvering, to increase or decrease turbulence depending on the desired effect. It sounds like a really fun control system problem.
    - JumpCrisscross 2y ago
      > I'm not seeing where they state whether it achieves any significant improvement in performance over existing cyclorotor designs like Voith Schneider Traditional V-S loses a tonne of efficiency in the gearbox. It's less efficient than conventional shaftline. So if this is more efficient than the latter, it stands that it's moreso than the former. (Agree that I'd like more technical details.)
- Cieric 2y ago
  That appears to have already been mentioned in the article itself. Reading over it it seems that the improvement here is fully independent control of all the blades. From what I can see in diagrams of the Voith Schneider Propeller it seems to be a single linkage to all the blades that cause them to all be at the same angle depending on their current position in the rotation. If I'm getting this all wrong please someone correct me, I am interested in learning what the differences are.
  - dylan604 2y ago
    > That appears to have already been mentioned in the article itself. I like how you let it go that it was the opening sentence.
    - TeMPOraL 2y ago
      There rarely is any useful information in opening sentence or paragraph of a typical article, so as with banner blindness, it's excusable to read the article and still miss it.
      - kayodelycaon 2y ago
        Yeah. That's an oops on my part. The "first paragraph" isn't part of the article text. It's styled as a quote, summary, or caption. Safari's reader view displays it as such. (Gray sub-heading) I tend to skip those because they are often misleading.
  - all2 2y ago
    The linkage system in helicopters was called a "swash plate", a rather ingenious method of controlling pitch of rotating elements.
- supportengineer 2y ago
  They had these for radio-controlled boats in the early 1990's.
- pixelesque 2y ago
  And many smaller ferries.
- godelski 2y ago
  If you simplify anything enough it isn't new. If we required everything to be done in leaps and bounds, we'd never get anything done. Better to re-frame this as "looks to be an improvement on Voith Schneider Propellers". We can recognize the history while recognizing improvements. Progress is made by continual small steps, not giant leaps. If you see giant leaps, it is generally because you just aren't familiar with the topic enough (they do happen, but they are quite rare). Over trivializing improvements and dismissing them because they are abstractly similar only stops the world from moving forward. To reference a clique (something everyone can recite but something nobody knows): "the devil is in the details." If you read the article, they say that the propeller decrease energy consumption by 22% from conventional shaftline (the video says "up to 25%" though...), that seems like a pretty big win to me. And seems like something that you shouldn't so quickly dismiss. This kind of issue seems prominent around here and among engineers. Just remember how your work's merit relies so much on the details. What makes you think that this is any different for others? Why conclude that just because you understand something at an abstract level that you understand it at a nuanced level? Edit: don't use this comment as a reason to downvote them. If you actually like this message upvote them to make this more visible because you're probably frustrated with this issue too.
  - deleted 2y ago
    [deleted]
  - tda 2y ago
    The article is to light on details to claim anything radical. The operating principal is the exact same principal as a Voith Schneider Propeller, but then with more actuators and less linkages. That too me could just as well be a cost saving thing. Especially as they compare it too "conventional shaftline", and not to a Voith Schneider (I think). Also Voith Schneider's are already available in a in an electric version (eVSP) for diesel-electric drives. Perhaps this new Dynafin is much more efficient than an eVSP because better tuned individual control optimised by AI and industry 4.0 allows for much better control. But it is equally possible that there is exactly zero advantage to this system and all we read is marketing BS. Hefty improvement claims without details are usually BS in my experience
- deleted 2y ago
  [deleted]
- michaelcampbell 2y ago
  This intrigues me although I'm convinced almost anything that touches water is more expensive than I'm willing to pay for a hobby/pastime, but I went and looked up to see how these work. Neat. https://www.youtube.com/watch?v=Ub563Yc3xls https://www.youtube.com/watch?v=Ub563Yc3xls
lawlessone 2y ago
looks like bundles of kitchen knives.
- nickpinkston 2y ago
  That was my thought too, shoved through slots in a marble countertop.
- interstice 2y ago
  As if I wasn’t already reasonably scared of swimming near boats
  - apendleton 2y ago
    If it's any consolation, I'm pretty sure the leading edge is the blunt one, not the sharp one.
    - vlachen 2y ago
      Further more: sharp or dull, Ginsu-style or traditional prop, putting a part of your body in the interaction zone is a bad day. The article's style just gives it a more body-horror feel.
      - interstice 2y ago
        Yes, but a traditional prop doesnt extend down like that. Come to that, shallow water would be fun.
  - klyrs 2y ago
    I'm not a swimmer but that sounds like a pretty reasonable fear. A propeller of any sort will mess you up pretty bad. And if I understand correctly, the larger vessel gets the right of way so if you aren't in a vessel you just go smoosh.
    - scheme271 2y ago
gravescale 2y ago
> Each blade is individually controlled by an electric motor, a frequency converter (to control torque and rpm) and control logic" I know it's far from the only, or even most critical, embedded system on a ship, but being stuck at sea because your propellor CPU crashed, bricked during an OTA update or got taken over by a crypto miner does feel like it lies squarely on the current trajectory of reality.
- TeMPOraL 2y ago
  Reminds me of a seaQuest episode, in which they had to hit a black market for an A/C chip for their sub; the captain was complaining that they can't get it through procurement, but were he to ask for a nuclear warhead, he'd have the weapon helicoptered in a hour later.
  - gravescale 2y ago
    I don't think ABB would sell you just the chip, you just know that's going to be a sealed module that costs POA dollars per unit!
ermir 2y ago
So this is like a helicopter propeller system, but the individual blades point upwards.
- t0mas88 2y ago
  Jup, except that a helicopter system does not use independent control. The blade angle is controlled mechanically, each next blade will at the same position have the same angle. This new thing seems like it has independent control of each blade. But I'm not sure what they can do with that that wasn't possibe with a helicopter-like setup. I think it's unlikely you'll see a helicopter with this tech soon. This runs at 40 rpm. A helicopter main rotor is more like 400 rpm. And getting a blade "misaligned" at speed in a helicopter would immediately tear the whole thing apart.
hasoleju 2y ago
During the last centuries there was a technological shift in cargo ship drives roughly every 100 years. From sailing to steam boat over combustion engines to these drives?
- psunavy03 2y ago
  The basic principle has been around for decades.
sp332 2y ago
> 85% efficiency Hm, is that a lot? > independent testing of a passenger vessel fitted with different propulsion systems found that the ABB Dynafin solution managed energy savings of 22% compared to conventional shaftline configurations. Oh. That's a lot!
- pixelesque 2y ago
  That's compared to propeller shafts I think (and powered by what? Diesel, Gas turbine?). Voith Schneider systems are generally used on tugs and smaller ferries due to the manueverbility control they provide, it's not clear how energy efficient Voith Schneider systems are to shaftline systems.
- Eddy_Viscosity2 2y ago
  Its efficient at low speeds which is why it can be used on tugs. You want see these on a speed boat.
ilove_banh_mi 2y ago
In case you wonder how landlocked Switzerland would be so involved in such marine work, ABB is a Swedish-Swiss corporation and the pictures were clearly taken in the Baltic Sea (in the Gulf of Bothnia or Gulf of Finland).
- psunavy03 2y ago
  Still not unusual. MSC is one of the largest ocean shippers and based in Switzerland.
perlgeek 2y ago
I really hope this works out. The cynic in me immediately says "so many moving parts, maintenance will be quite a problem", but I don't really have the expertise to make that a argument against the success of this concept.
- n3storm 2y ago
  I am more worried about there is no video of a ship moving on three main website and youtube videos. One is 12 min. Only men talking, 3d animation and lots of waves. Did not search further though. Should this be called foamware?
- TaylorAlexander 2y ago
  Wikipedia says this type of propeller is widely used on tugs, so I guess the ABB product is either just their own version of this tech (maybe a patent expired) or they have evolved it somehow, maybe to increase efficiency depending on how you interpret the article. https://en.wikipedia.org/wiki/Voith_Schneider_Propeller https://en.wikipedia.org/wiki/Voith_Schneider_Propeller Here is a video of a tug boat using this technology, sadly only showing the boat moving but no close up of the propeller. https://www.youtube.com/watch?v=u6uNECa_X8Q https://www.youtube.com/watch?v=u6uNECa_X8Q
  - Tuna-Fish 2y ago
    It's not quite the same. In a Voith Schneider propeller, there is one power input (as in a rotating shaft) plus a second shaft input that gives the desired thrust direction, and a complex gearbox that drives all the blades and the collective. These are in wide use in tugboats and the like, desired for their ability to output thrust in any direction at a moment's notice. However, their disadvantages are that they are less efficient than traditional propellers, and they don't scale up to high revs or high power output all that well, because of the gearing and the mechanical losses involved. In this design, there is one large electric motor that drives the collective, and an individual electric motor at the base of every blade. The claim is that this gets you the maneuvering advantages of a V-S, while not suffering from the same disadvantages, and because of better control over the blades is not just more efficient than a V-S prop, but more efficient than traditional screws. And in theory it should scale as big as you want it, which would genuinely make it a significant advance that would see fairly rapid adoption. That's if it actually works in practice, the only prototypes so far are very small and you don't really know if something scales until you actually scale it.
ChrisMarshallNY 2y ago
Looks like a Ginsu Propeller™. Slices, dices, etc... In all seriousness, it would be great if it worked out, but we are constantly seeing marine tech being messed up by the marine environment. There's a reason that every damn thing that has "Marine" in its title, costs ten times as much. It really, really sucks to be stuck out in the middle of the ocean, because your shaft rusted.
geor9e 2y ago
I'm so confused how this works, but based on this animation I found, it seems like it just shoves the water sideways in the direction of thrust, then turns so it's cutting though the water in the opposite direction https://www.youtube.com/watch?v=Ub563Yc3xls https://www.youtube.com/watch?v=Ub563Yc3xls

100 points by Zobat 2y ago

This isn't exactly a new concept: https://en.wikipedia.org/wiki/Voith_Schneider_Propeller https://en.wikipedia.org/wiki/Voith_Schneider_Propeller Tugboats use them.

agos 2y ago
individual blade control seems like a pretty big difference
- wtallis 2y ago
  It's a big difference in implementation, but I'm not seeing where they state whether it achieves any significant improvement in performance over existing cyclorotor designs like Voith Schneider. I think when they compare against "conventional shaftline configurations" they are talking about ordinary screw props.
  - mlhpdx 2y ago
    I can see the potential for dramatic improvements in efficiency and control using individual blade tuning, particularly during maneuvering, to increase or decrease turbulence depending on the desired effect. It sounds like a really fun control system problem.
  - JumpCrisscross 2y ago
    > I'm not seeing where they state whether it achieves any significant improvement in performance over existing cyclorotor designs like Voith Schneider Traditional V-S loses a tonne of efficiency in the gearbox. It's less efficient than conventional shaftline. So if this is more efficient than the latter, it stands that it's moreso than the former. (Agree that I'd like more technical details.)
Cieric 2y ago
That appears to have already been mentioned in the article itself. Reading over it it seems that the improvement here is fully independent control of all the blades. From what I can see in diagrams of the Voith Schneider Propeller it seems to be a single linkage to all the blades that cause them to all be at the same angle depending on their current position in the rotation. If I'm getting this all wrong please someone correct me, I am interested in learning what the differences are.
- dylan604 2y ago
  > That appears to have already been mentioned in the article itself. I like how you let it go that it was the opening sentence.
  - TeMPOraL 2y ago
    There rarely is any useful information in opening sentence or paragraph of a typical article, so as with banner blindness, it's excusable to read the article and still miss it.
    - kayodelycaon 2y ago
      Yeah. That's an oops on my part. The "first paragraph" isn't part of the article text. It's styled as a quote, summary, or caption. Safari's reader view displays it as such. (Gray sub-heading) I tend to skip those because they are often misleading.
- all2 2y ago
  The linkage system in helicopters was called a "swash plate", a rather ingenious method of controlling pitch of rotating elements.
supportengineer 2y ago
They had these for radio-controlled boats in the early 1990's.
pixelesque 2y ago
And many smaller ferries.
godelski 2y ago
If you simplify anything enough it isn't new. If we required everything to be done in leaps and bounds, we'd never get anything done. Better to re-frame this as "looks to be an improvement on Voith Schneider Propellers". We can recognize the history while recognizing improvements. Progress is made by continual small steps, not giant leaps. If you see giant leaps, it is generally because you just aren't familiar with the topic enough (they do happen, but they are quite rare). Over trivializing improvements and dismissing them because they are abstractly similar only stops the world from moving forward. To reference a clique (something everyone can recite but something nobody knows): "the devil is in the details." If you read the article, they say that the propeller decrease energy consumption by 22% from conventional shaftline (the video says "up to 25%" though...), that seems like a pretty big win to me. And seems like something that you shouldn't so quickly dismiss. This kind of issue seems prominent around here and among engineers. Just remember how your work's merit relies so much on the details. What makes you think that this is any different for others? Why conclude that just because you understand something at an abstract level that you understand it at a nuanced level? Edit: don't use this comment as a reason to downvote them. If you actually like this message upvote them to make this more visible because you're probably frustrated with this issue too.
- deleted 2y ago
  [deleted]
- tda 2y ago
  The article is to light on details to claim anything radical. The operating principal is the exact same principal as a Voith Schneider Propeller, but then with more actuators and less linkages. That too me could just as well be a cost saving thing. Especially as they compare it too "conventional shaftline", and not to a Voith Schneider (I think). Also Voith Schneider's are already available in a in an electric version (eVSP) for diesel-electric drives. Perhaps this new Dynafin is much more efficient than an eVSP because better tuned individual control optimised by AI and industry 4.0 allows for much better control. But it is equally possible that there is exactly zero advantage to this system and all we read is marketing BS. Hefty improvement claims without details are usually BS in my experience
deleted 2y ago
[deleted]
michaelcampbell 2y ago
This intrigues me although I'm convinced almost anything that touches water is more expensive than I'm willing to pay for a hobby/pastime, but I went and looked up to see how these work. Neat. https://www.youtube.com/watch?v=Ub563Yc3xls https://www.youtube.com/watch?v=Ub563Yc3xls

lawlessone 2y ago

looks like bundles of kitchen knives.

nickpinkston 2y ago
That was my thought too, shoved through slots in a marble countertop.
interstice 2y ago
As if I wasn’t already reasonably scared of swimming near boats
- apendleton 2y ago
  If it's any consolation, I'm pretty sure the leading edge is the blunt one, not the sharp one.
  - vlachen 2y ago
    Further more: sharp or dull, Ginsu-style or traditional prop, putting a part of your body in the interaction zone is a bad day. The article's style just gives it a more body-horror feel.
    - interstice 2y ago
      Yes, but a traditional prop doesnt extend down like that. Come to that, shallow water would be fun.
- klyrs 2y ago
  I'm not a swimmer but that sounds like a pretty reasonable fear. A propeller of any sort will mess you up pretty bad. And if I understand correctly, the larger vessel gets the right of way so if you aren't in a vessel you just go smoosh.
  - scheme271 2y ago

gravescale 2y ago

> Each blade is individually controlled by an electric motor, a frequency converter (to control torque and rpm) and control logic" I know it's far from the only, or even most critical, embedded system on a ship, but being stuck at sea because your propellor CPU crashed, bricked during an OTA update or got taken over by a crypto miner does feel like it lies squarely on the current trajectory of reality.

TeMPOraL 2y ago
Reminds me of a seaQuest episode, in which they had to hit a black market for an A/C chip for their sub; the captain was complaining that they can't get it through procurement, but were he to ask for a nuclear warhead, he'd have the weapon helicoptered in a hour later.
- gravescale 2y ago
  I don't think ABB would sell you just the chip, you just know that's going to be a sealed module that costs POA dollars per unit!

ermir 2y ago

So this is like a helicopter propeller system, but the individual blades point upwards.

t0mas88 2y ago
Jup, except that a helicopter system does not use independent control. The blade angle is controlled mechanically, each next blade will at the same position have the same angle. This new thing seems like it has independent control of each blade. But I'm not sure what they can do with that that wasn't possibe with a helicopter-like setup. I think it's unlikely you'll see a helicopter with this tech soon. This runs at 40 rpm. A helicopter main rotor is more like 400 rpm. And getting a blade "misaligned" at speed in a helicopter would immediately tear the whole thing apart.

hasoleju 2y ago

During the last centuries there was a technological shift in cargo ship drives roughly every 100 years. From sailing to steam boat over combustion engines to these drives?

psunavy03 2y ago
The basic principle has been around for decades.

sp332 2y ago

> 85% efficiency Hm, is that a lot? > independent testing of a passenger vessel fitted with different propulsion systems found that the ABB Dynafin solution managed energy savings of 22% compared to conventional shaftline configurations. Oh. That's a lot!

pixelesque 2y ago
That's compared to propeller shafts I think (and powered by what? Diesel, Gas turbine?). Voith Schneider systems are generally used on tugs and smaller ferries due to the manueverbility control they provide, it's not clear how energy efficient Voith Schneider systems are to shaftline systems.
Eddy_Viscosity2 2y ago
Its efficient at low speeds which is why it can be used on tugs. You want see these on a speed boat.

ilove_banh_mi 2y ago

In case you wonder how landlocked Switzerland would be so involved in such marine work, ABB is a Swedish-Swiss corporation and the pictures were clearly taken in the Baltic Sea (in the Gulf of Bothnia or Gulf of Finland).

psunavy03 2y ago
Still not unusual. MSC is one of the largest ocean shippers and based in Switzerland.

perlgeek 2y ago

I really hope this works out. The cynic in me immediately says "so many moving parts, maintenance will be quite a problem", but I don't really have the expertise to make that a argument against the success of this concept.

n3storm 2y ago
I am more worried about there is no video of a ship moving on three main website and youtube videos. One is 12 min. Only men talking, 3d animation and lots of waves. Did not search further though. Should this be called foamware?
TaylorAlexander 2y ago
Wikipedia says this type of propeller is widely used on tugs, so I guess the ABB product is either just their own version of this tech (maybe a patent expired) or they have evolved it somehow, maybe to increase efficiency depending on how you interpret the article. https://en.wikipedia.org/wiki/Voith_Schneider_Propeller https://en.wikipedia.org/wiki/Voith_Schneider_Propeller Here is a video of a tug boat using this technology, sadly only showing the boat moving but no close up of the propeller. https://www.youtube.com/watch?v=u6uNECa_X8Q https://www.youtube.com/watch?v=u6uNECa_X8Q
- Tuna-Fish 2y ago
  It's not quite the same. In a Voith Schneider propeller, there is one power input (as in a rotating shaft) plus a second shaft input that gives the desired thrust direction, and a complex gearbox that drives all the blades and the collective. These are in wide use in tugboats and the like, desired for their ability to output thrust in any direction at a moment's notice. However, their disadvantages are that they are less efficient than traditional propellers, and they don't scale up to high revs or high power output all that well, because of the gearing and the mechanical losses involved. In this design, there is one large electric motor that drives the collective, and an individual electric motor at the base of every blade. The claim is that this gets you the maneuvering advantages of a V-S, while not suffering from the same disadvantages, and because of better control over the blades is not just more efficient than a V-S prop, but more efficient than traditional screws. And in theory it should scale as big as you want it, which would genuinely make it a significant advance that would see fairly rapid adoption. That's if it actually works in practice, the only prototypes so far are very small and you don't really know if something scales until you actually scale it.

ChrisMarshallNY 2y ago

Looks like a Ginsu Propeller™. Slices, dices, etc... In all seriousness, it would be great if it worked out, but we are constantly seeing marine tech being messed up by the marine environment. There's a reason that every damn thing that has "Marine" in its title, costs ten times as much. It really, really sucks to be stuck out in the middle of the ocean, because your shaft rusted.

geor9e 2y ago

I'm so confused how this works, but based on this animation I found, it seems like it just shoves the water sideways in the direction of thrust, then turns so it's cutting though the water in the opposite direction https://www.youtube.com/watch?v=Ub563Yc3xls https://www.youtube.com/watch?v=Ub563Yc3xls