Toroidal Prop

Hi guys,

Did anyone look into toroidal props?



Looped propellers: A noise-killing game changer in air and water


Much quieter, with 20% fuel consumption at 2500 RPM - 3000 RPM.

They are around $2500, and with the current diesel price, 20% more efficiency may pay for itself in a couple of seasons.
Right now, Sharrow makes those for big outboards, but there is no reason they will not work for fast trawlers (if such a thing really exists).
... if they fit behind the rudder.

I wonder how closely it would align with parameters such as torque at the lower prop RPMs on a trawler? My guess is that it achieves the better fuel efficiency through reduced resistance/drag at high speed of a gas powered planning hull. Would be eager to understand more about this design.

Oh I just reread your post and saw you mentioned "fast trawler" so my comment may not apply. Although I am sure the term fast trawler would raise a lot of debate here !

Those props are very pricey. $5000+ for an outboard model

Hopefully, this technology will be useful for low speed trawlers and get adopted enough to bring the cost down.
The "modern" prop style is over 100 years old, it's time for some innovation.

Greetings,
I've been intrigued since I first saw the design. I may "do the math" and get a pair for the new boat IF company claims are semi-accurate. 20% increase in efficiency is mighty attractive but as has been mentioned, one log strike can ruin your day not to mention your cheque book.


The trend is to go with SS props for outboards BUT I've heard it mentioned, more than once, that in shallow/iffy/shoal waters you're better to use an aluminum prop. A hit might ruin your Al prop but save your bottom end. A prop is a lot cheaper than a lower unit UNLESS one chooses a Sharrow-double jeopardy

3D metal printed toroidal props?
Will be much less expensive to manufacture.
I wonder if it will handle the load of 3000 RPM using the materials available. Probably not yet.

Would be nice to cruise this 2 bedroom apartment at 18knots with 5gph consumption. I'd make it across the Atlantic

I wonder what an 18" diameter log would do to one? How easily repaired could they be? I mean, not that I've ever hit one myself. I'm asking for a friend.

Inbreaker said:

I wonder what an 18" diameter log would do to one? How easily repaired could they be? I mean, not that I've ever hit one myself. I'm asking for a friend.

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Easy. Just have a 3D printer on board with extra metal filament and print yourself a new prop.
Quick dive, replace, continue your trip

It sounds great, but I have to ask myself why aren't they gaining mainstream acceptance ? The easy answer is price, but when you have a 50 foot center console with 4 x 600 hp outboards you are talking well over 2 million dollars. $20k for props isn't really all that significant.
I think those engines are about $75 grand each. If speed and horsepower are that important to you, a little extra for a better prop is a no brainer. Plus, all the big outboard manufacturers would love to have their marketing material say " look at us, we use this fancy new prop....", but it doesn't seem to be gaining traction.

As I understand the design, the efficiency isn't likely to translate to slower moving props like ours.

Waterant said:

3D metal printed toroidal props?
Will be much less expensive to manufacture.
I wonder if it will handle the load of 3000 RPM using the materials available. Probably not yet.

Click to expand...

Since 3D printing is currently being used to manufacture jet turbine blades that are running 20,000 rpm, it really should not be a problem. But at this stage, not less expensive to manufacture. Right now, investment casting followed by finish machining is probably the cheapest, and a well worn path for making props.

I just watched a YT video on this and came here to see if yall had any discussions on this, glad to see it has. Will link the video I just watched for yall, but its my understanding that this prop designs sweet spot is in the mid RPM range, which would certainly benefit us all as most of us cruise in the middle of our tach curve.

Certainly the price point is just silly stupid at this point.

Probably going to take some Chinese company to rip off the design, copy it, then figure out how to mass produce it in order to get the price to come down, of course first few Chinese generations will probably break and sheer off with little effort, but after some trial and error, maybe in 5 years we will get some sweet new props.

Ive seen props go from the standard three blade to four blade, then five six and ten. Materials from aluminum to stainless to brass to bronze and others. Ive seen variable pitch, dual prop, counter rotating and combinations thereof.

When new designs come out they are touted as the latest greatest, blah blah, blah. Some are good, some are gimmicks all are expensive.

Time will tell on this new design.

pete

Pete Meisinger said:

When new designs come out they are touted as the latest greatest, blah blah, blah. Some are good, some are gimmicks all are expensive.

Time will tell on this new design.

pete

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Totally agree, however, if you watch that video I linked, seems like the Drone industry is driving the innovation on this design way more than the Marine industry, the part about MIT spending time on this makes me think that it will get researched a bit past the gimmicky phase.

Wouldn't make my boat go any faster, maybe could improve range. Would be interesting to compare vs Kort or Rice-Speed nozzles on slow boats.

I refuse to watch videos that have click-bait titles with the words "this genius" in it. Always seem to deliver less than the hype they're trying to generate

James