Switzerland · 1953
The Modern Diving Watch and its Locking Bezel (Fifty Fathoms)
Partially verifiedThe rotating dive bezel and the Fifty Fathoms' other features became the pattern for diving watches generally.
Blancpain's Fifty Fathoms of 1953, developed by its chief executive Jean-Jacques Fiechter, combined water resistance, a double-sealed crown, automatic winding, a dark dial with luminous markers, a lockable rotating bezel and antimagnetic protection.
Background
Jean-Jacques Fiechter, who served as Blancpain's CEO from 1950 to 1980, developed the Fifty Fathoms while pursuing his personal passion for diving. Fiechter sought to address the difficulties of underwater timing and the risk of the bezel rotating accidentally, which would result in an inaccurate dive duration reading. Independently, Captain Robert Maloubier and Lieutenant Claude Riffaud of the French combat diving corps were also defining specifications for a professional dive watch because existing market options were prone to leakage and poor legibility.
Fiechter combined his inventions, including a double-sealed crown and his locking bezel system, into the Fifty Fathoms, which successfully passed the rigorous tests conducted by the French military. According to Blancpain, the Fifty Fathoms became a seminal timepiece, establishing the archetypal characteristics that define modern diving watches.
Written from the sources listed under Sources (makers, museums, auction houses and specialist publications are paraphrased, not reproduced); each statement was checked against the cited text, and claims a maker makes about its own work are attributed to it.
How it works
- The mechanism requires a push on the bezel to enable its rotation, which prevents the timing function from being changed unintentionally.
Later history
- Fiechter secured patents for his innovations, including the bezel locking mechanism, the double-sealed crown, and a specialized system for the screw-on case back.
- Following its development, the Fifty Fathoms was adopted as a staple instrument by the French combat diving corps and various international navies.
Impact on watchmaking
- Blancpain — The maker of the Fifty Fathoms.
- Dive Watches — The family of watches the Fifty Fathoms helped define.
- Unidirectional rotating bezel — How a timing bezel is used on a dive.
How to verify this yourself
Check the cited museum record or maker's archive first; for patented work, confirm the number and date from the specification itself (Espacenet covers most European, US and Japanese patents) rather than from secondary retellings.
Manufacturers known to have used it
- Blancpain
- Most later dive-watch makers
Related photographs
No confidently matched photograph of this subject has been found yet. These photographs show a closely related record, and are not examples of the type described on this page.
Sources & references
- Diving watch, Wikipedia (English), retrieved 2026-11-02 (text CC BY-SA 4.0)
- Fifty Fathoms origins, Blancpain Ocean Commitment, retrieved 2026-11-02 (paraphrased; text © the publisher)
- The History and the Legend of the Fifty Fathoms, Lettres du Brassus (Blancpain), retrieved 2026-11-02 (paraphrased; text © the publisher)
- Blancpain, Fifty Fathoms 70th anniversary; Fifty Fathoms origins; Lettres du Brassus no. 13
- Wikipedia, Diving watch (revision cited below)
Where sources disagree, the disagreement is stated rather than resolved silently.