The Science
An airboat is basically a flat-bottomed boat propelled by a fan, often with the type of propeller that would normally be found on a light aircraft. Because the airboat uses rudders acting on the air, rather than rudders in the water, it can travel on very shallow water and over swamps and obstacles.
Airboats rely on Newton's third law: equal and opposite reaction – throwing air behind you pushes you forward, at some speed. The most powerful airboats can travel at 60mph on land and over 130mph on water.
By altering the size of the propeller, its pitch (the angle of the blade) and the rpm of the engine you can make the airboat as efficient as possible. The ideal airboat has high thrust at low rpm, so you can travel at speed, but with less noise, while also burning less fuel.
