Shaft coupling loose bolts

Edo Kazumichi · #1 (**permalink**) 11-22-2006

I was examining the drive shaft of my new very old boat and I noticed something peculiar. There were six bolts in the coupling. Every other one went through some sort of rubber bushing. (First question - what are these?) Between these were bolts through both plates but they were NOT TIGHTENED DOWN. The nuts had been tightened down as far as the threads went but this was not far enough to actually exert any pressure to hold the plates together. They were just hanging there.

Second question: What in the world?!? Was somebody snorting epoxy when they were installing the coupling? Surely this can't be normal. It seems so unbelievable that someone would do this that I just had to ask.

cardiacpaul · #2 (**permalink**) 11-22-2006

It'll help if you tell us what great old boat you're now tied to!

the rubber thingy between the two metal pieces is a "shock absorber/very slight minimal alignment devise". think of it as like of like a automotive driveshaft universal joint.
The bolts are "loose" because the rubber has deteriorated.
The joint should be "tight" but not binding.

depending on the type of "joint" you have you can have bolts threading into each side of the joint, or, all of them being thru bolts with bushings inside of the rubber piece, or a combination of the 2. Or something else all together

The bolts should have "shoulders" on them, meaning they aren't threaded the full length of the bolt.

Oh, by the way, welcome to the joys of boat ownership/maintenence.

billangiep · #3 (**permalink**) 11-22-2006

Sounds like A Flexable shaft coupling or what they call a drive shaft saver? http://www.pyiinc.com/?section=brows...ku=910002&sn=1

Edo Kazumichi · #4 (**permalink**) 11-23-2006

It's an Ericson 32 with a Kubota 3-banger.

I don't think I made it clear. Every other bolt was tightened down to the shoulder but the shoulder did not end inside the coupling. Picture the two sides of the coupling as a wall. Looking left to right with x-ray vision: bolthead, prop side of coupling, transmision side of coupling, 3/4 OF AN INCH OF SHOULDER, nut tightened to the end of the shoulder putting it 3/4 OF AN INCH away from the wall. Bolt was thus free to move back and forth through the hole 3/4 OF AN INCH.

You're probably having a hard time picturing it because it is so unbelievable that anyone would leave it like that at installation.

Edo Kazumichi · #5 (**permalink**) 11-23-2006

It's an Ericson 32 with a Kubota 3-banger.

I don't think I made it clear. Every other bolt was tightened down to the shoulder but the shoulder did not end inside the coupling. Picture the two sides of the coupling as a wall. Looking left to right with x-ray vision: bolthead, prop side of coupling, transmision side of coupling, 3/4 OF AN INCH OF SHOULDER, nut tightened to the end of the shoulder putting it 3/4 OF AN INCH away from the wall. Bolt was thus free to move back and forth through the hole 3/4 OF AN INCH.

You're probably having a hard time picturing it because it is so unbelievable that anyone would leave it like that at installation.

cardiacpaul · #6 (**permalink**) 11-23-2006

ahhhh... got it...i think... so looks like the vibration/insulation/alignment-ruber thingy in the middle wasn't thick enough, or not there, or ripped out, or they just put in too long of a bolt? duh?

sailingdog · #7 (**permalink**) 11-23-2006

Again, a photo of the beast would help, instead of trying to use words, where a photo would make it very clear and unambiguous, provided it is a good photo.

pigslo · #8 (**permalink**) 11-23-2006

I have a flexible coupling on mine and this description sounds close. Search the term on google and you will find pics. The brand i have is R&D and they have a website www.pyiinc.com

wlcoxe · #9 (**permalink**) 11-24-2006

I discovered a problem in my bolts the hard way when leaving my slip. The transmission went into forward and reverse properly with no effect. After the foredeck fire drill to set the anchor, I found that all four bolts (1989 ODay 40, Westerbeke 46) had spun out. I managed to salvage three sets from the bilge, which was enogh to get back to the slip. Next day, an enitire new set of bolts and washers were installed, and I check them regularly, although no sign of loosening has occurred-yet. Previous boat was a saildrive, so very few similarities. There was no compression piece between the flanges, but I will check the manual (again) now that I recognize the possibility that one should be there.
Bill Coxe, O40, New London, CT