Posted on 09/23/2024 1:09:41 PM PDT by Red Badger
Sharrow. reaches out to a larger market with the aluminum MX-A propellerSharrow Marine View 2 Images
Sharrow Marine has quietly been working to disrupt the marine industry with a reimagined propeller it calls the "future of propulsion." The tech originally looked like it might be too expensive and make/model-specific to see that future to fruition in a substantial way, but Sharrow has now introduced the more affordable, consumer-friendly MX-A. Less than half the price of previous models, the latest Sharrow propeller works with smaller outboards of just 40 hp and up, and it's compatible with motors from a who's who of the largest, most popular brands in the industry.
Sharrow has redesigned the common marine propeller by replacing the usual blades with gently twisted loops that promise to eliminate efficiency-sapping tip vortices and cavitation. Put simply, less energy is wasted, leading to claimed efficiency boosts of up to 30%, not to mention smoother, quieter overall performance.
Not only has Sharrow's 150-patent-deep design won a host of major awards from the marine and tech industries, it's been put to the test on numerous vessels, both internally and by third-party reviewers, with some intriguing results.
The first time we took a look at Sharrow's unique propeller design, we noted that the one big drawback seemed to be price. At about US$5,000 a pop to start, they were an estimated 10 times more than a typical propeller, a steep upfront investment that might be difficult to recoup even with a 30% efficiency boost.
(Excerpt) Read more at newatlas.com ...
"A boat is a hole in the water you throw money into."
I can't see why these can't be made from hard vinyl for way way less.
These have been around for a few years. Cnc is for stainless steel. They have started using aluminum and casting. The 30% gain is in a narrow band around optimal fuel use. Most other ranges are better than standard props but only slightly. Hard to recover cost on smaller boats, but 30% gain on boats <.5 mpg at over $4.50 gallon may make sense.
Probably prototyping right now. Investment casting molds would be quite tricky with that shape.
Machining these from billet only needs one shop, one machine, and one or two setups. With casting you need a foundry, wax molds, and you still need the fancy cnc for the finish pass to get it balanced. Then ad the QC process transfering between shops and processes, billet ends up being cheaper.
Speed. I’ve pointed this out in my sailboat group. I’m from Savannah, Ga and one day at the beach, I saw a boat called the Philadelphia Express leaving out. I was tracking it on an AIS app and noted that 4 days later, it was in Lisbon Portugal. 4 days! Great if you need something there fast.
But, like I said, our boat (a Tashiba 36) is slow, no matter how we propel it! But, she can sail the world given time.
Forgings can be stronger, but it also depends on the alloy, heat treatment, stress relief etc.
What I read here, Mercury uses a proprietary alloy and all their propellers are cast.
https://www.mercalloy.com/mercury-castings/
I don’t know about all the variations in propellor pitch, but this one look like a good candidate for lost foam, although I guess it depends on volumes.
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