Marine chronometer · Chronometer deck watch

Johannsen of London Admiralty Pattern Chronometer Deck Watch

Partially verified

This Admiralty pattern chronometer deck watch is documented by dealer FJ & RD Story Antique Clocks as manufactured circa 1916 by Asmus Johannsen & Co, 149 Minories, London, numbered 8064 and retailed by Lawrence & Mayo. Fitted in a brass carrier inside a mahogany transport box, the instrument features an enamel dial with Roman hour numerals, blued steel spade hands, and sweep centre seconds with outer fifth-of-a-second track markings. The dealer describes a top-wind, three-quarter plate English lever movement with a free-sprung bimetallic balance and an accompanying 1927 rating certificate.

Dial view of the Johannsen & Co Admiralty Pattern chronometer deck watch in fitted brass plate — FJ & RD Story Antique Clocks / Sellingantiques.co.uk. Rights pending — permission not yet requested. Original source

Catalogue identity

Source: www.sellingantiques.co.uk
Category: Marine chronometer · Chronometer deck watch
Maker / attribution: Asmus Johannsen & Co
Reference: Deck/24
Catalogue / lot identifier: SA1039362
Source-reported date: circa 1916
Country: United Kingdom
Source-reported serial: 8064

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 Visual Presentation

The deck watch displays a white enamel dial with black Roman hour numerals, an outer chapter ring calibrated to fifths of a second, and Arabic five-minute numerals from 5 to 60. The time is indicated by blued steel spade hour and minute hands accompanied by a sweep centre seconds hand with a counterpoise. Direct visual observation records the dial signature as 'A. JOHANNSEN & CO 149 MINORIES LONDON 8064'.

Although the dealer's text opens by referring to a '24 hour Admiralty Pattern Chronometer Deck watch', the visual dial layout displays a standard 12-hour Roman numeral track. The watch is positioned within a circular bezel set into a shaped brass mounting plate, with a fluted winding crown situated at 12 o'clock, housed within a wooden outer box.

Evidence for this section

“White enamel dial signed 'A. JOHANNSEN & CO 149 MINORIES LONDON 8064'”
“Blued steel spade hour and minute hands accompanied by a fine sweep centre seconds hand with counterpoise”
“24 hour Admiralty Pattern Chronometer Deck watch”
“Fluted winding crown located at 12 o'clock above a shaped brass mounting plate”

Casing and Housing Details

The instrument is housed in a two-tier mahogany display box with physical dimensions listed as 5 cm in height, 9.5 cm in width, and 12 cm in depth. The seller states that the watch itself is 'Cased in a polished round, screw down back stamped 8064' and sits in a 'fitted brass carrier numbered 8064, and is topped with a protective window with screwed-in bezel.'

The upper lid of the wooden case is documented as featuring an inset ivory name plaque signed 'for the retailer Lawrence and Mayo, London 8064 - Admiralty Pattern chronometer watch.' The listing provides a UK Ivory Act 2018 Exemption Submission Reference of 163KFG19.

Evidence for this section

“Height 5cm (1.97") Width 9.5cm (3.74") Depth 12cm (4.72")”
“Cased in a polished round, screw down back stamped 8064.”
“The chronometer watch rests in a fitted brass carrier numbered 8064, and is topped with a protective window with screwed-in bezel.”
“The fine quality mahogany two-tier display box, with ivory name plaque inset into the top lid, signed for the retailer Lawrence and Mayo, London 8064 - Admiralty Pattern chronometer watch.”
“UK Ivory Act 2018 Exemption Submission Reference - 163KFG19”

Reported Movement and Rating Documentation

The internal mechanism is not visible in the provided photograph, and all movement specifications represent seller-reported claims. The dealer reports a 'three quarter plate English lever movement having tangential club toothed lever escapement with steel escape wheel' driven by a top-wind spring. The balance assembly is described as an 'Overcoiled free sprung bimetallic balance with gold compensation and quarter screws', signed 'Asmus Johannsen, 149 Minories, London' and numbered 8064.

The seller also notes that the instrument is 'Accompanied by a rating certificate dating 21st July 1927 from the Kom El Nadora Observatory, Alexandria, Egypt. Rated to Egyptian meantime.' While the seller dates the piece to 'circa 1916' (and the dealer declaration cites the '1910s'), these dates remain unverified claims from the listing.

Evidence for this section

“three quarter plate English lever movement having tangential club toothed lever escapement with steel escape wheel”
“Overcoiled free sprung bimetallic balance with gold compensation and quarter screws.”
“Signed Asmus Johannsen, 149 Minories, London and numbered 8064.”
“Accompanied by a rating certificate dating 21st July 1927 from the Kom El Nadora Observatory, Alexandria, Egypt. Rated to Egyptian meantime.”
“circa 1916”
“FJ & RD Story Antique Clocks has dated this piece to the 1910s.”

Open research questions

Why does the seller description specify a '24 hour Admiralty Pattern' watch when the physical enamel dial features a standard 12-hour Roman numeral chapter ring?
Can physical inspection of the movement confirm the serial number 8064, three-quarter plate configuration, and free-sprung overcoil balance described by the seller?
Does the 1927 Kom El Nadora Observatory certificate specifically cite serial number 8064 and detail the Egyptian meantime rate?

Source evidence

Recorded claims and source quotations for Johannsen of London Admiralty Pattern Chronometer Deck Watch
Field	Source-reported value	Source quotation
Maker	Asmus Johannsen & Co	“Asmus Johannsen & Co, 149 Minories, London”
Serial number	8064	“numbered 8064”
Retailer	Lawrence & Mayo, London	“Retailed by Lawrence & Mayo, London.”
Date of manufacture	circa 1916	“circa 1916”
Movement escapement	English lever movement	“three quarter plate English lever movement having tangential club toothed lever escapement with steel escape wheel”
Dimensions	Height 5cm, Width 9.5cm, Depth 12cm	“Height 5cm (1.97") Width 9.5cm (3.74") Depth 12cm (4.72")”
Ivory Act exemption reference	163KFG19	“UK Ivory Act 2018 Exemption Submission Reference - 163KFG19”
Historical observatory rating	21st July 1927, Kom El Nadora Observatory, Alexandria, Egypt	“rating certificate dating 21st July 1927 from the Kom El Nadora Observatory, Alexandria, Egypt. Rated to Egyptian meantime.”
Dial diameter	45mm	“with a 45mm enamel dial”

Visible details

White enamel dial signed 'A. JOHANNSEN & CO 149 MINORIES LONDON 8064'
Blued steel spade hour and minute hands accompanied by a fine sweep centre seconds hand with counterpoise
Outer track calibrated to fifths of a second with Arabic five-minute numerals (5 to 60)
Fluted winding crown located at 12 o'clock above a shaped brass mounting plate
Mounted in a round metal bezel casing set within a wooden transport case

Research qualifications

Internal movement details and rating certificate are source-reported and not visible in the supplied single photograph
The source description mentions a '24 hour Admiralty Pattern' in the opening sentence, but the dial clearly displays a standard 12-hour Roman numeral track

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

Consulted source

Johannsen of London, Admirality Pattern Chronometer Deck Watch | Sellingantiques.co.uk

Reviewed 2026-10-21 · Record fe9aff817f

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