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The Encyclopedia of Horology

Marine chronometer · Two-day marine chronometer

Hamilton Model 21 Two-Day Marine Chronometer

Partially verified

This Hamilton Watch Company Model 21 two-day marine chronometer is housed in a brass-bound mahogany three-tier gimbaled box with reinforced brass corners, side drop carrying handles, and a glazed viewing lid. The silvered dial features Arabic numeral hour markers, an up/down power reserve register at 12 o'clock, and a subsidiary seconds dial. Source reports indicate the dial is signed Hamilton, Lancaster, Pa., U.S.A., bearing serial number N2738 and dated 1941. The chronometer is reported to contain a 14-jewel chain fusee movement and retains a winding key.

Hamilton Model 21 two-day marine chronometer mounted in its gimbaled brass-bound mahogany case
Hamilton Model 21 two-day marine chronometer mounted in its gimbaled brass-bound mahogany case — Hill Auction Gallery. Rights pending — permission not yet requested. Original source

Catalogue identity

Source
www.invaluable.com
Category
Marine chronometer · Two-day marine chronometer
Maker / attribution
Hamilton Watch Company
Reference
Model 21
Catalogue / lot identifier
30
Source-reported date
1941
Country
United States
Source-reported serial
N2738

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

Dial and Identity Markings

The instrument is reported to feature a silvered dial displaying Arabic numerals, an up/down power reserve indicator at 12 o'clock, and a subsidiary seconds dial. According to the auction catalogue, the dial is signed 'Hamilton, Lancaster, Pa., U.S.A.' alongside the serial number N2738 and dated 1941.

External markings noted in the lot description state that 'the front of the case bears the original Hamilton Watch Company brass nameplate.' Direct visual observation records that a brass key is inserted in the lower front lock escutcheon of the wooden case.

Evidence for this section
  • “The silvered dial features Arabic numerals, an up/down power reserve indicator at 12 o'clock, subsidiary seconds dial, and is signed Hamilton, Lancaster, Pa., U.S.A., with serial number N2738 and date 1941.”
  • “The front of the case bears the original Hamilton Watch Company brass nameplate”
  • “A brass key is inserted in the lower front lock escutcheon.”

Case Construction and Gimbal Mounting

Visual observation confirms that the chronometer is gimbal-mounted in a brass bowl and ring within a brass-reinforced wooden case. The case features a folding brass carrying handle mounted to its side, and the open upper lid retains a rectangular glazed viewing panel and an interior brass latch plate.

The source describes the housing as a 'brass-bound mahogany three-tier gimbaled case with brass corner mounts, inset brass carrying handles, locking lid, and glazed viewing panel.' Recorded dimensions for the case are 7.25 by 7.5 by 7.5 inches.

Evidence for this section
  • “The chronometer is gimbal-mounted in a brass bowl and ring within a brass-reinforced wooden case.”
  • “A folding brass carrying handle is mounted to the side of the wooden case.”
  • “The open upper lid retains a rectangular glazed viewing panel and an interior brass latch plate.”
  • “Dimensions: 7.25 X 7.5 X 7.5 in.”

Movement Specifications and Reported Condition

The source description states that the instrument 'features a precision 14-jewel chain fusee movement and was produced for marine navigation and military service during World War II.' The chronometer is also noted as retaining its winding key.

Because the mechanism is housed inside the gimbaled bowl, the internal movement components are not visible in the photograph. The auction catalogue characterizes the lot as being in 'good overall condition with typical age-related surface wear' and explicitly notes that the 'movement has not been tested for accuracy.'

Evidence for this section
  • “Features a precision 14-jewel chain fusee movement and was produced for marine navigation and military service during World War II.”
  • “Good overall condition with typical age-related surface wear.”
  • “Movement has not been tested for accuracy.”

Open research questions

  • Does the pillar plate or balance bridge of the movement bear serial number N2738 matching the dial?
  • Does the reverse of the brass gimbal bowl or the wooden box display any US Navy or Bureau of Ships contract markings?
  • Does the movement retain its original chain and helical balance spring configuration?

Source evidence

Recorded claims and source quotations for Hamilton Model 21 Two-Day Marine Chronometer
FieldSource-reported valueSource quotation
ModelModel 21“Hamilton Watch Company Model 21 two-day marine chronometer”
Serial NumberN2738“with serial number N2738”
Date1941“date 1941”
Jewels14 jewels“Features a precision 14-jewel chain fusee movement”
Dimensions7.25 X 7.5 X 7.5 in.“Dimensions: 7.25 X 7.5 X 7.5 in.”
Dial SignatureHamilton, Lancaster, Pa., U.S.A.“signed Hamilton, Lancaster, Pa., U.S.A.”
AccessoryWinding key“the chronometer retains its winding key”

Visible details

  • The chronometer is gimbal-mounted in a brass bowl and ring within a brass-reinforced wooden case.
  • A brass key is inserted in the lower front lock escutcheon.
  • A folding brass carrying handle is mounted to the side of the wooden case.
  • The open upper lid retains a rectangular glazed viewing panel and an interior brass latch plate.

Research qualifications

  • The internal 14-jewel chain fusee movement is not visible in the photograph.
  • Source reports the movement has not been tested for operational accuracy.

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

Consulted source

Sold at Auction: Hamilton 20C Model 21 Two-Day Marine Chronometer

Reviewed 2026-10-21 · Record e6f88d3a62

Terms in this record

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

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