Abstract: An electric propulsion system for use in marine applications. The system comprises rechargeable battery cells, AC or DC electric motors for propulsion, control units to manage the flow of energy between the battery cells and the motor, a water cooling loop that pumps water through heat exchangers then out of the watercraft for thermal management. Closed cooling loops may be employed to thermally manage the motor, batteries, controllers, inverters, charging apparatus and other components by running through coolant through the cooling loops to properly chill or heat the coolant fluid. The unit is charged through shore based power, solar and other sources, including the possibility of power sources through hull or hanging turbines to generate mechanical energy from the flow of water as the watercraft is propelled. The whole system is controlled by a vehicle control unit and a battery management system.