Rolex Reference 1665 · Circa Late 1960s
Patent Pending
Double Red Sea-Dweller
Origin Story
History
The Rolex Sea-Dweller was developed in close collaboration with the French deep-sea diving company COMEX. Their divers required a timing instrument that could withstand their working depths, plus remain intact during ascent and decompression. Most watches manufactured at that time could not tolerate the extreme depths. Helium gas would build up inside the case and at decompression the gas pressure would increase. The rising inner pressure would eventually be released by breaking the crystal — the weakest point in the case design.
Rolex first developed the helium release valve in the 1960s and incorporated it into some of their Submariner watches delivered to the French diving company, COMEX. The testing of these specially adapted Submariner 5513 models was so successful that Rolex specifically made a batch of watches for COMEX and the watch was given an official model number, 5514. This was such a success that Rolex decided to market the watch as model number 1665 by 1967.
The 1665 was initially rushed to production and some early watches were sent to dealers for promotion or early sales. Some authorities state that the number is less, about 150, while others argue that the number is much larger and that several hundred may have been made.
The helium valve had been developed and the patent had been applied for, but Rolex had not received final approval. Therefore, the engraving on the caseback of these early Sea-Dwellers stated in parenthesis: “Patent Pending.”
Regular production of the Double Red Sea-Dwellers started in 1971 and ended in approximately 1977. The Patent Pending examples predate this run entirely, setting them apart in both chronology and rarity.
Patent Pending DRSD — Full Watch View
Identifying Features
Case
There were some characteristics on these watches that made them different from the regular production of Double Red Sea-Dwellers.
Case Profile
Noticeably thinner than regular production (1971–77)
Helium Valve
Small valve at the 9 o’clock position
Model Number
1665
Serial Range
1.7 million – 2.2 million
Dial close-up — note the red text faded to light pink
Mark I Dial — close-up detail
The Signature Detail
Caseback
The caseback features the Rolex coronet with “ROLEX” engraved across the back — not circularly around the caseback as on later models. The following is also engraved: “Oyster Gas Escape Valve” and in parenthesis, “Patent Pending.”
Interior Markings
Standard Rolex markings with model number 1665
Serial Engraving
Last three digits of the serial engraved inside
Production Date
Quarter and year of caseback production engraved — all done in the late 1960s, often with a notably poor date stamp
Caseback — “Oyster Gas Escape Valve (Patent Pending)” engraving
Movement Access
Crown & Crystal
Crown Type
Triplock — without the external rubber O-ring in the tube
Coronet Detail
No line or dots under the coronet, unlike later Triplock models
Crystal Type
Acrylic with a high dome profile
Crown — early Triplock without external O-ring
Crown close-up detail
The Face
Dial
The dial is matte black with white indices and plots. The coronet features a “flat” bottom and the “L” of Rolex lines up precisely beneath it — a hallmark of the earliest production. The words “Sea-Dweller” and “Submariner 2000” appear in red, possibly printed directly on the dial or over white paint. The print is clear and easily demarcated.
Text Lines
“Sea-Dweller” and “Submariner 2000” — same font size for both lines, unlike later dials which used a smaller font for “Submariner 2000”
Depth Marking
2000ft = 610m, sans serif
Lume Marking
Swiss – T < 25 (tritium dial)
Colour Aging
On most surviving examples the red text has faded to a light pink or near-yellow — giving rise to the collector terms “double pink” or “double yellow.” The Mark I dial is the only dial found exclusively on the PPDRSD — it appears on no other model.
Mark I Dial — tritium indices, flat-bottom coronet, faded red text
On the Wrist
Bracelet
The bracelet is a Rolex Oyster 9315 with folded links and 380 end pieces. About thirteen links should be present. The extension clasp of the bracelet may itself be engraved “patent pending” — a defining detail carried through from case to wrist.
Bracelet — Rolex Oyster 9315, folded links, 380 end pieces
Bracelet clasp detail — may read “patent pending”
Full Set
Box, Papers & Provenance
As with any production Rolex of the era, these Sea-Dwellers were sold with inner and outer boxes, green tags (model number on one side, full serial on the other), a Rolex booklet with full serial, a certified chronometer tag, and a chronometer certificate.
One documented example came with a personal letter from its original owner, detailing the watch’s history over its initial 34 years. A pretty unique watch — and an extraordinary level of provenance for any collector.
Collector Intelligence
Production Numbers & Known Batches
Detailed records suggest at least 114–120 of these watches survive in various configurations. The PPDRSD was made in batches, similar to the COMEX or Military Submariner production runs. Three batches have been identified by serial clusters:
1.7 Million Batch
2.1 Million Batch
2.2 Million Batch
All the casebacks were produced in the late 1960s and bear a notably poor date stamp inside. The most common dial is the Mark I, followed by the Mark II. As noted, the Mark I dial is solely associated with the PPDRSD.
“In all and from my experience, the PPDRSD is truly a very rare watch. In my estimation, there were less than a few hundred examples ever made. Those in original condition with documented provenance are probably few and far between.” — Ed Delgado
The complete Patent Pending Double Red Sea-Dweller