Notes: In 1967, the new Rolex Sea-Dweller was born. The official name of the inaugural model was the Sea-Dweller Submariner 2000. But, it’s more commonly referred to as the Double Red Sea-Dweller or DRSD for short. Rolex modified the Submariner ref. 5513 and fitted it with a Helium Escape Valve (HEV). The patented Helium Escape Valve mechanism permitted the watch to release built-up helium and other gasses as the watch traveled down to more extreme depths. As a result, this prevented pressure damage to the watch, thus Rolex now had the ability to produce extreme diving watches.

Compared to the Submariner, it has, among other things, a thicker case, the helium escape valve, a domed crystal protecting the face of the watch, engravings on the caseback, and no Cyclops lens over the date window. However, one of the most distinguishing factors, and the reason for the watch’s nickname, are the two lines of red text on the black dial. In red, we read “SEA-DWELLER” followed by “SUBMARINER 2000,” clearly indicating that this is a souped-up version of the Sub. Rather than the 660 feet (200 meters) depth rating of the preceding Submariner, the Sea-Dweller boasted one at 2,000 feet (610 meters). This was an impressive feat for the era indeed.

Mechanism: The 1575 is the date version of the 1570. Like many rolex movements the date version will be stamped with the same number as the non-date version. Hence you will see "1570" stamped into most (if not all) 1575 movements. The sure fire way to tell the difference is the presence of the date wheel.

The 1570 movement superseded the 1560, but shared the vast majority of its elements, with a few notable improvements. The 1570 marked the third generation of the 1500 series. It comes with the balance assembly Rolex p/n 8106, again with a Breguet hairspring. However, it’s with a higher frequency of 19,800 bph, or 2.75Hz.

Similarly to its predecessor, Rolex also manufactured it as a date and GMT version, the 1575, which proved the perfect companion to the Explorer II released in 1971, as well as the GMT-Master and Datejust series. As with many of the date equipped mechanism made by Rolex, the number stamped into the metal is the NON-date version. Hence in the case of the 1575, the mechanism will be stamped "1570".

Although there is no Quickset mechanism, the 1500 calibers came with the cam and jewel system. This system was able to create an instantaneous date change at midnight, still used by Rolex today.

Family Notes: Since its production in 1967, the Rolex Oyster Perpetual Sea-Dweller has established itself as the world's most impressive dive watch. The Sea-Dweller can remain waterproof for up to 4,000 feet.