Patent ID: 7806065

Claim:
A modular removable externally mountable diesel electric thruster system for dynamic positioning of a floating semi-submersible vessel with a ballasted waterline comprising at least one pontoon, wherein each pontoon comprises at least one vertical column integral with a top of the at least one pontoon, and wherein each vertical column supports a deck above the ballasted waterline, the system comprising: a. at least one pair of azimuthing thrusters, wherein each azimuthing thruster is removably mounted to the at least one pontoon of the floating semi-submersible vessel, wherein each azimuthing thruster generates a variable thrust and, wherein each azimuthing thruster comprises: 1. a skid removably secured to a top portion of the pontoon below the ballasted waterline; 2. an upper thruster housing removably connected to the skid, wherein the upper thruster housing contains a slewing bearing with at least one electric motor driven slewing drive, at least one electrical steering angle feedback sensor for indicating a steering angle of the azimuthing thruster, and a multi-conductor slip ring assembly; 3. a tube moveably connected to the upper thruster housing on one end and removably connected on another end to an electric pod having a nozzle; 4. an electric motor inside the electric pod with a propeller drive shaft, wherein a fixed pitch propeller is removably mounted to the propeller drive shaft; and 5. a thruster electric power cable connected to the electric motor on one end and to the multi-conductor slip ring assembly on another end; b. at least one pair of diesel electric power units removably secured to the deck, wherein each diesel electric power unit engages one of the azimuthing thrusters, and wherein each diesel electric power unit comprises: 1. a power unit housing; 2. a diesel engine within the power unit housing, 3. an electric generator driven by the diesel engine; 4. a variable frequency drive connected to the electric generator; 5. a fuel tank connected to the diesel engine; 6. a cooling system for cooling within the power unit housing; 7. a starter system for the diesel engine; 8. an exhaust system connected to the diesel engine; and 9. a control system for controlling the diesel engine, electric generator, starter system, cooling system, fuel tank, variable frequency drive and combinations thereof; c. at least one pair of electric power cables and a thruster electric control cable, wherein one end of each electric power cable and each thruster electric control cable is secured to the diesel electric power unit and another end is secured to one of each pair of azimuthing thrusters; d. a dynamic positioning system connected to the diesel electric power unit; and e. at least two position reference sensors and at least two environmental reference sensors connected to the dynamic positioning system.