Hanhart produced watches and stopwatches for the German armed forces, including the Kriegsmarine (German Navy), during World War II era. Hanhart chronographs and stopwatches were issued to naval officers and personnel, most notably for use in submarine (U-boat) operations, such as for torpedo timing and ship's artillery. 
Key aspects of Hanhart's Kriegsmarine history:
Primary Supplier: Hanhart, along with Tutima, was a major supplier of chronographs to the German military, though Hanhart watches with specific "KM" (Kriegsmarine) markings were produced in relatively small numbers compared to the Luftwaffe (Air Force).
"KM" Markings: Authentic Hanhart timepieces for the Kriegsmarine typically feature the "KM" designation on the dial or caseback, often accompanied by the German eagle insignia.
Types of Timepieces: The range included both wrist chronographs and handheld stopwatches. The stopwatches often had specific scales designed for naval applications, like measuring sea miles or water depth for anti-submarine warfare.
Rarity: Hanhart chronographs specifically marked for the Kriegsmarine are considered exceptionally rare and highly sought after by collectors today due to their limited production.
Wartime Focus: Toward the end of the war, Hanhart's watch production was curtailed to focus on manufacturing time fuzes for torpedoes, highlighting their direct contribution to the naval war effort.
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Short description of the watch
I bring to your attention this scarce vintage German collectible: a UNIQUE men's wristwatch CHRONOGRAPH HANHART service wristwatch for the German Navy (Kriegsmarine), U-boat Officers 1939-1945 WWII. Early single-pusher chronograph with a partially nickel-plated brass case and no rotating bezel. Black dial with luminous numerals and hands (luminous in the dark), small seconds at 9 o'clock, chronograph function above the central seconds hand, 30-minute counter at 3 o'clock, and the company name "Hanhart" and "KM" for Kriegsmarine (German Navy) - manual winding. The screw-down case back is hallmarked "Boden Edelstahl" (stainless steel base) and serial number 115296. The balance on the watch movement has a shock-proof device. This watch has an original Silvered HIGHER-QUALITY movement, with serial number 115296. A number mechanism and a number case on a watch are identical - 115296, which specifies the authenticity of the watch. On the face side, the dome glass is plastic (Plexiglass). The watch has been restored, checked, and calibrated by a master watchmaker and is in good running condition. Chronograph functions – working very well. This unique wristwatch was kept in very good condition until our time. To the watch, a NEW watchband is added as a GIFT. This wristwatch is a stylish acquisition for collectors, 100% satisfaction, and a good present or for everyday use!

Technical information:

Diameter of the case with crown: 45.5 mm

Diameter of the case: 41 mm

Diameter of the dial: 35 mm

Thickness: 16 mm

Band size: 20 mm

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