Author Topic: Wanted: folding prop 2- or 3-bladed  (Read 337 times)

Bav32

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Wanted: folding prop 2- or 3-bladed
« on: March 10 2019, 20:58 »
I would like to buy a folding prop 16x10 or 16x11 for a saildrive. I would prefer a 3-blade version, but a 2-blade would also be an option.

rbrtmccorkle

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Re: Wanted: folding prop 2- or 3-bladed
« Reply #1 on: March 11 2019, 16:32 »
The Owners Manual for my Bavaria Ocean 42 calls for a three blade 17X12 LH propeller.  When I bought the boat the survey show the Fixed 17X12 prop to be badly pitted so after consultation with Volvo I purchase and ran for two years a 3 bladed folding Volvo prop  16X11 prop (17X12 was not available as a folding prop).  It is my belief that both the 17X12 and 16X11 props are undersized for my boat as both would allow me to over rev the engine getting as high as 5000 RPM and both needed close to 3000 RPM to motor @ 5 knots. 

Recently had the boat out of the water for some bottom paint and while I was at it replaced the 16X11 blades  (uses the same hub) with 18X12 blades.  the boat will now motor at 2.5 knots with throttle just out of the detent and engaged  -  @ 1800 RPM it easily makes 5kts.   I can still get 4000 RPM when floored so am researching how to adjust the governor. 

My advice would be, if your happy with how the fixed prop performed go with that size or maybe think about one size larger.  I certainty prefer the larger prop in my usage.  I did keep the 16X11 blades as spares should something happen.

Bob - SV Chaos

Bav32

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Re: Wanted: folding prop 2- or 3-bladed
« Reply #2 on: March 11 2019, 19:38 »
Thanks for the pointers. I had an Volvo Penta salesman calculate the right prop for me. He suggested a 3 bladed 16x10 or a 2 bladed 16x11. He also told me that there should not be that big of a difference between a 2 bladed 16x10 and a 16x11.

But having bought a slightly too small prop for my previous boat I have to say that I agree with you on this one.

A thing I worry about is reversing or "breaking" with a 2 bladed folding prop. Is there a significant difference with these two options?

Symphony

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Re: Wanted: folding prop 2- or 3-bladed
« Reply #3 on: March 12 2019, 10:44 »
Your choice is appropriate. However, recommendations of size can be specific to a particular brand of prop and it is risky buying a folding prop without checking the actual manufacturer that the size is correct for your boat.

My experience with a Flexofold 2 blade on both a 37 is in fact better than the fixed prop. You really do not need a 3 blade for performance. Some 3 blade props (as well as being typically 50% more than 2 blade) are notorious for anode wear because of the mix of metals used and small size of anodes.

Chances of finding a decent used prop of the right size in decent condition are pretty small - why would anyone want to sell one? Suggest you contact Darglow Engineering and get a quote for Flexofold 2 blade. You only buy once and you will not be disappointed.

IslandAlchemy

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Re: Wanted: folding prop 2- or 3-bladed
« Reply #4 on: March 12 2019, 13:54 »
The most efficient prop is a 2-blade with the biggest diameter you can swing.

However, the physical blade area has an effect on the grip/slippage that a prop provides/suffers.

More blades typically equals more grip as there is more blade area.

The shape and profile of the blades also has an effect.

Not all props are equal.

IslandAlchemy

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Re: Wanted: folding prop 2- or 3-bladed
« Reply #5 on: April 04 2019, 08:09 »
This of any use?  You'll have to be quick at this price though

http://www.ybw.com/forums/showthread.php?518492-2blade-sail-drive-propeller-17X12-left-hand

Bav32

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Re: Wanted: folding prop 2- or 3-bladed
« Reply #6 on: April 04 2019, 17:36 »
This of any use?  You'll have to be quick at this price though

http://www.ybw.com/forums/showthread.php?518492-2blade-sail-drive-propeller-17X12-left-hand

Thanks, but that ones a bit big for my engine.

I ordered one from ebay.de, let's hope it's not a hoax  :)