Air-cushion vehicles

Claim 1

An air-cushion vehicle comprising a vertically extending shaft, means for impelling air down said shaft to produce an aircushion capable of supporting the vehicle at an operating level above a surface, means for driving the vehicle at said level over said surface, a rigid chamber extending along each side of the vehicle, means for communicating the interiors of the chambers with the interior of the shaft, an annular inflatable skirt having a cross section of a closed loop surrounding the marginal part of the undersurface of the vehicle, and means communicating the interior of the skirt with the interiors of the chambers, said skirt and said undersurface of said vehicle forming a cavity over said surface for receiving air directly from said shaft for production of said air-cushion, said skirt being inflated by the means for producing the flow of air to form and maintain the aircushion, the arrangement being such that with the vehicle at rest, inflation of said skirt raises the vehicle so that the vertical distance that the vehicle has to be raised to said level by the means for forming and maintaining the air-cushion is reduced, each chamber has a horizontal floor, wherein the undersurface of said floor forms the upper wall of the inflated skirt and wherein said means communicating the interior of the skirt with the interiors of the chambers comprises, for each chamber a pipe extending upwardly from a through bore in said floor, the upper end of said pipe being disposed above the position at which the means communicating the interior of said chamber with the interior of said shaft enters said chamber.