The porthole that conquered Patek
Four years after the Royal Oak, Patek Philippe asked the same designer, Gérald Genta, for its own luxury steel sports watch, and in 1976 launched the result: the Nautilus reference 3700/1A. Genta took his inspiration from the porthole of a transatlantic liner, giving the case a distinctive rounded-octagonal form with "ears" on either side — hinges, in the porthole metaphor — and an integrated bracelet flowing from it. For Patek Philippe, the most conservative and classical of the great houses, building a steel sports watch was a genuine departure, and the famous launch advertisement leaned into the paradox: "One of the world's costliest watches is made of steel." It was a watch that should not have fit Patek's identity, and it became one of the pillars of it.
The "Jumbo," and a movement shared three ways
Like the Royal Oak, the original 3700 is known as the "Jumbo" — at around 42mm it was large for its era — and it shares the Royal Oak's mechanical heart: the ultra-thin automatic caliber 28-255, based on the same Jaeger-LeCoultre 920 ébauche that powers the AP 5402 and the Vacheron 222. This shared foundation is one of horology's great curiosities: three of the most important luxury sports watches ever made, from three different houses, all built on one supremely thin automatic movement. The 3700's blue-grey horizontally embossed dial, its slim profile, and its case-integrated bracelet established a design language Patek has evolved but never abandoned across the 3700, 3800, 5711, and the current references.
The Nautilus's modern descendant, the steel 5711, became the epicenter of the 2017–2021 hype cycle — waitlists stretching years, secondary prices many multiples of retail, the watch transformed into a financial instrument and status token. Then, at the peak of demand in 2021, Patek did the almost unthinkable: it discontinued the steel 5711, walking away from its most demanded product rather than dilute its exclusivity, replacing it with the white-gold 5811 in 2022. The final flourish was a 5711 with a Tiffany-blue dial, made with Tiffany & Co., one example of which sold for $6.5 million at charity auction in December 2021. The original 3700 is the dignified ancestor of all that noise — and a reminder that today's frenzy attaches to the descendant of a watch that, in 1976, Patek's own retailers feared would never sell.
Reading and valuing a 3700
Vintage 3700 collecting turns on originality and configuration. Collectors examine the dial for correct embossing and patina, the case for sharpness (the Nautilus's flat, wide surfaces show polishing cruelly, so unpolished examples command a strong premium), the bracelet's stretch and correctness, and the details that distinguish the earliest examples. As with the Royal Oak's A-series, the first-execution 3700s are the most prized. Because the Nautilus design depends so heavily on crisp case geometry and the interplay of brushed and polished surfaces, a polished or refinished example loses much of what makes the watch special — the same lesson the 5402 teaches, that on these finishing-dependent designs the condition of the case is as decisive as originality of the dial.
The sibling rivalry that defined a category
The Nautilus and the Royal Oak are inseparable in any serious account of modern watchmaking — Genta's twin creations, four years apart, sharing a movement and a thesis, that together invented and still rule the luxury sports watch. Where the Royal Oak is angular and architectural, the Nautilus is rounded and fluid; where the AP saved its maker through the quartz crisis, the Patek extended the category's reach to the most prestigious house of all. The two watches are the parallel poles of the most important idea in modern luxury watchmaking, and the 3700 is the moment that idea conquered the summit of the industry. That Patek Philippe — the house of the perpetual calendar and the minute repeater — now counts a steel sports watch among its most coveted products is the measure of how completely Genta's concept triumphed.
The Nautilus 3700 took Genta's luxury-sports thesis to the most classical house in watchmaking and won — a porthole-cased steel watch advertised as costlier than gold, built on the same legendary movement as its Royal Oak sibling, and ancestor to the 5711 that became the defining grail of the modern hype era. Together the Nautilus and Royal Oak are the twin foundations of the category that now rules the high end, and the 3700 is where it claimed Patek Philippe itself.