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The Encyclopedia of Horology

Pocket watch · Deck watch chronometer

Vacheron & Constantin Deck Watch Chronometer

Partially verified

This open-face deck watch chronometer by Vacheron & Constantin is reported to date to circa 1942. The piece is housed in a 59 mm sterling silver case, with the dealer stating the case back bears Hydrographic Service markings HS 55076 and the dust cover bears serial number 286408. The dial features a light silvered finish, Arabic numerals, outer minute and fifth-of-a-second track, and blued-steel hands with center seconds. The movement is reported by the seller as a 21-jewel caliber 166 full-bridge mechanical design fitted with a Guillaume alloy bimetallic split balance and swan's-neck regulator.

Dial and case view of the Vacheron & Constantin deck watch chronometer
Dial and case view of the Vacheron & Constantin deck watch chronometer — FJ & RD Story Antique Clocks. Rights pending — permission not yet requested. Original source

Catalogue identity

Source
www.sellingantiques.co.uk
Category
Pocket watch · Deck watch chronometer
Maker / attribution
Vacheron & Constantin
Reference
166
Catalogue / lot identifier
SA923164
Source-reported date
circa 1942
Country
Switzerland
Source-reported serial
286408

Source-reported attribution and specifications are not independent authentication. A listing does not establish present ownership, current display, availability or permission to reproduce.

Object description

Case and External Identification

The timepiece is housed in a 59 mm diameter open-face sterling silver case. The listing notes the case back bears an inscription for the Hydrographic Service, 'HS 55076'.

A polished silver dust cover is located inside the case back, which is engraved with the manufacturer's name, '0.925' silver purity, and the serial number '286408'. The watch is described as including a fitted brass carrier and protective window with a screwed-in bezel.

Evidence for this section
  • “The case is sterling silver and 59mm in diameter, the back of the case is marked for Hydrographic Service HS 55076.”
  • “Opening the back reveals a polished dust cover with hallmarks repeated on the inside; 0.925 Vacheron & Constantin Swiss 286408”
  • “For safe transport the watch rests in a fitted brass carrier, and is topped with a protective window with screwed-in bezel.”

Dial and Visual Features

The dial has a brushed silvered finish with black Arabic numerals and a track calibrated for minutes and fifths of a second.

Time is indicated by blued-steel poire-style hands for the hours and minutes, accompanied by a slender blued center-seconds hand.

Evidence for this section
  • “brushed silvered dial, blued-steel poire hands and simple black Arabic numerals and track.”
  • “The movement ticks five times per second, so the smallest markings exactly correspond to the second-hands progress.”

Movement Specifications

The movement is identified as a 21-jewel, 21-ligne (approx. 47 mm) Caliber 166. It is a full-bridge design equipped with a swan's-neck regulator, a Guillaume alloy bimetallic split balance, and an overcoil blued-steel hairspring.

The mechanism uses an indirect center-seconds configuration, utilizing a cock on the main bridge to support the center-seconds jewel, with a spring intended to minimize hand wobble.

Evidence for this section
  • “The 21-jewel, 21-ligne (about 47mm diameter) caliber 166 is a full-bridge design and features a swan's-neck regulator, Guillaume alloy bimetallic split balance, and overcoil blued-steel hairspring.”
  • “Atop the main bridge is an elegant little cock which carries the jewel for the center-seconds; the spring lightly presses on the stem to prevent the hand wobbling”

Open research questions

  • Do the markings 'HS 55076' align with documented Admiralty-issued deck watch inventories?
  • Can the serial number 286408 be confirmed against manufacturer records for dating purposes?
  • Are there extant historical records detailing the production volumes of the Caliber 166 in this configuration?

Source evidence

Recorded claims and source quotations for Vacheron & Constantin Deck Watch Chronometer
FieldSource-reported valueSource quotation
Case diameter59mm“The case is sterling silver and 59mm in diameter”
Service markingHS 55076“the back of the case is marked for Hydrographic Service HS 55076.”
Movement caliberCaliber 166“The 21-jewel, 21-ligne (about 47mm diameter) caliber 166 is a full-bridge design”
Internal hallmark and serial0.925 silver, serial 286408“0.925 Vacheron & Constantin Swiss 286408”
Regulator mechanismSwan's-neck regulator“features a swan's-neck regulator, Guillaume alloy bimetallic split balance, and overcoil blued-steel hairspring.”
Dealer-stated Datecirca 1942“A fine quality Vacheron and Constantin deck watch chronometer circa 1942”
Finishing DetailsGeneva stripes and polished anglage“Excellent Geneva stripes and polished anglage all around”

Visible details

  • Light silvered dial signed 'VACHERON & CONSTANTIN GENÈVE' below 12 o'clock and 'SWISS' at 6 o'clock.
  • Blued-steel poire-style hour and minute hands accompanied by a slender blued center-seconds hand.
  • Black Arabic hour numerals with an outer track calibrated for minutes and fifths of a second.
  • Open-face silver case with a prominent fluted winding crown and top bow.

Research qualifications

  • Movement specifications and case back markings (HS 55076, serial 286408) are source-reported and not visible in the primary photograph.
  • The fitted brass transport carrier mentioned in the description is not shown in this image.

Photograph identity and source facts were screened before import; rights clearance remains pending.

Consulted source

Sold: A Fine Quality Vacheron & Constantin Deck Watch Chronometer | Sellingantiques

Reviewed 2026-10-25 · Record c4c727d3d8

Terms in this record

Glossary explanations for terms named in this object’s record.