Development of a self-contained heater for military divers

Divers in cold water require supplemental heat to function effectively for extended periods. Described is the design, fabrication and testing of a self-contained diver-worn heater that supplies hot water to closed circuit thermal protection suits. Heat is produced by the electrochemical reaction of magnesium in seawater. The reaction is accelerated by shorting the magnesium anode to an iron cathode. Up to two kilowatts for eight hours endurance have been produced. Characteristics of the reaction are discussed. A test of a one kilowatt eight hour heater with a diver immersed in2\degC water confirmed that the magnesium reaction is a feasible means of supplying heat.