Frigate

A frigate is a medium surface combatant smaller than a destroyer, built mainly for escort and anti-submarine and anti-air defense of merchant convoys, amphibious groups, and carrier screens. Modern frigates run roughly 3,000 to 7,000 tons full load on 120 to 150 meters, carrying a hull-mounted and towed sonar, a medium gun, surface-to-air and anti-ship missiles, and a flight deck for one or two helicopters. In US Navy hull classification the symbol is FF, and FFG for a guided-missile frigate; the FF/FFG type was established on 30 June 1975, reclassifying former ocean escorts. Frigates give navies a cheaper escort hull than a destroyer while keeping multi-role sensors and weapons.