SailNet Community banner
1 - 20 of 25 Posts

·
Registered
Joined
·
88 Posts
Discussion Starter · #1 ·
In my mental list of worst case scenarios, some kind of shaft seal failure while underway ranks pretty high for 'scary'.

Is there common thinking on how you would deal with this? Lets assume your shaft is still in place, but your whole stuffing box is gone - however unlikely. How would you stem the flow of water in such an awkward place?

Ideas?
 

·
Registered
Joined
·
1,172 Posts
With routine maintenance, a shaft seal failure is one of the more unlikely scenarios and easily preventable. Having said that, the amount of water which would be expected with the shaft in place isn't that disasterous and most reasonably sized bilge pumps should be able to keep up with it. Certainly, you would have something like a towel, rags, etc which could be used to further reduce the flow rate to a manageable amount. The most problematic issue you might face is identifying it as the source of water once it is under water.
 

·
Registered
Joined
·
19 Posts
maybe have a plug handy on board, a cone cut into halves with a hollow center for the shaft. that could be jammed in there if the packing failed... i wouldn't run the engine though
 

·
the pointy end is the bow
Joined
·
6,265 Posts
I"d probably wrap a towel and plastic bag around the shaft/stuffing box and hose clamp/duct tape the crap out of it. You could dive underneath the boat and stuff the shaft tube from the outside too. A person would be properly motivated to find a fix.
 

·
Senior Member
Joined
·
19,488 Posts
I think Ray's plan above is most practical... but K1vsk is right in saying that that particular scenario is pretty unlikely. Even a completely loosened follower is unlikely to result in an unmanageable amount of water intrusion if we're talking about a traditional stuffing box with packing rings.

But hey... It's always good the think these things through beforehand!

Breaking the seal on a "dripless" shaft seal is another story altogether - and you really need to take care if you ever remove the tranny/motor while still afloat.
 

·
Registered
Joined
·
79 Posts
d,
I read someone's website where this did happen. Long story short, he had a diver waiting at the dock when he got back with a toilet wax sealing ring; really just a big lump of sticky, squishy wax.
 

·
Super Moderator
Joined
·
6,815 Posts
I carry

I carry rubber strips for events like this. I get stuff from my wife's medical supply catalogs called Thera-Band. 12" of Thera-Band wrapped tight and some self sealing tape or zip ties goes a long way. Don't forget to lock the tranny in reverse before wrapping the shaft & shaft log.. Oh and I keep both gold and green strength of Thera-Band on-board. I'm surprised no one has marketed it as a boaters emergency repair kit..

That being said if maintained and installed correctly it is highly unlikely this will ever happen..

Cut into strips truck inner tubes are also invaluable.
 

·
Telstar 28
Joined
·
993 Posts
The self-fusing silicon tape works wonders for things like this. :)
 

·
Registered
Joined
·
311 Posts
I know someone that had this happen to them.

She had just had the dripless seal system replaced, but something (a bolt??) was not done correctly. She motored for over a day before the seal blew, offshore, at night. Floorboards awash. Once she identified where the water was coming from, she was able to stem the flow to a manageable rate. It was a long night, particularly since they didn't want to tow her through the inlet at night. She often sails single-handed, but was lucky to have crew this time.

Yes, the problem may be rare, but not rare enough.
 

·
Super Moderator
Joined
·
6,815 Posts
I know someone that had this happen to them.

She had just had the dripless seal system replaced, but something (a bolt??) was not done correctly. She motored for over a day before the seal blew, offshore, at night. Floorboards awash. Once she identified where the water was coming from, she was able to stem the flow to a manageable rate. It was a long night, particularly since they didn't want to tow her through the inlet at night. She often sails single-handed, but was lucky to have crew this time.

Yes, the problem may be rare, but not rare enough.
Sounds like a bad installation. My guess is they messed up using the rotor set screws, which are a one use item. If you tighten the stainless rotor down then decide to move it and make another adjustment you need to replace the set screws.

I use a 316 stainless steel split collar placed behind the stainless rotor as an added level of safety.

The split collar is sitting on top of the seal in this photo. I feel every PSS installation should have one.


These are PSS set screws. Tighten them down ONLY once. Once you do you dull the point and they should never be reused to bite the shaft again. There should also always be two set screws one on top of the other in the hole to lock the one in contact with the shaft from backing off. I have come across more than one PSS with only one set screw in each hole!!
 

·
Senior Member
Joined
·
19,488 Posts
I know someone that had this happen to them.

She had just had the dripless seal system replaced, but something (a bolt??) was not done correctly. ....the seal blew, offshore, at night..
Yeah, case in point... a dripless seal doesn't have the packing rings to minimize clearance around the shaft... and the leak profusely if the pressure is reduced or lost on the collar....

Mainesail... that locking collar is a great idea.. is it a custom piece made in your own shop?
 

·
Super Moderator
Joined
·
6,815 Posts
Mainesail... that locking collar is a great idea.. is it a custom piece made in your own shop?
I got it from McMaster Carr who else..;) P/N 9633T19 <nobr> </nobr>
McMaster Carr 316 Stainless Split collar For 1" Shaft

Of course McMaster will never let you know, on their web site, who makes the product until you get it in the mail. If you search the manufacturer you might find it for less than $33.00. It take pictures of everything cause my memory sucks..

 

·
Registered
Joined
·
311 Posts
I think you've got it right, Maine. When I saw her that day she was pretty tired and we didn't get into the details. I just remember her saying that there was a problem with a bolt, or it could have been a screw.

Thanks for the detailed explanation.
 

·
Telstar 28
Joined
·
993 Posts
Maine Sail—

They do...it also comes in 2" widths and is used for sealing the mast-deck opening. I've also seen it in 4" widths...but can't find a link for it ATM.

Yeah I just wish they made it in wider widths.
 

·
Super Moderator
Joined
·
6,815 Posts
Maine Sail—

They do...it also comes in 2" widths and is used for sealing the mast-deck opening. I've also seen it in 4" widths...but can't find a link for it ATM.
i've been looking for some 4" as i used to have a roll. the only stuff I found in 4"= widths was close to $80.00 per roll??? I still prefer the Thera-Band as it is latex rubber and once stretched it really sucks down onto and around whatever you are wrapping and it's wide enough too..

If you find reasonalble 4" wide stuff send me a link!!..
 

·
Sea Slacker
Joined
·
1,789 Posts
I have a dripless seal (with a hose connecting it to stern tube, and a hose is slightly oversize and clamped down - which does not make me all that happy).

I carry a toilet wax ring for this particular emergency - presumably if the hose is still in place, I may be able to stuff it (or parts of it) in the opening, then tape or otherwise clamp down.

If the hose blows - it may be more difficult (presumably would have to remove the old hose first, which may not be fun to do.

Prop shaft is certainly one of the more dangerous places on a boat - it's a thruhull that can never be closed and is under constant mechanical strain. Oh well.
 

·
Telstar 28
Joined
·
993 Posts

·
Registered
Joined
·
1,297 Posts
To add to Maine Sail's comments in post #11 above in regard to set screws:

You can use Loctite to secure the outer set screw. DO NOT under any circumstances use it on the inside set screw or it will glue the collar to the shaft and make disassembly difficult. The yard did that once on BR and it took them over 4 hours (on their nickel) to fix things.

Also, after the shaft seal is installed in the proper position I use a black permanent magic-marker to note the point where the aft end of rubber bellows joins the stern tube and the forward edge of SS seal ring is positioned on the shaft. A quick look at the shaft seal is part of my daily engine maintenance routine and with these marks I can quickly see if either the rubber bellows or the SS seal ring has moved.
 
1 - 20 of 25 Posts
Top