After a frustrating week, I have finally started actually making something! As soon as there is something interesting to see I will post about it, but until then, just a quickie about wood, which is now all here.
I was gripped for weeks in my usual paralysis of indecision about the plywood. I’m sure anyone who has made a boat will recognise the symptoms – total fear that the decision at hand might ruin thousands of hours of hard work. Before the work starts, this fear is especially crippling, as every decision is yet to be made, and most of them need making now, before one has gained any experience on which to base them. It’s a wonder anyone ever starts.
Anyway, plywood needed choosing. I was clear that I would go with decent marine ply, and had heard good things about Bruynzeel, so that was a start at least. Next, should I use okoume (gaboon) or mahogany? Mahogany was my first thought, but it is a lot heavier – maybe as much as 30%. I knew that the original Haiku had had weight issues, and Iain himself says sharpies should be ‘lightly built’, so this didn’t seem such a good idea. On the other hand, okoume is not a durable wood, which worried me. However, I always planned to sheath the hull with epoxy and glass, and have been convinced that given the right maintenance, there is no reason why okoume should be a problem – there are certainly a lot of boats made of it. Lower resale value is another thing people mention in connection with okoume, but I have no intention of ever selling Luely, and I don’t think the British market is receptive to second-hand sharpies anyway, whatever they are made of. The bonus is that I have saved thousands, since okoume is much cheaper than mahogany.
One problem though, was that Bruynzeel don’t do 9mm ply, but do 10mm instead, so I had to amend my CAD drawings. You might think that a) 1mm difference in a few components is hardly worth bothering to reflect in plans for a 30-foot boat, and b) even if I insist on making that change, it surely couldn’t take more than 5 minutes. Because I want to make maximum use of our CNC machine, I really do want millimetre-perfect parts so that they all fit together first time. Unfortunately, my software (Rhino) is not parametric – a feature of the most advanced and expensive modelling software, which enables changes like this to ripple through a whole plan automatically. For 99% of the time, my trusty non-parametric friend Rhino is fine: it is remarkably good value, and is very quick to use – much quicker than the disciplined way in which parametric drawings have to be done… until you need to make a change that is! So, in this case it bit me badly, and I spent several days rebuilding sizeable portions of the model and swearing loudly.
The solid wood was much easier: Iain speaks highly of douglas fir, and given that it is easy to find, reasonably durable and quite inexpensive, it seemed silly to look any further. Naturally, I did not miss the opportunity to make things hard for myself, by forgetting to order one of the thicknesses I needed!
I am using small amounts of other woods too. The plans call for ‘oak’ floors. However, I have some fantastic stuff called black sucupira, which is stronger, stiffer, stabler, more durable and cheaper than oak, so I am using that. It is somewhat denser, but the extra weight will be as low down as the internal ballast, so I can simply omit some of that if necessary (and it is only a tiny amount overall).
The only other woods are those that I am using in the centreboards, and again, I happen to have something already that will fit the bill. This time it is a selection of various timbers I had left over, including coracao de negro, preciosa and muirapiranga. They are all woods we bought years ago when we were researching sustainably produced exotic timbers for use in our furniture, but never really found they were suited to much of our work. What they all have in common is that they are denser than water (i.e. they sink) and ridiculously hard: perfect centreboard materials, and a perfect way to use them up.