Hi Rob!
In doing research, I hope you’ve seen
this article on Folding & Feathering props from Yachting Monthly Magazine? There is also some pretty good video. After doing the research like you’re doing I settled on a Flexofold, but realized I didn’t have the space to fit it in the aperature due to my limited distance (9-3/4”) between the rudder and the cutlass bearing.
I ended up settling on a Max Prop ‘Easy’ model, 16” diameter. They recommended a 14” pitch with our new Yanmar 4JH45 (45 HP) and our 2.36:1 Transmission. This model is about 8-1/2” from the front to the back of the anode. I was told that I needed at least 1/2” space between the front of the prop and the cutlass bearing for water flow.
I was very impressed with Fred at PYI (US distributor of Max Prop). He was very knowledgable and helpful. Patient with answering questions.
We hauled out a few weeks ago and had our bottom sanded/painted and the Max Prop installed. We knew that our shaft would have to be shortened. We also had a little nub (don’t know what it’s called) that sticks out of the skeg where the cutlass bearing is. The mechanic @ the boat yard claimed that we should cut off the nub and move the cutlass forward in order to have enough space. Fred @ PYI said he thought it would fit without doing that because we only needed about 1/2” between the anode on the prop and the rudder.
I also thought it should fit but ultimately decided to have the mechanic move the cutlass forward. Because it only cost a few hundred $ and would make servicing the anode and prop easier, especially since we will be diving to do that.
I think the “post install” photo below sort of proves there was room.
Very happy with the performance while motoring - I get about 7.1 knots thru the water with the Yanmar at 2250 RPM, consuming 0.95 gallons per hour. With our old engine/transmission/prop combination, the prop would start cavitating when it would get up near 7 knots. If we up the RPM to 3000 it shows 7.9 knots, which is above our calculated hull speed and it consumes about twice as much fuel/hr.
There is far, far less prop walk to port than I had with my old propeller. I got used to it, but it was still really difficult to back to starboard in a short distance. Needed to get some speed up to overcome the prop walk. Now there is not much difference between forward and reverse.
Haven’t tried sailing yet, maybe this weekend. The ultimate test will be when we race this summer.
One final point: we have a 384, which have larger rudders than 382s. I don’t know if the opening where the prop is (aka aperature or aperture) is exactly the same. My guess is they might be.
That’s all I can think of for now ... let me know if you have any questions.
Cheers,
-Mark