Hi,
I have been helping some friends fix their new-to-them
boat and have a few questions on how best to proceed.
Their prop shaft slid out of the coupling but luckily the
rudder stopped it from falling all the way out of the
boat. The key was rounded, the coupling bore worn (unevenly to one side) and the keyways on the coupling and shaft worn to more of a v shape.
We wanted to see if we could rig it to
work for the rest of the season until
haul out to deal with properly. The coupling is a straight bore and should be an
interference fit but slides freely on and off the shaft without a key. In order to fit a new key in, I had to file the keyways which had spots that mushroomed over, particularly on the shaft near where the set screw for the key had been pushed into the shaft. Even though it seems most of the wear is on the coupling (I don’t really trust my reaching one handed shaft measurements), I figure both need replacing and no sense
buying a new coupling until you fix both at
haul out.
The key by itself in the shaft keyway wants to knock back and forth, but with coupling on there is no wiggle room for now. I put locktite on the shaft set screws and the thing is solid for now but who knows how long.
The problem is that when I then go to reattach the coupling halves, the alignment is way off. It’s not a bent shaft because the gaps stay to the same side when I rotate the shaft. It’s so far off (like a 1/4” gap, that the
motor bottoms out the
motor mount slots and can’t be moved further without drilling new holes.
The misalignment could be because of the fit of the worn coupling or from the cutlass bearing. Maybe bad
engine alignment was part of the original problem that led to the shaft coming out. Is there a safe way to proceed without hauling out? I imagine misalignment of that scale would be way too rough on the bearings to tolerate for the rest of the season. Should I just drill new holes for the
engine mounts and align it as is or buy a relatively cheaper new coupling and see if the alignment is better or is the answer just haulout now? (For this couple’s
budget by haulout now, I mean treat it as a floating
dock for the first of the summer until haulout time)
(I didn’t take great photos throughout. First is from trying to fit key and second is how I found it)