Some Coast Guardsmen participated in a formerly SECRET operation dubbed Tight Reign.  The Air Force and Navy needed a reliable, all-weather, navigation system to support combat operations.  The Coast Guard's Long Range Radio Aid to Navigation, better known as LORAN-C, was at the cutting edge of electronic navigation before the age of GPS.  Therefore, the Coast Guard supervised the construction and manned a chain of LORAN stations in Thailand and Vietnam.  These units were protected by the elite Air Force Security Police and augmented by Army infantry units.  During the Easter Offensive in 1972, the Coast Guardsmen of LORAN Station Tân Mỹ witnessed the bitter fighting near Quang Tri.