Can I use composite wood for boat repairs?

lyndonmarch

PBO reader Colin Doyle needs to make repairs to his cabin sole. Is using composite wood a good idea? Boat builder and finisher Lyndon March has the answer

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I am in the process of replacing the complete floor and sub-structure of our 18ft glassfibre cabin cruiser, and have to replace the rotten softwood floor bearers that are glassed into the glassfibre hull.

The floor is about 5ft wide by 6ft long, and the bearers are about 8ft long in total as they go through the stern locker back to the transom. I am thinking of using composite wood – the sort of thing used for park benches and garden furniture etc – as this is practically rot-proof, being made from wood fibres and recycled plastic.

Do you see any problems with me using this, such as a differential in the expansion and contraction when the boat is in the water or parked up on its trailer? Or is there anything else you think I should be aware of?

Colin Doyle

Lyndon March replies: It doesn’t matter what your boat is made from; it seems that at some point you’re going to have to deal with some soggy timber.

In this instance, it sounds like you are dealing with the most classic of them all, water eating away at the internal structure of the hull. You’re also not the first to ponder the question of using recycled wood.

I’ve seen it done and, personally, I think it should continue to be used on park benches – but then perhaps I should have a more open mind.

While in theory I’m sure there’s nothing wrong with using this recycled composite timber, especially within the sizes mentioned, my concerns lie in its actual structural strength and integrity.

This is, of course, why we use timber within some glassfibre constructions – wood is stiff, light and strong. There’s also the issue of weight.

In my experience, composite timber is rather heavy, and in a boat that originally just had softwood runners, you could potentially add a lot more weight, upsetting the boat’s balance and bringing in a heap of further issues.

I think a bit of faith in good old timber and making sure that it’s well sealed into a dry space should see your vessel last much longer and perform like new.

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