Almost every watch sold as a "Patek Philippe 3700/11" is not a Patek Philippe. The reference is a genuine vintage Nautilus Jumbo from 1976 to about 1982, and real ones trade well into six figures at auction. If a listing sits under roughly $40,000, you are looking at a counterfeit, a franken build, or a watch described with the wrong reference number. There is no honest middle market here.
What the 3700/11 actually is
The Nautilus launched in 1976, drawn by Gerald Genta, and the steel Jumbo was the first version. It measures 42mm across and only about 7.6mm thick, which is the part fakes almost never get right. The case is a monobloc: one piece of steel, front-loaded, no removable caseback in the usual sense. Inside sits the caliber 28-255 C, an ultra-thin automatic built on the Jaeger-LeCoultre 920 base shared with Audemars Piguet and Vacheron Constantin of the same era.
About that "/11" suffix
Patek's reference system puts the case number before the slash and the bracelet or case variant after it. The standard steel Nautilus Jumbo is written 3700/1A. Sellers, forums, and search terms have mangled that into "3700/11" for years. A seller using the wrong suffix does not automatically mean a fake, but it does mean they may not know the watch they are holding. Judge the object, not the listing title.
The tells I check first
- Case profile. Thin, flat, and sharp. A screw-down sapphire display back is an immediate disqualifier, because the original does not have one.
- Dial. Horizontal grooves across a black surface, crisp printing, correct typeface, and even spacing between "Patek Philippe" and "Nautilus." Blurry text or a printed texture instead of real grooves is a fake.
- Crown. Flat, recessed, sitting nearly flush with the case band and carrying the Calatrava cross.
- Bracelet and clasp. Integrated and tapering, with a signed clasp and correct hallmarks. A rattly, hollow bracelet with soft edges is a copy.
- Movement. Caliber 28-255 C, 36 jewels, bi-directional winding, Geneva seal, JLC 920 lineage. If the watch is quartz, stop there. The 3700 was never quartz.
Franken watches are the harder problem
A genuine case with a reprinted or service dial is still a problem, and so is a real movement dropped into a recased package. These pass a quick glance and fail an expert one. Ask for clear photos of the movement, the caseback interior stamps, and the serial numbers. Patek keeps records and will issue an extract from the archives, which confirms the original date of manufacture and the details of the watch as it left the factory. If a seller refuses to pursue that document on a six-figure watch, that tells you something.
Price and paperwork together
Condition, dial originality, and box and papers all move the number. Auction results for the 3700/1A are public and easy to check, so compare any asking price against recent realized prices rather than against other listings. A watch priced far below the market is not a bargain. On this reference it is a warning.
Bottom line
If you want a Nautilus Jumbo, buy from a dealer or auction house that stands behind the reference and offers documentation. Treat every cheap "3700/11" as a fake until the case, dial, movement, and paperwork prove otherwise.