Purchased at the North West Regional this month in Portland. As described in the Demeter's Chelsea Clock book, cased in a brass case and painted satin black. "It includes two electrical terminals mounted on the side of the case for attachment to a ship's steering servos. An cam mounted on the rear of the movement opens and closes, causing a ship to automatically change course to deter an enemy submarine from plotting an accurate torpedo solution." From the serial number this one was made in 1982.