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Rolex Patent Pending Double Red Sea Dweller

by Jason 2 May, 2011 View Comments

Patent Pending Double Red Sea Dweller

When it comes to vintage watches, Rolex sport models are in the top level of the collector’s market. Few brands have the pedigree, the cachet, or the desirability of vintage Rolexes. And within the realm of Rolex collecting there are certain models and variations that make collectors swoon. The “Patent Pending” Double Red Sea Dweller is one such model.

Patent Pending Caseback

When you work with watches on a daily basis, you tend to become attached to certain types and models very quickly. Where the average person might be overwhelmed by the choices available, we watch nuts often fall into niches of particular brands, models or periods. In my case I adore vintage pieces from the 1960s and 1970s, particularly Rolex sport models from that era. Owning a rare collectible vintage piece requires the skill to hunt it down, authenticate it, and purchase it. So when a client of ours acquired a “Patent Pending”, I knew I had to showcase it in the Baily Blog.


The Rolex Sea Dweller came about during the late 1960s as a type of heavy-duty Submariner built for deep sea diving. Specifically, it was designed to handle the rigours of decompression as well as deeper diving pressures. As divers ventured further and further into the deep, new forms of controlled decompression needed to be developed. Under the pressure of the water, nitrogen concentrates in the blood and upon rising to the surface it bubbles out, causing “the bends”. Decompression chambers were the solution where commercial divers would be gradually decompressed in an artificial atmosphere, and where they could live for long periods without having to decompress after every dive.

Rolex Ref 1665


The diving firm COMEX was one of the main deep-sea diving companies and began a long-standing partnership with Rolex in the late 60s. Something COMEX was familiar with was the problem of decompression on watches. While in a decompression chamber the divers breath a special gas mixture – a mixture of helium and oxygen. Helium is lighter and thinner than regular air, and can seep into a watchcase that is otherwise airtight. As decompression progresses the pressure drops, the helium expands, and POP – the watch blows open. Usually the crystal would crack or pop off altogether. Something needed to be done, and Rolex took up the charge.

The deceptively simple solution was what would become known as the Helium Escape Valve (HEV). It’s a small one-way valve on the side of the case that can only open outwards. When the pressure builds in the case, the valve pops and lets the helium escape. Because it only moves outward, it doesn’t affect the water resistance of the case. Problem solved, and a series of legendary models are born – first the Comex 5513 and 5514, and then the 1665 Sea Dweller.

Patent Pending Extension Link

The Sea Dweller took the Submariner design and beefed it up for more rigorous diving. The first prototypes lacked the HEV system but had much higher depth ratings than the standard Sub. The case was reinforced, the crystal was thicker, heavily domed, and dropped the Cyclops date magnifier, and the case featured the newly developed HE valve. Water resistance was 1650 feet on the prototypes, then 2000 feet on the production examples (the contemporary Submariner was rated to 660 feet). Inside was the reliable and proven automatic-winding 1570/1575 calibre movement shared with the 1680 Submariner Date. The Oyster link bracelet was also shared with the Submariner and featured an expansion link in the clasp to fit over a wetsuit.      

Like any collectable, earlier and rarer examples are the most valuable. In the case of the Sea Dweller, the Double Red (so named for the two lines of red script on the dial) are the earliest versions, replaced by the “Great White” 1665 with all white printing around 1977. The rarest of the Double Reds is the Patent Pending – a pre-production model that was made in small numbers while Rolex was still in the process of getting a patent on the HE valve design.

Patent Pendings are distinguished by a few notable features. The most obvious is the script on the caseback, which says “Oyster Gas Escape Valve (Patent Pending)”. The expansion link in the bracelet clasp also has a “Pat. Pend.” stamp. The dial is usually a “Mark I” example, an early Double Red dial that featured red ink printed overtop of white lettering (later dials had red printed directly onto the dial). Less obvious is the slimmer case compared to production 1665s, and the pointy crown guards. Serial numbers fall into the 1.7 to 2.2 million range (late 1960s). This particular example dates to 1969.

How rare is the Patent Pending? Nobody is certain of the exact number produced, with guesses ranging from 120 to a few hundred at most between 1967 and 1970. Regular production of the 1665 didn’t begin until 1971, and even then it was not produced in large numbers compared to the more popular Submariner. A good Patent Pending can fetch two to three times the price of later Double Red 1665 (sometimes more). Rarity is key when collecting vintage watches, and the Patent Pending is one of the rarest of all Sea Dwellers (outside of the mythical “Single Red” factory prototypes).

Patent Pending 1665

The owner of this watch is very lucky to have acquired such a good example, with the original dial, the original hands, the original bracelet with Patent Pending extension link, the original crown, and the correct “fat font” bezel insert. Originality is key to collecting vintage, and this Patent Pending is a good example of what to aim for. The average person may be tempted by a shiny restored example, but a true collector will seek out perfect originality while avoiding replacement parts. That’s most of the fun in collecting vintage, hunting down original examples and knowing how to identify the various details.

Patent Pending Crown

I’d like to say this watch is available to purchase… But it isn’t. It’s part of a private collection. I would like to thank the owner for letting us photograph this Patent Pending and several other pieces in his collection. Having the opportunity to handle and profile exceptionally rare watches such as this Sea Dweller is the part of my job that I really adore. And it speaks to our expertise in rare vintage watches here at Matt Baily’s. We built our reputation selling pre-owned and vintage watches starting in the early 1980s, and we pride ourselves in our knowledge of the collector’s market.


Jason Cormier

Double Red MK I Dial


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