A
hovercraft (air-cushion vehicle, ACV) is a craft capable of traveling
over land, water, mud or ice and other surfaces both at speed and when
stationary. They operate by creating a cushion of high-pressure air
between the hull of the vessel and the surface below. Typically this
cushion is contained within a flexible "skirt". Hovercraft are hybrid
vessels operated by a pilot as an aircraft rather than a captain as a
marine vessel. They typically hover at heights between 200mm and 600mm
above any surface and operate above 20 knots and can clear gradients up
to 20 degrees. The first practical design for hovercraft derived from a
British invention in the 1950s to 1960s. They are now used throughout
the world as specialised transports in disaster relief, coastguard,
military and survey applications as well as for sport or passenger
service. Very large versions have been used to transport hundreds of
people and vehicles across the English Channel whilst others have
military applications used to transport tanks, soldiers and large
equipment in hostile environments and terrain.
