A 1960's vintage Zig Zag course clock made by the Chelsea Clock Co, Boston as marked above the clock hands. A brass bulkhead clock with serial number 738436 with matching movement serial number(1965-1969). Silvered dial with black Arabic numerals and seconds to the exterior. A wonderful time piece for collectors of U.S. Government clocks.
Heavy cast brass case
6" silvered brass dial
stenciled arabic numerals in black
fast-slow wheel adjustment
moon style sweep second hand
8 day jeweled movement
7 1/4 inch bezel and 3 1/2 inch depth
two electrical exterior terminals
interior cam designed for course change
Comes with a new Chelsea clock key
weighs 8 pounds 7 ounces
Clock description below is reprinted and featured in the book "Chelsea Clock Company, the First 100 Years" written by David D. and Andrew C. Demeter.
"This course clock has a 'hack' switch for synchronization with others and external electrical terminals on the side of the case for attachment to the ship's steering servos. A cam mounted on the rear of the movement is positioned to open and close the electrical circuit on a (U.S.N) specified schedule. When activated, the clock will cause the steering mechanism of the ship to automatically change course to deter an enemy submarine form plotting an accurate torpedo solution. The WWII version was produced in phenolic cases while current versions (marked US Government) are housed in brass cases painted satin black. The dial positioned within the case so that the bezeled in hinged at 12 o'clock. Gravity assures the closure of the bezel and keeps it protected within the closure quarters of the pilot house. Despite the precaution, early models made of a brittle phenolic resin seem subject to hinge fractures. Still in production."