sharrow propeller. a revolution?

[adornato]

As someone who hates prop cavitation noise, particularly on my Mainship 30 , i was interested in this post on another trawler forum

https://www.boattest.com/Sharrow-Engineering-Propeller

Not yet available but sounds like a winner.

 

[RT Firefly]

Greetings,
Mr. a. I'd heard about this prop design before BUT I have also been looking at Mainship 34's with the big (370HP) Yanmar engine, some of which have vibration problems that are seemingly unsolvable by changing props. I wonder if THIS is the solution?

 

[MurrayM]

Impressive real world test. What's also impressive is how he visualized the prop in his head, then went about bringing it into existence.

 

[rslifkin]

I'd like to have seen them include a 4 blade in that comparison as well.

 

[Nomad Willy]

I think it could have golden speeds where it performed better. Not unlike bulbous bows.
I haven’t read the link but it looks like a prop designed to trade less blade tip losses for more surface area drag losses. Under some speed/load circumstances one could gain more on tip loss .. losses and not so much lost to prevent it from being a plus.

I suspect it will be more a benefit because of it’s strength. But repairs will probably be pricy.

 

[Art]

As someone who hates prop cavitation noise, particularly on my Mainship 30 , i was interested in this post on another trawler forum

https://www.boattest.com/Sharrow-Engineering-Propeller

Not yet available but sounds like a winner.

Video is impressive! Sharrow props may be the best prop design for many many boat designs.

 

[Haloo]

I have a feeling it’s going to be expensive. But if it reduces fuel consumption, extends range, reduces vibration, makes it easier to back into slips, and makes things quieter...it could be worth a higher price than existing premium props. And there may be a benefit in terms of less wear and tear due to less vibration.

 

[Art]

I have a feeling it’s going to be expensive. But if it reduces fuel consumption, extends range, reduces vibration, makes it easier to back into slips, and makes things quieter...it could be worth a higher price than existing premium props. And there may be a benefit in terms of less wear and tear due to less vibration.

I agree!

And, I have a couple of relatively fast boats [25 to 35 knot cruise speeds / 39 to 55 knot top ends]. So, in similarity to the video-boat... for these boats of mine the new Sharrow design props would likely work quite well.

However, I'd like to see Sharrow prop tests done with some of the primary boats on TF. Will these props make much difference in 6 to 8 knot speeds of FD 7 to 30 or 40 ton "trawlers"?

Would Sharrow prop make much difference to big, multi ton boats of SD or P hull design that occasionally or more so cruise at 16 to 24 knots... but often cruise at single digit speeds... under their hull speed?

People want to know!!

 

[Xsbank]

This is one of those game-changers, like leds and lithium batteries. Neat!

 

[MurrayM]

If these are proven to be robust long term, they should be mandatory for container ships, super tankers, etc. to reduce emissions from burning bunker fuel.

 

[Art]

If these are proven to be robust long term, they should be mandatory for container ships, super tankers, etc. to reduce emissions from burning bunker fuel.

I appreciate your thought!

 

[rslifkin]

If these are proven to be robust long term, they should be mandatory for container ships, super tankers, etc. to reduce emissions from burning bunker fuel.

If they give a significant efficiency gain in those applications, I'd expect companies would start moving to them for fuel / money savings, even if they're not forced. But yes, I agree, that's an industry that stands to make a big difference.

 

[MurrayM]

If they give a significant efficiency gain in those applications, I'd expect companies would start moving to them for fuel / money savings, even if they're not forced. But yes, I agree, that's an industry that stands to make a big difference.

According to this article, 2 billion barrels of bunker fuel is burned by the global shipping industry per year. Yikes!

https://www.ft.com/content/642b6b62-70ab-11e9-bf5c-6eeb837566c5

Hmmmm...Financial Times link doesn't work now...

 

[moparharn]

I hope it has all the promise it seems to have. I would rather have not seen the test performed on the Detroit River. Current variations are everywhere. I assume it was same day, same location, same direction, but still an issue. I also would rather the prop had been made from stainless as it makes it more of an apples to apples, even though the aluminum should perform worse in most aspects. Get out your wallets boys, if this thing is what it appears to be it will likely be well worth it. Sounds like at trawler speeds and loads even more so.

 

[Nomad Willy]

Art wrote;
“However, I'd like to see Sharrow prop tests done with some of the primary boats on TF. Will these props make much difference in 6 to 8 knot speeds of FD 7 to 30 or 40 ton "trawlers"?”

The biggest advantage will probably be in high load situations. Quite likely boats designed w insufficient prop clearance and props too small or repowers significantly increasing power will benefit from vastly reduced tip losses. Big outboards will fall into that category too.

 

[DDW]

Prior art exists:

 

[Fletcher500]

Agree, the results shown in the video are impressive.

I have a hard time believing that the big players with large R&D departments staffed by people who have PHD/PE after their name would not have implemented this technology earlier if it is so much better.

We may not have the full picture, but it will be interesting to see where it goes.

 

[Benthic2]

I remember 10 years or so ago, there were some tests done with flying large kites off the bow of supertankers. It looked like a cheap easy way to increase efficiency...a real no brainer...but it never really got any traction. I'm not trying to create thread drift into the merits of kites....just pointing out that the shipping industry may have inherant resistance to newer technology. Who wants to be the executive that sent a billion dollars of cargo out to sea with a new idea and had it go wrong?

I'd guess if this gets a foothold it will be in competitive fishing and ski boats first, maybe pontoons, and work its way up from there.

Guys like this:

 

[Haloo]

Agree, the results shown in the video are impressive.

I have a hard time believing that the big players with large R&D departments staffed by people who have PHD/PE after their name would not have implemented this technology earlier if it is so much better.

We may not have the full picture, but it will be interesting to see where it goes.

Well, it took quite a while before the aircraft industry started to curl wing tips to reduce drag.

 

[Nomad Willy]

That’s true Haloo,
Radial tires didn’t take ofer overnight either.

Re aviation there is an aircraft called a “joined wing” aircraft. Uses a swept lower wing just about normal but usually w a bit more sweep. A “T” tail w an upper wing that sweeps forward to “join” with the up swept winglet or air dam ... that joins the two wings together. Probably reduces tip losses to next to nothing.

 

[OldDan1943]

And now, move it up to bronze and trawlers.
I hope the results are equally favorable.

 

[OldDan1943]

Prior art exists:

Hmmm, that's the current design for nuclear powered submarine props.

 

[markpierce]

I'll wait and see. No need to hurry. Perhaps something the next owner of the Coot would consider.

 

[stubones99]

Part of the vibration reduction may be because of reduction of mass and material flex.

Has Sharrow produced a stainless steel version comparable to the other two test props?

Having less mass means less vibration, since it has less mass to shake the boat.
Having aluminum fins compared to stainless steel blade, the aluminum blades will flex more in peak power spikes and could reduce the vibration.
On the other hand, run it 500 hours and it may not be back there.

 

[Art]

IMO - Vortice reduction at balde tips is one of the most important improvement efficiency features of Sharrow prop design. See 13 min 55 sec into video:

https://www.boattest.com/Sharrow-Engineering-Propeller

 

[diver dave]

I hope it has all the promise it seems to have. I would rather have not seen the test performed on the Detroit River. Current variations are everywhere. I assume it was same day, same location, same direction, but still an issue. ....

They used a speed thru the water sensor, and not GPS apparently.

 

[Art]

They used a speed thru the water sensor, and not GPS apparently.

That does seem to be true... as they mentioned it was speed through water and not speed over land. I'm not in knowledge of water sensor type that is 100% accurate. Guess there may be some. Interesting they did not mention [or show] water sensor used nor its reputed %age of accuracy??

With that said: I hope [and believe] test results were not being skewed in favor of the new prop design.

The reduction of vortex off prop tips [because there are no prop tips] is a feature that interests me very much. My engineering mind's eye tells me the removal of vortex has got to be one of the features that helps improve efficiency.

 

[rslifkin]

Reduced vortices also might allow tighter prop to hull clearance. And that might be a big benefit for boats with more than original power that could benefit from bigger props.

 

[High Wire]

Wow. One whole prop comparison published. What if the conventional props were the wrong fit for the test boat? No one has ever cherrypicked tests to make their product look good? Color me skeptical. I honestly hope they find a true step change in performance.

 

[Codger2]

Although I find the posts interesting, I am certainly not an engineer and can offer no observations that could be technical in nature. I can, however, offer a "first thought" after seeing a photo of the subject propeller. It looks like it could attach itself to all kinds of fowling material, quicker than most other propellers! Seaweed, fishing tackle, lobster trap lines, plastic bags, etc.