Disclosed is a vessel with two watertight flaps attached in a tensioned state on the two sides of the longitudinal keel, each being under one of the two rear side portions of the V-shaped hull, the outer side edge of each flap being connected under the shell covering the bottom compartment on the same side, and the bottom side edge being connected to the bottom along a line which is angled from the rear to the front and angled toward the lower compartment, with a flap width tapering from the tensioned, free rear edge between the ends at the transom, toward a front portion connected to the bottom and/or to the shell at the connection between the upper and lower compartments, defining, with the latter and the bottom, a channel converging from front to rear and angled toward the rear end of the edge of the V-shaped craft hull.