funnily enough my second post seems to have disappeard!?! I'd concur with Jim's point which I referred to without explaination at the end of my first post.

Also, from posting from half remembered Naval Architecture lectures 20 odd years ago, the ship's centre of gravity needs to be below the metacentre but above the centre of bouyancy. This give the necessary turning moment to right the ship when it tilts over. The rest of the post is valid though. (Slinks off, embaressed, to the back of the class)