Aquanaut Travel Time "Advanced Research"Limited / 500 pieces, 2017

The 5650G is a single-year Advanced Research edition that wrapped Patek's travel time complication in a 40.8mm white gold Aquanaut case and debuted two proprietary technologies: the Spiromax silicon balance spring and the Pulsomax silicon escapement, plus a flexible composite strap hinge called Caoutchouc. Produced only in 2017, it sits in the Advanced Research line that Patek uses to field-test materials and mechanisms before mainline production. Collector demand is real and consistent because the 5650G is both a working travel time watch and a documented technology milestone.

What it is

The Advanced Research series launched in 2005 as a platform for testing silicon-based movement components, and the 5650G is the fifth reference in the program. It uses caliber 324 S C FUS, a self-winding movement with an instantaneous-jumping local time display and a patented flexible strap attachment that eliminates the rigid lug-to-case junction found on standard Aquanaut references. Patek produced the 5650G in 2017 only, with official allocation through boutiques and select authorized dealers.

No subsequent production runs were announced, and no dial variants exist. The "FUS" suffix on the caliber designates the Spiromax/Pulsomax silicon component package.

Buying notes

Confirm the flexible strap hinge is intact and operates smoothly before purchase. The composite hinge mechanism is unique to this reference and cannot be sourced from a standard Aquanaut parts supply. Ask for the original Patek box, papers, and any Advanced Research documentation; the 5650G was delivered with reference materials explaining the technology, and a set without these raises authenticity questions.

The white gold case should show typical light surface wear only. Any polishing history significantly reduces collector value on a watch produced in this volume. Verify the silicon escapement has not been replaced with a conventional lever-and-balance assembly during a prior service, which would defeat the technical purpose of owning an Advanced Research piece.

Market read

The 5650G trades well above its original retail of approximately $65,000 USD. Auction results and private sale records from 2023 to 2025 place clean examples with full set in the $120,000 to $160,000 range, with exceptional examples occasionally crossing $175,000. The Advanced Research designation carries its own premium independent of the Aquanaut name, and that premium has held steady even as the broader luxury watch market softened in 2024.

Gray market supply is thin because original buyers have limited incentive to sell.

Service expectations

Caliber 324 S C FUS should be serviced approximately every ten years under Patek's current guidance, though the silicon escapement components require no lubrication and extend intervals compared to conventional movements. Factory service at a Patek Philippe service center is strongly recommended because the Pulsomax escapement and Spiromax spring require proprietary tooling and trained technicians. Expect service costs in the $2,500 to $4,000 USD range at an authorized center, depending on work required.