Sharrow props might be going places

Bouba

Well-known member
Joined
6 Sep 2016
Messages
36,234
Location
SoF
Visit site
This is like waiting for the first person to drive an electric car....we are all desperate for some first hand feedback
 

Bouba

Well-known member
Joined
6 Sep 2016
Messages
36,234
Location
SoF
Visit site
I do wonder if the average shaft....from P bracket to threaded end....will be long enough on existing boats for this new propeller
 

j24jam

Active member
Joined
17 Jul 2011
Messages
236
Visit site
We enquired about having a set of these custom made for a clients 75ft mobo. Initially they said $40k for R&D and another $40k per prop. Our client was willing to go ahead but they changed their mind as didn't want to do a one off!
 

Bouba

Well-known member
Joined
6 Sep 2016
Messages
36,234
Location
SoF
Visit site
We enquired about having a set of these custom made for a clients 75ft mobo. Initially they said $40k for R&D and another $40k per prop. Our client was willing to go ahead but they changed their mind as didn't want to do a one off!
That’s a pity...because they would then have a new size range available without having to pay for R&D....probably the company is overwhelmed trying to ramp up
 

Portofino

Well-known member
Joined
10 Apr 2011
Messages
12,118
Location
Boat- Western Med
Visit site
Been around for a while aimed at “ Apache “ stye outboard race boats .Petrols .so fuel savings running at 3500 rpm as opposed to 4500 rpm , or when sea states permit “58% “ faster .

How ever with big boats diesel powered you have to think load , EGT s and the actual power band of the set up .
Then ( hate to mention it ) deadrise and seakeeping .

So let’s just grab J rudges Squadie 58 on D12 s .The manufacturers, both Volvo and Fairline would havs initially worked closely with the prop guys to come up with the correct size .So the motors have a reasonable power band range , the boat a reasonable turn of speed etc .
Say 1800-2100 rpm design for the rated 715 Hp D12 s , the prop pitched ( no pun intended ) so Volvo are happy with the EGT , Load , oil temps etc .All signed off .Every stake holder happy .

You can’t just throw $20000 at a pair of theses props and bolt on .
You are upsetting , or very likely to screw up Volvos graphs .Dropping the rev down to day 1200 to achieve his cruise of 22/24 knots , the engines rated for 1700-2100 all day setting .
Or turned around the relative shallow deadrise in any decent sea state would slam like hell shake it bits if at 2000 rpm it cruised at 32 knots or maxed at 42 knots , the alleged speed gain .The hull wasn’t built for this .

An Apache OB on Yam 350 s or Evenrude 400 s running poker runs ….sure go ahead start wining Sunday afternoon races .

Then there’s what happens if J rudge dinges his new Props say while in Sardinia ……He’s stuck a very long time until a replacement is manufactured, or has to drop back to OEM .
 

Alicatt

Well-known member
Joined
6 Nov 2017
Messages
4,234
Location
Eating in Eksel or Ice Cold in Alex
Visit site
There has been a lot of experimentation with this design of propellor for use on drones, with the higher RPM of the airscrew they are not seeing any advantage other than it is quieter than the conventional airscrews.
Lots of youtube videos on them. As Porto above says when they are running at a lower RPM they are more efficient but those efficiencies are lost as the RPM goes up
 

julians

Well-known member
Joined
11 Jun 2006
Messages
2,548
Visit site
There have been a couple fitted to axopars on the axopar owners facebook page, some very minor gains are reported (mainly things like steers better in reverse,less vibration), the fuel economy improvements are minor/non existant/hard to detect, nothing like the figures they talk about in their marketing fluff. No noticeable increase in top end speed. The general concensus seems to be that they're not worth the cost - at current prices. If they can bring the costs down to be competitive with regular stainless props, then they may be worthwhile just for the less vibration and better steerage in reverse etc.

One of the people has tried 9 different designs of prop from sharrow, but so far none have been better (ie better fuel economy or top speed) than the factory fitted mercury prop.
 
Last edited:

Bouba

Well-known member
Joined
6 Sep 2016
Messages
36,234
Location
SoF
Visit site
Boattest.com are very upbeat about Sharrow and have published numerous articles and test...all with very satisfying results
 

julians

Well-known member
Joined
11 Jun 2006
Messages
2,548
Visit site
Boattest.com are very upbeat about Sharrow and have published numerous articles and test...all with very satisfying results
They did indeed, the general concensus is that the normal prop they compared against in those tests was not optimal for the test boat /engine hence the sharrow prop showed significant improvements in fuel economy and top speed when compared to that sub optimal prop
 

Bouba

Well-known member
Joined
6 Sep 2016
Messages
36,234
Location
SoF
Visit site
They did indeed, the general concensus is that the normal prop they compared against in those tests was not optimal for the test boat /engine hence the sharrow prop showed significant improvements in fuel economy and top speed.
True...the other scenario is they have invested in it😎...but those who are not satisfied with their current setup are the logical first customers for Sharrow..so perhaps not surprising
 

jakew009

Active member
Joined
29 May 2012
Messages
297
Visit site
True...the other scenario is they have invested in it😎...but those who are not satisfied with their current setup are the logical first customers for Sharrow..so perhaps not surprising

If you were a sharrow sales person you would be motivated to go after boats you already knew were sub optimally propped…
 

Bouba

Well-known member
Joined
6 Sep 2016
Messages
36,234
Location
SoF
Visit site
If they were any good they've have been adopted by the major manufacturers years ago. As they say, if it sounds too good to be true, it usually is.
I remember trying to find a prop cage or tunnel to protect my outdrive in a river…they didn’t exist and when I thought about making one all the experts I could find said ´cavitation’ and other warnings.
A few years later…someone brought one to market ..and not only did it protect the prop but it actually increased efficiency.
So challenging accepted wisdom is no bad thing
 

westernman

Well-known member
Joined
23 Sep 2008
Messages
13,059
Location
Costa Brava
www.devalk.nl
I remember trying to find a prop cage or tunnel to protect my outdrive in a river…they didn’t exist and when I thought about making one all the experts I could find said ´cavitation’ and other warnings.
A few years later…someone brought one to market ..and not only did it protect the prop but it actually increased efficiency.
So challenging accepted wisdom is no bad thing
You were looking for something like this??

1699183668959.png

I think the boat is a tad bigger than yours.
 

MapisM

Well-known member
Joined
11 Mar 2002
Messages
20,317
Visit site
You were looking for something like this??
Or even better this, with Azipod.
Eat your heart out Volvo Penta, this is the real thing, which was already tried and tested (successfully!) well before IPS was still on the drawing board...
Oh, and it's actually installed in a pleasure boat of relatively human size, at 65'.
Qi7VogLC_o.jpg
 
Last edited:

MapisM

Well-known member
Joined
11 Mar 2002
Messages
20,317
Visit site
An Apache OB on Yam 350 s or Evenrude 400 s running poker runs ….sure go ahead start wining Sunday afternoon races.
You must be joking. Those things run on cleavers, which Sharrow props aren't even remotely meant to compete with.
 

Alicatt

Well-known member
Joined
6 Nov 2017
Messages
4,234
Location
Eating in Eksel or Ice Cold in Alex
Visit site
Or even better this, with Azipod.
Eat your heart out Volvo Penta, this is the real thing, which was already tried and tested (successfully!) well before IPS was still on the drawing board...
Oh, and it's actually installed in a pleasure boat of relatively human size, at 65'.
Qi7VogLC_o.jpg
Azipods are quite popular on the canal and river barges on the inland waterways of Europe
 
Top