Hovercraft and the Environment
For any vehicle to operate economically the drag, or resistance to motion, must be kept to a minimum. On water, the majority of drag arises from the motion of the vessels hull through the water; therefore we can reduce drag and consequentially propulsive power by minimising hull contact. The hovercraft achieves this by using low-pressure air to form an air cushion underneath it, thus actually lifting the hull clear of the water. In addition, by using air propulsion to generate forward movement, the hovercraft becomes amphibious, and able to traverse land, soft terrain or water.
Being amphibious, the hovercraft can use direct routes across sandbanks, marshes and flats, with no loss of speed or comfort. Channel dredging becomes unnecessary, whilst rivers and tidal estuaries present no problem for the passage of the vessel. Previously inaccessible areas may be accessed economically with little or no impact on their environment.
Damage to the shore environment, such as beaches, mudflats and vegetation is virtually nil because of the hovercraft's low pressure "footprint?. For example, the average human being when standing on a beach exerts a pressure of some 3lbs per square inch underfoot, rising to 25lbs per square inch when walking. The average hovercraft by comparison, exerts a pressure of approximately 1/3lb per square inch on the surface regardless of speed.
The fact that there are no underwater protrusions or propellers eliminates the usual thrashing noise signature associated with conventional propeller driven craft, as well as negating any possible seabed erosion when operating in shallow waters. It therefore becomes obvious that fish and other marine life are in no way affected. This has been confirmed by independent scientific tests. The major noise factor with any hovercraft is the propeller noise, which in any case is largely directional in characteristic.
A fully loaded six-person hovercraft burns less fuel per hour than a typical jet ski, it does not pollute the water and does not disturb the bottom in shallow areas that many fish rely upon for food and breeding.
The wake created by the passage of a hovercraft is minimal, ensuring
that riverbank erosion and damage to foreshore by the waves created
is virtually nil. A study in the United Kingdom concluded that the passage
of hovercraft over inter-tidal areas caused no damage to sea grasses
or invertebrates. It was also noted that bird life rapidly adjusted
to the presence of hovercraft. This has been confirmed on the Gold Coast
in Australia, where a commercial operator passed over the same area
of beach many times a day for more than three years without any affect
to the population actually living in the sands directly under the flight
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