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 Post subject: Feathered Props
PostPosted: 01 Aug 2017 07:00 
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Skipper

Joined: 09 Jul 2008 12:51
Posts: 251
Of those who upgraded to a feathered prop... for the old factory fixed... can you give me your opinion/review of the performance of the new prop ?

Performance in forward... and performance in reverese ? Please add what prop you purchased,, model and cost...

I'm especially interested in reverse performance.

My thanks in advance !!


 
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 Post subject: Re: Feathered Props
PostPosted: 01 Aug 2017 07:09 
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Skipper

Joined: 16 May 2009 08:06
Posts: 236
Gori or Flex-a-Fold. Mine is 17" I think and it could be smaller. I bought it at a flea market for $250 about 18 years ago so I live with the slightly over prop situation. I think they are around $1,200 or so new. Great performance in forward and reverse. With the folding prop, you can sail over crab/lobster traps without hooking. I have about 3,500-4,000 engine hours on this prop and it is great.


 
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 Post subject: Re: Feathered Props
PostPosted: 01 Aug 2017 08:17 
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Skipper

Joined: 21 Jan 2010 12:57
Posts: 168
Kiwi feathering propellor. I'm happy with its' performance. The "P" factor is apparant in reverse: you can't get away from the physics of a prop shaft that's not parallel to the flow of the water/air. I seem to recall that it cost a bit north of a thousand US.


 
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 Post subject: Re: Feathered Props
PostPosted: 04 Aug 2017 05:55 
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Skipper

Joined: 29 Dec 2006 09:38
Posts: 656
I put a 17" Autostream (Austrailian made, sold by Martec here in the US) on my T37 more than 20 years ago. It is rugged (I picked up a 1" poly line with it that sheared my coupling, ripped out my cutless bearing and did nothing to the prop) and it is externally adjustable in forward and reverse. I think the Max Props are grossly overpriced and their bronze construction is beautiful but delicate. Boat builders gave up bronze prop shafts many years ago because they are too maleable. Fixed props need to be maleable to be repitched but with feathering props this is not required. You need whatever you buy to be externally adjustable---every boat, even the same design, is going to be a little bit different and getting the pitch to match the torque of your engine is going to require some serial adjustments to get it right. I get about .6 kt more sailing speed as opposed to dragging the old, grossly over pitched prop that came with the boat. I am able to get exactly 80% of hull speed with 80% of engine rpm (recommended for engine life over the "lugging" of the old over pitched prop) I get better reverse thrust that reduces, but does not eliminate the "walk" you get with reverse.
One of the best improvements in my boat's performance. I think I paid something like $1700 for it (probably more now) and installed it myself--getting the old one off was the issue.
Ray Durkee
Velera #373


 
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 Post subject: Re: Feathered Props
PostPosted: 07 Aug 2017 20:48 
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Skipper

Joined: 14 Jul 2012 20:36
Posts: 495
Location: Norfolk, Va
I've had a Gori and Flex-a-fold. The current FAF is a great prop in forward, reverse is an adventure. Really helps with sailing in light wind. Gori did better in reverse, but was under pitched. I bought three FAFs for other Tartans. Well made, next year going to switch to the FAF three blade. Less vibration and better in reverse with less prop walk. I can't remember the price, maybe $700.

_________________
Hull #208, Puff Card
Southern Chesapeake Bay


 
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 Post subject: Re: Feathered Props
PostPosted: 18 Oct 2017 08:09 
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Midshipman

Joined: 01 Nov 2014 12:50
Posts: 68
Location: Toledo
Have a 17" 2-blade Max-prop. Found it used on ebay. Works great but optimal would be a 16" 3-blade. Still some prop walk. Feathering props generally reverse by spinning and still using the same leading-edge. Because of this they don't "cup" the blades, which means they might actually perform better in reverse than a fixed-blade prop.
Anyone know anything about wear tolerances on these?


 
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 Post subject: Re: Feathered Props
PostPosted: 26 Oct 2017 19:14 
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Skipper

Joined: 29 Dec 2006 09:38
Posts: 656
I am not sure what you are referring to as “wear tolerances”. I bought my AutoStream 17” feathering prop about 17 years ago and put a lot of miles on it. It came with some replacement parts delrin bearing, but I have never had to replace them. I have cleaned the thing annually and put new O rings to hold the grease in, but I am not sure the rings were needed. if you think about it there is not much to wear out as the blades are fixed except when you shift. I think you are right about getting a 16”. I know you are supposed to swing the biggest prop you can—and a 17” fit on my boat with the required clearance, but I think there is more prop noise and a bit of vibration that would go away if you had a 16”. Having said that, it is the best modification of my boat for speed and efficiency.

Ray Durkee
T37 #373


 
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