Ship gun fire-control systems (GFCS) are fire-control systems to enable remote and automatic targeting of guns against surface ships, aircraft, and shore targets, with either optical or radar sighting.

Most US ships that are destroyers or larger (but not destroyer escorts or escort carriers) employed GFCS for 5 -inch and larger guns, up to battleships, such as the USS Iowa. Beginning with ships built in the 1960s, GFCSs were integrated with missile fire-control systems and other ship sensors.

The major components of a GFCS are a manned director, with or replaced by radar or television camera, a computer, stabilizing device or gyro, and equipment in a plotting room[1]

For the USN, the most prevalent gunnery computer was the Ford Mark 1, later the Mark 1A Fire Control Computer, which was an electro-mechanical analog ballistic computer that provided accurate firing solutions and could automatically control one or more gun mounts against stationary or moving targets on the surface or in the air. This gave American forces a technological advantage in World War II against the Japanese who did not develop Remote Power Control for their guns; both the USN and IJN used visual correction of shots using shell splashes or air bursts, while the USN augmented visual spotting with Radar. Digital computers would not be adopted for this purpose by the US until the mid-1970s; however, it must be emphasized that all analog anti-aircraft fire control systems had severe limitations, and even the USN Mk 37 system required nearly 1000 rounds of 5″ mechanical fuze ammunition per kill, even in late 1944.[2]

The MK 37 Gun Fire Control System incorporated the Mk 1 computer, the Mk 37 director, a gyroscopic stable element along with automatic gun control, and was the first USN dual purpose GFCS to separate the computer from the director.

Source: Ship gun fire-control system – Wikipedia