How does a hovercraft work?

           Hovercraft is an example of the technological advancement succeeding the era of aeroplanes and ships. It is a new mode of transport—quite different from any other vehicle, ship or aeroplane. A hovercraft can be described as either a plane with no wings or a ship that rides out of the water. It can carry heavy loads on land, can operate on the sea and fly in airborne operations.

          Hovercrafts hover or ride on a cushion of air. A cushion of air is maintained between the craft and the surface by driving air constantly at pressure under the hovercraft. If a vehicle is made to float on a cushion of air, it can be easily moved in any direction by a little force. The air cushion vehicles on water move very fast, even upto a speed of 150 km per hour, as they do not face any resistance due to water. An ordinary ship travels slowly in comparison because of the friction between the hull and the water. 

          In a hovercraft, the air is sucked in through the top of the vehicle by a large fan. It is then blown through nozzles to the bottom of the hovercraft. The hovercraft is raised by downward air currents blown from large lifting fans. The air currents are partly trapped within the flexible enclosing skirt which contains the cushion of air. This produces the increased air pressure that forces the vehicle upwards.

          Hovercrafts work best over flat surfaces like water. But they can also overcome beaches and flat land with the only risk of getting snagged at the bottom. It has several advantages over a normal ship as they skim over waves and not through them. It can ride small waves quickly and smoothly as well as can fly over a slope from water onto the land. Another advantage is that they can carry heavy loads — a large craft can carry dozens of cars and upto 400 passengers. Also they do not use harbours or runways to land.

          Christopher Cockerell, a British engineer, invented the hovercraft in 1955. In Europe, hovercrafts are used these days in large numbers to carry hundreds of cars and passengers every day. Recently they have been introduced in Bombay.