Marine vessel shaft bearing overheat monitor and alarm system

A system comprising:

• a bearing adapted to support a rotatable drive shaft for a propeller of a marine vessel with a hull, wherein the bearing is in communication with water surrounding the vessel for cooling the bearing;
• a first temperature sensor in communication with the bearing for sensing and communicating the temperature of the bearing;
• a second temperature sensor in communication with the water surrounding the vessel for sensing and communicating the ambient temperature of the water
• a processing unit in communication with the first temperature sensor and second temperature sensor for receiving and comparing the temperature of the bearing and the ambient temperature of the water, wherein the processor is operable to generate a signal if the temperature of the bearing exceeds the ambient temperature of the water by more than a selected amount;
• and
• an alarm device in communication with the processing unit and responsive to the signal to provide an indication that a bearing overheat condition exists.