New Sharrow propeller

M

Micahbigsur@msn.com

New member
One of the earlier posts mentioned the Sharrow propeller so when it just came up in a BoatTEST.com email I clicked on the test. They did a carefully balanced test of fuel flow, speed at plane, & speed @ rpm with 2 conventional 3 blades and a Sharrow on a 150 Merc. All 3 parameters tested significantly better, check it out. They are rolling out production next year in the most in demand sizes. Frankly if these continue to test faster, smoother and more efficient, then next year I'm buying one.
 
The performance of the Sharrow prop is indeed amazing. But what happens when you hit a log and bend a blade. I will bet your local prop shop can't fix it like they can for most conventional props. Can Sharrow and at what cost?

David
 
I’d love to test a pair out on our CD22 with twin Honda 60’s with no concern at all about prop shop repair. I won’t hold my breath, as I think it will be quite some time before availability works it’s way to the mid size Honda outboards.

Jay
 
From Ken at Prop Gods

Always interesting with new props.

Numbers are a little odd with all the props as all 3 props are getting negative slip numbers at wide open.

Narration about Fuel economy is a little gimmicky, as I hate when they say, at "X" RPM we are 179% better fuel economy, as they are comparing a boat on plane and a boat that isn't.

But other then that, looks like it performs impressively well.

Looking at the design, I'm curious about how well it hooks up when surfaced, and the durability of the blades.
Most propeller companies have a hard enough time keeping the blades from cracking/slinging off the prop, and this one looks like a lot more blade surface with less contact with the hub.
I'd love to try one out.
 
There is an interesting thread on The Hull Truth on the Sharrow prop.

The discussion begins with a report from Sharrow Engineering.

The discussion of negative slip (no comment from Ken @ Prop Gods in this thread), but there is by Tom Clark, whose opinions I highly respect.

It is pointed out that prop slip really does not always mean a lot, for several reasons, except if excessively high, there is something wrong with the prop or the boat.
The negative slip can occur for several reasons, and some props always have a negative ship at high RPM.

The Merc 150 rev limits at 5800, and is a 'soft' limiter. Thus all props are hitting the rev limiter, and that more aggressive props may have been a better test.

There is also a link to a PowerTech piece on prop basics.. The first Is about thru hub exhaust, the second part is about pitch, cup and rake.

Boat test also has a short piece on prop construction/terminology: prop pitch, cup, material, blade number and rake is here.

A more comprehensive set of pieces is at Mercury Racing Prop School:
here is #1 introduction. Then part 2 Terminolgy.. Part3. Blade rake.. Part 4 Blade cup. Part 5. Blade efficiency. Part 6 Slip.
 
From another boating forum:

So I just received an email from Sharrow they are ready to take orders. The aluminum prop will be $4,500 and the stainless steel prop will be $9000. They are shipping to Canada currently.
Click to expand...

:shock:
 
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