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post #21 of 38 Old 10-28-2015
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Re: Pros and Cons of Folding Propellers:Avoid J Props

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Originally Posted by Melrna View Post
What they don't tell you is the other side of the story: motoring. Most if not all folding propellers lose power, the ability to propel your boat as fast as your fixed propeller. How much is lost will depend type of boat.

Cruising Sailboats - Those sailors that are full-time/part-time cruising, and/or with heavy displacement boats and need all the performance they can get while motoring should consider not putting on a folding/feather propeller. Major power losses of up to 1-2 knots could result in putting on one of these propellers. With my J Prop I have seen losses of up to 2 knots.

In summary, the pros of a folding/feathering propeller, less drag while sailing and better reverse performance when docking (no or little prop walk) Cons: loss of horsepower while motoring and expense.

The big question: Is gaining .25-.5 knots sailing at certain wind speeds and angles worth the loss of 1-2 knots of motor speed?
For me a fulltime cruiser, NO. A big mistake on my part or I just bought the wrong feathering propeller.
With all due respect, you may accurately be describing the behavior of the specific prop on your boat, but your conclusions are way too broad a generality which really do not seem to apply in all cases, or even in most cases. I believe that it was Max Prop who used to publish a detailed scientific comparison of their prop vs fixed props of equal thrusts at equal effective pitch. They claimed that they had lower blade drag when motoring and so were getting better fuel efficiency and requiring lower RPM's to obtain the same thrust.

That is similar to my experience with my boat which has an ancient Martec folding (not feathering) prop. When I bought the boat, there was a spare fixed prop that was supposedly the original prop that came with the boat. I had Martec recondition the old prop and so used the fixed propeller for a while. The fixed prop clearly had slightly but noticeably less speed at the same rpm and poorer ability in reverse. During the swap I noted that the folder had a larger blade area than the fixed which may be part of it. I did not run a precise fuel comparison but I would have to assume that the fixed propeller was using more fuel since it required more rpms to achieve the same speed through the water as the folder. This was especially noticeable on a day with big chop and wind on the nose.

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post #22 of 38 Old 10-28-2015
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Re: Pros and Cons of Folding Propellers:Avoid J Props

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Originally Posted by Melrna View Post
I am starting this thread for two reasons. My utter disappointment in my feathering propeller, J Prop, and "Buyer Beware" of performances gained and lost when putting on a folding/feathering propeller.....In summary, the pros of a folding/feathering propeller, less drag while sailing and better reverse performance when docking (no or little prop walk) Cons: loss of horsepower while motoring and expense.
I would be interested to hear how the issue was resolved - I hope it has been! I have the Max-prop (feathering). The guys at PYI could not have been more helpful. I have gained:
* 1+ knots speed increase under power (same RPM).
* Increased efficiency and reduced propwalk in reverse (difficult to quantify)
* 0.5kn+ more speed under sail.
* Ability to sail in light airs.
* Actually won a beer can! :-)

My old gal is 32', around 13klbs dryweight.

I agree that props like the Max are very expensive, but I regard it as one of the better upgrades I have recently undertaken. My experience seems to have been reflected by all of the other posters. I am so sorry that your experience has been so poor - I am guessing that there must have been something wrong with the sizing, installation or adjustment. But don't write off the technology...
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post #23 of 38 Old 10-28-2015
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Re: Pros and Cons of Folding Propellers:Avoid J Props

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Originally Posted by Fstbttms View Post
There are several Max Prop models (one of which has been available for quite a few years) that have external pitch adjustment controls.

That said, any model Max Prop can be installed or removed or lubricated or have its pitch adjusted while the boat is in the water. Never a need to haul for any of this.
While it is true that you can install, remove, adjust my older 3 blade MaxProp in the water, PYI does not recommend this for the DIY types. We had to do this once and it took an hour and a half with SCUBA gear to reinstall mine. You'd better hope the water is warm enough to work without gloves when you replace those little cutoff cotter pins! Won't do this again.
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Re: Pros and Cons of Folding Propellers:Avoid J Props

There was ONE guy in Seattle who would adjust a Max Prop with the boat in the water. One guy.

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post #25 of 38 Old 10-28-2015
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Re: Pros and Cons of Folding Propellers:Avoid J Props

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While it is true that you can install, remove, adjust my older 3 blade MaxProp in the water, PYI does not recommend this for the DIY types. We had to do this once and it took an hour and a half with SCUBA gear to reinstall mine. You'd better hope the water is warm enough to work without gloves when you replace those little cutoff cotter pins! Won't do this again.
I wasn't inferring that it should be done by anybody but a qualified diver, which PYI will happily recommend.
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Re: Pros and Cons of Folding Propellers:Avoid J Props

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There was ONE guy in Seattle who would adjust a Max Prop with the boat in the water. One guy.
One guy could handle the amount of business we're talking about, I guarantee.
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Re: Pros and Cons of Folding Propellers:Avoid J Props

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I wasn't inferring that it should be done by anybody but a qualified diver, which PYI will happily recommend.
And PYI had NO recommended divers in my area. That's why we did it ourselves. It isn't brain surgery, but there are a lot of parts still subject to gravitational pull!
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Re: Pros and Cons of Folding Propellers:Avoid J Props

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Any down sides? Loss of top end performance? Same or different rpm to reach hull speed?

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Didn't notice any downsides. Rpm's and speed the same.
Plus sides. Prop walk in reverse pretty much went away and no loud clunk when you engage reverse.
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Re: Pros and Cons of Folding Propellers:Avoid J Props

So if you don't want the intricacies of a folding or feathering prop and a fixed-blade prop gives you too much drag but you still want the efficiency of the fixed blades, how about one of these - seems like a nice combination :-)
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Re: Pros and Cons of Folding Propellers:Avoid J Props

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Originally Posted by Omatako View Post
So if you don't want the intricacies of a folding or feathering prop and a fixed-blade prop gives you too much drag but you still want the efficiency of the fixed blades, how about one of these - seems like a nice combination :-)
Looks cool, but I don't see either the avoidance of complexity or the retention of reliability there.

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