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If you want a 3B folder also check out Brunton's Varifold actually German made by SPW

http://www.bruntonspropellers.com/varifold/

I have a 21" version behind my 54hp Yanmar and am very pleased - I can do 8.5kts flat out with a clean bottom.

I think Leigh Michau is still the agent. It was not cheap but a little cheaper than Flexofold. Both the Varifold and Flexofold are much more efficient than a Maxprop due to their correctly shaped skewed blades. Also they work fine going astern.

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If you want a 3B folder also check out Brunton's Varifold actually German made by SPW

http://www.bruntonspropellers.com/varifold/

I have a 21" version behind my 54hp Yanmar and am very pleased - I can do 8.5kts flat out with a clean bottom.

I think Leigh Michau is still the agent. It was not cheap but a little cheaper than Flexofold. Both the Varifold and Flexofold are much more efficient than a Maxprop due to their correctly shaped skewed blades. Also they work fine going astern.

 

Same engine as me then.

What boat are you driving with this?

And what is astern performance like including braking / reverse thrust and prop walk?

I've inherited a Volvo folding prop and when I go into reverse it feels like the prop isn't there. And that I have a 10-hp outboard going full noise pushing my stern to port.

Cheers

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My yacht is a Farr 46, sistership to Mustang Sally who used to be at GH, but without the super deep keel

Dimensions are 14.5m x 3.9m x ~11,000kg. The engine has a 2.62:1 reduction and prop is 21 x 15". Over pitched by about 1/2" because I cannot quite pull full revs, but of no concern.

Astern performance is great, there is some prop walk which is useful to take advantage of in manoeuvering and there is no problem "braking".

I looked closely at a Flexofold, the problem being that then (in 2005) they only came in even inch increments and 22" was going to be too big. Henleys proposed taking 1" off the dia of the Flexofold which was not ideal then the Varifold agent came up with the correct dia prop at a better price so that closed the deal.

Just for a bit of a bench mark for a similar size yacht on typical performance from the Yanmar with a Flexofold (size?), this link is quite useful

http://www.hallberg-rassy.com/fileadmin/user_upload/pdfs/boats_pdfs/HR40propellerFlexofold.pdf

My performance is a little better thanks to longer waterline

I am working overseas at present but will be back in NZ over Xmas - Jan, pm me if you would like to arrange a ride - I am moored at Sandspit.

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Maybe the Volvo prop is not the correct size for your vessel, I have a Volvo prop and find it great. Stops on a sixpence, with just a little prop walk in reverse. Maybe the boat is heavier than what the prop is designed for. The problem with not being able to pull full revs is that you are constantly straining the engine. When I repowered last year i was running a 3 blade Gori. With the new engine i could only pull about 400rpm less than max. Volvo would not warranty the engine unless a prop was fitted that would pull full revs because of increased load. 

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I think the prop size & pitching must be about right because I can get the engine to full rated rpm (3000) at which point I'm motoring about 8.5kts.

 

So plenty of grunt & bite going ahead.

 

Will inspect it more closely under the water again this w/e in case it's doing something strange when it reverses but currently it feels like it has fallen off.

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