Mark I Fire Control Computer

Weighing more than 3,000 pounds (1,400 kg),[2] the Mark 1 itself was installed in the plotting room, a watertight compartment that was located deep inside the ship's hull to provide as much protection against battle damage as possible.

Using the range finders and telescopes for bearing and elevation, the director was able to produce a continuously varying set of outputs, referred to as line-of-sight (LOS) data, that were electrically relayed to the Mark 1 via synchro motors.

The LOF data, bearing and elevation, as well as the projectile's fuze time, was sent to the mounts by synchro motors, whose motion actuated hydraulic servos with excellent dynamic accuracy to aim the guns.

While these fire control systems greatly improved the long-range accuracy of ship-to-ship and ship-to-shore gunfire, especially on heavy cruisers and battleships, it was in the anti-aircraft warfare mode that the Mark 1 made the greatest contribution.

Among the upgrades were removing the vector solver from the Mark 1 and redesigning the reverse coordinate conversion scheme that updated target parameters.