Abstract: A tunnel-type boat-hull construction is operative with substantially reduced frictional resistance in the water and also with improved high-speed stability. An air-withdrawal port is provided in the bow portion of the tunnel, and exit ports which are interconnected to the withdrawal port are provided along generally downwardly facing submerged surfaces of the hull. When the boat hull is operated in a forward direction, air is captured in the forward portion of the tunnel, and a portion of the air is withdrawn through the withdrawal port and is exited through the exit ports. The air which is exited through the exit ports provides lubrication for the submerged hull surfaces so that the hull is operative with substantially improved efficiency; and because the air is withdrawn from the bow portion of the tunnel, the bow uplift effects which are characteristic of conventional tunnel-hull-type vessels when they have been operated under high-speed conditions are substantially reduced.