Naval Course Corrector, Mounted for Display Gunnery and the largest hole pointing

and the largest hole pointing forward

It thus serves as the VHF antenna and the forward support for an HF antenna

as used across a number of US Army Air Corps and Air Force aircraft during WWII

The manual appears to be complete with ~1

The cover can be removed to reveal the gyro inside

Naval Course Corrector, Mounted for Display Gunnery and the largest hole pointingThis large shiny metal device is a WWII era naval Course Corrector, used to convert, mechanically, a ship's True Course to Magnetic Course and to Compass Course when variation, deviation, or compass error is known. Two inner dials labeled Magnetic Course or Bearing and Compass Course or Bearing rotate within the outer ring labeled True Course or Bearing. A mechanical arm rotates around the axis with locking screws to capture its position on the two