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endvr32 · Posted: Wed Sep 10, 2008 10:15 am Post subject: Folding vs Feathering Props

Does anyone feel like having a discussion on folding vs feathering props? Fixed 2-blade and 3-blade props, despite being powerful, create a lot of drag slowing boats down under sail. The design of some of the folding/feathering props today come very close to the performance of fixed blade props, significantly reduce drag and can eliminate prop walk.

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Paul Uhl
Endeavour Owners Forum
www.endeavourowners.com

SLOboat · Joined: 10 Aug 2008 Posts: 7 Location: Port San Luis, CA

Elva Ann is a 1980 Endeavour 37, and she came with a fixed three-blade Federal bronze 17" (rh16), which is about max size (17.5 is max I think). Measured by my GPS, she has done up to 7 knots under sail (6.5 is not uncommon, and 6 is "routine"). That's about max hull speed. I do not have a through-the-water instrument, but I know the tides pretty well that she was in, and I'm pretty sure that is a pretty accurate idea of her speed; I was sure enough to give up on the idea of investing in a folding prop some time ago. BTW, she does 6.5 - 7 under power at about "20" RPM without stressing the old Perkins. I never dreamed of her -- or me -- as a racer, but I never cease to be impressed with her.
Now, if I could just do something about the "prop-walk" in reverse . . .
Great topic, though, and I'd love to hear what others think!
Glenn Rogers
s/v Elva Ann (Eneavour 37)
Port San Luis, CA

FastFred

Our E-40 came with (courtesy of the dpo) a feathering, variable pitch, reversing, 3 blade bronze MarTec prop. It's a beautiful thing to behold. When it works, it accelerates like a Formula 1 car, backs like there was no tomorrow and feathers while sailing. A splendid prop....except when it goes to no pitch (as in ZERO pitch)...at the worst possible moment. Twice! No propulsion either forward or astern. The screws holding it together backed out just a tiny bit, but enough to disengage the gears.
*&^%$#@!
The MarTec is now brightly polished and lubricated and safety wired so that it can't happen again....theoretically. But it resides under the Starboard settee....and will remain there for a while.
Now we use a fixed pitch prop and although the backing is abominable, we don't have angst every time we get underway....and no more "how fast can we get the anchor down and set" drills.
ymmv,
Fast Fred (E-40 'Liberty')

Beethoven · Joined: 30 Jul 2007 Posts: 3 Location: San Diego, CA

I have had a two bladed Maxi-Prop on my E38 for many years. Very satisfied with it. Boat still has a bit of prop walk, but it's manageable. No problems, service it every two to three years when the boat is hauled.

bobfnbw · Joined: 10 Aug 2008 Posts: 73

Have a fixed 3 blade prop now on E40. One day (way in the future, its a low priority item) I would go with a feathering prop like a paul luke, or a adjustable maxprop.
I also have a spare prop that came with the boat, also 3 bladed fixed. not sure what the specs are on either though.

rdunncpa · Joined: 29 Jul 2007 Posts: 9 Location: Coconut Grove SC

Started in May, 2008. 1978 E32 repowered last year with a new volvo 30. Bot a max prop 2 blade. after a professional install recommended by frank and jimmies prop shop in ft laud, horrible vibration. after mucho $$$, replaced shaft, realigned engine etc etc. still unacceptable vibration. maxprop agreed to a swap for a 3 blade feathering, which after 2 unsuccessful attempts at an underwater install by a talented diver, hauled out. in less than an hour, splash and sea trial:

Hooray!

Great performance for my old cruising boat and new phrf racing boat!

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Russell Dunn
Invicta
E32 1978