Hi seeker,

I'm sorry for my late answer.

I used PS-25; which is polystyreen foam with a density of 25 gram/liter. In reality it weighs however 22 or 23 gram pro liter. This density delivers with a skin of about 1,5 mm epoxy laminate just a strong enough and stiff enough result.

Per hull there is about 450 liter content which gives about 10 kg foam per hull. Mind you, this is exclusive the wooden inserts (abachi and redcedar) for the points where f.i. bolts had to be fixed etc.

I made onforehand two cutting templates from plywood for cutting the foamblocks in the two directions with a hotwire in the desired shape. The rest was handshaping. Don't forget that the actual asymmetrical hullform was in the three dimensions rather complicated (and in mirror of the other).
In fact there was three months between the building of them and they are not 100% exactly each other mirrorimage. I can feel the difference with sailing.

It stays handwork!