A radio controlled propulsion device for use with multiple buoyant objects. The device contains a radio receiver circuit, a motor drive circuit, and motors for steering and propulsion. The device also contains a battery pack to provide power to the circuits and motors. The circuits are responsive to signals from a transmitter controlled by the operator of the propulsion device. With the propulsion device inserted into a cavity formed in the body of the buoyant object, the output signals from the drive circuit are provided, to control the motion of the buoyant object.