Timber clinker launch.....Where next?

[EdgarCove]

Following my previous posts....I have now managed to strip all of the existing epoxy coating (applied by others before purchase) back to the mahogany planking ( which has come up nicely)...and 'flipped' the boat over. ........My next problem is...where do I go from here ?

1) Do I sink her, filling her with water for a few weeks or more..hoping that the boards swell up closing the 'joints' ? ( Baring in mind the previous owner 'caulked' the joints with 2 pack epoxy so some of the boards may be 'stuck' together)
2) Re-apply new epoxy from the keel to the waterline only...thus 'water proofing' the hull before re-painting.(It was always my intention to varnish the planks from the waterline to the gunwale.
3) Any other ideas?

I don't want to 'botch' the job....and have worked hard to remove the offending item..but as expressed before...the boating world is completely new to me and I REALLY appreciate all comments especially the constructive ones.
Steve

 

[DoubleEnder]

Yes it’s a quandary. I would definitely avoid adding any new epoxy to the boat, certainly for now and ideally for ever. There are examples of epoxy and clinker construction working out successfully ( I think there’s a growing number of Stellas that have been treated like this) but unless you can do something at industrial scale, I’d avoid it.
I’d be tempted to launch her now that you’ve got rid of all the old resin. See how she takes up. There is a risk - if the planks are glued together in some places it could cause some stress and potential cracks. But that’s a bridge you’re going to have to cross at some point anyway. The fastenings may turn out to need some attention. Is she riveted with copper nails?

 

[Hacker]

If you have the time then sinking her (in salt water) will swell the planks and close the lands. If any are stuck together then they will (should) be watertight. Another version would be to support the hull and fill with salt water. You will see where the leaks are! Keep the water topped up for a week or so to see if it stops. Assuming she is riveted the you might need to harden up the roves at any leak points. If all ok let her dry and paint/varnish as required. Do not put epoxy anywhere near her as you will lock in any rot or damp.

 

[EdgarCove]

Thank you for your response DE....it is causing some...no..a lot of head scratching.

Ans yes...she is riveted with copper nails (which I have a shipwright hopefully coming to inspect the fixings)

Steve

 

[DoubleEnder]

Copper nails/rivets is good news. Keep well away from epoxy. Get her wet. Better to launch her rather than fill her up IMHO. Boats are not designed to contain the weight of a hull full of water

 

[Tremyporth]

If the plank seams and lands were/are not stuck together with epoxy, then I would agree, get the boat wet so the planks swell up and any leaks are sealed by wood to wood contact. BUT if the planks are held together at their edges by solid, rigid epoxy filler, that will not expand with the wood when it gets wet. Result of that is likely to be that the planks will not be able to slide against each other as they expand. Instead, as each plank expands it will tend to bulge or bow away from the fixed edges, bending away from the ribs and putting great stress on the copper nails and rivets so they become loose. Also, if they are a bit tired, the ribs might be inclined to crack as well. If you want to avoid the significant amount of work involved in re-fastening the boat, should that end up being necessary, then it might be better to re-skin the wood, both inside and out, with epoxy and lightweight glass cloth, so as to minimise scope for the planks to get wet and swell or expand. It is a matter of personal preference as well as cost, but in a case such as this where the eventual outcome is uncertain, some people might be content to use polyester resin instead of epoxy, provided it is preceded with a coat of the speciaI primer which the larger glass and resin suppliers sell for use when skinning wood with polyster and glass. If, however, you are determined to restore the boat in a traditional fashion, then I suggest before getting the planks wet, get rid of the epoxy caulking between the planks first.

 

[EdgarCove]

Tremyporth....many thanks for your useful and detailed answer.

This is exactly my problem as I can not 100% guarantee that every plank seam and lands shall be epoxy free and as pointed out bulge the planks.
IF....I were to soak the timbers I guess this has to be before any varnish goes on?....and if so..how long would it take the timber to dry out ready to accept the varnish.

(The previous owner applied the epoxy with no glass to the outside skin only)

Steve

 

[oldbloke]

A variety of opinions already, and I am going to give another!. My general rule in life is that if there are lots of ways to do something, then it probably doesn't matter much which you choose.
Having got her clean and dry and back to the wood I would be reluctant to get her wet again. Certainly don't fill her with water as the stresses are all wrong. I would just get on and paint her. I would probably just use one of the yacht enamels , with undercoat etc, but I don't think using epoxy first will hurt, ( you already have epoxy between the planks).
If the lands all look nice and tight I would do nothing else and allow "taking up" to do it's magic. If the are big gaps you could tighten up the rivets or replace some (not difficult). Or , once you have some layers of well cured paint, apply a non setting caulk such as sikaflex. Sikaflex can stop some paints from setting so apply over paint but you can the paint over it to cover it.

 

[Hacker]

When I said fill I didn’t mean to the top. When we are restoring gigs we might fill to the waterline (as above it doesn’t really matter) but the boat is well supported by keel blocks and frenchmen. If you don’t mind the boat rotting in a few years then epoxy sheathing is fine, on the other hand…..

 

[Tremyporth]

Tremyporth....many thanks for your useful and detailed answer.

This is exactly my problem as I can not 100% guarantee that every plank seam and lands shall be epoxy free and as pointed out bulge the planks.
IF....I were to soak the timbers I guess this has to be before any varnish goes on?....and if so..how long would it take the timber to dry out ready to accept the varnish.

(The previous owner applied the epoxy with no glass to the outside skin only)

Steve

I suppose the course of action you choose depends on how long you want to keep the boat and how much effort (and cost) you want to put into it. I agree with Hacker's warning about the likely outcome of putting a GRP skin onto it. But if the boat were to be in structural decline, maybe nailsick and with cracked ribs, that might be deemed a relatively easy way of getting a few more years use out of it before repurposing as biomass. But a traditional wooden boat is like a three dimensional jigsaw. If its shape and design please you, it is possible to make it last forever by removing worn out or rotted components as and when that becomes necessary, and replacing with new, like for like. For that to succeed, you need to avoid preventing normal working , flexing and expanding and contracting of the timber, and avoid fixing components together in such a way that you cannot replace them without also destroying what they are attached to. That means avoiding super tenacious modern gloops like epoxy, sikaflex, cross polymers, etc, especially at locations prone to movement such as plank lands. One thing you might try in order to free the plank lands on your boat from their epoxy grip could be to run something like a hacksaw blade or a thin multi-tool cutter blade along each plank land very carefully to trim away the epoxy, but not wood, so the potential for movement is restored when you wet the wood to make it expand and take up the gaps. As for varnish, I would say avoid it, especially on the inside of the hull. With time it will crack, craze, and peel off the wood. Scraping and sanding traditional paint or varnish on the inside of a clinker hull is a fiddly and time consuming chore. Modern low-build low viscosity woodstains are my preference. Elsewhere on YBW another poster recently advocated decking stain, so I am not alone. Choose a water-based product, so you can still apply it in slightly damp conditions, and on mahogany use the palest tint you can get- light oak or pine works for me.

 

[EdgarCove]

Once again Tremyporth many thanks for a detailed and constructive reply..in answer to a couple of questions..

The boat seems to be in very good condition not in structural decline at all..and being a 15/16 ft Edgar Cove launch has relatively little value..and yes..I have to be realistic how much (£) to spend....but as previously stated I also do not want to 'botch' the job.

As Oldbloke (Thank you) kindly pointed out...there's more than one solution for my problem here and to a degree I feel as 'i am damned if I do'...and 'I am damned if I dont'.....

My train of thought at the moment is to sand/clean plank land's/and prep the complete hull to the best of my ability.
Undercoat and paint ( to manufacturers recommendation ) up to the waterline.
Put her in the water...and stand back and wait...fingers crossed.

(IF this course of action fails..would I be able to epoxy on top of the new paintwork to the outside and from the keel to the waterline only?

Thank you...Steve

 

[oldbloke]

You could....., but it wouldn't work! The epoxy has to be stuck to the wook to do anything.
Re epoxying. There are 2 different things being conflated. Sheathing , using resin and cloth, is essentially constructing a, hopefully, waterproof and strengthening skin round the outside. It can be used as the final stage of building a wooden boat and done properly is a good thing, it is also used as a last gasp solution to a dying boat where it postpone but usually not prevent the inevitable as it is v difficult to avoid trapping water.
You can also use epoxy, resin or paint, as a harder more waterproof alternative to other coatings. On a clinker boat it will also get between the planks and to a greater or lesser extent fix them together. This can be a good thing, such as on my ratty old boat but ,as others have said, clinker boats move around and creating hard points just moves the stresses and you run the likelihood of cracked planks etc.

If you go down the paint/varnish route then you are committed to soft methods of leak stopping...taking up, sikaflex, duct tape etc etc.

 

[Hacker]

I agree with @oldbloke . I can offer another couple of wooden boatbuilding “tricks”. If you launch the boat and there are a few leaks then chucking a load of sawdust into the water around the boat can help; the sawdust gets dragged into the seams, swells and blocks/reduces the leak until the planks take up. The second one, to avoid using anything permanent that sets hard, is to pay the seams with red lead putty; it remains flexible and moves with the boat.

 

[winch2]

Yes as above really. Dont fill it up and I would counter against putting it in the water bare wood. Our old Folk Boat was fully painted before launch and took a bit of water but then tightened up smartly and remained that way for the next 40 years. Even with paint on there's always a bit of bare wood somewhere on an edge which will close up.

 

[Tremyporth]

Yes as above really. Dont fill it up and I would counter against putting it in the water bare wood. Our old Folk Boat was fully painted before launch and took a bit of water but then tightened up smartly and remained that way for the next 40 years. Even with paint on there's always a bit of bare wood somewhere on an edge which will close up.

We seem almost to have achieved a consensus of agreement! Most certainly, don't apply epoxy over paint. Secondly, if a clinker-built boat is structurally sound, no good reason to go to the expense of coating it with epoxy. Not least because epoxy works best when used on a dimensionally stable base. Something like a stiff modern designed monocoque hull in plywood would be appropriate. Small traditional clinker boats are inherently prone to flex, and the components shrink and expand in response to changes of weather, sunshine, and wetness. Epoxy does not share that level of flexibility, so it will not move with the wood. Consequently a thin coating will tend to part company with the sub-strate over time, allowing water ingress, which in turn will cause discolouration and deterioration of the wood. A coating able to flex and breathe with the wood is a more sympathetic choice.