A very rare relic reminiscent of the Battle of the North Atlantic, a wood-cased merchant ship convoy zig-zag clock with integrated 8-minute buzzer which would notify the ship's helmsman that the time had come to change course to avoid interception by U-boats, raiders, etc. The clock's movement is made by Seth Thomas, further adapted for its intended use by the Kelvin-White Co. in Boston. The movement bears a white circular dial with Roman numerals 16 x 7.75 x 4.75 in. white painted wood case with a hinged lid and circular glass viewing pane. The movement (with key present) does not work at this time but seems tight and repairable. On the reverse of the hinged door are pasted-on operating instructions for this 'CONVOY ZIG ZAG CLOCK'. There is a switch fitted to turn off the alarm, two hasps to secure the door, and two fittings to secure the door to a bulkhead. The mechanism could be better secured within the cabinet, box and dial face are soiled and worn as one would expect. Truly an evocative relic from a service which lost a greater percentage of men than any other branch.