1940s stainless steel vintage Longines ‘Weems RAF Mark VIIA’ watch
Date: 1940
Case: Stainless steel, 33mm
Movement: Longines 10L
Dial: Champagne with Arabic numerals
Lugs: 16mm
A stunning vintage Longines ‘Weems RAF MK VIIA’ watch!
A 1940s, stainless steel vintage Longines Weems RAF Mark VIIA watch. The case measures 33 mm in diameter, with engraved name Aidan Skehill 20.9.38 to the back and 16mm lugs. The case, with rotating bezel, is signed Longines Watch Company, Swiss, Acier Inox, Staybrite and numbered. The 10L calibre, manual wind movement is signed Longines, Swiss Made with 15 jewels and numbered, circa 1937. The champagne dial has black Arabic numerals with centre sweep seconds, fine blued steel ‘Poire Indes’ hands and outer minute track. The dial is signed Longines Weems above the centre with U.S.PAT 2008734 below.
Longines Weems Patent 2008734 – “US Pat. 2008734”, this referring to Philip Weems’ original registration of his design as a pilot’s navigational aid in 1935.
Longines ‘WEEMS’ Pilot’s watch
The “Weems” 6B/159 with specification Mk. VIIA needed to meet the following requirements of Building Specification G.535:
“The movement needed to be wound by the crown instead of using a separate key. The movement should run for a minimum of 36 hours (fully wound). The hands should be made of blued steel and the case should have a rotating lunette. The case could be made from steel, chrome or hardened brass. The dial needed to be light silver or white (like enamel). The deviation needed to meet the following requirements: after three hours +/- 3 seconds, after six hours +/- 5 seconds, after twelve hours +/- 8 seconds and after 24 hours +/- 15 seconds.”
By linking the outer bezel with the second hand and linking it to the air navigation system devised by Colonel Philip Van Horn Weems of the United States Army. The time in seconds can be synchronized and locked after the bezel setting, as that time Innovative structure full of innovative creativity. The large ball-shaped winding-crown enables the watch to be wound by a pilot wearing gloves. It is practically impossible to build a commercial timepiece which will keep time to the exact second under the conditions met in a ship or in an airplane. The inevitable variation from true time necessitated an extra calculation in navigation to compensate for this chronometer error. Weems noted that in an airplane moving at speeds of 200 to 300 miles an hour or more, the time required for calculating chronometer error was a danger that should be eliminated. Since the high gear ratio made it impractical to set the second hand to the dial, Weems chose to set the bezel to the hands. He trained the famous Charles A. Lindbergh (1902-1974), who set the record for the first non-stop transoceanic flight. Lt.Cdr P.V. Weems who was a well-known aviator, navigator and instructor at the Naval Officer School at Annapolis, Maryland, in the U.S.A.
The watch, as a navigational instrument for airplane pilots, is used in conjunction with a sextant and the appropriate nautical tables, to permit the rapid computation of the Greenwich hour angle, i.e. the aircraft’s longitude.
There were five manufacturers of these very special timepieces; Longines, Omega, Jaeger-LeCoultre, Zenith and Movado. It is believed only around 7,000 were issued to the RAF in 1940 at the outbreak of hostilities and many will have no doubt seen action during the early dark days of the Battle of Britain and beyond.
