R.A.F. Bigsworth Chart Board, Type 'B', MK.2. Stores reference 6B/137. Manufactured by O.P.C. Ltd. Wooden plotting board approximately 43.5 x 43.5cm fitted with a hinged articulated brass plotting arm and adjustable perspex rules. Marked to reverse with Air Ministry King's crown and reference stamps and 1940 date code. The board has scratches, scuffs, marks and wear but is in good '+' overall condition. The plotting arm is also in good useable/working condition although the rule doesn't lie completely flat to the surface. The board retains the often missing canvas pen pocket and elasticated hanging loop (stretched). These chartboards were used by aircrew navigators to plot routes during flight. A lovely display item. Stock code M27474.