Early warning of marine cooling system failure

Claim 1

In a marine cooling system wherein cooling water is drawn from the body of water supporting a watercraft utilizing a marine engine, said water being drawn through a water inlet, circulated to cool said engine, and discharged back to said body of water through an exhaust conduit of said engine, an early warning system for detecting the failure of said marine cooling system comprising: a temperature sensing element presenting an electrical resistance which varies with temperature supported within said exhaust conduit, said sensing element being cooled by said water as it is discharged through said exhaust conduit to provide a connection to ground potential through the resistance of said sensing element thereby defining a resistance ground signal having a low resistance value during proper operation of said cooling system and rapidly rising in temperature to provide an increased resistance value upon failure of said cooling system; circuit means connected to said sensing element for generating an alarm signal in response to a resistance ground signal having an increased resistance value exceeding a selected resistance value; and alarm means responsive to said alarm signal for warning the operator of said watercraft of impending engine overheating.