Rare silver deck watch of the British Royal Navy Circa 1917

Rare steel “Fishtail” caliber 
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An extremely rare Schaffhausen deck watch of the British Royal Navy executed legendary “fishtail” caliber and centre seconds, circa 1917. Steel case, polished, reeded screw back. Enamel dial, Arabic numerals, centre seconds, “broad arrow”, blued spade hands. Bridge movement so called “fishtail calibre”, frosted, gilt, chatoned, indirect centre seconds, “Patent 55231”, screw compensation balance, index spring fine adjusting device.
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Diameter: 51 mm
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Weight: 96 g
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Signed: International Watch Co
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This is one of the most successfull watch movement designs ever made. The aesthetical beauty of this construction is unmatched. At the same time, this is one of the rarest IWC-works, of which only 600 pieces were produced.