The ref. 1665 was developed to push deeper than a Submariner, the first Rolex built to task to survive saturation diving. The 1960s saw energy move toward offshore oil rigs, which pushed the limits of dive watches available at the time. In addition, the world was installing underwater communication cables, pipelines, increasing military diving capabilities, and pushing the edges of human exploration with missions like the US Navy SEALAB experiments. Think of it as a ref. 5513 turned up to 11.

SEALAB aimed to test the health effects of underwater isolation to prove saturation diving viability long-term. SEALAB divers switched from Subs to Sea-Dwellers because the Sub’s crystals kept popping off on ascent. This was fixed through a very thick plexi crystal, thicker 39mm steel case, and helium escape valve which allowed helium to exit the case during decompression and prevents the plexi from popping. That HEV was pioneered in a series of Comex 5513/4 Subs and early Sea-Dwellers at about the same time, and these early efforts gave rise to the official relationship Rolex developed with Comex in ’71 as leaders in their respectable fields. It also spawned this, the ref. 1665, the first commercial Rolex Sea-Dweller.

The very first were single red dials, given to professional divers chosen by T. Walker Lloyd, an Oceanographic Consultant of Rolex, for testing or as awards. There are thought to be 11 or 12 of these. Following these were the Double Reds, an early dial with two coveted lines of red text in production from 1967-1978. These all preceded the ‘Great White’ 1665 with all white text. This Mk3 dial was the penultimate produced before the Great White took over.

It wears similar to a Sub if a bit more substantial, but compensates without a cyclops on its beat up original domed crystal. You’ll also spot near-pumpkin tritium and deep purple (not the band) ghosted bezel. There’s a lot to be said for a vintage watch showing it’s years on its metal. Patina is the whole point. This one shows its time on wrist, likely diving, everywhere, and that’s as it should be. If not a tool of purpose today, it is certainly still an object of desire.

This example presents in an overall heavily patinated but beautifully original state. Starting on the case (5.17 M case serial), it's probably seen one extremely polish but retains a strong and thick bevel on all lugs, the lugs look as the should. The caseback engravings are also very deep, same with serial. The Mark 3 dial is nearer pumpkin in tone than cream, with hands matching the very orangey tritium. Its bezel has ghosted to a deep blue with a hint of purple. The red Sea-Dweller script is very clear. Buyers should note that there are two small sections of dial discoloration running from 12:01 to 2:04 and again towards 6 at the very outer edge of the dial. This does run across a part of the SWISS T < 25 signature. We've tried out best to photograph this closely in the latter photos here. On wrist, it's almost impossible to see. You do have to get it under a macro lens in good light to observe, as you can tell from our photography as well. This is why the watch is priced as it is. The acrylic crystal has light scratches all over, which could be easily polished over but we love. It is running well in spec and comes on its original, matching 93150 bracelet. It's a very original and hard worn Double Red, which is surely how this watch was made to be worn.

This watch is modeled on a relatively large 7.7 inch wrist.

• Brand: Rolex
• Model: 'Double Red' Sea-Dweller
• Reference: 1665
• Size: 40
• Year: 1977
• Case Material: Steel
• Movement: Automatic Calibre 1570
• Scope: Watch Only