Editorial
The Aquanaut 5167A-001 is Patek Philippe's steel sport-watch on rubber strap, 40mm, the embossed checkerboard dial that traces back to the 1997 original, and the caliber 324 S C with a 45-hour reserve. The Aquanaut is the Nautilus's younger sibling and the reference forum-readers route around the 5711 with when the 5711 sat above its retail by a factor of six. The 5167A has since followed the same path: retail is approximately $24,000 but the watch has not traded at retail in years.
Patek introduced the original Aquanaut (ref. 5060A) in 1997, designed under Philippe Stern as a more-accessible, more-modern sport-watch than the Nautilus, with a rounded-octagonal case, the composite "Tropical" rubber strap, and the embossed grid dial that became the family's signature. The 5167A succeeded the 5066A in 2007 with a larger 40mm case (up from 38mm), the caliber 324 S C (replacing the 330 S C), and a redesigned strap-and-clasp system. Production has continued through multiple sub-references, 5167R (rose gold), 5167/1A (steel bracelet), 5168G (white gold, 42.2mm), and several limited dials.
The 5167A-001 (black dial, rubber strap) is the canonical reference.
Common things to check: papers and Patek extract (a 5167A without papers in this price bracket is a hard pass for most buyers, the Patek extract from the archive is the standard verification, and the wait for one is 6-12 months); strap (the Tropical rubber strap is consumable. Patek-supplied replacements are available at service and aged straps with the original deployant are correct; aftermarket straps are common and should be priced accordingly); dial originality (the embossed checkerboard dial is the most-counterfeited Patek dial element, verify the dial under loupe for crisp embossing and the correct "Patek Philippe Genève" wordmark placement); caliber 324 S C (robust modern Patek automatic; service intervals of 5-7 years; the Spiromax balance spring introduced mid-production is the easiest service-era marker); the 5168G (white gold, 42.2mm) is a different reference with a different case and dial layout, verify the case size against the reference number.