Calculate hull speed and power required for boat speed. New from psychosnail, Learn to sail online, course on how to sail for beginners. Yes, it's time for online sailing lessons. For a boat hull, a simple way to think of theoretical boat speed is that a vessel is limited by the wave that boats hull creates. That is, because it is a displacement vessel it doesnât climb its bow wave, as a planning vessel would, which limits the boats speed.