Abstract: A boat that is powered by an autogyro rotor is disclosed. A boat hull having a stern mounted rudder is provided with a selectively rotatable boom, preferably mounted in proximity to the rudder at the hull centerline. The boom is angled upwardly from its rotatable base, terminating at its upper extremity in a pivoting rotor mount and stops. The stops define the limits of pivot or cant of the rotor axis,the first being preferably horizontal and the second approximately thirty degrees (30.degree.) thereto. When disposed at thirty degrees (+.degree.) the axis passes through the center of lateral resistance of the rudder and hull combination, the effect being to minimize heel, ballast used to resist heel, and that part of a keel used to resist heel, resulting in less drag and greater speed. An upward thrust component of the autogyro rotor also results in reversal of the normally downward force component from heel, further reducing drag and increasing speed. Lee or weather helm is also substantially eliminated.