LONDON — Hovercraft (technical name air-cushion vehicles) ride on a cushion of air that is generated by engines and is trapped beneath the machine. The engines also provide propulsion.
The machines are able to operate over water and can readily make the transition to dry land and back.
The first experiments using an air-cushion system were conducted in the 1870s by Sir John Thornycroft, a British engineer. He was unable, however, to devise a system that satisfactorily solved the air-cushion containment problem.
In the 1950s Christopher Cockerell (later knighted), widely seen as the father of the Hovercraft, found that if air, instead of being pumped from a central point, was directed downward through a narrow slot around the periphery of the craft, it would flow toward the center and an external curtain would be formed. He added rubberized skirts to contain the air beneath the vehicle.
Large Hovercraft, such as the car- and passenger-carrying craft used on the English Channel route, can achieve speeds up to 60 m.p.h. They can be thrown quickly into reverse and are highly maneuverable. Militarily they are ideal for amphibious operations.