[OC] That grey thing in the middle is a MK1A Ford Range keeper. 100% analog mechanical ballistics computer for naval guns. The US Navy used these from the early '40's until the mid 90's.

This particular unit weighed 3150LBS, was built in Feb 1946, took 7 people to operate and all data was input by hand cranks. Photo credit OP, Gunnery Plotting Room USS Brumby FF-1044 mid 1980's.