Waterborne sidewall air cushion vehicle

A waterborne air cushion vehicle comprising, in combination, a flat rigid upper rectangular sheet-like platform, a plurality of flat rigid longitudinal walls including at least two outermost walls, attached substantially at right angles thereto and depending therefrom substantially parallel with the major axis of said platform, the outermost two of said walls being disposed as sidewalls along the respective edges of said platform, a plurality of longitudinally spaced laterally aligned arrays of flexible trough-shaped skirts respectively looped with a space therein and fastened via each longitudinal edge thereof with respect to the underside of said platform flush with but independently movable with respect to adjacent pairs of said walls but extendable to a lesser depth than that of said walls, a source of pressurised air admissible via apertures of fixed size at a relatively higher pressure to said skirts and also admissible at a relatively lower pressure via variable-sized openings capable of being remotely controlled and located in said platform in communication with each of at least four open-bottomed air cushion chambers each bounded by an adjacent pair of said skirts and by an adjacent pair of said walls, and wherein the depth of said walls and of said skirts is so related to the flow rate of said air that the vehicle is buoyant upon water with said walls protruding into said water sufficiently to prevent air spillage via said walls when the vehicle is urged longitudinally through said water by propulsion means, and wherein said apertures and said openings are adapted to re-admit by reverse flow at least part of the compressed air in any one of said chambers and its associated skirts independently in response to fugitive deflection of said skirts resulting from turbulence of said water, to thereby inhibit movement of said vehicle about the pitch axis thereof.