The Patek Philippe Aquanaut celebrates its 20th anniversary in 2017. The watch that commemorates this milestone — the Ref. 5650 Aquanaut Travel Time “Patek Philippe Advanced Research” — has an 18K white-gold case measuring 40.8 mm in diameter and 11 mm thick and water-resistant to 120 meters. It is equipped with the cleverly conceived dual time-zone function that Patek has used in previous models such as the Calatrava Pilot Travel Time and Nautilus Travel Time, and its self-winding movement features, for the first time, two major technical innovations: an optimized Spiromax balance spring with an inner boss; and the so-called flexible mechanism for the time-zone settings. The watch will be issued in a limited edition of 500 pieces.
The watch contains Patek’s automatic caliber 324 S C FUS, which in this model has been enhanced with two innovations developed by the Patek Philippe Advanced Research laboratory. The first is the Spiromax balance spring made of Silinvar, which is equipped with two terminal curves and optimized with an inner boss. It improves the isochronism of the balance in the vertical orientations of the watch. As a result, its rate accuracy ranges between -1 and +2 seconds per day — similar to the precision of Patek Philippe’s tourbillon watches.
The second innovation involves the time-zone setting device, which replaces the usual pivoting articulations with so-called “compliant” or flexible mechanisms. This device, which is composed of only 12 filigreed steel parts with several intersecting leaf springs — as compared to the 37 parts used in the more traditional mechanism — transmits the actuations of the two time-zone pushers to the local time display.
As on other Travel Time watches in other Patek Philippe families, this Aquanaut displays the local time and date as well as a second time zone (usually the wearer’s home time) and a day/night indicator for both time zones. Two pushers in the left-hand case flank control the settings. On trips across several time zones, the local time hour hand can be adjusted forward or backward in one-hour steps. In the process, the day/night indicators and, if applicable, the date are also changed. When the owner is headed east, the local time is set with the pusher at 8 o’clock. The pusher at 10 o’clock corrects the local time on westbound trips.
The Aquanaut Travel Time Ref. 5650 features a bright blue dial adorned with the collection’s familiar embossed pattern and light-to-dark color gradation. At 9 o’clock, the watchmakers have carved out an ample aperture through which the silvery steel flexible mechanism — with its four crossed leaf springs, meticulously finished surfaces, and chamfered edges — are on dynamic display.
The Patek Philippe Aquanaut Travel Time Ref. 5650 “Patek Philippe Advanced Research” (the model’s full proper name) is mounted on a night-blue strap, with an embossed pattern that echoes that of the dial, made of a water-resistant composite material. It fastens with a three-part foldover clasp in 18k white gold. The U.S. retail price is $58,970.