Closed | Important watches – Saturday 15 November 2014

In ambition to make a watch that could cope with even higher pressure than their models of that time, Rolex started experimenting with two versions of the Submariner (Ref no. 5513 and 5514) in the late 1960’s. That led them to develop a whole new family of divers; the Rolex Sea-Dweller and its first reference 1665 was created.

The Sea-Dweller didn’t only look different from the Submariner, it also had a brand new function, the helium release valve, which let helium and other gases escape the watch case at high pressure.
Later on the Sea-Dweller would be elaborated further, and in 1978 the new reference 16660, also known as “Triple six”, was developed. The Triple Six had a lot in common with its forerunner but had a bigger and even more highly-developed helium release valve and also sapphire crystal instead of plastic crystal. After a while also the dial was changed. It had earlier been a painted dial but was now changed to a more modern version with white gold index filled with tritium, the so-called “Bicchierini”.

The first batch of the new dial, the Mark III, had a couple of unique features, for example wasn’t the text “ SWISS-T<25” completely centred underneath the six o’clock marker and the equal sign between 4000 ft and 1220 m was italic. This was later changed on the Mark IV and when Rolex made the Mark V they also took away the hyphen between the words Sea and Dweller. Today, the Mark III has become a much desired version of the Triple Six.