Posted on 09/23/2024 1:09:41 PM PDT by Red Badger
"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.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.