Abstract: The boat or craft disclosed includes two spaced parallel hulls that are connected together by a platform extending between the hulls. The platform and the two hulls form the top and sides of an air space beneath the boat with the hulls supporting the platform above the water. Curtains of flexible material are spaced longitudinally in the air space and extend downwardly from the platform and transversely between the hulls to close the forward and rearward ends of the air space, whereby the pressure in the air space can be maintained above ambient to provide an air cushion to support a portion of the gross weight of the boat. The hulls are designed to provide a buoyant force due to displacement that will support 100% of the design gross weight of the boat when there is no pressure in the air space and the boat is not moving or is moving at a relatively slow speed through the water.