Feathering propeller sailing improvement?

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Rick Simonds
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Joined: Fri Dec 05, 2008 8:49 pm
Location: Tallahassee, FL

Feathering propeller sailing improvement?

Post by Rick Simonds »

Saturday I finally put a Cruising Designs 3-blade feathering propeller on my Hoyt 32, one I've had kicking around my garage for a few years. It went on in place of a really big Michigan Wheel solid 3-blade, a terrific "motoring" propeller but about as awful a "sailing" propeller as I could possibly have. I tried it out Sunday in virtually no wind, just enough to fly the telltales and keep the boat moving at all, about 1 knot (I'm also in the middle of changing out the instruments so didn't have a GPS or anything else aboard to know my speed accurately.) It SEEMED better, I was much faster than a friend's boat but I'm always faster than him, so who knows?

I'll get some actual numbers in sailing performance over time but has anyone measured this?

What sort of real-world increases do you'd think I'll find?
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Michel
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Joined: Sun Dec 07, 2008 5:48 am
Location: Zaanstad, the Netherlands, EU

Re: Feathering propeller sailing improvement?

Post by Michel »

I think you'll see at least one knot improvement, depending on hull speed. Maybe even 1.5 if you are sailing around hull speed.
Michel Capel, Freedom 44 #4 1981 'Alabama Queen', NED8188, cat ketch with wishbones, home port Enkhuizen, the Netherlands, 52*42.238'N 005*18.154'E.

Mike Holibar
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Joined: Mon Jun 01, 2009 12:41 am

Re: Feathering propeller sailing improvement?

Post by Mike Holibar »

With our Kiwprop we picked up a knot or so and about 10deg in pointing ability. As a result we sail the boat a lot more where we would have motored previously. However motoring performance is not as good, down .5 knot, and 50 knots on the nose will pretty much stop us in our tracks.

Cheers,
Mike Holibar
S/V Fyne Spirit of Plymouth (Freedom 39PHS-1989)
Lyttelton
New Zealand

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THATBOATGUY
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Location: F40 CC CK Maryland
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Re: Feathering propeller sailing improvement?

Post by THATBOATGUY »

Mike, 50 knots on the nose... woof! I love the way Kiwis can just throw that out there like it was "normal". :) So much you guys just get right.

George
George and Kerri Huffman S/V Marquesa Freedom 40 CC CK Sail MarquesaImage

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Rick Simonds
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Joined: Fri Dec 05, 2008 8:49 pm
Location: Tallahassee, FL

Re: Feathering propeller sailing improvement?

Post by Rick Simonds »

“…50 knots on the nose will pretty much stop us in our tracks.” Well,...OK, ... you convinced me: I’ll try to avoid that.

But even that is no match for the Earth itself: I sailed aground into a soft mud bottom my very first day of using it. Backing off didn’t work but in just a minute or two I wiggled myself off in forward with a sharp pivot to port. I really believe with the old prop’s additional power I would have simply backed off without a moment’s hesitation.

My old prop was actually a big 3-blade designed (I think) for an inboard Mastercraft ski boat. It had immensely wide blades giving it wonderfully “grip” and “punching power”, probably as good as it gets. This one doesn’t have that sort of power; the boat doesn’t go as fast at a given RPM, it doesn’t accelerate from a standing start as well nor does it have the pulling power and “punch” of the old one. I don’t have numbers on this but, by feel, it runs smoothly but I’d say I lost something like .5 knots under power, maybe a bit more.

I’ll very happily trade that for a full knot or more under sail, though. I’m planning on stopping the engine with the blades open and sailing for a bit, carefully measuring my speed. I’ll then re-start the engine to feather the prop, sail some more and measure again. I’m anxious to see the results. I’ll post my data when I have it.
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Tallahassee

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