Sharrow Props

[backinblue]

Here's a pretty interesting and compelling update for Sharrow props. Not many of us run outboards but still, any thoughts?

https://boattest.com/Sharrow-Enginee...ource=hs_email

[Simi 60]

Seems to be trying to solve issues that rice or Kortz nozzles have already sorted.
Would be pretty easy to retrofit a shaped nozzle to an outboard Cavitation plate with the added advantage of prop/swimmer protection.

[rslifkin]

Originally Posted by Simi 60

Seems to be trying to solve issues that rice or Kortz nozzles have already sorted.
Would be pretty easy to retrofit a shaped nozzle to an outboard Cavitation plate with the added advantage of prop/swimmer protection.

Aren't nozzles typically more effective at lower speeds? I'm not sure I've ever seen them in a higher speed application.

[Simi 60]

Originally Posted by rslifkin

Aren't nozzles typically more effective at lower speeds? I'm not sure I've ever seen them in a higher speed application.

There is that
But not at all sure

[backinblue]

I found this....

Kort nozzles or ducted propellers can be significantly more efficient than unducted propellers at low speeds, producing greater thrust in a smaller package. Tugboats and fishing trawlers are the most common application for Kort nozzles as highly loaded propellers on slow moving vessels benefit the most. Nozzles have the additional benefits of reducing paddlewheel-effect (e.g. the tendency of a right-hand wheel to back to the left) and reduce bottom suction while operating in shallow water. The additional shrouding adds drag, however, and Kort nozzles lose their advantage over propellers at about ten knots (18.5 km/h).

I still think the Sharrow prop looks like a pretty good leap in prop technology at least for some boats. I wonder if some of the outboard manufacturers will offer them as an option. Seems like an easy bolt on advantage over the competition, unless it needs to be matched to the type of boat the motor is attached to. But I think that would also apply to a standard prop. Not sure why they are often criticized on TF as a gimick or something similar.

[socalrider]

It's a pretty compelling test to my non-expert eyes. 16% efficiency/speed gain is pretty significant, as is the lower RPM planing ability.

I also wonder how this translates across different speeds - I think a lot of boats would appreciate a 16% boost regardless of the reason (speed, range, opex, etc.) I wonder how this would compare to other prop alternatives (more than 3 blades, for example)

[backinblue]

Originally Posted by socalrider

It's a pretty compelling test to my non-expert eyes. 16% efficiency/speed gain is pretty significant, as is the lower RPM planing ability.

I also wonder how this translates across different speeds - I think a lot of boats would appreciate a 16% boost regardless of the reason (speed, range, opex, etc.) I wonder how this would compare to other prop alternatives (more than 3 blades, for example)

Good point but I would think that all props have the same issue that Sharrow is allegedly fixing. I'm guessing most outboards would come with a prop that is more or less optimal for that motor. I wonder if similar increases in speed and efficiencies would be obtained on inboard motors driving a shaft. Probably not a big advantage on slow boats I assume, but maybe boats that plane like mine. Then again, if you read the article there is an interesting point about effciency gains at idle speeds.

[bnoft]

Probably be an "easy" upgrade on pod drives

[Nick14]

There are a few threads on Sharrow props. This is the first test of Sharrow props on a diesel inboard boat (a 65’ yacht).

Bottom line, maximum WOT speed with a Sharrow (vs. Veem props) is increased 12.5%, overall fuel efficiency is 9-11% improved, and at a sweet spot of 12 knots, the Sharrow uses 52% less fuel:

https://boattest.com/article/sharrow...ource=hs_email

The numbers look impressive to me. Once they start offering Sharrow props on a more standard basis, I’d like to get one.

[Portage_Bay]

The claimed improvement in efficiency is impressive. For a serious cruiser the payback on the purchase should be short enough to worthwhile.

Of note Sharrow is a brand name. Somewhat like calling an adjustable wrench a crescent wrench. I think the proper term is toroidal prop. Apparently toroidal props have been around for a long time. Hopefully Sharrow can be financially successful and bring them to the wide marine market.

https://en.m.wikipedia.org/wiki/Toroidal_propeller

[Nick14]

A recent article in Soundings on Sharrow props:

https://www.soundingsonline.com/feat...ource=hs_email

FWIW, I contacted Sharrow (again) asking about availability for diesel inboards (as they recently tested). Once again the response was the prop is not available for diesel inboards, no timeline for future availability, but I'll be put on a 'mailing list.'

They seem to be focusing on outboards. There are certainly more of them out there than inboards, but I would bet the market for Sharrow props for inboard boats might be even bigger. The fuel savings on a big inboard would make the Sharrow even more attractive. I'd buy one in a heartbeat (if it was reasonably priced).

[rslifkin]

Originally Posted by Nick14

A recent article in Soundings on Sharrow props:

https://www.soundingsonline.com/feat...ource=hs_email

FWIW, I contacted Sharrow (again) asking about availability for diesel inboards (as they recently tested). Once again the response was the prop is not available for diesel inboards, no timeline for future availability, but I'll be put on a 'mailing list.'

They seem to be focusing on outboards. There are certainly more of them out there than inboards, but I would bet the market for Sharrow props for inboard boats might be even bigger. The fuel savings on a big inboard would make the Sharrow even more attractive. I'd buy one in a heartbeat (if it was reasonably priced).

I think they're trying to target "standard" stuff to build at this point. Which pretty much means props for outboards, stern drives, pods, and maybe some OE stuff. But aftermarket sales of inboard props is likely low on their list (unfortunately for us). It doesn't help that so many fewer new boats (outside of trawlers) are being built with straight shafts.

[Nick14]

Originally Posted by rslifkin

I think they're trying to target "standard" stuff to build at this point. Which pretty much means props for outboards, stern drives, pods, and maybe some OE stuff. But aftermarket sales of inboard props is likely low on their list (unfortunately for us). It doesn't help that so many fewer new boats (outside of trawlers) are being built with straight shafts.

You make a good point about few new boats being built with straight shafts. But there are a great many existing boats out there with conventional drives, most of which could benefit from improvements in performance and fuel efficiency.

I wonder if the company has done any market research or market opportunity assessments of existing boats rather than new builds, to assess the sales potential? Most of the boats in marinas are older, not brand new, and could sorely use improving their fuel efficiency.

Of course my view is biased, and I have a personal interest in this. I'd love to have the kind of performance improvements the prop seems to provide, even on a conventional inboard. I supposed we're at the back of the line...

[hmason]

I visited the Sharrow booth at the West Palm boat show. They look like artwork. I asked about pricing and almost fainted.

[Art]

Originally Posted by Nick14

You make a good point about few new boats being built with straight shafts. But there are a great many existing boats out there with conventional drives, most of which could benefit from improvements in performance and fuel efficiency.

I wonder if the company has done any market research or market opportunity assessments of existing boats rather than new builds, to assess the sales potential? Most of the boats in marinas are older, not brand new, and could sorely use improving their fuel efficiency.

Of course my view is biased, and I have a personal interest in this. I'd love to have the kind of performance improvements the prop seems to provide, even on a conventional inboard. I supposed we're at the back of the line...

With the multi thousand dollar cost per prop I've heard of for large motor o/b's... then thinking of the potential for additional multi thousand dollars cost for much bigger props on trawlers... with the fact that many docked trawlers seldom get 100 hour a year run time... makes me think that trawler props would not necessarily be a very lucrative market for Sharrow to pursue.

[Nick14]

Originally Posted by hmason

I visited the Sharrow booth at the West Palm boat show. They look like artwork. I asked about pricing and almost fainted.

What kind of pricing were they talking about?

I'll be interested in doing a rough ROI analysis (admittedly a guesstimate) to see what the payback period would be for a prop.

The test on the big diesel inboard showed fuel savings ranging from 9%-52%, of course depending on speed (52% at 12 knots).

For the sake of a simple SWAG, assuming 20% improvement in fuel economy, and a base case fuel burn of 12 gal/hr, would suggest saving about 2.5 gal/hr - call it $12/hr.

200 hours/year of operation = very roughly $2,400/year? If those numbers are at all close, for me a 2-3 year payback would be a price I'd be willing to pay.

[hmason]

The prop cost was $5,000.

[Nick14]

Originally Posted by hmason

The prop cost was $5,000.

Thank you!

If (and that's a big IF) the price of a Sharrow prop for a diesel inboard was $5,000, I'd definitely be interested. I think it would be in that range of a 2-3 year payback, for my boat and expected use.

I priced several conventional props for my (upcoming) boat and some of those were over $5,000. If they sell it at that price, it would be comparable to other premium props such as Veem and ACME. I think it would sell well.

[Pete Meisinger]

Putting one on my 1978 trawler would be akin to an earing on a pig, me thinks,,

pete