American forty-eight hour chronometer deck watch Circa 1943

Metal U.S. Navy model 22 deck watch by Hamilton
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A rare American metal U.S. Navy model 22 forty-eight hour chronometer deck watch with double wooden flat boxes, circa 1943. Lever movement, 21 jewels, marked US. Navy-BU Ships, 1943, metal dust cover. Silvered dial with Arabic numerals, outer minute track, 48 hour up and down indication and subsidiary seconds. Oversized case, coin edged bezel and rim, plain screwed back. Dial and movement signed by manufacturer, case signed Keystone, case and movement numbered.
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Diameter: 71 mm
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Signed: Hamilton Lancaster PA USA