Can anyone provide advice for this? We will be putting them in the school's pool and racing them. But I really want some advice. (1) Formulas to find if the boat will float or sink (we'll be able to make measurements and stuff). (2) Plan ideas. (3) Stuff to focus on in building. We only have cardboard. It needs to be 8 feet long (max) and 6 feet wide (or somehow fit through a normal doorwar). We can use tape to only seal up places where we put together two pieces of cardboard. So...help?!