Reference:3666
Submarine -> 3666
The 3666 is a pre-Oyster Rolex Submarine in the original 1920s sense of that name, not in the later dive-watch sense. It is the clearest surviving example of the Finger double-case system Rolex sold before the Oyster replaced it.
Core facts
| detail | value |
|---|---|
| reference | 3666 |
| family | Submarine / Hermetic (pre-Oyster) |
| production | ~1924 onward (patent architecture from 1921) |
| case construction | double case — one-piece outer with screw-down bezel, separate inner movement case with no stem hole |
| case diameter | 32.35 mm overall (Boettcher measurement of a documented Hermetic) |
| movement diameter | 21 mm (9.3 ligne, nominal "9½") |
| case materials | sterling silver (most common), 9ct pink gold, 18K gold |
| case markings | "JF / Double Boitier Brevet 89276" — Jean Finger, Longeau, Berne |
| inner caseback | signed W&D (Wilsdorf & Davis) |
| crown/winding | pendant winder on inner case; outer case must be unscrewed to access |
| trademark | "Rolex Submarine" — Swiss registration 31 March 1922 |
| British patent | GB 197208 "Improvements in and Relating to Watches," priority 26 May 1922, granted 10 May 1923 (Wilsdorf, no credit to Finger) |
A second, entirely different watch also carries reference 3666: a 1940 Valjoux-22 antimagnetic chronograph, addressed at the end of this article. Everything above this paragraph refers to the 1924 Hermetic.
Where it sits in the line
The 3666 is Rolex selling Jean Finger's Hermetic double-case idea through its own network. Finger developed the architecture and made the surviving cases. Rolex commercialized it. That is the cleanest way to read the credit.
Production of the 3666 starts around 1924 inside the broader Hermetic line. That chapter ends as soon as the Oyster case arrives in late 1926 and makes the double-case architecture obsolete. What survives is the name: the 1922 Rolex Submarine trademark returns in 1953 on a completely different watch.
The double-case architecture
The 3666 is a watch inside a watch. The movement sits in a sealed inner case, and that inner case sits inside a larger protective shell closed by a screw-down bezel. To wind or set it, the owner has to open the outer case and remove the inner one. That is what makes the design both ingenious and inconvenient.
The inner caseback, where visible after disassembly, is typically signed W&D, the mark of Wilsdorf & Davis, the firm's legal name in Britain before the 1919 rebrand to Rolex. W&D stamps appear on Rolex-era pieces into the mid-1920s as a legacy supplier convention. On the Hermetic, they confirm the inner case originated in the Wilsdorf retail chain rather than through a third-party assembly.
The Hermetic solved water resistance by removing the exposed stem from the problem entirely. That made it genuinely water-resistant for its day, but awkward to live with: every winding or setting operation meant partial disassembly. The Oyster solved exactly that usability problem a few years later.
Dimensions
The measured dimensions tell the story clearly enough. The outer case is about 32 to 33mm, but the actual dial is much smaller because the watch has to carry a full sealed inner case inside the outer shell.
Dial and hand variants
Known 3666 dials fall into three practical groups. Most are white enamel or silvered Arabic-numeral watches with sub-seconds at 6. A smaller group keeps the same basic layout with sector styling. The rare outlier is the black radium military-style dial with cathedral hands. The variety is real, but the run is still narrow enough that these feel like branches of one short-lived model, not a sprawling family.
There is no Rolex wordmark styling of the "Submarine" trademark on any known 3666 dial. The Submarine name appears in trademark filings and period marketing material, not on the dials of the watches themselves, which read simply "Rolex" above the sub-seconds register. This is consistent with 1920s Rolex practice. Model trademarks were retailer-facing and legal-facing, not dial-facing, and would remain so until the Submariner dive watch of 1953 put the name back on the dial.
The Cargills Ceylon example
The best-documented surviving 3666 is a 1924 sterling silver Hermetic retailed by Cargills Ltd. Ceylon, the Colombo department store that distributed Rolex across the British colonial market in the 1920s. It surfaced publicly through Bold Timepieces. The case is hallmarked silver, the case markings include the Finger patent text ("JF / Double Boitier Brevet 89276"), the inner case is signed W&D, and the dial is white enamel with black Arabic numerals and subsidiary seconds at 6. The watch is presented as a working example of the architecture: the outer case unscrews, the inner case lifts out, and the movement winds through the pendant of the inner case.
The Cargills retail signature places the watch in the early 1920s colonial supply chain that Rolex used for India, Ceylon, Singapore, and Hong Kong, a route that would matter again twenty years later when wartime contracts for the Bombay Presidency passed through the same network. The 1924 dating is the standard Cargills period; company records tie the Rolex distribution agreement to that decade.
Auction and dealer record
The 3666 has no deep auction history at the major houses, which is typical for Rolex references of the pre-Oyster period. Too early, too small, and too operationally awkward to hold broad modern appeal. The watch's public-market trail runs through specialist dealers and smaller lots at the major houses.
The 3666 has a small but real market record. Bold Timepieces anchors the best-known Cargills Ceylon example, Bonhams has catalogued a c.1925 Hermetic Submarine, and Connoisseur of Time has documented the same architecture from the dealer side. That is enough to keep the reference grounded even if auction depth is thin.
The market for the early Hermetic is a niche inside a niche. Examples in good condition with original enamel dials trade modestly compared to later Rolex sport references; the absence of any dive heritage, chronograph complication, or auction-house framing narrative keeps prices well below what the historical significance might suggest. A collector buying a 3666 is buying a documentary object, not a performance piece.
The 1940 reference 3666 chronograph
Rolex reused the reference number. In 1940, the firm fitted a Valjoux-22 antimagnetic chronograph movement into a completely different case and stamped it ref 3666. Phillips has sold that watch under catalog number CH080216 for CHF 162,500. It is a waterproof-cased chronograph with a tachymeter scale, pump pushers, and a round steel case in the 35–37 mm range, visually and mechanically unrelated to the 1924 Hermetic. The two watches share nothing but the four-digit reference.
Rolex reused four-digit references regularly in this era, so a 3666 can mean two totally different watches. The movement settles it fast: a small Hunter movement means the 1920s Hermetic, a Valjoux chronograph means the later 1940 reference.
Collecting considerations
Case markings are primary. A genuine 3666 Hermetic inner case carries the Finger patent text "JF / Double Boitier Brevet 89276" visibly on either the outer case flank or inside the outer bezel, and the inner caseback carries W&D. Both should be present. Cases lacking the Finger patent text are either from a different Hermetic variant or from a Wilsdorf alternate-brand Hermetic (Aqua or pre-Oyster brand experiments) that shared the architecture but not the Rolex retail chain.
Enamel condition is the next filter. White enamel dials on silver Hermetics are brittle and have been vulnerable to hairline cracks across nearly a century of survival. Original enamel with no cracks is exceptional and commands a meaningful premium. Small hairlines around the subsidiary seconds or near the dial feet are typical and not disqualifying. Full cracks across the dial face or significant chipping are. Refinished enamel dials exist but are difficult to execute convincingly, and a re-enameled Hermetic is usually detectable under strong light.
Operational condition matters because the architecture is the point of the watch. A 3666 that no longer disassembles cleanly, with the outer bezel seized onto the outer case body or the inner case corroded into the outer shell, is a real service problem. The bezel threads are fine and old; a cross-threaded repair attempt can destroy the waterproof seal that was the entire point of the architecture. A working disassembly, with the outer bezel turning smoothly onto the outer body and the inner case seating correctly, is evidence of competent prior servicing.
Movement integrity sits alongside that. The inner case has no opening back, so access to the movement runs through the pendant winder end only. A 3666 with a modified inner case, meaning any evidence of cutting, flat-backing, or case alteration for service access, has been compromised relative to original Finger construction. Original inner cases with intact W&D stamps and original pendant-winder access are the benchmark.
Price anchoring is approximate, because the public market for the 3666 is thin. Surfaced examples in good enamel condition with clean case markings trade in a range that reflects documentary significance rather than broad collector demand: well below even mid-range Oyster references of the 1930s, and a very long way below the 1940 Valjoux chronograph that shares the reference number. The historical significance is real; the market valuation is not yet aligned with it.
What the 3666 established
Three things survive from the Hermetic era into the Rolex canon. The first is waterproofing as a design priority. Before the 3666, no wristwatch manufacturer had committed seriously to sealing against water, and the dominant position was that waterproofing was a pocket-watch problem that did not apply to wristwatches. Finger solved it brutally, Wilsdorf saw the solution, licensed the case, registered the Submarine trademark, and put the first genuinely waterproof Rolex wristwatches onto the British and colonial markets through 1922 and after. Everything that follows (the 1926 Oyster, the 1927 Gleitze Channel swim on ref 34075, the 1953 Submariner dive watch) is downstream of that commitment.
The second is the Submarine name itself. Registered on 31 March 1922 and held in reserve for thirty-one years before the dive watch picked it up again, the trademark survived corporate reorganization, the Oyster transition, and the Second World War. The 1953 Submariner did not arrive out of nowhere. Its name was sitting in the Rolex trademark portfolio from the previous decade.
The third is the lesson about daily use. The Hermetic is the counter-example that justified the Oyster. Wilsdorf commissioned the Perregaux-Perret screw-down crown, the Spillmann three-piece case, and the Aegler movement integration because the Finger double case, however waterproof, had made itself a daily annoyance. The Oyster is what a watchmaker builds after three years of selling Hermetics and learning what the customer actually wants. Without the 3666, there is no Oyster; with the 3666, the Oyster is inevitable.
Sources
- VintageWatchStraps (Boettcher) — hermetic
- Bold Timepieces — 3666 cargills
- Bonhams — 29150 lot48 hermetic
- Connoisseur of Time — of time hermetic
- Mokum Watches — hermetic submarine aqua
- Phillips — 3666 valjoux chronograph
- Wind Vintage — The Oyster Story (Part 1) — Owen Lawton / Wind Vintage, Wind Vintage
- The Vintage Rolex Field Manual, Chevalier Edition — unknown, Morning Tundra