Abstract: A V-bottom for fast motor boats with longitudinal reaction walls reacting to a lateral trust from an air-water mixture which are substantially parallel and symmetrical in relation to keel is formed so that the reaction walls are the walls of flat-based grooves in a bottom joined to a flat base by a widely curving radius, or the reaction walls are the walls of ribs having a substantially trapezoidal cross-section and a flat horizontal lesser external base.

Abstract: V-shaped bottom (94) for fast motorboats (90) that presents a number of longitudinal means substantially parallel and symmetrical to the keel having walls that react to the lateral thrust from the water-air mixture, formed either of grooves (15, 18, 91, 92) or of ribs, their sides being widely curved at the junction respectively with the base of the grooves (15, 18, 91, 92) and with the surface of the bottom (94) of the boat.

Abstract: A V-shaped bottom for speedy motorboats of the type provided with planing supporting skids, wherein said skids have the supporting planing surface thereof rising from the bow towards the stern and gradually projecting from the section of said bottom, each supporting surface having a triangular conformation and each being provided with side walls forming the attachment elements for said skid to said bottom, the height of said walls gradually increasing from the bow towards the stern.