Dive watches

ISO 6425 sets the requirements and the tests for a divers’ watch. It covers watches built to withstand diving to at least 100 metres that carry a secured way of measuring the time of a dive which can be read in the dark, and an annex adds the tests for watches used in saturation diving. The current edition, the fourth, was published in 2018 and replaced the edition of 1996.¹

The tools of the type were settled early: a case closed by a screw-down back and crown, luminous hands and markers, and a rotating bezel set at the start of a dive to show the time spent underwater.^4, 6, 7

Saturation divers brought a different problem. Helium from their breathing gas works its way into a watch case and has to get out again during decompression; Rolex’s Sea-Dweller of 1967, rated to 610 metres, had a valve to release it.^2, 4

Keeping water out came before diving. Rolex sealed its Oyster case against water and dust in 1926 and calls it the first waterproof wristwatch.^8, 9

From 1935 Panerai in Florence supplied diving watches to the Royal Italian Navy’s underwater units. Its prototype of that year was built on a base supplied by Rolex; accounts differ on how much of the later watches Rolex made, from the base alone to all but one model.^{2, 10, 11}

Two makers claim the modern diving watch for 1953. Blancpain says its Fifty Fathoms, designed by Jean-Jacques Fiechter with a lockable rotating bezel and a double-sealed crown, was the first modern diver’s watch; Rolex says its Submariner of the same year was the first divers’ watch waterproof to 100 metres.^3, 4, 7

Other accounts differ again. One puts the Fifty Fathoms about ten months ahead of the Submariner; another calls the Submariner, shown at Basel in 1954, the first modern dive watch and dates the Fifty Fathoms to the mid-1950s; and both point to the Omega Marine of 1932 as a diving watch made for sale long before either. This page gives each account and does not choose.^{2, 3, 4, 9}

The United States Navy tested both kinds in 1959, and Blancpain quotes the navy’s report as recommending its watch’s features. Tudor had its own Submariner from 1954.^2, 3, 6

Going deeper

In 1960 an experimental Rolex rode the bathyscaphe Trieste 10,916 metres down into the Mariana Trench. In Japan, Seiko made what it calls the country’s first diver’s watch in 1965, rated to 150 metres, then a 300-metre model in 1967 and, in 1975, a 600-metre watch with a titanium case, built after a professional diver wrote to the company. In Germany, Sinn says it was the first watch company to have diving watches certified by Germanischer Lloyd, in 2005, the year it began making them from submarine steel as part of its case engineering.^{4, 9, 12, 13}