Hydroplane

A hydroplane (or hydro, or thunderbolt) is a very specific type of motorboat used completely for racing.
One of the unique things about these boats is that they only use the water they're on for propulsion and steering (not for flotation)—when going at full speed they are primarily detained aloft by a principle of fluid dynamics known as "planning", with only a tiny portion of their hull actually touching the water.
The basic hull design of most hydroplanes has remained comparatively unchanged since the 1950s: two sponsors in front, one on either side of the bow; behind the wide bow, is a narrower, mostly rectangular section housing the driver, engine, and steering equipment. The aft part of the vessel is supported, in the water, by the lower half of the propeller, which is intended to operate semi-submerged at all times. The goal is to stay as little of the boat in contact with the water as possible, as water is much denser than air, and so exerts more drag on the vehicle than air does. Basically the boat 'flies' over the surface of the water rather than actually traveling through it.