German 32-hour power reserve submarine chronometer Circa 1940

Rare chronometer of the German Kriegsmarine by G.D. Wempe
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A remarkable, rare German compression wave resistant submarine chronometer of the German Kriegsmarine with 32-hour power reserve indicator, external hand setting device and external winding, circa 1940.
The case is a mahogany box, with applied signature shield, hinged handles at the side, black lacquered brass gimbals and bowl, facetted glass, black lacquered solid brass case with special rubber seal and 18 screws, a two-body, and engraved swastika and Navy inventory no. M348. The signed, numbered, silvered dial, has Arabic numerals, auxiliary seconds, and gilt spade hands.
And the polished, decorated, brass movement, has solid movement pillars, going barrel, lever escapement, lever and escape wheel made of antimagnetic beryllium bronze, heavy Gerstenberger chronometer balance with four weights and two screws, blued helical balance spring with both sides passing terminal curves, and chatoned sapphire endstones on balance and chronometer wheel.
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Dimensions: 190 x 170 x 190 mm
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Signed: Gerh. D. Wempe, Abt. Chronometerwerke, Hamburg
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This chronometer is one of 12 that were produced on order for the German Navy in 1940 after it was discovered that the launch of several torpedos at the same time caused unusual rate variations. In “Alte Uhren” 1/79, the maker of this chronometer Herbert Müller describes the navy’s requirements and the chosen solutions for the chronometers. He concludes that “only little is known about they fared in real life. I have never seen any of them again; I suppose the chronometers are all on the bottom of the sea together with the submarines.”