Abstract: A control system for a hydrofoil characterized in that a transition from the foil-borne to the hull-borne mode of operation is initiated and the craft caused to descend or land automatically due to a failure in the primary power source for the control system or some other off-normal condition. The invention constitutes an improvement in prior art systems of this type in that, should the primary power source fail, an auxiliary gyroscope automatically provides stabilization about the roll axis to the unstable craft. This causes the craft to maintain an essentially level deck attitude or, should the craft be in a turn, to roll out of an inclined deck attitude toward a level deck attitude as the craft descends to the hull-borne mode of operation subsequent to primary power source failure. In this manner, the severity of impact with the water as the craft descends during a turning maneuver is reduced.