Patent ID: 7604520

Claim:
An electrical linear motor on a marine vessel for propelling the marine vessel through a liquid medium, comprising: a housing secured to the marine vessel and submerged in the liquid medium; a guide tube disposed within the housing, the guide tube having an axial length, an inlet and an outlet; electrical coil windings disposed within the housing and positioned parallel to the axial length of the guide tube, the electrical coil windings configured for being energized by electric current; a thruster subassembly disposed within the guide tube and configured for reciprocating linear motion, the thruster subassembly having opposing first and second ends and a check valve; permanent magnets attached to the thruster subassembly, the permanent magnets disposed outside the guide tube and maintained in sufficiently close proximity to the electrical coil windings so that an electromagnetic field created by energizing the electrical coil windings interacts with a magnetic field from the permanent magnets to provide a reciprocating linear motion to the thruster subassembly within the guide tube; wherein the check valve is in an open position during a back stroke of the thruster subassembly so that the liquid medium enters the guide tube through the guide tube inlet and the thruster assembly first and second ends, thereby substantially filling the guide tube with the liquid medium, and wherein the check valve is in a closed position during a work stroke of the thruster subassembly so that the medium within the guide tube is forced out of the guide tube outlet thereby providing sufficient force to propel the marine vessel through the liquid medium.