Flexofold prop for IP380

Has anyone installed a Flexofold prop on their IP? If so, how do you like its performance and did you need to make any modifications (e.g. shorten prop shaft, etc.)? Was the recommended size Flexofold appropriate? I love my 1999 IP380, but my fixed prop has developed a crack and this seems to be a good time to look into alternatives to the fixed blades and perhaps gain a little speed. Thanks for your input.

I don’t know about the Flexofold but I had a Maxprop on my IP420 which was never as good through strong seas when the going got tough. It seemed to cavitate in bad conditions. I then went back to a fixed prop which performed more effectively in rough seas. I still have the Maxprop which is in good condition but this only helped my lighter wind sailing marginally.
I would stick with a good quality fixed pitch - Island Packet knew what they were doing!

I appreciate the response. I hear a lot of good things about Maxprop and am surprised things didn’t work out for you. Did you try to work with Maxprop to resolve the issue? Maybe a different size or pitch? But as you say, IP has a reason for what they do. Thanks.

I think Maxprops are well made and suit a lot of boats. They also have the advantage that they can reduce prop walk. I did reduce the pitch from that recommended by the supplier and this helped. However the long keel and weight of an Island Packet tends to reduce the impact of prop walk and does not result in much less saving in drag with a folding or feathering propeller. Obviously a fixed pitch propeller can be designed to be more efficient when under power in forward motion than is possible with a propeller that changes blade angle in reverse. It should also be born in mind that if there is enough wind to enable maximum hull speed under sail, nothing will be gained with slightly reduced drag from a propeller. Perhaps, to be fair, I should point out that I consider the Island Packet to be a cruising boat that will take heavy weather and do not race ours in light winds. If one wants to race one’s yacht, a lighter displacement would be more appropriate.

Agreed. I’ve done a couple mainland/Hawai’i crossings and picking up debris on my fixed prop is a chore. Planning on cruising Alaska waters this coming summer and like the idea of a feathering prop to help keep from picking up debris, crab pot lines, kelp, etc. but the full keel does help protect the prop and helps to minimize the problem. My speed comment is really more tongue in cheek re. IP design and purpose. Also like the idea of taking the strain off the transmission since I normally sail with the transmission in reverse to prevent the prop from spinning. But that is another topic.

I agree with your comments regarding debris etc. However if you have a fixed three bladed propeller and a Yanmar engine the latter manufacturer recommends leaving the gear in neutral and allowing the propeller to rotate. This takes the strain off the system and reduces drag but will, of course, ultimately result in more cutless bearing wear(whilst still allowing a shaft cutter to operate to a lesser extent).

I appreciate all your input and am putting the Flexofold on hold for now. The IP manual that came with my boat basically said a free-wheeling prop in light winds would create less drag (and therefore increased speed) and in heavier air locking the prop in reverse gear would not affect either very much leaving the decision to the skipper. Nice to know that Yanmar recommends free-wheeling.

But still hoping someone with a feathering prop will weigh in.

We put a maxprop on out IP380. Yes the shaft needed to be shortened slightly. We found the big advantage was handling in tight marinas; significantly better handling when shifting to reverse. When we shut down the engine for sailing in fwd gear, then we go neutral,reverse then back to neutral this ensures the prop has feathered and stopped turning. This is as per the Yanmar service bulletin re maxprop. The prop has been on our boat for 10 years, and regularly serviced during haulouts. Hope that helps.

Thanks for the additional input. Have you noticed any change in performance under sail? Seems the Flexofold doesn’t have any IP followers.

Difficult to tell any difference in sailing performance; perhaps about half a knot better. For us, the prime purpose was handling in very tight quarters...and that has been impressive compared to the fixed prop.

Thanks. The way the MaxProp turns the blades in reverse is advertised to improve performance in reverse. Nice to see support for that claim.

I’ve been looking at the Flexofold since it should minimize catching debris, etc. any extra speed would just be icing on the cake. But even only a half knot on a Hawaii - West Coast crossing takes a day or two off the passage. I’ve wondered if the reduced prop drag would really be noticeable on the full keel design of the IP.

Happy sailing.