A fake Patek Philippe 3700/11 is a counterfeit of the first Nautilus Jumbo, the 42mm steel sports watch Patek Philippe introduced in 1976. Genuine examples use a one-piece "monobloc" case, an ultra-thin 28-255 C automatic movement, and dial printing that few factories can match. Most watches sold today as a 3700/11 are later Nautilus copies with fake reference markings.
This guide covers what the real reference looks like, the tells that separate a genuine watch from a counterfeit, and the risks that come with buying one.
The real Patek Philippe 3700/11 at a glance
The 3700 family is the first Nautilus generation, drawn by Gerald Genta and shown in 1976. It was the most expensive steel watch of its day, which is why it became a target for counterfeiters.
- Case: 42mm wide, about 7.6mm thick, steel or gold, with a porthole shape and a hinge barrel on the left side.
- Movement: Caliber 28-255 C, an ultra-thin automatic built on the Jaeger-LeCoultre 920 base.
- Water resistance: 120 meters from the factory.
- Bracelet: Integrated, with a gradual taper and a folding clasp.
- Production: About 1976 to 1982 for the first Jumbo run.
Why the 3700/11 reference number trips people up
Patek uses slashes and letters to code metal and bracelet type, so one base number can carry several suffixes. Collectors read /1A as stainless steel on an integrated bracelet, while other suffixes mark gold and two-tone versions. Because few 3700 watches survive with full paperwork, sellers apply whichever suffix helps a listing.
How to spot a fake Patek Philippe 3700/11
Case shape and proportions
The Nautilus case is not a simple cushion. It has a flat top, a rounded right side, and a hinge barrel on the left where the bracelet attaches. Copies use a two or three piece case that looks symmetric and wrong from the side. Measure the width: a genuine Jumbo reads 42mm across the bezel, not 40mm like a 5711.
The monobloc case and how the movement loads
Genuine 3700 watches have no separate caseback. The movement goes in through the front, then the bezel and crystal hold it in place. Turn the watch over: you should see a solid metal back with engravings, not a screwed-down caseback ring. Almost every replica uses a standard snap or screw back, which is the fastest way to rule one out.
Dial printing and the date window
Early 3700 dials carry a ribbed horizontal texture and a deep blue to black gradient. The signature reads "Patek Philippe" and "Geneve" with thin, even strokes and sharp serifs. Fakes show thick paint, a crooked date window, or a font that looks close but sits too high on the dial.
Hands and crystal
Genuine hands have beveled edges that catch light along one side and stay dark on the other. Replica hands look flat and painted. The crystal sits flush with the bezel on a real watch, with no visible lip.
Bracelet, clasp, and crown
The integrated bracelet tapers in small steps and the links flex without rattle. Counterfeit bracelets use fewer links, sharper edges, and clasp markings that are stamped rather than engraved. The crown on a real 3700 sits partly inside the case and shows a crisp Calatrava cross.
Movement and engraving
Ask a watchmaker to inspect the movement through the front opening, since a 3700 has no back door. A genuine 28-255 C shows Geneva stripes, polished bevels, and heat-blued screws. Copy movements are Chinese or Japanese automatics with rough finishing and the wrong bridge layout.
Gold hallmarks
Gold 3700 watches carry Swiss assay marks and a purity stamp on the case. Fakes use gold plating and either skip hallmarks or stamp them in the wrong place. Plated cases wear through at the lugs and crown, which shows as gray metal under the gold.
Why the 3700 is hard to copy
The case is thin for its width, and that ratio drives everything else. A movement that is too tall forces the case to grow, which throws off the bezel slope and the bracelet line. Few factories bother with a monobloc case because it raises cost and complicates assembly.
Price signals that give a fake away
Genuine first-generation Nautilus watches trade in the six figures at auction, and even rough examples with replacement parts sell for large sums. Replica listings run from about $50 for a basic quartz copy to $800 for a decorated automatic sold as a "super clone." If a seller asks four figures for a steel Jumbo, the watch is not real.
Legal risk of buying or selling a counterfeit
Counterfeit watches infringe Patek Philippe trademarks, and US customs can seize shipments at the border. Selling one exposes a seller to civil liability and, in repeat cases, criminal charges. Reputable auction houses and dealers refuse them, so resale channels are limited to gray markets and online listings.
Frequently asked questions
Can a watchmaker tell a fake 3700/11 from a real one?
Yes, often in minutes. The case construction, movement layout, and dial printing give it away without a full teardown. A watchmaker with Nautilus experience will spot a copy before the watch reaches the bench.
Do any fakes use solid gold?
Almost none. A solid gold case costs more than the finished fake sells for, so makers use brass or steel with plating. This shows at the lugs, the crown, and the case edges after a few years of wear.
Does a fake 3700/11 hold value?
No. Replicas lose most of their resale value as soon as they leave the seller, and no authorized service center will touch one. Money spent on a counterfeit is gone.
Where can I get a 3700/11 checked before buying?
Take it to an auction house specialist, an independent watchmaker who services Patek Philippe, or an authorized retailer. Ask for a written opinion that names the case and movement details. Never rely on seller photos or a certificate printed by the seller.
What to remember
The 3700/11 is a 1976 Nautilus Jumbo with a monobloc case and an ultra-thin automatic. Any watch with a screw-down caseback or a 40mm cushion case is not one. Check the case construction, the movement, and the dial printing before money changes hands.