Abstract: A sonic motor comprising housing means with a closure at each end thereof and having an axially extending cavity therein, with a transmission member having spaced apart surfaces with a cylindrical output end the diameter of which substantially matches the diameter of said cavity. Coupling means connects the transmission member to the housing means so as to maintain the output end of the transmission member in energy transmitting relationship to the housing means, and transducer means is connected to one of the surfaces on the transmission member substantially centrally thereof to provide longitudinal mechanical vibrations thereto, so as to cause the transmission member to vibrate in a radial mode such that the housing means in the area of the coupling means is radially vibrated. The motor is also adapted to be self powered for use in underwater applications.