J/30 Class Association Forums J/30 Forum The Boat, Sails and Equipment Prop Shaft Cutlass Bearing

You might take a good look at the shaft itself while you have it out. Two of the three J-30's on the dock have broken the shaft at the transmission coupling in the last two years, appreantly from extended vibration over the years. Both shafts broke while under very little load. Good luck...Mike

Log tube OD should be 1-3/4". Performance Yachts (425) 355-3669 p/n 01-034-134 is a PSS std 3/4 log 1 3/4 should fit.

My coupling was rusted solid too. Had to cut the shaft out ($$). Replaced coupling with a split-coupling: std flange bolts to the tranny and has a split hub with two bolts that sinch down on the shaft, with keyway and lock screw. I'm told it will never rust solid because you can always pry the split hub slightly to pop the shaft loose.

Thanks for the log tube dimensions! I'm going to order the cutlass bearing & PSS today.

Where did you get your split hub coupling? Did you have to have one machined? I'm still hoping I can get the shaft out without having to cut it out. I'd rather replace the entire coupling before I put it back in though.

you might want to measure first. J 30s have different dimensions. I don't know about the tube but the shafts vary from 7/8 to 1in that I know of. FYI It is my understanding that the original specs for J 30s were lost in a fire at TP.

Brian, There's some machining required to fit the coupling. I bought it from a local NJ prop shop. They need the original coupling to get the pilot diameter (raised lip on the flange face) to fit the tranny counterbore ID (it makes sure the coupling bolts on-center). I don't know if they also drill the bolt circle and broach the keyway to fit the shaft, or if those are standard. email if you want the address, but I would think a local shop would be easier to "show the parts". Good luck. seth.hunter@i-stat.com

Brian, one last thought - when buying a new coupling for an old shaft, check the position of the set screw(s) to make sure your shaft is held the same distance from the flange face - to avoid too small or too large a gap between the prop hub (or the key if it sticks out) and strut.

Shunter - Thanks for the info. I think I'm going to try to avoid getting it replaced this year. I was hoping I might be able to replace it with a standard off-the-shelf unit. Doesn't look like that is the case. I'll make an attempt to get the shaft out gracefully first. If that doesn't work I guess I'll be forced to get a replacement.

j30381 - Do you mean the size of the shaft? The shaft on joust is 3/4". I haven't measured the log tube but was going to go by Shunter's numbers.

The second screw came out last night. The shaft is still firm in the coupling though. It took so long to get the screw out of the coupling that I ran out of daylight and gave up for the night.

I was able to measure the shaft tube. Mine is 1 3/4 also.

We had to use a block of soft wood and a hammer against the front of the prop assembly to finally get the shaft out of the coupling. My boat has been in fresh water all her life and it was still a lot of effort. To get the coupling appart we first drenched it in liquid wrench. Then we tapped repeatedly at the seam with a cement chisel...for seemed like an hour. It finally came apart.

I'm hesitant to mention this but I've heard of people doing it - putting a 5/8" dia rod (or long socket) between the end of the prop shaft and the transmission (inside the coupling) and tightening the coupling flange bolts to press the shaft out. I would convince myself the mating flange on the transmission is solid and one-piece before trying it, but it might work. One other thought - broken shafts as described sound like misalignment problems to me. Always a good idea to have the engine alignment checked periodically (preferrably in the water so the hull's true).