Clinker plank ends to plywood transom - fixings?

[Mike2309]

12' Clinker built dinghy: original transom was mahogany, replacement will be 1" ply. Fixings are square copper boat nails. I have some, but I'm not sure they will be as effective edgewise into ply. So, ring-shank nails, screws? Perhaps an additional frame made up to fit in the angle and fixed both ways?
[The new transom will be made up of doubled 1/2" ply, because 1/2" is what I have , and the remains of the sheet will be more use to me than a whole lot of 1" stuff]

 

[srp]

Silicone bronze screws would be best, with the plank ends bedded in mastic. Obviously have to make sure that the two 1/2" laminates are soundly bonded otherwise the fixings will force them apart, (so for that reason an internal frame might be a good idea). I would also put a solid wood capping across the top of the transom to protect the ply.

 

[mikefleetwood]

12' Clinker built dinghy: original transom was mahogany, replacement will be 1" ply. Fixings are square copper boat nails. I have some, but I'm not sure they will be as effective edgewise into ply. So, ring-shank nails, screws? Perhaps an additional frame made up to fit in the angle and fixed both ways?
[The new transom will be made up of doubled 1/2" ply, because 1/2" is what I have , and the remains of the sheet will be more use to me than a whole lot of 1" stuff]

Can you not get mahogony, or other hardwood? I expect you can get sapele, or similar, from a decent woodyard. Or maybe oak.

The original would have been fastened into the endgrain, so I wouldn't have thought too much different to nailing into ply - providing it's a decent marine ply without voids. Ring-shank nails should grip, but if it was me, I'd look at the additional frame idea, then nail/rove both ways for long-lasting strength.

Nice to see someone's keeping a clinker dinghy alive!

 

[Lakesailor]

Get some mahogany. (or another suitable hardwood)
You could use epoxy to bond the planks to the ply (which would help seal the end of the ply) but epoxy fixing clinker planks rigidly isn't a very sound idea. The slight movement in the planks will be limited.

 

[30boat]

I would laminate (with epoxy)a few strips of mahogany on to the edge of the plywood transom.That way the planks would be screwed or nailed accross the grain.

 

[lw395]

I think it depends whether it's going to be kept as dry as possible like a racing dinghy or will live a harder life as a working boat.
For a racing dinghy, I would probably expect a much thinner ply transom with a wooden frame, but the real fastening would be epoxy.
For a working boat, I appreciate you might need screws etc rather than relying on glue.

 

[Even Chance]

I did a 12 foot cedar planked dinghy a few years ago with a transom made from two laminations of 18mm ply instead of the original mahogany. I used stainless woodscrews and cascamite to put it in. I have loads of pics I took somewhere...
I also moved the transom an inch forward, and therefore had fresh wood to use on the planks.

 

[Mike2309]

Moving the transom forward was already part of the plan . I think I'll go with that, screws, mastic and the extra frame copper-riveted both ways. (plus West Epoxy into the edge of the ply) .
As for "get a bit of Mahogany" - heresy it may be to use plywood, but I really cannot justify shipping a huge chunk of some poor Amazonians back garden up to Orkney just for my fun project. But aside from that one - thanks for your suggestions.
Mike

 

[Lakesailor]

Ah, The old cost/benefit argument.
See your point though.

 

[srp]

I'd still be tempted to stick a bit of solid wood across the top of the plywood transom though - a bit of softwood would be fine - it will protect the edge of the plywood much better than epoxy and varnish.

 

[Crabman]

AHHHHHRRRR Dont use ply thats a bodge and dont use epoxy on a clinker boat ,thats also a bodge . Use strips of mahogany for the transome and use proper fastners . The ends of the planking are called hood ends. When you have done it properly post some pictures and stand back and admire . If you need a filler use raw linseed and putty mixed together. If you use ply get a good lifejacket.

 

[lukedh]

Scottish grown larch is a very good timber. The cold winters and short summers gives it a close grain. An excellent boat building timber.

 

[Mike2309]

Oh come on people !!
It's a workaday runabout with a history of a variety of uses and abuses, patchings (and bodgings!) misadventures and possibly adventures. I don't intend to get too precious about it. I shall put it back into usable order, fit it out with a lugsail I made some years ago for another dinghy, out of a Brentford Nylons polycotton duvet cover, set on a Gunter rig which I found in a shed here about 20 years ago . It will then look rather like the one in the attachment (which lies in the Fisheries Museum in Anstruther). Then I shall be able to go fishing in it, lift and lay my mooring , transport gear and people out to Aida on that mooring and generally potter about in it.
I think that will be fun.
If it turns out that I'm wrong about that, and that nothing short of tropical hardwoods anointed with unguents concocted of bulls blood and mermaids tears will yield true and lasting satisfaction - I'll let you know.

 

[Crabman]

Yeah whatever bodge away ****.

 

[Tranona]

Oh come on people !!
It's a workaday runabout with a history of a variety of uses and abuses, patchings (and bodgings!) misadventures and possibly adventures. I don't intend to get too precious about it. I shall put it back into usable order, fit it out with a lugsail I made some years ago for another dinghy, out of a Brentford Nylons polycotton duvet cover, set on a Gunter rig which I found in a shed here about 20 years ago . It will then look rather like the one in the attachment (which lies in the Fisheries Museum in Anstruther). Then I shall be able to go fishing in it, lift and lay my mooring , transport gear and people out to Aida on that mooring and generally potter about in it.
I think that will be fun.
If it turns out that I'm wrong about that, and that nothing short of tropical hardwoods anointed with unguents concocted of bulls blood and mermaids tears will yield true and lasting satisfaction - I'll let you know.

Well said that man! In 50 years when all the real tree wood has reverted to its natural state, the ply transom will still be there waiting for some new planks to be attached to it to form a boat again.

Just do it and maximise your use out of the boat.

 

[Crabman]

Well said that man! In 50 years when all the real tree wood has reverted to its natural state, the ply transom will still be there waiting for some new planks to be attached to it to form a boat again.

Just do it and maximise your use out of the boat.

Another Bodger. Should have called the post Bodgers. You say on forums spurting your wisdom. Yeah Right. You have made my week.

 

[Even Chance]

Another Bodger. Should have called the post Bodgers. You say on forums spurting your wisdom. Yeah Right. You have made my week.

You just stay in the 1940's where you belong! Ply and epoxy is the way forward for wooden boats dont you know......

Mike,
They dont understand the way of life up here, and how we use whatever is available to us for free/cheap at the time of requirement! Use ply, and have fun. If it needs fixed in a few years again, so be it. It will do the job just great Im positive of that.
Islanders built boats from whatever logs washed ashore at the time of building. Some of the Shetland models I have seen are over a hundred years old and STILL being used for their original use, and you would probably knocked them as being built of "unsuitable wood" "wont last long- bodged together" Get a grip ya Southern softie.
(toungue planted in cheek by e way!)

 

[Tranona]

Another Bodger. Should have called the post Bodgers. You say on forums spurting your wisdom. Yeah Right. You have made my week.

Very happy to be called a bodger if it differentiates me from the sort of attitude you display.

 

[Even Chance]

Very happy to be called a bodger if it differentiates me from the sort of comments you make.

Too true Tranona! At least theres folk out there enjoying old wooden boats and keeping them alive.

 

[greenalien]

If ply is what you have, use it. Seal all the edges thoroughly, epoxy is good, don't even think about putting any fastenings into the edges - add some beading, through-fastened, and bedded on sealant or epoxy, then screw the planking onto the beading, again with plenty of sealant. Also, as already suggested, add a top capping strip. For a thorough job, you could also apply some capping strips to cover the end-grain of the planks.