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The Encyclopedia of Horology

Marine chronometer · Two-day marine chronometer

Hamilton Model 21 Two-Day Marine Chronometer No. 675

Partially verified

This Hamilton Model 21 two-day marine chronometer, numbered 675 and dated circa 1941, was produced in Lancaster, Pennsylvania. It features a 4-inch silvered dial displaying Arabic numerals, an up-and-down state-of-wind indicator below 12 o'clock, and a subsidiary seconds dial above 6 o'clock inscribed with the maker and serial markings. The instrument is mounted in a gimbaled brass bowl within a three-tier brass-bound wooden box equipped with external carrying handles. Its full-plate nickel-damascened movement is catalogued as having 14 jewels, a chain fusee with maintaining power, an uncut steel balance, a helical hairspring, and a spring detent escapement.

Top-down view of the Hamilton Model 21 marine chronometer inside its open brass-bound wooden box
Top-down view of the Hamilton Model 21 marine chronometer inside its open brass-bound wooden box — Bonhams Skinner. Rights pending — permission not yet requested. Original source

Catalogue identity

Source
www.bidsquare.com
Category
Marine chronometer · Two-day marine chronometer
Maker / attribution
Hamilton Watch Co.
Reference
Model 21
Catalogue / lot identifier
173
Source-reported date
c. 1941
Country
United States
Source-reported serial
N 675

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 catalog records a 4-inch silvered dial with Arabic numerals, marked "Hamilton Lancaster, PA., U.S.A./N 675/1941,". The production location is stated by the auctioneer as Lancaster, Pennsylvania, dated circa 1941.

Visible observation shows a state-of-wind indicator positioned below 12 o'clock and a subsidiary seconds subdial above 6 o'clock containing the maker and serial markings.

Evidence for this section
  • “4-in. silvered arabic numeral dial marked "Hamilton Lancaster, PA., U.S.A./N 675/1941,"”
  • “Lancaster, Pennsylvania, c. 1941”

Reported Movement and Internal Mechanics

The movement is not depicted uncased in the listing photograph, so internal specifications rely on the auctioneer's cataloguing. The text describes a full-plate nickel-damascened movement marked in part "Hamilton Watch Co. Lancaster, Penna. Model 21, 14 Jewels/N675-1941,".

Additional catalogued movement details include 14 jewels, a chain fusee with maintaining power, an uncut steel balance, a helical hairspring, and a spring detent escapement. Operationally, the cataloguer notes that the chronometer "ticks but does not stay running".

Evidence for this section
  • “full plate nickel damascened movement marked in part "Hamilton Watch Co. Lancaster, Penna. Model 21, 14 Jewels/N675-1941,"”
  • “chain fusee with maintaining power, uncut steel balance, helical hairspring, spring detent escapement”
  • “ticks but does not stay running”

Casing and Condition Observations

The instrument is mounted in a fully gimbaled brass bowl featuring a screw bezel and is housed in a three-tier brass-bound box with carrying handles. Observations note gimbal locking and winding hardware situated in the corner and surrounding woodwork.

Regarding physical condition, direct observation confirms a crack running across the glass bezel above the 8 and 9 o'clock positions, aligning with the cataloguer's note "glass cracked". The auctioneer also states that the "gimbal and brass bezel has lacquer loss and discolorization". Mounted to the interior of the upper lid are an instructional or inspection label and a plaque marked "HAMILTON WATCH CO.".

Evidence for this section
  • “fully gimbaled brass bowl with screw bezel, in a three-tier brass-bound box with carrying handles.”
  • “A visible crack runs across the glass bezel above the 8 and 9 o'clock positions.”
  • “gimbal and brass bezel has lacquer loss and discolorization.”

Open research questions

  • What specific text and operational instructions are printed on the label inside the upper box lid?
  • Does Hamilton Watch Co. factory ledger or U.S. Navy procurement documentation verify the original delivery recipient of serial N 675 in 1941?
  • What internal wear, gummed lubrication, or mechanical damage causes the movement to stop running after ticking?

Source evidence

Recorded claims and source quotations for Hamilton Model 21 Two-Day Marine Chronometer No. 675
FieldSource-reported valueSource quotation
Dial inscriptionHamilton Lancaster, PA., U.S.A./N 675/1941“marked "Hamilton Lancaster, PA., U.S.A./N 675/1941,"”
Movement inscriptionHamilton Watch Co. Lancaster, Penna. Model 21, 14 Jewels/N675-1941“full plate nickel damascened movement marked in part "Hamilton Watch Co. Lancaster, Penna. Model 21, 14 Jewels/N675-1941,"”
Dial diameter4 inches“4-in. silvered arabic numeral dial”
Escapement and balanceSpring detent escapement with uncut steel balance and helical hairspring“uncut steel balance, helical hairspring, spring detent escapement”
CasingFully gimbaled brass bowl in a three-tier brass-bound box with carrying handles“fully gimbaled brass bowl with screw bezel, in a three-tier brass-bound box with carrying handles”
Movement drive mechanismChain fusee with maintaining power“chain fusee with maintaining power”
Bezel constructionScrew bezel“screw bezel”

Visible details

  • A visible crack runs across the glass bezel above the 8 and 9 o'clock positions.
  • The interior upper lid features an inspection or instructional label and a brass plaque reading 'HAMILTON WATCH CO.'
  • Gimbal locking and winding hardware are mounted in the wooden deck box corner and surround.

Research qualifications

  • The movement is not pictured outside the gimbal bowl, relying on auction cataloguing for escapement and train details.
  • The cataloguer notes the glass is cracked and the chronometer ticks but does not stay running.

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

Consulted source

Hamilton Model 21 Two-day Marine Chronometer No. 675 sold at auction on 12th April | Bidsquare

Reviewed 2026-10-21 · Record 1ceb6b57a0

Terms in this record

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

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