 "Half Moon" was reclassified as a high endurance cutter and redesignated WHEC-378 on 1 May 1966.Her loan period from the U.S. Navy came to an end on 26 September 1966, when she was transferred permanently from the Navy to the Coast Guard.On 11 January 1967, "Half Moon" seized four American fishing vessels seven nautical miles (13 kilometers) northwest of Dog Rocks following a shooting incident in which one person was killed and another wounded.