Hovercrafts are especially valuable and functional because they can travel over flat ground and over water bodies too. Hence, they do not need to be anchored at a port or tied up. They can slide smoothly from the water up a slope or even onto the coastline. They can also travel on water that is too shallow or stony beneath for normal boats. The biggest hovercraft weighs almost 300 tons and carries more than 400 passengers and 60 cars. They are equipped with four gas turbine engines, each 50 times the power of a normal car engine, and travel at about 90mph (140kph) – the fastest big sea going vessel in the world.
But hovercrafts have restrictions and disadvantages too. With barely any contact with the land or water, it can be hard and tricky to steer, and it is pushed around by strong winds and violent seas.
A hovercraft works on a basic principle of air and propellers. The various major parts of a hovercraft are descriptively explained below:
Drive Propellers
These propellers thrust the hovercraft ahead. The hovercraft is steered by slowing the propeller on one side compared to the other and also by moving the rudders.
Drive Propeller Engines
Gas turbine engines are used to power the drive propellers and lift fans. They function in a parallel way to jet engines, burning fuel into hot gases that gush through a fan-shaped turbine with angled blades, making it spin on its shaft.
Drive Propeller Shroud
The drive propeller is enclosed in a large tube-shaped shroud. This shields it and makes its turning force more capable by avoiding air from leaking out to the sides.
Rudders
The rudders of a hovercraft function in a similar way as those of a aeroplane or boat. They thrust or deflect the air to one side and make the craft swing around for steering.
Skirt
The strong, stretchy rubberized skirt encompasses air from the lift fans underneath to thrust the craft up. The air makes the skirt inflatable and then spills out around the bottom of the skirt.
Lift Fan
Huge cylinder shaped fans suck air from above the hovercraft down through the lift fan air intakes. Then they thrust it out with immense force below the craft, to push it away from the ground or water.
Lift Fan Engine
The lift fans are power-driven by one or more gas turbine engines under the floor of the passenger cabin.
Passenger Cabin
The hovercraft carries about 50 passengers who sit in airline-type reclining seats. Some hovercraft can take more than 500 passengers.
Flight Deck
Hovercraft are typically run and structured more like airplanes than boats. The control area where the captain and main crew sit is known as the flight deck instead of a bridge or wheelhouse.
Buffer
The skirt operates as a shock absorber or cushion if the hovercraft is in threat of colliding with a wall or a boat.
