Gunwales for a GRP dinghy

Ubergeekian

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Me: Castle Douglas, SW Scotland. Boats: Kirkcudbri
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Dear All

I could do with some advice on gunwale materials. The dinghy is a 7'6" Jack Holt "Dittyboat" and I have just finished removing the rotten originals. They were wooden - possibly mahogany but I can't tell now - and made up in strips. One section 1" high by 1/2" thick inside the hull, two of the same outside.

With what material of what size does the panel think I should make new gunwales? At the moment I am thinking or Iroko, and using 1" x 1/2" inside as per original but 1" x 1" outside. I realise that will mean steaming, but I'd rather do that if possible than have a potential gap between two trips on the outside - that gap is where, in a very literal sense, the rot set in.

Curve radius is 2' at worst, near the bow but generally much more. I am not particularly bothered whether I use wood or plastic and I'll be using a rope rubbing strip round the edge in due course. Without the gunwale the dinghy is very floppy!

Over to you all ...
 

prv

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Could you laminate it from thinner strips, using epoxy? That ought to address any bend-radius concerns.

(When I do the quick-and-dirty dinghy build previously discussed on here, my plan for gunwales is to use my power staple-gun to rapidly tack on several layers of strips pre-coated with wet epoxy, to avoid the need for lots of clamps and the time to apply them. I wouldn't recommend this to anyone looking for a quality result though.)

Pete
 

Tranona

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You will struggle to get 1*1 iroko to go round even with steaming. Best to stick (?) to the original and use epoxy. If the epoxy cures properly ne water should get between the strips. You will probably need to put temporary spreaders in to keep the shape as you put the first two strips on.

Happy bending and gluing!
 

PetiteFleur

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You will struggle to get 1*1 iroko to go round even with steaming. Best to stick (?) to the original and use epoxy. If the epoxy cures properly ne water should get between the strips. You will probably need to put temporary spreaders in to keep the shape as you put the first two strips on.

Happy bending and gluing!

Make sure you start at the bows, both sides at a time, working towards the stern. Make sure they are longer than the dinghy by about 12" - you tie them together to pull into the sides, glue and fasten as you go along and when dry cut off the excess wood. Have plenty of clamps Good Luck!
 

TSB240

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I had a similar problem with our GRP dingy.. I replaced the rotten mahogany originals with 2 off 1.75'' by 0.5" Iroko without steaming or using any adhesives.

One on each side of the fibreglass clamped with numerous g clamps drilled through and fastened with 8mm Button Headed stainless bolts approx every 6 -8 inches.

Timber precoated with preservative and can easily be touched up each year.

Dinghy nice and stiff now!
 

VicS

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I dont think the inner or outer gunwales on my dingy are any thicker than ½".

It is a vague sort of copy of a Jack Holt design.
The bearers for the thwart helps to stiffen the sides and the knees make the sides right up to the gunwales quite rigid.

17a298bd.jpg


The dinghy was built in 1978. The above photo is about four years old but there is no rot anywhere. It does come home for the winter but spends every summer upside down by the yard slip way.
 
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