Leaking when dried out! Any suggestions?

[tillergirl]

Something odd is going on. While over wintering in a mud berth, I noticed that I had a slight leak at the stern. Nothing desperate but I thought I would do something about it.

So TG is neaped at present and barely gets wet on the current set of neaps.

However!

In the turn of the stern either side of the wooden keel for 'two frames' immediately in front of the stuffing box water appears. I dried out the bilge completely including toweling it completely dry with a view that on the next tide we could see if there is any trace of where it is coming in. However, having left the dried bilge for ten minutes or so, a film of water appeared - on either side of the keel! Now we are high and dry and away from the water's edge by some 250-300 yards. The film of water is appearing where the plank (on either side) tucks into the keel. There is a fairing piece between the keel and the inner side of the plank.

This photo is from 14 years ago when I re-engined and not the clearest - neither are the yellow boxes to indicate the site of the leaks. But the film of water (which obviously builds into a slight leak when afloat) is below the line of the shaft by about a foot.

Looking on the outside, we can find no obvious problems with the seams in the area. The only noticeable thing is the slightest weep from the back edge of the starboard joint of the deadwood with the fairing piece on which the bottom rudder fitting is fitted. This is a joint and not a seam.

Two questions: Any suggestions where the leak is, and how is the film of water still coming through when I'm high and dry?

 

[Tommyrot]

I had a grp sheathed (I know.... ) wooden boat which used to do the same thing, I put it down to waterlogged wood somewhere along the keel.
No matter how many times I dried it out, it would begin to seep back....

 

[sarabande]

either the timbers are soaked (have you gone round with a little tap hammer ?) or there's a leak from a pipe above which is trickling down un-noticed.

What about the shaft log ? Is the integrity beyond suspicion ? Are the seals working properly / what seals do you have ?

Does the water coming in when you are dried out taste salty ?

I see that TG is parked head up. Any chance of water making its way from for'd, e.g. along the garboard strake or false keel ?

 

[tillergirl]

"either the timbers are soaked (have you gone round with a little tap hammer ?) or there's a leak from a pipe above which is trickling down un-noticed."

There is no pipe 'above'. The timbers are rock hard but I can only assume they (somewhere) must be soaked. Question is 'where'?

What about the shaft log ? Is the integrity beyond suspicion ? Are the seals working properly / what seals do you have ?

Shaft tube was out last year when a new rear bearing was fitted. The tube will have water in it (it's water lubricated) but since it screws into the stuffing box at one end and the stern bearing at the other, I can't see that leaking. Water getting up the outside of the stern tube and working its way out between the Shaft log and keel? Possible but the rear end is pretty tightly bonded with Sikkaflex. I could try rebonding that.

Does the water coming in when you are dried out taste salty ?

I haven't tried - nor would you so far but I have no cleaned up some of the detritous so I might have a go. Can't see it being fresh, boat was in a mud berth all winter with a total cover all over it.

I see that TG is parked head up. Any chance of water making its way from for'd, e.g. along the garboard strake or false keel ?

Actually that's last year's picture when I was out and she is dead level (rubbish photographer). Where is it at the moment is on the beach slightly heads up. But I've checked for that and there is no doubt that in fact the water emerges from aft!

I deduce that there must be some soaked timber somewhere but I am clear that I cannot find anything soft. I haven't gone a tapping and so I'll try that tomorrow. I would like to think it's water finding its up the outside of the stern tube - ie behind the stern bearing - I'll post a picture in a minute. That would also explain the tiny seepage of water from the deadwood and its pretty easy to cure!

Thanks for the ideas

 

[tillergirl]

If I didn't get the gap round the tube perfectly sealed, then water could be penetrating behind the stern gland and up into that void. The seepage from the deadwood which was tiny was just to the right although that diagonal joint. Could all make sense, particularly as it is the only bit to be disturbed in recent times.

 

[cliffordpope]

Even if the housings at each end are sealed into the wood, water can still get from the shaft side of the tube into the void by running around the threaded ends.
A screw thread alone is not a water seal. (Like ants getting screw-top jars)

 

[Seanick]

When you refitted the stern tube did you inject the void?

If not..........mark out the line of the tube......drill in through the keel untill you just touch the tube.
Screw in a long grease nipple, or make a hollow screw with a nipple welded or soldered on top.
Fill a grease gun with slightly thinned white lead paste and inject untill it emerges at both ends.
I don't use white lead paste as it seems to ruin the grease gun. I use Arbomast Butyl rubber, but thin it with white spirit until it is pump-able.

Remove the nipple and sprig the hole.

Should take about an hour to make the screw, mix the goo, and tidy up.

Same kit very useful for cabin corner posts....re-bed in situ.

 

[planteater]

Have you tasted it to ensure it is seawater? I had a similar problem once that turned out to be rainwater saturating wood and foam hidden behind the galley fittings.

 

[tillergirl]

Even if the housings at each end are sealed into the wood, water can still get from the shaft side of the tube into the void by running around the threaded ends.
A screw thread alone is not a water seal. (Like ants getting screw-top jars)

I accept that. I didn't remove the tube so the inboard end was untouched but I may not have done the outbaord end well enough. Would the water pump feed keep the water in the tube pressurised so it feeds into the void under pressure as wll??

 

[tillergirl]

When you refitted the stern tube did you inject the void?QUOTE]

Not in the way you are suggesting. At the moment, this is the best explanation for the seeping so tomorrow.........

 

[tillergirl]

Have you tasted it to ensure it is seawater? I had a similar problem once that turned out to be rainwater saturating wood and foam hidden behind the galley fittings.

I refer to an answer given on an earlier occcasion! I've had an all over cover on all winter!

 

[tillergirl]

Not the stern tube; dry as a bone, shaft void correctly filled, threads sealed.

I remain perflexed!

 

[gary3029]

ho dear

how weird, i have exactly the same problem with a small leak from the the same area. Just brought the boat out for one week for its yearly check and tidy up below the waterline. The wood is iroko and it feels sound, however it is a large, thick piece so wondering if waterlogged in its middle. Would this be possible? Was thinking of making a small drill hole to see what the condition of the wood comes out. Hope this is not a warning to a very sinister problem!! I suppose someone has hinted to a possible cause...the screw holes for the stern tube.

 

[tillergirl]

I'm iroko as well. What I can really get my mind round is that the timber is waterlogged. It sounds ok, the seams are all sound, it's rock hard inside (where I can get at it) and outside. Not sure how it could be waterlogged in the middle and not on the outside.

I wonder if the deadwood joint is leaking (it looks sound) and somehow the water is being channeled up to the point I see it.

I am now satisfied that it is not my stern tube. Never seen anything drier!

 

[BrendanS]

am i correct in thinking you are purely trying to find out where the water ingress is coming from? Get talc in a puffer bottle, and spray it everywhere. You'll see where the water ingress is from

 

[tillergirl]

'fraid that doesn't work. I know where the water is appearing. It's emerging on the top of the fairing piece between inside of the bottom plank and the keel. It is not coming from the front, rear or top. I cannot see under the fairing piece where the problem is - and everything on the outside is - or appears to be as tight as a drum. Certainly the seams at the immediate point of the area of concern are perfect. It is obviously travelling from somewhere. I had hoped it was the stern tube but definitely not.

 

[Seanick]

Maybe your stop water (softwood bung fitted between keel and sternpost or whatever) has become tired.

Sounds like she leaks 'just enough to keep her sweet'.
I wouldn't worry about it!

 

[tillergirl]

That's an idea! If I can find it/them.

No I probably won't worry. It's just a tad annoying. I might come out next year and 'do' the bottom all over and see what I can find.

 

[tillergirl]

For anyone who is follow this saga, we (the yard) raked out two apparently ok seams to find them wanting, one with some dampness in it right behind the frame at the rear of where the water is apparing. So one possibility is that water is coming down the back of the frame, hitting the fairing piece and coming into view.

We will know tomorrow after tonight's tide!

 

[Simon_and_Tanja]

I seem to remember the definitition of seaworthy is a ship leaking no more than two fit and able seamen can counter working the bilge pump non-stop.

I personally don't worry if the electronic bilge pump keeps the water level below the floorboards.

Wooden strakes like to be kept wet