Diving into the Fifty Fathoms legend

It all begins with a potentially fatal accident. In the 1950s, Jean-Jacques Fiechter, head of Blancpain and passionate diver, loses track of time underwater... This marks a turning point. Jean-Jacques Fiechter begins to reflect on the limitations of watches at the time: uncertain water resistance, poor readability, vulnerable mechanisms. He wants to go further. His goal: to design the first truly reliable diving watch. Three patents would give birth to the Fifty Fathoms — not a beautiful object to show off on land, but a tool designed to survive the depths.

To these three patents, Fiechter added visionary choices: automatic winding, large diameter, high black-and-white contrast, luminescent markers, and even anti-magnetic protection with an internal soft iron cage — anticipating the electromagnetic disturbances encountered during diving.

Bob Maloubier and Claude Riffaud, founders of the French combat divers unit, were looking for a watch that met the specific needs of underwater missions. Fiechter’s prototype ticked all the boxes: water-resistant, legible, and robust. The Fifty Fathoms became the standard-issue instrument for the French Navy, and later for other armed forces.

But an administrative obstacle arose: France required military equipment to be purchased from domestic companies. Blancpain then partnered with Spirotechnique (part of the Air Liquide group), distributing the watches under the “Aqualung” brand. This partnership created a strong connection with Jacques-Yves Cousteau — as Air Liquide belonged to his wife's family. The Commander chose the Fifty Fathoms for his team during the filming of The Silent World.