Abstract: A propeller pitch control apparatus for an aircraft in which the vector sum of the aircraft forward speed and the propeller rotational tip speed is a selected fraction of the speed of sound, the fraction based on percent power and altitude, to maximize efficiency and minimize noise.

Abstract: A boat hull having a bow lifting surface, a stepped bottom aft of the bow to create an air space between the water and the bottom of the hull and a stern lifting surface extending downwardly from the stepped bottom such that the bow lifting surface and the stern lifting surface angle of attack is fixed at the angle for maximum lift to drag for a given deadrise angle. The effect is to lift the hull vertically the maximum possible, so the wetted hull area and drag are reduced to the minimum. As the deadrise angle changes from 0 degrees to 25 degrees, the angle of attack for best lift to drag changes from approximately 7 degrees to 14 degrees. For a V-shaped hull the angle of attack is in a range of nine through fourteen degrees. A flat bottom hull should have an angle of attack in a range of six through eight degrees, preferably seven degrees.