71 Blancpain Very Well Preserved and Rare, Fifty-Fathoms Milspec I, Automatic Wristwatch in Steel, Black Glossy Dial, With Humidity Indicator

Estimate: €5,000 –⁠ 10,000

Model: Fifty-Fathoms Milspec I
Case Material: Stainless Steel
Bracelet Material: Rubber Strap
Year: 1960's
Movement: Automatic
Caliber: 1700/1
Case N°: 100363
Dimensions: 36 mm
Signed: Dial, Movement and Case

Launched in 1953, Blancpain’s Fifty Fathoms has set the standard for modern diving watches. Originally commissioned by the French Navy, this iconic timepiece was developed with the input of Captain Robert Maloubier and Lieutenant Claude Riffaud, who outlined the critical specifications needed for a combat diver’s watch. Among its groundbreaking features, it introduced the unidirectional bezel, a revolutionary advancement that ensured divers could not accidentally rotate the bezel backward. The Fifty Fathoms incorporated an anti-magnetic case and a “double O-ring crown system” for enhanced durability. It wasn’t long before the watch was adopted by other military forces around the world, solidifying its reputation as the ultimate diving watch. Blancpain also introduced an innovative humidity indicator: this indicator would remain blue when the air inside the case was dry, but if any moisture infiltrated the case, it would turn pink. Initially designed for military use and supplied to forces in countries such as the France, Israel, Pakistan, and the United Kingdom, the Fifty Fathoms eventually became popular among civilian, often sold through specialized dive shops. The watch takes its name from the British measurement of 50 fathoms, around 91.45 meters—the maximum depth considered achievable by a diver using the oxygen mixtures available at the time. The present example, offered in excellent condition with a superb glossy black dial, represents a rare opportunity to acquire a truly historic icon of horology.