mate). In 1969 the crew was supplemented with a Vietnamese trainee. The first two PCFs were delivered to the Navy in late August 1965. The original water taxi design had been enhanced with two .50 caliber M2 Browning machine guns in a turret above the pilot house, an over-and-under .50-caliber machine gun – 81 mm mortar combination mounted on the rear deck, a mortar ammunition box on the stern, improved habitability equipment such as bunks, a refrigerator and freezer, and a sink. The 81 mm combination mortar mounted on the rear deck was not a gravity firing mortar as used by the Army and Marine Corps, in which the falling projectile's primer struck the fixed firing pin at the base of the mortar tube, but a unique lanyard firing weapon in which the projectile was still loaded into the muzzle. The gunner could "fire at will" by the use of the lanyard. The weapon had been tested in the 1950s and discarded as the U.S. Navy lost interest in the system. The United States Coast Guard maintained the gun/mortar system before the Navy incorporated it into the PCF program. Many boats also mounted a single M60 machine gun in the forward peak tank, just in front of the forward superstructure. The original order for 50 boats was followed shortly by an additional order for 54 more Mark Is. Mark II and Mark III In the latter half of 1967, 46 Mark II boats, with a modified deck house set further back from the bow. The newer boats also had round port holes (replacing larger sliding windows) in the aft superstructure. From 1969 through 1972, 33 Mark IIIs, which were a larger version of the Mark IIs, arrived in Vietnam. Use Most of the 193 PCFs built were used by the U.S. Navy in Vietnam and the two training bases in California. About 80 of the boats constructed were sold or given away to nations friendly to the United States. The original training base for Swift Boats was at Naval Amphibious Base Coronado. In 1969 training was moved to Mare Island near San Pablo Bay, California, where it remained for the duration of the war. Though not a deep water boat, PCF training boats frequently transited from Mare Island, through the Golden Gate Bridge to cruise either north or south along the Pacific Ocean coastline. PCF-8 sank in a storm off