Whether you have a multihull or a small monohull, do you know whether your boat will float if it is completely full of water? How can you find this out before you are in a life-threatening situation? We beachcat sailors all seem to complacently accept that our boats will capsize but at least they will not sink. But is that definitely true? Nobody seems to know. I have recently heard that some of the newer, lighter, more high-tech cats, partly because of their hull construction, can definitely sink. So how can you be sure, aside from taking your boat out into relatively shallow water and deliberately trying to sink it? But nobody wants to do that, because if it really does sink, how do you get it floating again so you can get it back on shore? So if you have any doubt about whether your boat would float, do you stuff it full of styrofoam -- how do you know how much is enough?