1 ton of foam? Foam used in boating is usually in the 2-4lb range, which means 2-4lb per cubic foot. There's not much chance a 40' yacht has 1000 cubic ft of

1 ton of foam? Foam used in boating is usually in the 2-4lb range, which means 2-4lb per cubic foot. There's not much chance a 40' yacht has 1000 cubic ft of foam in it - far more likely it's got 20-30 cu ft, which is under 100lbs of foam. Not enough to move the needle a bit. Plus, foam provides displacement in case of breaches as a matter of it's nature. This lattice wouldn't provide any displacement, so a small breach would mean you're 2" thick composite hull would fill with water, which would be bad.