by Peter

What sort of timber quality or grading is required for keel timbers say 300 x 200 x 8.5 m long


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Backbone Timber
by: Mike

Hi Peter,

When you say timber quality or grading are you referring to the type of standard grading rules that are used in the industry?

If so all I can say is that they seem, to a layman like me, to be merely broad categorizations, within which there can be a great deal of variation.

Let’s face it there can be a variation in quality with in one tree.

This is why it is always a good idea to find a timber merchant who has some understanding of wooden boat building and one who is happy to give advice.

Also if you can buy locally you can see and choose the pieces you are buying.

Obviously you want timbers with as few defects as possible, however don’t worry too much about longitudinal checks as these will most likely take up when the boat is launched.

The grading system in most countries is split between three main categories.

The look and feel of the timber isn’t really a concern for backbone timbers what you are interested in are the structural strength and stiffness and the durability or rot resistance.

You also want well seasoned timber.

I'm a great believer in using locally grown timbers where there is something suitable.

Oak, iroko, pitch pine, kauri pine have all been used successfully for backbones.

But you might want to look at some native timbers.

Blue Gum is a hard, heavy, tough timber which is comparatively easy to work.

Merbau is another hard timber with medium stiffness but it is heavy.

Jarrah is another heavy timber, which is very durable but it is difficult to work when seasoned.

Of course price is always a factor so shop around.

If possible buy your timber rough sawn and oversize, then allow it to acclimatize for as long as possible, stored off the ground.

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