he result of a true lightbulb moment, the Fifty Fathoms is the fortunate outcome of a dive whose consequences could have been quite different. One day when then Blancpain co-CEO and passionate diver Jean-Jacques Fiechter was diving in his favourite resort of Cannes in the south of France, he suddenly ran out of air. This dramatic and pivotal experience made him realise the extent to which divers needed a time-measuring instrument tailored to the needs of scuba diving, and led him to create the Fifty Fathoms, the world’s first true diver’s watch.

Its self-winding mechanism (involving less wear on the crown gaskets than in a hand-wound movement); its resistance to magnetism (present in the world of diving); its watertightness to at least 10 bar; along with its XXL luminescent hour-markers contrasting with the dark dial (for improved legibility) represented a set of key elements presented on the 1953 model.

The crown fitted with a double watertight seal; the caseback sealing system (to prevent any distortion of the O-ring when the case is fitted); as well as the lockable rotating bezel would all be patented. The functions, features and performance of this model naturally led the main armed forces of the day (France, Germany, the United States and Norway, to name but a few) to adopt this timepiece for their combat divers. The relevance of Jean-Jacques Fiechter’s ideas was such that the Fifty Fathoms became the archetypal diving watch for the entire watch industry at the time – and remains so this day.

But the story doesn’t end there. Although this timepiece established the fundamentals for safe diving, in the 1950s Jean-Jacques Fiechter also developed a moisture indicator, an additional safety feature whose purpose was to provide divers with the confirmation that the watch had not been damaged by another diver on a previous mission. Appearing on the dial of the MIL-SPEC watches in 1957 – some of whose variants are among the rarest and most sought-after timepieces by collectors – this moisture indicator was part of the specifications of the US Navy, which regarded this model as the only one to meet all the strict criteria laid down for its underwater missions. The Fifty Fathoms 70th Anniversary Act 3 pays tribute to that watch.

It is immediately apparent that this third anniversary timepiece is indeed inspired by its non-magnetic parent used by the US Navy. The matt black dial with vintage Super-LumiNova^®-enhanced moisture indicator and hour-markers; the unidirectional rotating bezel with black ceramic insert featuring a vintage Super-LumiNova^® diving scale; as well as the two-tone NATO strap featuring the colour code of the original timepiece and made from fishing nets recovered from the oceans are all features that demonstrate their close kinship.

They are however distinguished from each other by the material used for the case. While the MIL-SPEC from which the anniversary model is inspired is made of German silver, the Fifty Fathoms 70th Anniversary Act 3 is clothed in 9K Bronze Gold, a patented alloy enriched with 37.5% gold (hallmarked 9K), copper – 50%, allowing it to be called “bronze” – silver, palladium and gallium. Designed to offer a pink hue and pleasing aesthetics, this type of bronze stands out by the fact that it can be worn in direct contact with the skin, unlike traditional bronze, not to mention that it has a longer lifespan, since oxidation to a verdigris colour is prevented by the addition of gold. This anniversary model therefore honours the DNA of the original timepiece while adapting it to the everyday use required nowadays.

The 1154.P2 movement is housed in a 9K Bronze Gold case that is water-resistant to 30 bar and measures 41.30 mm like the historic MIL-SPEC. Its twin barrel endows the timepiece with a substantial 100-hour power reserve, while a silicon balance-spring ensures the movement’s resistance to magnetism. For the first time, Blancpain is offering a 1000-gauss version of its movement, thanks to the use of this material coupled with exclusive alloys for the escapement.

Unlike the original version – whose movement is not visible because resistance to magnetic fields was only possible at the time by encasing the mechanism in a soft iron cage – the heart of the Fifty Fathoms 70th Anniversary Act 3 can be admired through a sapphire crystal caseback, as the use of a non-magnetic spiral enables the timepiece to feature such transparency without compromising its resistance to magnetism.

The open caseback reveals bridges enlarged to the diameter of the mainplate, enhanced by decoration inspired by that of the period. For its part, the oscillating weight boasts a geometry inspired by the historical rotor – with an opening designed to make it more supple and therefore more resistant to shocks -, as well as a snail-shaped finish reminiscent of its rotating motion. The engraved vintage logotype, that sheds light on 18K gold, sets the finishing touch to the watch’s vintage look.

Issued in a 555-piece limited edition, the Fifty Fathoms 70th Anniversary Act 3 is presented in a box inspired by a historic camera housing, echoing Blancpain’s ocean protection initiatives. Since underwater photography developed at the same time as the diver’s watch, it indeed helped highlight the discovery of the seabed. Thus uniting the best of two eras, this commemorative timepiece continues to write the history of the world’s first true diver’s watch.