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Mainebristol · 19-12-2013, 08:42

well, I have trolled here for many years, but now I could use some help. A little more than a year ago I backed my old Bristol down onto a mooring line, wrapping it around the shaft, and stopping the engine. The prop on a B32 is so well protected, that I had never had this happen before. I was in the process of hauling the boat, so I trucked the boat home, and cut the line out.

The problem is that the shaft had backed out a shy 1/4". The motor mount hasn't moved, and what little I can see behind the tranny doesn't show any obvious problem. The shaft rotates freely, has no play, and no inclination to back out any more, nor does it want to go back in. I didn't bang on any thing, but I weigh 220 and pushed and pulled to the limit of my strength. The local brain trust said drop it in in the spring, sail it, and don't worry. So I did. But the boat used to be dry, and now after motoring for several hours, the bilge pump gets to eject maybe two or three gallons.

I have a fifteen year old yanmar 2gf, I believe, and a PSS seal. A B32 has EXTREMELY tight quarters back there. Now, I know I've got to get down there this spring and service that PSS, but where do you think that 1/4" came from? Did I do any real damage? What should I look for? How do I lose at least fifty pounds so that I can fit? Thanks in advance.

Mainebristol

Mainebristol · 19-12-2013, 08:44

I put this in anchoring by mistake, dammit. Mods, please move to drivetrain.

Cheechako · 19-12-2013, 08:56

Can you see if the shaft moved out of the engine coupling a 1/4"? Gotta be something like that. A shaft will often have corrosion where the packing is, (especially if the boats sits a lot) and movement may have damaged the packing, however, I'm not sure how a PSS might be effected.

**HappyMdRSailor** · 19-12-2013, 08:58

Honestly... I bet you didn't do any real damage.... Probably pulled the flange a little on the shaft moving the PSS lip on a "non-fair-non-smooth" section of the shaft... ALSO... Pull that zinc! Look at the shaft under it....I would harbor a guess that it slipped at least half of your "new shaft length" !

MarkSF · 19-12-2013, 09:02

My guess is that when the shaft moved, the PSS seal is now trying to seal on a rough, corroded, section of the shaft - so the seal is poor (and probably damaged)

This is what a coupler looks like :

Prop Shaft Flang Splt Hub 1 1/4 Ductile Iron 1-1/4""

As you can see, there is potential for the shaft to pull out of it. What would worry me is, if the shaft is pulled out by an inch, there isn't much left in the coupler (and even less extending past the securing bolts)

Personally I'd haul the boat and wouldn't put it back in the water until it's fixed. I certainly wouldn't be doing any reversing!

BTW, the PO of my boat nearly sank the boat, wrapping a line around the prop, as the shaft came out far enough to jam against the rudder. He couldn't even sail back. Very nasty situation.

Edit : just realised it's a 1/4", not an inch. I think I'd at least tighten up the coupling bolts.

Neo · 19-12-2013, 09:33

Quote:

Originally Posted by Mainebristol

The local brain trust said drop it in in the spring, sail it, and don't worry.
Mainebristol

Oh my. Had the brain trust put a few back when they said that?

I have pretty good access to my stuffing box, but even still, I remove some cabinetry to create more space when working down there. If you have that option I think it is worth the extra day it may take. Otherwise, you may end up taking shortcuts and saying things like "drop it in the water and don't worry".

MarkSF · 19-12-2013, 09:36

So this boat is currently on the hard? and you're debating whether to fix it?

The question is, what happened to the rotor on the PSS coupling? Either it moved, in which case the rotor is no longer well attached to the shaft. Or it didn't, in which case the seal between rotor and stator is wrecked. Either way, very dangerous. My neighbour's boat nearly sank when the rotor starting spinning on the shaft. He spent a merry night on the boat, with a number of pumps running, before he could haul it.

Capt.Alex · 19-12-2013, 09:53

What makes you believe it moved at all? Was that shaft zinc that snug of a fit between the prop and the stern tube? Could the zinc have slid back on the shaft?

MarkSF · 19-12-2013, 09:56

The fact that the PSS coupling is leaking suggests something moved. At this stage, I'd be most worried about what's going on with it.

**roverhi** · 19-12-2013, 10:40

The flange at the transmission has set screws that hold the shaft in the coupling. Loosen the set crews and gently tap on the shaft to see if it will move back in that 1/4". If you don't loosen the set screws and pound on the shaft, you risk scoring the shaft worse than it already is. Probably not a big thing just to leave it but I'd want to try and tighten the set screws in any case just in case the accident loosened them up. If the set screws aren't holding the shaft, it could back out of the coupling. You probably wouldn't lose the shaft and prop if that happens but could chew up the rudder a bit.

MarkSF · 19-12-2013, 10:50

Quote:

Originally Posted by roverhi

The flange at the transmission has set screws that hold the shaft in the coupling. Loosen the set crews and gently tap on the shaft to see if it will move back in that 1/4". If you don't loosen the set screws and pound on the shaft, you risk scoring the shaft worse than it already is. Probably not a big thing just to leave it but I'd want to try and tighten the set screws in any case just in case the accident loosened them up. If the set screws aren't holding the shaft, it could back out of the coupling. You probably wouldn't lose the shaft and prop if that happens but could chew up the rudder a bit.

One problem : the PSS coupling is already leaking, with it's current adjustment. What happens when you move the rotor 1/4" forward? Potentially, a massive leak, that's what.

Mainebristol · 19-12-2013, 12:02

ok, I appreciate all of the responses. First, the boat is on the hard, it being that time of year up here. And I am going to work on it. That zinc, even when new, showed that extra bit of shaft, so I'm convinced that it really did back out. And the PSS now really does seam to leak. So, so far, it seems that the best thing to do might be to loosen the set screws at the coupling, pull the shaft, inspect the setscrew, service the PSS which is well overdue anyway, then put it all back together? Does that make sense to everybody?

Mainebristol · 19-12-2013, 12:04

Oh, and of course I will replace the zinc. The boat gets a new one every year.

**HappyMdRSailor** · 20-12-2013, 09:22

Quote:

Originally Posted by Mainebristol

ok, I appreciate all of the responses. First, the boat is on the hard, it being that time of year up here. And I am going to work on it. That zinc, even when new, showed that extra bit of shaft, so I'm convinced that it really did back out. And the PSS now really does seam to leak. So, so far, it seems that the best thing to do might be to loosen the set screws at the coupling, pull the shaft, inspect the setscrew, service the PSS which is well overdue anyway, then put it all back together? Does that make sense to everybody?

That sounds like the right plan to me !