Sharrow Propeller Thread

[CamB25]

Here's a thread to discuss the Sharrow Marine technologies.

https://sharrowmarine.com/

Caveat: This is new technology and expensive. The technology is just starting it's journey along the adoption S-curve, so if you are interested in monetary return on investment, you'll have to wait until this technology is in mass production. The MX props are about $5k right now.

I've been working with Sharrow since early 2023 testing a number props and prop diffuser configurations on my B25. My application engineer and the company as a whole have been great to work with provided you have some patience to wait for new props to exit the manufacturing process. These are the MX props for outboards. I see they have teamed with VEEM for inboard applications which is a great sign that this prop design has a future.

My starting point for this "experiment" was what I consider an optimized traditional prop for my boat/engine. I was running a Mercury Enertia Eco 16 x18. Big diameter, big blade area...well matched to the torque of the Evinrude G2 300. Cruise comfortably at 4000 rpm, 30 mph, 3.0 mpg. Up on plane quickly, top end about 43mph. All good. The Sharrow prop is better (yes, the enemy of your wallet is better).

The Sharrow I'm now running full-time yields:
- lower cruise speeds. I can cruise, comfortably on plane, in the low 20 knot range. Great for my cocktail cruises.
- lower rpm per mph. 30mph comes at 3700 or so now.
- launches onto plane. quicker. These props have a HUGE amount of stern lift. No more bow in the sky, it lifts from the stern. Scary at high speeds as a result. Skip the trim tabs.
- top speed is the same as before, but at higher rpm. 5600 versus 5300. The effect is is a wider cruise range, effectively from 3700 - 5000.
- overall efficiency is the same, but the efficiency curve is wider and shifts lower into the rpm range, starting around 3500 or so. I've seen 2.9 - 3.1 mpg in light chop conditions. I haven't been off shore with this one yet.
- noise and vibration at all rpms is DRAMATICALLY reduced. Engine seems happy at all rpms. At cruise it just hums along happily. You know that sweet spot where everything seems to be working together? That spot is almost the entire rpm range.
- clear wake at troll...few if any bubbles at displacement speeds.
- GRIP...GRIP...GRIP. This prop grips the water so well that I can heel the boat over to the gunnels in a hard turn without a blow out. It's actually scary having the water touching the rub rail. Handles like a jet ski or a competition ski boat. Will almost turn in it's own wake. Fun factor is high.
- low speed tracking is greatly improved (see GRIP, above)
- Reverse thrust is much better.

Overall I'm happy with it and I've have moved the Merc to the spare prop bin.

As with any boat-related performance data, you should ignore all the fancy curves and other "data" coming from manufacturers. There are far too many uncontrolled and unaccounted for variables in prop testing results. Any boat on any given day will produce different data. Obviously, if your boat is not well-propped now, the differences between standard and Sharrow (the right Sharrow) will be dramatic. And i think the performance differences will be greater in multi-engine configurations than with a single like mine, but that is just a hunch. The physics of why the Sharrow props work are clear, but you have to try it for yourself, on your boat to know if it works for you. Consider it like a pair of shoes. The nice thing about working with a new company like Sharrow is the support. They pledge to work with you until you are happy and I can attest to this. The UPS man knows my house well...lots of Sharrow boxes going in and out over the past 10 months!

Fun!

[Ironworker]

I called Sharrow about props for my 31 but unfortunately they don't make one. I'm a fan of these props.

[Tony Meola]

I called Sharrow about props for my 31 but unfortunately they don't make one. I'm a fan of these props.

Rick

The partnership with Veem is only a month or two old. Give them a year and you can probably find one for 31.

Cam

You said the top end needs you to run a higher RPM. Are the props just allowing the engine to over rev to the higher RPM's or did they need to tweek the engine electronics to get it up there?

With diesels even though we don't push the top end, I would be afraid that if you had too, you could damage the engine or shorten its life.

[CamB25]

Tony,

I wasn't clear. The max RPM range for the engine is 5400 - 6000rpm. The Sharrow prop gets me to 5600 max while the Merc was a bit too much pitch and I topped out at 5300 and change. I'm not over-revving. I never run up at those speeds anyway as the boat gets squirrely!

For outboards - Sharrow has been working with Yamaha in the US to develop a mass production casting process. If successful, this should bring prices closer to earth.

For the B31s: I'll ask my Sharrow rep about the VEEM process and report back.

[Craig Mac]

I have a friend with a 33 Pursuit with twin Yamahas He has tried the props and did not see the claims for the technology and
is back to running the factory props.

[ktm_2000]

It does seem to me that compared to standard props, these are more efficient at lower speeds and then equal at higher speeds as Cam reports good improvements down low and same WOT speed. It almost seems like they are effectively slightly lower pitch than his previous props at top end, mid range lower rpm, I don't understand how that happens.

I personally am not as worried about how fast WOT is rather than what speeds and how efficient I am at cruise, if they come down in price and have consistently improved GPH at cruise I would probably get one.

Cam - I am curious about your rig at higher speeds, I can hit 40kts and she isn't squirrely. Not that I have a lot of experience as I maybe have a combined 2 minutes at that speed over the season.

[CamB25]

That seems to be the performance magic...quicker and efficient in the low and mid range while not sacrificing top end. It's a bit like 2 props in one. I don't know what the "pitch" is...they don't describe their props in that way and the part numbers don't provide a clue. The looped design is able to reduce tip losses that are found in standard blade props. Reduced bubbles and wash = more grip, energy directed towards thrust. At least that's my guess.

The story of the 3 bears:

The first prop I tried was a tie with the Merc in terms of performance. Way better grip and smoothness, but a performance tie. Free UPS return
The second prop had better performance than the Merc, but was I "over-propped" and could not spin more than 5200 rpm. Free UPS return
The third prop hit the sweet spots in both low and high range. At some point Sharrow started producing bolt-on diffusers (flare at the exhaust end of the prop hub) to fine tune the performance. I tried the small and medium flare and both work well, but the medium flare had a bit more lift and slightly quicker time to plane, so I am running that one.

The engineer in me took over and I started recording my screens with a go-pro camera to collect all the data. That was fun, but I had to go through the videos frame by frame to record speed, rpm, mpg, trim levels etc. Painful and in the end the data told me exactly what my ass-o-meter measured, so I stopped being so analytical about the testing. To do this data collection correctly you need a NMEA 2000 data logger which I don't have and I don't want to buy, and many of the benefits are difficult to measure. It just feels better. Example - hole shot normally requires a significant over-rev to climb onto plane. Once you are up, you back down to cruise speed. The Sharrow's grip means you don't over-rev nearly as much. The boat lifts up and goes. Fun!

[Carl]

Thanks for sharing the Sharrow prop info with us Cam.

It is a tough comparison when you were a bit over propped with the Merc wheel. My guess is if you lost a little pitch on that wheel your top end would be a bit less, and the motor would have more low-end push. Fewer gallons per hour burnt at the same rpms...but not sure if that equates to better mileage though. Overall being overproped should make the Sharrow shine brighter in a true apples-to-apples comparison.

Seat of the pants better sounds great, I do like smoother and quieter but it is alot of coin for that. Well as not an option for me just yet, I can sit back and let the technology continue to unfold.

[Tommy]

The discovery of the new prop technology is quite interesting. Gregory Sharrow was working on new aerial drone designs trying to figure out how to reduce blade noise that was interfering with his audio-visual recordings. He figured it out in the aerial application and recognized it's value in the marine propellor field. I take my hat off to the guy; this is what's known as building a better mousetrap (but for now, more expensive).

[Carl]

I take my hat off to the guy; this is what's known as building a better mousetrap (but for now, more expensive).

I couldn't agree with you more Tommy. It is one thing to have an idea, and a whole different ballpark to turn that idea into a reality. If it truly is revolutionary I expect there will be competition and that has a way of bringing prices down.

[Yannis]

Tommy, tell us please which is the subject you have just inferior knowledge on !

[Tommy]

Yannis, my friend, that list would be WAY too long to publish here!

[Yannis]

Haha, you know, each one here plays a role!
You have it with the old Bertram models and you’re not shy with modern props either!

[DanielM]

Yannis,

I’ll wager the only thing that out shines Tommy’s knowledge of Bertrams is his gracious welcoming hospitality. He made an non-B31 out-of –
towner feel very welcomed when we made the North Carolina rendezvous a few years back.

Tommy, hope you’ve been doing well.


Cam,

That looks like some interesting technology, glad they are working out for you. I have occasionally bumped the oyster reefs over the years in our shallow muddy water down here it Texas. So I think I’ll stay old school, but the new tech is intriguing.

[Tony Meola]

Daniel

At the price if the spharrow, and I am sure lack of repair shops, bending a wheel would be a good reason to cry.

[Yannis]

Tony, this is another parameter for sure.

I fear the complexity of the math equations that have to be fed to the mending machine (which one?) to unwharp any dented prop...

[DanielM]

Higher upfront cost is to be expected with the onset of new technology. If they perform as expected that should come down as they become more common.

Hopefully, it will be the same with this tech eventually.

[Carl]

Higher upfront cost is to be expected with the onset of new technology. If they perform as expected that should come down as they become more common.

Hopefully, it will be the same with this tech eventually.

Ditto

LOl, I tried to say what Daniel just said in a few words...after two or three rambling paragraphs, I gave up.

[CamB25]

The discovery of the new prop technology is quite interesting. Gregory Sharrow was working on new aerial drone designs trying to figure out how to reduce blade noise that was interfering with his audio-visual recordings. He figured it out in the aerial application and recognized it's value in the marine propellor field. I take my hat off to the guy; this is what's known as building a better mousetrap (but for now, more expensive).

I bet he has some DoD work, as well. Quieter props mean stealthier submarines.

In my experience (always need this caveat) the difference between props when considering noise and vibration has been dramatic. I started with 4 blades that were extremely angry props, always growling and vibrating. I assumed the water coming of the back of the boat was turbulent and the 4 small blades were cavitating. I switched to 3 blade props and they were much better. The Sharrow is night and day better than any 4 blade I've tried and big step improvement over the 3 blades. Difficult to measure, but it's one of the performance attributes that I value.

Matt - these Sharrows have so much stern lift that I essentially loose steering at top speeds...squirrely in wind and waves. I can crank the wheel over 90 degrees with zero effect. Not great, but it's one of the trade-offs.

[Yannis]

Cam,

This with the outboard. With inboards positioned half way under a heavier hull would they still lift the stern?

[CamB25]

Good question! We need an inboard test mule with a good bank account!

[Carl]

I can pony up a boat, we just need to find somebody with a good bank account.

[Tony Meola]

I can pony up a boat, we just need to find somebody with a good bank account.

You need someone with more than a good bank account. I can't imagine the cost of testing a pair on a 31. If we pony up a boat, they may eat the cost just because they need to.

[CamB25]

What would make a good test? What boat configuration would have the broadest application? SF diesel, gas, shaft size, rudders, hp...lots of variables.

[Tony Meola]

Cam

I would say at this stage diesel. One of the older ones in the 200 to 330 hp range. Problem is Yanmar, Cummins or Volvo. Ugh. That would be 1 1/2 inch shaft.

They have to start some place.

[Carl]

Tony I think they started already from the looks of the pictures on the VEEM website. Looks like they are going after the performance boats where the money is. I say that as the wheels shown are all splined hubs. It makes sense that they went after the bid dollar outboard market first to get their Wheels Wet, perfect the evaluation and design process, and grow from there.

[CamB25]

Seems like this deal with VEEM is an IP license. I get the sense that Sharrow is not directly involved in the inboard market any longer. From VEEM website:

"VEEM has the exclusive rights to manufacture and sell the Sharrow propellers for 17 years..."

I'm sure they are helping some capacity, but we'll probably have to ask VEEM to support B31 demos!!

[Tony Meola]

I hope I am around long enough to see it, but I bet there is a 31 running with them within 5 years.