Cushion barriers for air cushion vehicles

Claim 1

A barrier for bounding at least part of the periphery of the cushion area of an air cushion vehicle, the barrier being constructed at least in part from composite materials so as to have an acutely bent normal cross section comprising an upper part constructed to have high stiffness and a lower part constructed to have high flexibility at least in the region of its free edge, connected by a normally sharply curved part constructed to have high resilience, the free edge of the upper part being adapted for attachment to the rigid structure of the vehicle, the barrier construction being such that when it is so attached to a nonoperational vehicle the upper part of the barrier extends outwardly with respect to the vehicle, to merge with the sharply curved part which curves first downwardly and then inwardly to merge with the lower portion which then extends inwardly with respect to the vehicle, to terminate in a free edge, and when the vehicle becomes operational the action of the air cushion pressure on the barrier overcomes the resilience of the sharply curved part and moves the free edge of the lower part downwardly and outwardly in opposition to the normally sharply curved configuration of said resilient part, the resilience of the sharply curved part being enhanced by the insertion of spring steel strip and being sufficient to return the barrier to its original more acute configuration when it ceases to be acted upon by the air pressure.