It's coming along well, the decks were glued on last weekend and the top skin is going on the decks this weekend. Then a quick fair and paint and put it all back together.
I'm pretty happy with how it's going, a few notes on things I'd do differently in terms of construction though...
- Thinner foam, more frames.
- I had planned to use 6 or 8mm Corecell but none was available at the time of ordering. Ended up buying 10mm Airex. It was difficult to heat and bend into shape. Maybe that's because it was so thick and the heat didn't transfer through the foam well or maybe it was my technique (although it got quicker with practice). It has also ended up being heavier than I wanted, original weight estimate with thinner cores was 5kg underweight for each hull, that has been eaten away with the thicker core. The minimum number of frames I have in this hull is satisfatory for the thicker core, but more would be needed with a thinner core, probably twice as many.
- The reason I built it in a female framed mould was because I wanted to install as much of the internal structure before pulling it out of the mould. I have had previous experience with a hull that was difficult to maintain the shape of. When it came off a male mould without any internal structure it was very wobbly. The MDF framed mould was very cheap to get CNC cut.
- Leaving the bow open enabled a reasonably easy method to skin the inside right to the bow and join it with glue and an exterior tape later. I don't like adding lots of useless foam in the form of a sacrificial bow here, just a personal preference. The method worked really well, it wasn't hard to join the bow and maintain a fair hull shape.
- Foam fibreglass construction automatically complies with the 50L flotation per hull. Each of my hulls has 60L of foam in it. (PS. I don't understand the point of this rule. Is it for safety? This seems pointless with a redundant second hull to keep crew afloat in the case of a big leak, plus only stupid ppl don't wear life-jackets. Or is it to restrict builders/designers to closed hulls, ie. no **** boats? Can someone please explain...)
There's not much more I can think was different to any other boat build. There were a couple of structural items that I did maybe a little differently to standard boat building practice. I don't think those photos are up yet, except for the tapered plywood beam mounts.
Infusion is great if you do it properly. This requires experience and a female mould of some description. I didn't want to build a female mould and would think that doing so would be beyond most home-builders, in terms of both cost and skill. Don't forget that the whole point of home-building is to reduce the cost. Building a female mould generally costs more than a simple frame mould. Although infusion does look good and can produce lighter hulls. I've heard stories from a large production stink-boat builder reducing the weight of some small parts to a fifth of the original by converting from choppy gun open mould to infused production.
Excluding tools, I've spent about $2000-$2500 on materials including some carbon double bias I haven't used. This is to just build the hulls. Compared to buying a pair of foam glass/kevlar mosquito hulls at about $7000-$8000 (from memory), I think it is very good value. Plus I've learnt a bucket-load about boat building while I've done it.
I'd better get back to work.