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The Encyclopedia of Horology

Pocket watch · Deck watch

Longines Royal Navy Hydrographic Service H.S.3 Deck Watch

Partially verified

This military pocket deck watch by Longines is reported by the seller to have been issued for the British Royal Navy Hydrographic Service, bearing caseback markings for code H.S.3 along with the broad arrow. Housed in a 52 mm nickel-chrome plated case with a screw-in bezel and screw-down caseback, the watch features a white enamel dial with black Arabic numerals and blued steel hands. It is powered by a manual-wind Longines calibre 19.70N gilt mechanical movement with 16 jewels.

Movement view showing Longines calibre 19.70N with serial number 6686016
Movement view showing Longines calibre 19.70N with serial number 6686016 — Vintage Watch Specialist. Rights pending — permission not yet requested. Original source

Catalogue identity

Source
vintagewatchspecialist.com
Category
Pocket watch · Deck watch
Maker / attribution
Longines
Reference
Not recorded
Catalogue / lot identifier
vws1671
Source-reported date
1940s (Approx)
Country
Switzerland
Source-reported serial
6686016

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

Identity and Military Specification

The item is described as a Longines deck watch. The seller states the piece is marked for the British Royal Navy Hydrographic Service, bearing the 'H.S.3' code and the British Government Broad Arrow on the caseback.

The source describes the 'H.S.3' code as a designation used by the Royal Navy between 1939 and 1946 to indicate a deck watch adjusted for isochronism and performance in at least two positions.

Evidence for this section
  • “A Longines Royal Navy Hydrographic Service marked, HS /I\ 3, Deck Watch”
  • “The caseback has the British Government Broad Arrow on it, together with 'H.S.3' - Hydrographic Service code H.S.3 which was used by the Royal Navy between 1939-1946 to denote a deck watch that had been adjusted for isochronism and in at least two different positions.”

Mechanism and Construction

The watch utilizes a manual-wind Longines calibre 19.70N movement. The movement bridge is engraved with 'LONGINES SWISS MADE 16 JEWELS 6686016', with the calibre designation stamped on the plate near the balance wheel.

The movement features a screw-compensated balance wheel, index regulator, and blued screws. The watch is housed in a 52 mm nickel-chrome plated case with a screw-in bezel and screw-down caseback.

Evidence for this section
  • “Longines caliber 19.70N dating from around 1940s.”
  • “Gilt movement bridge is engraved 'LONGINES SWISS MADE 16 JEWELS 6686016'.”
  • “The case has a screw in bezel, and screw-down case back”

Dial and External Observations

The watch features a white enamel dial with black Arabic numerals and an outer track calibrated to half-second increments. It is fitted with blued steel leaf and sword hands.

The nickel-chrome plated outer case rim displays fine surface wear, consistent with the seller's report of age.

Evidence for this section
  • “The stark white enamel dial is signed Longines”
  • “The absolutely beautiful blued steel leaf and sword hands”
  • “Nickel-chrome plated outer case rim displays fine surface wear.”

Open research questions

  • Can the serial number 6686016 be verified against manufacturer production records to determine the date of manufacture?
  • Does independent archival evidence confirm that 'H.S.3' markings on Longines deck watches strictly correlate with the reported adjustment standards?

Source evidence

Recorded claims and source quotations for Longines Royal Navy Hydrographic Service H.S.3 Deck Watch
FieldSource-reported valueSource quotation
Calibre19.70N“Longines caliber 19.70N dating from around 1940s.”
Military MarkingsHS /I\ 3“Longines Royal Navy Hydrographic Service marked, HS /I\ 3, Deck Watch”
Case MaterialNickel Chrome“Case Nickel Chrome”
DialWhite Enamel“Dial White Enamel”
Jewel Count16“Jewels 16”
Case Width52mm“Width 52mm”
Inside Caseback InscriptionLongines 22684 160“The inside caseback reads 'Longines 22684 160'.”

Visible details

  • Gilt movement bridge is engraved 'LONGINES SWISS MADE 16 JEWELS 6686016'.
  • Calibre designation '19.70N' is stamped on the plate adjacent to the balance wheel.
  • Movement features a screw-compensated balance wheel, index regulator, and blued screws.
  • Nickel-chrome plated outer case rim displays fine surface wear.

Research qualifications

  • Case exterior markings, military broad arrow, and inner caseback inscriptions described in the source are not visible in the movement photograph.
  • Dial condition and configuration cannot be verified from the single provided movement photograph.

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

Consulted source

Longines - A Royal Navy Hydrographic Service Deck Watch - With Militar – Vintage Watch Specialist

Reviewed 2026-10-22 · Record 15a54cdcce

Terms in this record

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

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