WWII British AP No 6 Anti-Submarine ASDIC Stopwatch


A scarce original WWII Royal Navy issue Admiralty Pattern No. 6 Anti-submarine Stopwatch, which in conjunction with Sonar helped calculate the depth and distance of enemy submarines.
The stopwatch is in good working condition. It has a large chrome plated case, with a large 5.2 cm circular face on which are black and red markings and is calibrated to measure up to 5000 yards over a maximum six second time period. The stopwatch face also has the maker’s details: Waltham USA and the model: Admiralty Pattern No. 6. The timer starts, stops and resets by pressing the winding crown. The back of the watch has the War Department engraved broad arrow and PATT. 6 and U372. Removing the back cover reveals the case serial number 82428. Removing the inner dust cover shows the clock mechanism, stamped WALTHAM U.S.A. 16 ’43 – T A – NINE JEWELS. The serial number is 31454838.
These stopwatches were specially developed to be used on board Royal Navy warships in conjunction with the ‘ASDIC’ (Anti-Submarine Sonar Device). Comparing several readings from these watches along with the direction finding capabilities of the Asdic apparatus allowed the course, speed and range of U-Boats to be accurately plotted. This information was then used to set-up and launch depth charges.
Size: 5.5 x 8 x 2 cm (2 1/8 x 3 1/8 x ¾ inches)
Weight: 128 g