Prop rotation question

dLj

dLj

.
Mar 23, 2017
4,186
Belliure 41 Back in the Chesapeake
Scott T-Bird said:
Nope! It's Autostream. I'm packaging it up tonight to send to Martec in Arizona. Hopefully, it will come back looking like new. The inside of everything looks pristine to me, but the blades and casing has caked-on paint. The man said he will set the pitch for my engine configuration. Replacement parts will be locking pins for the drive gear, rubber O-rings, locking wire, and a new zinc. He said to keep the propeller nut and the ss key. They don't have spare propeller nuts any longer. I'm hoping they can clean up the cap head screws as the heads seem pretty rounded. I'm not sure how the yard got them off.
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While you still have a good original nut and you are waiting on the prop to get refurbed - might be a good time to get a machine shop to make you spare propeller nut...

dj
 
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robbjd

robbjd

.
Nov 17, 2020
13
Catalina 34Mk II 1344 Sarnia
Mark Maulden said:
I have a feathering J-Prop. It has no prop walk and does just as well in reverse as it does in fwd. This last summer, I backed out of a narrow fairway with a X wind with an audience of other boats. Once out, I had an ovation and I took my obligatory bow. Concerning maintenance, removal and install is a bit of a pain as there some small bits that lock the nut and takes some time getting it right. The yards get very specific instructions that I and I only mess with prop. The yards around here have no experience with such. The prop goes on as a complete assembly and you can even quickly change pitch while in the water.
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Mark, I also have a two blade J Prop on my Catalina 34MkII. I definitely have typical prop walk (stern to port). Is yours a three blade?
 
Scott T-Bird

Scott T-Bird

.
Oct 26, 2008
6,234
Catalina 320 Barnegat, NJ
An additional follow-up based on in-water usage! ... It appears that performance has improved significantly since I have been using my re-conditioned prop! I believe I am achieving at least half knot extra speed while motoring at above 3000 rpm. The other day, I was seeing 7 knots on both SOG & boat speed (current is pretty slack in our area) at 3000 rpm, which I've never seen before. Feathering while sailing is functioning well! The re-conditioning was well worth it!

Installation was very straight-forward. The only issue that I ran across was that instructions call for a locking pin to fit in grooves that have to align. I could see right away that I didn't have grooves that could ever fit the locking pin that was supplied with the re-conditioned prop. I called for explanation and found out that my prop is so old that the modification for locking pins came after my model was built. He said that it was really just a safe-guard for sailors who don't torque the locking nut properly or use the correct lock-tite. He said that as long as I follow specs, I would never lose my prop!
 
Maine Sail

Maine Sail

.
Feb 6, 1998
11,700
Canadian Sailcraft 36T Casco Bay, ME
Scott T-Bird said:
I didn't realize that I was going to have to know this before taking my PYI Max Prop off for re-conditioning! I'm pretty sure it's left hand rotation. Boat is a Catalina 320 with Yanmar 3gm30F and Kanzaki KM2P transmission with gear ration 2.21 as seen on the stamp. I had the yard remove the prop and I didn't realize that they would remove the blades in the process of getting the prop off the shaft. When they gave me the prop, the blades were really in an odd configuration, which really freaked me out until I realized that they simply were a little careless in putting the assembly back together! As seen in the photo, one of the leading edges is reversed! Look which way blade 3 is pointed! The fact that it is marked on the opposite side is a clue.

The problem is, I don't really know which way the leading edges were oriented before this was taken apart. I guess I just never focused on this issue. Since 2 of the tree blades come to a stop with leading edge forward when rotated ccw (viewing from the trailing edge) I assume it is left hand. But I'd like to know if there is another way to confirm it. Yanmar specification sheet for 3GM30 says crankshaft rotation is CCW when viewed from the stern. I've heard some transmissions can drive the prop shaft in the opposite direction, but that doesn't appear to be the case.

View attachment 222042
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That's not a MaxProp....
 
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