LSM(R)-196 LSM(R)-190 and LSM(R)-199 firing rockets off Tokashiki Island in Kerama-retto in support of the landing of the 306th Regiment of the 77th Infantry Division. The island was declared secure on March 29, 1945; Japanese continued to hold out until the end of the war. The US Navy adapted the Landing Ship Medium as a gunboat/rocketship in 1944. Built at Charleston Navy Yard, South Carolina, the LSM(R)'s carried one 5-inch (127 millimeter) dual-pupose gun, two 40mm Bofors and three 20mm oerlikon antiaircraft guns, and 75 5-inch four-rail Mark 36 (capable of variable elevation) and 30 5-inch six-rail Mark 30 (fixed at 45 degrees) rocket launchers that could fire either spin-stabilized or fin-stabilized rockets. The warheads were usually modified 5-inch/38 caliber artillery shells with 8.6 pounds (3.9 kilograms) of trinitrotoluene (TNT). The entire complement of 380 rockets could be fired in under one minute to a range of 10,000 yards (9.1 kilometers). After supporting amphibious landings in Kerama and Okinawa with rocket barrages, LSMs were detailed to provide additional antiaircraft support to radar picket ships protecting the invasion fleet from kamikaze attacks. LSM(R)-190 was sunk by a kamikaze on May 4, 1945 while on picket duty.