The A-11

The A-11 was a wristwatch made to a US Army Air Forces specification of the Second World War; the name came from the specification, not a model name.^1, 2

The specification asked for a movement of at least 15 jewels with hacking, 30 to 56 hours' power reserve, accuracy within 30 seconds a day, a dustproof or waterproof case and a black dial with white numerals.^1, 2

Hacking stopped the movement and second hand when the crown was pulled, so a crew could set all their watches to the same second before a mission.^1, 2

Worn & Wound calls it 'the watch that won the war' in a 2018 headline; it is a later slogan, not a wartime title.²

Elgin, Waltham and Bulova made it. The Henry Ford's example is a Waltham of 1943 to 1945 with a 16-jewel movement; makers usually added a jewel for the centre-seconds pinion.^2, 3, 4

Early dials were white; after 1942 they were black with white markings, Worn & Wound says, and the Navy's Bureau of Aeronautics ordered a fully luminous version.^2, 4

Sources differ on its size: about 32 mm according to Worn & Wound, 30 mm according to the National WWII Museum.^1, 2

Some cases had an inner cover of Invar against magnetism; cases were usually chromed brass, with olive-drab canvas straps.^2, 4

Britain issued Bulova's version as the Mark VIII and used the type as 6B/234; Worn & Wound adds the Royal Canadian Air Force and the Soviet air force.^2, 4

How many were made is not stated in the sources read; Worn & Wound says tens of thousands.²

Other navigation watches

Navigators also carried larger instruments: the Smithsonian's Hamilton 4992B 24-hour navigation watch in a steel case, and the A-8 stopwatch.⁵