Leaking hull – help!!

[JeremyParticipant @jeremy15845]

Boat close to completion and weighted down with about 1 kg of lead to float on an even keel sloghtly above the water line.  All looked OK until, a few hours later, I noticed water dripping from the keel.  Tipping the boat upside down, a fair amount of water came out and here is
a  split between the keel and the first planks towards the front
of the hull. Looking inside, the PVA glue used to attach the planks has turned white – a sign that it is wet?  I am paying the price for my intial error – that of fixing
the deck in place before planking the hull. One side at the front,
forward of my battery hatch, was not accessible for coating with epoxy.
The rest I did coat. What to do now? First I will dry it out overnight and hope that none of
the planking becomes so distorted by wetting and drying that the hull
starts to split. Hopefully, the two coats of epoxy resin on the outside
of the hull will be flexible enough to counter any slight stresses.
Next, I will strip the paint along the base of the keel and add a
really thick cost of epoxy. I might then varnish over the Halfords red primer with a matt varnish.  I could try to spray the inside of the
front of the hull with a varnish – holding the boat upside down and
spraying through the battery hatch. Any ideas or suggestions would be
appreciated – I don’t really want this to become a static model only.

 

Jeremy

 

 

[JeremyParticipant @jeremy15845]

Billings Nordkap

[Bob Abell 2Participant @bobabell2]

Drill a hole in the deck and pour varnish in………then roll it about

 

But dry out the hull first………….Bob

[JeremyParticipant @jeremy15845]

Thanks for the advice Bob.  Would you recommend the use of an acrylic or of a polyurethane varnish?  Pouring the varnish in and swilling it around will leave a thick  coat and puddles – should this influence the choice of varnish?  Would you advice thinning the varnish?

Jeremy

[Bob Abell 2Participant @bobabell2]

Sealing with varnish was the norm in the old pond yacht days.

 

They don`t mention thinning down either

 

In the old bread and butter construction days, they didn`t use bulkheads, so the varnish had a clear run up and down the hull.

 

It would solve your leak problem, though

 

You could pour the varnish in, move the hull about, till you`re sure the leak area has been coated, then turn the hull over and let the surplus drain out, through the hole

 

Bob

[JeremyParticipant @jeremy15845]

Bob – sorry to be a complete pain but would you recommend acrylic or polyurethane?

Jeremy

[Bob Abell 2Participant @bobabell2]

Sorry Jerry

 

I would use polyurethane…….only because it`s thinner

If you cold reach the leak spot with a long brush…….Then Acrylic would be quicker drying

 

Bob

[JeremyParticipant @jeremy15845]

Bob

 

I will go with Polyurethane – if its thinner it will swill around more easily.  I don’t know exactly where the leak is although I think its near if not right at the prow. and probably along the keel – at least that’s where the water came out.  The planks either side of the keel former were probably not well enough glued on.

Rather than drill another hole, I will stand the hull on end and pour the varnish down towards the prow through the battery hatch.  With luck, by changing the angles, I should be able to get the varnish into all the forward sections.  I will poke around with a brush as best I can.  I’ve added another good coat of epoxy resin up to the water line in the proabable leak area so hopefully the internal varnish will just be ‘belt and braces’.

 

I would prefer not to pour out any surplus varnish as it would probably run over the deck and mess up the planking or get onto other areas of finished paintwork.  Where the varnish puddles, can it be safely left and will it eventually harden?  I understand that the curing process can generate some heat.

 

Thanks again for your advice.

 

Jeremy

[Bob Abell 2Participant @bobabell2]

Don`t think poly varnish has a heat problem on drying………..But acrylics certainly has!

 

Bob

[Colin BishopModerator @colinbishop34627]

Yes, go with Polyurethane, my experience of acrylic is that it isn’t 100% waterproof anyway. The polyurethene should sink into the wood and seal it from the inside but you still need to make sure that outside is watertight too.

 

And, as Bob says, don’t do anything until you are sure that the hull has properly dried out.

 

Colin

[ashley needhamParticipant @ashleyneedham69188]

I would be worried that water got in in the first place,unless,by some chance the hull was full of hairline cracks, which surely you would have spotted before dunking??

 

Are you sure the water is not coming in elsewhere…rudder tube/propshaft??

 

I wouldnt have thought there should be ANY water in any hull after a simple bath test, and water inside would certainly  melt the pva and cause the cracks observed after fishing the boat out. Painting the inside may well stop the hull de-laminating but there should be no water in the hull to start with !

 

Generally I just use sanding sealer, as it seeps in the wood, but on the other hand, if I happen to have a painty brush in hand, I use that instead . OR after having just put a fibreglass patch on HMS Glorious, I treated the inside to the rest of the resin…and while I was at it, Berengars aircraft carrier (as its always full of water due to to excessive high speed manoevering). You get my modus operandi?

 

Ashley

 

 

 

[JeremyParticipant @jeremy15845]

Ashley

 

Thanks for the comments.  I didn’t see any evidence of water coming in through the propshaft (which is greased) or the rudder tube which is above the water line..

 

I think the problem is at the bow end where I was unable to epoxy internally on one side because of my initial mistake of fixing the deck in place before planking – never again!  The rest I could access through hatched in the deck.

 

The planking wasn’t perfect as you will see on my photos but I had hoped that two coats of epoxy resin would have sealed any gaps.  With the resin in place and overpainted below the waterline with Halfords red oxide primer, there were no visible cracks.  The only one which has opened up is along the bottom of the keel where the first plank on either side is fixed directly to the keel former – in hindsight probably with gaps in the glueing.

 

I have now added a third coat of epoxy in the suspect area and will re-apply the primer.  I will then seal that with varnish.  I have acrylic varnish in a spray can – will this waterproof the primer ot must I go for a solvent based varnish – polyurethane?

 

The hull is now completely dry and I will try to cover the bow end internally with varnish as discussed in earlier postings.  Hopefully that will solve the problem.  It is my first plank on frame boat – indeed my first boat of any sort for probably 15 years.  We live and learn – helped in no small way by the contributions on this forum.

 

Jeremy

[Colin BishopModerator @colinbishop34627]

I would stay clear of acrylic varnish on the hull. It can look OK but I have found that in practice it puts a flexible film on the underlying surface which can sometimes absorb water and go milky for a while. More seriously, if the film is broken you can find the acrylic coating starting to peel off in patches which can make you really miserable!

 

Something like Ronseal polyurethane solvent based varnish is a much better bet.

 

Colin

[JeremyParticipant @jeremy15845]

What a relief!  Hull now watertight after additional epoxy coat at the prow, double coat of varnish below the waterline, varnish swilled interior at the prow and epoxy flooding the join between the planking and the keel at the stern andsealing the propellor tube at its point of entry to the hull..  Thanks to all for their advice.  I will never never again fix a deck in place before complete waterproffing of the inside of the hull and successful leak testing.

[Peter FitnessParticipant @peterfitness34857]

I’m pleased you got a good result, Jeremy, and you’ve learned from the experience. As the saying goes, experience is not making the same mistake twice 

 

Peter. 

[JeremyParticipant @jeremy15845]

Maiden voyage successfully undertaken.  Now to take to the open sea or at least to a nearby lake.

Jeremy

[Colin BishopModerator @colinbishop34627]

Very nice looking boat Jeremy. Glad you appear to have got her sorted out.

 

Colin

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