Ship Gun Fire-control System - US Navy Systems - MK 56 Gun Fire Control System (GFCS)

MK 56 Gun Fire Control System (GFCS)

This GFCS was an intermediate-range, anti-aircraft gun fire-control system. It was designed for use against high-speed subsonic aircraft. It could also be used against surface targets. It was a dual ballistic system. This means that it was capable of simultaneously producing gun orders for two different gun types (e.g.: 5"/38cal and 3"/50cal) against the same target. Its Mk 35 Radar was capable of automatic tracking in bearing, elevation, and range that was as accurate as any optical tracking. The whole system could be controlled from the below decks Plotting Room with or without the director being manned. This allowed for rapid target acquisition when a target was first detected and designated by the ship's air-search radar, and not yet visible from on deck. Its target solution time was less than 2 seconds after Mk 35 radar "Lock on". It was designed toward the end of World War II, apparently in response to Japanese kamikaze aircraft attacks. It was conceived by Ivan Getting, mentioned near the end of his Oral history, and its linkage computer was designed by Antonín Svoboda. Its gun director was not shaped like a box, and it had no optical rangefinder. The system was manned by crew of four. On the left side of the director, was the Cockpit where the Control Officer stood behind the sitting Director Operator (Also called Dirctor Pointer). Below decks in Plot, was the Mk 4 Radar Console where the Radar Operator and Radar Tracker sat. The director's movement in bearing was unlimited because it had slip-rings in its pedestal. (The Mk. 37 gun director had a cable connection to the hull, and occasionally had to be "unwound".) Fig. 26E8 on this Web page shows the director in considerable detail. The explanatory drawings of the system show how it works, but are wildly different in physical appearance from the actual internal mechanisms, perhaps intentionally so. However, it omits any significant description of the mechanism of the linkage computer. That chapter is an excellent detailed reference that explains much of the system's design, which is quite ingenious and forward-thinking in several respects.

In the 1968 upgrade to the USS New Jersey for service off Vietnam, three Mark 56 Gun Fire Control Systems were installed. Two on either side just forward of the aft stack, and one between the aft mast and the aft Mk 38 Director tower. This increased New Jersey's anti-aircraft capability, because the Mk 56 system could track and shoot at faster planes.