Blancpain Fifty Fathoms watches

The Blancpain Fifty Fathoms is the brand's dive watch, first presented in 1953. Jean-Jacques Fiechter, Blancpain's CEO from 1950 to 1980 and a diver himself, developed it while Captain Robert "Bob" Maloubier and Lieutenant Claude Riffaud were setting up the French combat swimmers corps.

The design answered a diver's problems. The rotating bezel turns one way only, to prevent accidental rotation, and the self-winding movement meant the crown was handled less often, which helped keep the case watertight. Jacques-Yves Cousteau chose the Fifty Fathoms for his dives, and his divers wore it while filming The Silent World. In 2013 Blancpain presented a new Bathyscaphe whose design echoes its 1950s divers: a 43 mm watch with a ceramic bezel and the automatic calibre 1315, which has a 120-hour power reserve, with a 38 mm steel version alongside.

The Automatique has a 45 mm case in steel, titanium, red gold or DLC-coated steel, and the same case size carries the Automatique Grande Date, the Flyback Chronograph and its Speed Command variants, and the Tourbillon 8 Jours in red or white gold, some with gem-set bezels. The Bathyscaphe is the smaller line: 43 mm in steel, titanium or Sedna gold and 43.6 mm in ceramic, with flyback chronograph, annual calendar and complete calendar versions. Its 38 mm steel model is 10.77 mm thick, against 13.4 mm for the 43 mm steel watch.

Several models are limited editions. The 40.3 mm MIL-SPEC, No Rad and Barakuda come in runs of 500, as do the 48 mm 500 Fathoms in titanium and the 48 mm GMT in steel. The 45 mm Nageurs de Combat, French for combat swimmers, is limited to 300. Blancpain made unique Barakuda and 500 Fathoms pieces for the Only Watch charity auction.