Good stuff- heels over a lot though when the wind catches it.
You could try adding more foam and lead in the keel to increase stability.
Another thing that might work is to try a trick passed onto me By Ron Perrott. Use hollow tanks with as small hole at the top, and a couple of larger holes at the bottom. These should be fitted above the waterline, and they act as bouyancy chambers and help stability by providing a righting moment without incurring a big weight penalty. Because the flood holes are small the tanks take time to flood.
If you want a practical example of this, get an old plastic milk bottle, drill a small hole in the top, say 3mm, and a couple of larger holes in the bottom, try pushing it under water, and you'll see it bobs straight back up again, but place a weight on it, and you'll see it slowly fills and sinks.
