Vehicles for operating over water

Claim 1

A VEHICLE FOR TRAVELLING OVER WATER HAVING A MAIN BODY WHICH IS OPERATION IS AT LEAST PARTLY SUPPORTED ABOVE THE SURFACE OF THE WATER BY AT LEAST ONE CUSHION OF PRESSURISED GAS FORMED AND CONTAINED BENEATH SAID BODY, COMPRISING SIDE WALLS EXTENDING SUBSTANTIALLY PARALLEL TO THE FORE-AND-AFT AXIS OF THE VEHICLE AND DEPENDING FROM THE BOTTOM SURFACE OF SAID MAIN BODY, SAID SIDE WALLS FORMING PART OF THE LATERAL BOUNDARY OF SAID CUSHION, MEANS FOR CLOSING THE GAPS BETWEEN THE ENDS OF SAID SIDE WALLS AND FORMING THE REMAINDER OF THE LATERAL BOUNDARY OF SAID CUSHION INCLUDING A VERTICALLY MOVABLE STRUCTURAL MEMBER AT ONE END OF THE VEHICLE FORMING THE UPPER PART OF THE CUSHION BOUNDARY BETWEEN THE ENDS OF SAID SIDE WALLS, AND MEANS FOR CAUSING A FLUID CURTAIN TO ISSUE FROM THE LOWER PORTION OF SAID STRUCTURAL MEMBER AND TO FORM THE LOWER PART OF SAID CUSHION BOUNDARY BELOW SAID MEMBER AND MEANS FOR ADJUSTING THE POSITION OF SAID STRUCTURAL MEMBER VERTICALLY WITH RESPECT TO SAID MAIN BODY AND SAID SIDE WALLS SO AS TO NORMALLY MAINTAIN THE BOTTOM OF SAID MEMBER AT A DISTANCE ABOVE THE BOTTOMS OF SAID SIDE WALLS WHICH IS APPROXIMATELY EQUAL TO THE HEIGHT OF THE WAVES OVER WHICH THE VEHICLE IS TRAVELLING, WHEREBY, WHEN THE BOTTOMS OF SAID WALLS ARE JUST EIMMERSED BENEATH THE SURFACE OF THE TROUGH OF WAVE, SAID STRUCTURAL MEMBER IS JUST CLEAR OF THE CREST OF SAID WAVE.