As fielded, the 24 monitors of the U.S. Navy in Vietnam averaged about 10 tons of armor, were about long, had two screws, were powered by two 64NH9 diesel engines, (maximum speed), wide, draft, and were normally manned by 11 crewmen. When South Vietnam fell on 30 April 1975, all monitors fell into the enemy's hands; leaving only one survivor, a training monitor, that never left the US. "Training" monitor #C-18 is on display, along with one Swift Boat and one PBR at the U.S. Naval Amphibious Base in Coronado, California.