The United States Navy's DDSs are 11.6 meters (38 feet) long by 2.7 meters (9 feet) high and wide, add about 30 tons to its host submarine's submerged displacement, can be transported by trucks or C-5 Galaxy aircraft, and require one to three days to install and test. They have three HY-80 steel sections within the outer glass-reinforced plastic (GRP) fairing: a spherical hyperbaric chamber at the forward end to treat injured divers; a smaller spherical transfer trunk; and a cylindrical hangar with elliptical ends. The hangar can support a Swimmer Delivery Vehicle (SDV), four Navy SEALs to man the SDV, and a crew of Navy Divers to operate the DDS and launch the SDV; or 20 SEALs with four Combat Rubber Raiding Craft (CRRC). The SDV release team consists of 2 officers, 2 enlisted technicians