Re: [math-fun] Free surface effect

If CG means center of gravity, then I don't understand this. Otherwise, I don't understand it because I don't know what CG means. —Dan ----- Sure. Imagine a circular cylindrical tank. When partially full roll of the ship would leave the tankage CG unchanged while the CG of the rest of the ship (assuming it's stabilized by a keel) would move opposite the roll. So the overall CG would change. But you can't tell the stability of a floating object in general just by considering the CG location. You have to consider the center of buoyancy too and their relative motion. Think of a catamaran. The CG doesn't change when it rolls, but the center of bouyancy moves to provide a righting moment. -----