Here is a video from BoatTest.com on an interesting new propeller design from a company called Sharrow Engineering.

Wow! I wonder how expensive.

Good question. Looks like they would be complicated to fabricate. They might also be fragile if making contact with the bottom or debris. Where would you get one fixed if you bend a blade?

Wondering if they would make models for the counter rotating stern drives (DP/B3)?

Wow. Not just a placebo, measured effects.

Interesting.

I had those same thoughts in the video that FR posted.

The dramatic increase in speed at idle has me interested. I often run at hull speed (8.5 knots on my boat) and if I could reach that speed without throttling up above idle (which is currently 6 knots), without over-propping the boat, that would save me a lot of fuel, probably enough to pay for the props in a couple of years, unless they are absurdly expensive.

Repair would have to be done at the factory until independent repair shops invest in the tools to repair these props.

I would think DP/B3 models would be planned for sure, those drives are really popular and it would make sense to offer an upgrade.

I hope these are the real deal, it would be really cool if there was a revolutionary improvement in prop efficiency.

Very interesting. Will be interesting to see if they catch on or not. Not much really changes in props. Remember years ago they had shifting props but they didn't become popular. Cost could have been a factor but still would have thought the gains would have made it worth while.

Word on the street was those Land and Sea shifting props were really hard to set up. There was also a short period in the late 80s or so when Mercruiser offered a two speed transmission option between the engine and the stern drive. If memory serves, it was basically the planetary gear set out of a GM Powerglide and a simple ring gear brake in a fairly thin (front to back) package. It did not catch on either.

Not much room in an outdrive for a CVT type setup either

I wonder about what this prop could do with 'too much' horsepower... My little old Sea Ray, during the brief period my friend owned it, had what was close to a 500hp 383 pushing her around. Once that engine was installed, the 15x19 SS prop that worked just fine for 15 years blew it's hub out at the first WOT stab. 3 spare aluminum props didn't last long either, they wouldn't grab during a WOT holeshot at all, they'd just start making air, IIRC they blew their hubs during high speed runs at well past 5000 rpm. I drove the thing at Yellowstone Lake with a 15x17 plainjane Merc prop, the boat worked wonderfully until you tried to go fast, even at 6500' that 383 could ventilate that prop at will. That much power in that boat was almost useless -- so without any trailing edges, I wonder how the Sharrow would've done in that setup...

Anyway, very interesting. I also wonder, due to it's design, seems do-able to just 3D print one out of some decent material and go boating! Hit a rock, just make another one...

"Remember years ago they had shifting props but they didn't become popular. Cost could have been a factor but still would have thought the gains would have made it worth while."

Land & Sea Torque Shift props are on eBay.

Some of you may remember I had an Aerostar shifting propeller. Completely satisfied. Yes expensive but it worked! When it shifted, it was much like a Two-speed Chevy Power Glide transmission. Sold it to the owner of an under powered boat when we bought the Montery. I don't know if they are currently selling propellers, but they did help the buyer of my prop in 2012 to purchase a Mercruiser hub (mine was for OMC stringer mount).

Here's a prop comparison article from a 1997 issue of Popular Mechanics.
https://www.popularmechanics.com/adventure/outdoors/a5650/1276976/

Here's a link to Aerostar Marine
http://aerostarmarine.com/

https://www.boattest.com/review/sharrow-engineering/3986_propeller

Just got this

Very interesting... revolutionary?

I just had captkevin's link sent to me by a friend, I somehow missed this thread here, this is really remarkable.. See the MPG difference at 3000 RPMs? The captkevin article is pretty thorough and well worth the read.

Looks like they got the price down to $2k with a 1 year total warranty, including damage. I think the video on the right is pretty new - https://boattest.com/Sharrow-Engine...stcom-newsletter&utm_content=Fri+2.5

The original video is on the left, the pricing and ordering info video is on the right. Still expensive certainly compared to other SS but, considering its the first year of production, at least it is in the realm of the same market, vs the $10k it was. I'm kind of excited to see how this is adopted over the next 5 or 10 years. I'm sure it will mostly start with the big, pricey, expensive boats/vessels and then trickle down....how far down is the question.

It's just cool to see someone improve a design in so many ways in an industry that has been around as long as shipping and boating.

Some updated videos and info at the Boattest link above....really remarkable. Plan to make 10k units in 2022. I can't remember if all of the development backstory info was posted back in 2021, if it was I forgot it, but interesting read if you scroll down a ways.

Sharrow Prop Production for 2022

Greg Sharrow, the propellers’ inventor, has made agreements with three foundries in the U.S. Midwest to cast his props. His company is currently planning on doubling the number of CNC 5-axis routers needed to finish the props to within a tolerance of .003, something nearly impossible to achieve with standard-design cast props. He is planning on casting 10,000 props next year.

Because the Sharrow props are designed for each specific engine and its gear ratio, Sharrow plans to cast the same 15.5" x 15.4" (39.37 cm x 39.12 cm) props used on the twin Yamaha 300s in this test.