Elgin A-8, A-11, A-13 and AN-5740 Navigation Watches
Navigation Watches, Types A-8, A-11, A-13, and AN-5740 are manufactured by Elgin National Watch Company, Elgin, Illinois, and supplied to the Army Air Forces.
The watch, navigation (ground speed), type A-8, is a pocket type timer for use in accurate time interval computation necessary to the successful navigation of aircraft. Its black dial, with white figures and markings, is divided into ten major sections, each of one second, and each major second is divided into tenths of a second. A minute totalizer dial is inset in the upper half portion of the dial. The full sweep second hand and totalizer hand are also white to match the dial markings.
The watch, navigation, (Hack) type A-11, is a wrist type watch with black dial, white figures and markings, white hour, minute, and full sweep second hands. Earlier models, manufacturer’s part number 1768, carried a white silver dial with black figures and markings, and black or blued hands. This watch is designed for second setting so that it may be synchronized with any master timepiece as described in section IV. One model, manufacture’s part number 1783, was furnished with a moisture-proof type case. The earlier mode 1768 was furnished with a two-piece, black strap, while the two succeeding models, 1783 and 2114, are furnished with a sturdy, once-piece, safety type, waterproof, fabric strap; however, this newer strap will fit all three models of this type watch. The watch is designed for second setting, so that it may be synchronized with any master timepiece.
The watches, navigation, master, types A-13 and AN-5740, are of the pocket type. The earlier model, manufacture’s assembly part number 1767, carried a white enamel (24-hour) dial with black figures and markings and black or blued hour, minute, and full sweep second hands. The later models, manufacture’s assembly part numbers 1786 and 1790, carry a black (24-hour) dial with white figures and markings, and white hour, minute, and full sweep second hand. This watch is also designed for second setting so that it may be synchronized with any master timepiece. It maintains the highest degree of accuracy of any of the navigation watch group, because of its design and inherent quality of material and workmanship and should be handled with care in use. Although designed as a pocket type, it should be carried during flight in a special magnetically shielded and cushioned watch carrying case to prevent impairment of its accuracy.