Leaky clinker planking

Saddletramp

Saddletramp

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I have a Thames skiff that used to be on the water all the time. It has now dried as it is stored ashore and is leaking. I need to bring it down the river where it will be stored ashore again. I need to fix the leaks at least temporarily. Mahogony planking. It needs to be a flexible glue as she is over 20 ft long and flexes. Any suggestions?
 
Sink it for 24 hours and then empty it out. It should have taken up by then at least enough to keep ingress under control. Don't foget to tie it firmly before you do sink it though!
 
Thanks both for your comments. I did not make it clear. As she is dried out I want to keep her that way as that is how she will be used over the summer and in future. I was once told that you can keep them dry or wet but not both. So I am looking for something that will seal the leaks. Epoxy would be too hard and would crack. Maybe pva glue. I have an idea that tallow is sometimes used.
 
You could try a polysulphide caulking like BoatLfe. However you will find it difficult to get it into all the seams. When you put it in the water the wood will expand and squeeze the sealer and in extreme cases put pressure on the fastenings. Think you just have to accept that a clinker hull gets its watertightness from being in the water.

Some people have taken clinker boats apart, dried out all the timber, epoxy coated and put them back together with sealer in the seams - but leaving aside the huge amount of work, you no longer have a wooden boat but a composite!
 
Why do you think epoxy will crack?
If you intend to actually seal the wood it's about your only option, but it will only work if the structure is rigid enough for the joints not to crack. This means frames or bulkheads that take the loads and don't let the hull change shape in the process. So you may have to re-engineer the boat!
Otherwise, waxy grease or tallow will fill the gaps and allow movement, but water will still penetrate the wood.
All my opinion on an emotive subject, good luck!
 
Trying not to hijack this thread - and in danger of ressurecting previous discussions but ...

Is a little Sikaflex on the lands really such a bad idea. A few Stella owners swear by their very dry behinds that there is a lot of benefit and no significant downfall to a judicious application. Having suffered a fairly constant bilge pump action last year, I must say I am very tempted. A dry bilge sounds quite exciting. Interestingly my leak seems to be one-way - twice over this winter the boat has filled with rainwater and this never leaks out????
I have decided to totally strip below the waterline and reprime/reantifoul from scratch this year, so now there is the opportunity to apply a little sealent eased up with a thumb. Or perhaps some putty if you all tell me I'm an idiot to even consider Sikaflex. I will of course be checking fastenings and soundness of strakes as I go.
Whilst on the subject, what's the best way to strip 5+ years of dodgy paint from a clinker mahogany hull. Stripper? Blow-torch? or just lots and lots of elbow grease?
Any product recommendations gratefully received.
 
I take your point about the wood taking up and squeezing out any gunk that was put in. (hopefully that would then also seal the hull) A lot of skiffs are kept ashore a nd do not leak so it can be done. Though I expect it would be a case of tightening/ replacing the roves and lots of varnish on the outside of the hull. Thats a point, the varnish has to flex which i don't think modern varnishes do. Any suggestion son that one?

I will have a look at the ply wotsit caulking.

Magknight - It would be funny if it wasn't true. I used to have to bail out every couple of miles when the water came over the floorboards - just before it soaked my camping gear.
 
Is the sikaflex removeable? I know people complain about windows on cruisers being sikaflexed and it being a bu**er to remove. I dont want to ruin the chances of the skiff being restored properly at some point in the future. Maybe not by me.

As for scrapping off old paint. I should have left mine. It had been on there years, boat is about 70 years old. It was bitumen type stuff. A file bent over and sharpened makes a really good sraper and holds its edge for a while. This was recommended by the boatbuilder. I would avoid a blow torches, too easy to burn the wood. Electric ones are much easier to control and not so fierce. Nitromors burns like hell if it gets on you, and if you are working on the bottom of a boat, (ie overhead), it will at some point.
 
[ QUOTE ]
Why do you think epoxy will crack?
This means frames or bulkheads that take the loads and don't let the hull change shape in the process.

[/ QUOTE ]

The hull flexes because it is long and thin. Around 22 ft long 3'6" wide. I don't want to seal the wood, only the joints.
 
I have an old (i learnt to sail in her, and she was old then) clinker dinghy that I still use as a tender and was nearly killed by rot and sand. The sand got into the lands from the inside and sanded away the lap, and they were never tight. I dried her out, replaced the planks as necessary and then used very thin epoxy (mixed 70/30 with acetone) to soak the outside. I then stickyflexed all the seams and deks olje'd inside. She now lives on deck, gets used occaisionally, and only leaks through a couple of bolts in the deadwood.

Not a trad (lots of raised eyebrows) solution, but it has worked well for the last 7 years, and she doesn't leak from any of the seams.
 
Think you are always going to struggle with flexible structures. If you are going to effectively caulk, my somewhat limited experience is that BoatLife is superior because it never fully sets like an adhesive and is easier to remove at a later date. No harm in trying.
 
Flexible and removeable fits the bill. I will give it a try. Pyro james solution is a bit more involved. I need a fairly quick fix at the moment.
 
I hold to the theory that sikaflex type sealants can hold the joint apart when movement occurs. And its a sod to remove sometimes. Other times you just pull an end and loads of it falls out.
Best advice is get it in the water before the weather warms up!
All this reminds me that I don't really have the time or skills to buy and old Victory!
 
If she is a real old wreck by all means garm her up with sikaflex or polysulphide and enjoy a few years of use before the inevitable bonfire. If she is half tidy i would use a soft non setting oil based mastic such as EVOMASTIC, it is great stuff, cheap and will not damage the boat as she takes up, it can be purchased from jewsons. If you ever decide to replace planks or refasten you will have no problems either.
 
No to Sika and epoxy BETWEEN the lands. A liitle bead if Sika ok in the corner-removeable and reversable.
Butyl rubber stays soft 'forever'. Arbomasat BR knifed into the land will do the trick.
Clean off excess with whits spirit.
Paint over.
Will get squeezed out if 'in the way' of lands closing-no damage.
Apply plenty of paint over the top.
 
Traditional sticky black tar below the waterline. It fills the gaps, but never really sets so just squeezes out when the wood swells. .

My boat has had an annual mixture of melted road tar and Stockholm Tar since about 1880. The planks are saturated in it, so don't take up much water, or dry out, anyway. She didn't leak much even when I put her back in the water after 24 years ashore.
I scrape it down each year and apply another coat. If the previous coat is sound I thin the tar with B&Q wood preserver or creosote which just softens the previous one and works into the seams again.
 
The solution to stop serious leaks with clinker is normally refastening especially with a Stella as they tend to be driven hard. A small bead of sika (onto bare wood) will solve your problem unless you're prepared to refasten. Don't put the Sika on paint or varnish as it will peel off. If you want it to last forever then use the Sika primer - at £25 it's a bit painful but you'll never need to do it again!
 
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