Superior Chelsea MK I Navy Deck Clock 1941

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Naval Observatory
Cartouche 1941

Chelsea MK I Deck clock on stand image


$75.00 VALUE

The WW II Chelsea MK I Deck Clock’s case was made
differently than the ubiquitous nickel plated Seth Thomas version. It is
more refined and far better looking in polished



Diameter of face 3
Deep 8″ Full Diameter Weight 10 lbs 6



is another outstanding example of a
Chelsea, back winding, Navy MK I Deck Clock
with a hinged front that is complete
with both backing plates making up 3 pieces. Originally, one plate acted as a water
tight cover and shock absorber and the other mounts it to a bulkead
or wall. It is unusual to get this clock with its
back cover plate and more so with the original mounting plate making this an even rarer

exception. The Chelsea version of what was supposed to be a
standardized mil-spec design is more refined and has a different
hinge arrangement than the thousands of nickel plated clocks that were
made by Seth Thomas. This clock is in polished brass with
a lacquer coating to preserve its luster. The movement, serial
number 286932 dates from 194. It is keeping good time compared to a
quartz comparison watch.



Navy MK I DECK clocks of WW
II were manufactured in accordance with

military specifications 18C-11 and 18C -13. This Chelsea example
has modifications which are unique. The front section holds the
movement and has an integral stud on the backing plate that acts
as the hinge. This compares to the more common Seth Thomas version
which uses a removable pin, and has a chrome plated case. In both
designs, the back of the front section has all the controls on the


Picture shows the three components of clock
Chelsea clock has an integral
stud on the mounting plate as
a hinge

plus shock
damper. 3 pieces total


Typical Seth Thomas MK I casting
uses a separate pin as a hinge


Both Andrew Demeter in his
definitive book, “Chelsea Clock Company,
the first 100 years
” and Marvin Whitney in his encyclopedic
work, “MILITARY TIMEPIECES” say that
these clocks were chromium plated up to 1941 when cases were
switched to Bakelite, a phenolic.





Movement of clock image
Movement of clock in pristine



A Mark I Deck clock made by Chelsea is a rare find, as is a
clock of this age and service at sea to be found with all its parts. It
is a great find for a collector of military pieces or as an important


the hand arbor is etched:



(NO) 9346

NO) represents the Naval Observatory which
means the clock not only met the military specifications, but also
met the stringent standards of this institution which maintains
the Nation’s Time Standard. At the bottom of the dial it is marked

The following
controls are accessed on the back:

  • Fast – Slow adjustment. To
    regulate turn towards S to Slow and vice versa
  • Stop – allows to precision
    setting with master clock
  • Set – moves hands
  • Wind – a key is included


MOVEMENT:It has a Chelsea Model 17K, 11
jewel 8 day movement that is wound, set and adjusted through a
slotted dust cover at its rear which closes. A separate start/stop
mechanism allows it to be synchronized with a master time

The removable vibration dampener
backing plate is attached to the bulkhead plate by six
screws and holds the front case secure by a wing nut

Three quarter view of image Opposing three quarter view of image

Opposing views of this
special MK I Deck


This example has seen about
73 years of service, much of it at sea, and has been
restored to “like new” condition. The face is in very
good condition without any faults. The irradium dots over the
numbers for night viewing have been removed because they were radio active.
The lens under most
light conditions shows clear, but has some faint masking. The
movement has been recently serviced and is keeping good time.
A Chelsea key is included. The case has been recently polished
and lacquered.

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The cost of shipping, packing, handling, and insurance to your destination, will be calculated point to point and is an additional charge. You may email us to get these costs. We price our shipping honestly, but we expect to be reimbursed for the nominal cost of packaging materials and handling.

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Celebrating 18 Years of Exellence in Nautical Antiques

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