A sea water cooling system including a first fluid cooling loop coupled to a first side of a heat exchanger and to a thermal load, a second fluid cooling loop coupled to a second side of the heat exchanger and including a pump for circulating fluid through the second fluid cooling loop, and a controller operatively connected to the pump, wherein the controller is configured to monitor an actual temperature in the first fluid cooling loop and to adjust a speed of the pump based on the monitored temperature to achieve a predetermined temperature in the first fluid cooling loop. The system may be selectively operable in one of a plurality of operating modes, wherein in a first operating mode the pump operates based entirely on cooling demands of the thermal load, and in a second operating mode the pump operates to maintain a fluid pressure above a predefined pressure.