Reference
The Frédéric Piguet 1185: One Thin Chronograph Under an Audemars Piguet, a Vacheron and an Omega
A 5.5 mm column-wheel chronograph from 1987 sits under the Royal Oak Chronograph, the Overseas Chronograph and, in a larger form, 203 Omegas. Where it is in this library, and what each maison did with it.
The Lemania 2310 is the hand-wound chronograph that several maisons shared. Its automatic counterpart is less famous and, in this library, more common: the Frédéric Piguet 1185, a column-wheel chronograph with a vertical clutch that Piguet introduced in 1987 and that sits, under three different names, inside 333 watches here.
Why it exists
In 1987 the automatic chronographs available to a maison that did not make its own were thick. The Valjoux 7750 is 7.9 mm; the Zenith El Primero, 6.5. Frédéric Piguet, the movement house in the Vallée de Joux that had built ultra-thin calibers for Blancpain, Breguet and Audemars Piguet, designed the 1185 at 5.5 mm, and did it without cutting corners: a column wheel rather than a cam, a vertical clutch rather than a horizontal one, and 37 jewels at 26.2 mm across, beating at 21,600 vph with a 40-hour reserve. The chronograph piece explains why that pairing is the one a movement designer wants and the reason it is usually tall; the 1185's achievement was fitting it into the height of a three-hander.
That is why the maisons whose cases could not tolerate a 7750 came to it. Piguet became part of Blancpain and then of the Swatch Group in 1992, which is how Omega later got a version of its own.
Where it sits in this library
| Caliber | Maison | Watches | Base |
|---|---|---|---|
| 3313 | Omega | 122 | 1285, co-axial |
| 2385 | Audemars Piguet | 120 | 1185 |
| 3303 | Omega | 23 | 1285 |
| 3603 | Omega | 18 | 1285, GMT |
| 3612 | Omega | 17 | 1285, split-seconds |
| 3301 | Omega | 16 | 1285 |
| 1137 | Vacheron Constantin | 10 | 1185 |
| 3320, 3321, 3205 | Omega | 7 | 1285 variants |
Audemars Piguet: the Royal Oak Chronograph
Audemars Piguet took the 1185 as it was, finished it to its own standard and called it the 2385. From 1997 it was the movement of the Royal Oak Chronograph, and it is the reason that watch kept the proportions of the time-only Royal Oak: a 39 mm case, later 41 mm, at a thickness a 7750 could never have allowed. In this library the 2385 powers 77 Royal Oak chronographs and 41 of the 37 mm Royal Oak Offshore models, and it served until the in-house 4401 replaced it in 2021. It has a date at 4 o'clock, which the base movement dictated and which the Royal Oak's dial has carried ever since.
Vacheron Constantin: the Overseas
Vacheron Constantin's 1137 is the same base under the Overseas Chronograph from 1999, with a large date added and the finishing the Hallmark of Geneva requires. It is the smallest group here, ten watches, all in the Overseas. Vacheron replaced it with its own 5200 in the 2016 Overseas, so the 1137 marks a specific generation: the second-series Overseas, whose chronograph was 42 mm and which the library still holds in steel and gold.
Omega: the 1285 and the co-axial
Omega's route was different. As a Swatch Group brand it could ask Piguet for a version of its own, and the 1285 is the result: the 1185's architecture enlarged to 27 mm and 30 mm, beating at 28,800 vph, with a 55-hour reserve and 33 jewels. The 3303 was the first, and its less decorated sibling the 3301; then Omega did the thing that made the family its own, fitting the co-axial escapement to make the 3313, the chronograph of the co-axial era from the De Ville to the first Planet Ocean.
Omega then built outward from it. The 3603 adds a GMT hand, the 3612 a split-seconds mechanism, and the 3320 and 3321 are the decorated and skeletonised versions of the Speedmaster Broad Arrow. With 203 watches across those calibers, Omega is the largest user of the family here, and its distribution shows the movement's reach: 37 De Villes, 26 Planet Oceans, 20 Aqua Terras and 17 Constellations on the 3313 alone, plus the Speedmaster Broad Arrow on the 3303.
How to tell
The layout is the signature. A 1185-based chronograph has two counters, running seconds at 9 o'clock and a 30-minute register at 3, a 12-hour register at 6 and a date beside it. On the Royal Oak the date sits at 4 o'clock; on the Omegas it sits at 6 between the counters. Start the chronograph and the seconds hand moves off cleanly, the vertical clutch's tell, and the pusher gives the short click of a column wheel. The thinness is the other tell: a Royal Oak Chronograph on the 2385 is 11 mm high, a figure no 7750 watch can match.
What replaced it
All three maisons have since moved on, and in the same direction. Audemars Piguet's 4401, Vacheron's 5200 and Omega's 9300 and 9900 are in-house column-wheel chronographs with vertical clutches, which is to say they are the 1185's architecture rebuilt at home. The design that made a thin chronograph possible in 1987 became the design everyone builds now. Each caliber above has its own page listing the watches here that carry it.