Results 1 to 7 of 7

Thread: Ship's Chronometer Quartz of the USS Abraham Lincoln

  1. #1
    Member kfranzk's Avatar
    Join Date
    Feb 2007
    Location
    Dusseldorf/Germany
    Posts
    221

    Default Ship's Chronometer Quartz of the USS Abraham Lincoln

    Hallo friends,
    I just acquired an interesting military artefact. Nowadays I think the mechanical chronometers have all left the modern navy vessels to give place for the quartz controlled timekeepers. If these are not integrated in the bridge and navigation systems they are relativly simple boxes like this shown:
    Marathon Chronometer coming from the US Navy Aircraft Carrier CVN 72 Abraham Lincoln.
    The box is made of light plastik, the movement is a high quality Swiss quartz made by Imhof SA, a now gone La Chaud de Fonds manufacturer of high class table clocks. A clear readable white dial with centre second hand and military time indication, two 1,5V LR50 batteries fuel the clock.
    I must say I hate all the quartz clocks and watches in my collection giving me the never ending job to control the batteries, if you leave them for years the movement will stop unrepairable. If they are kept without power, at least the mechanical parts will be stuck by drying oil. I just had to change the movement 2250Q of my IWC Ocean 2000 BUND ref 3314. (And I have another Imhof clock I can't get working again. For this I had to get are rare replacement movement.)
    --
    . Gruesse/Regards/Salute Konrad Knirim
    PS: Have a look at my books on Military Timepieces:
    . http://www.knirim.de


  2. #2
    Senior Member lysander's Avatar
    Join Date
    Mar 2007
    Posts
    2,961

    Default

    The mechanical ship's clock was superceded by a quartz clock in 1975(ish).

    MIL-C-24523 covered quartz ship's chronometers. It has since been canceled without replacement, but seems to still be used as a basis for chronometers. That looks to conform the MIL-C-24532 in size, shape and display....

    Should be an NSN 6645-01-067-0780

    These cost the US Government around $1000 to $1100 new...quite a bargain ... and around 360 have been purchased so far.

    Oh, and if they kept the power supply requirements of the original specification, the clock should run for 2 to 3 minutes even after the batteries are removed, so you don't lose time during a battery change.
    Last edited by lysander; 07-23-2012 at 06:04.

  3. #3
    Member kfranzk's Avatar
    Join Date
    Feb 2007
    Location
    Dusseldorf/Germany
    Posts
    221

    Default

    Thanks Lysander for this additional info!
    Astonishing how expensive these supposed simple electronic clocks were in 1975! But the Imhof movement was really hightech.
    ==> Can anyone provide me with a scan of the original specs: MIL-C-24523?
    Would be great, thanks Konrad Knirim
    konrad.knirim@t-online.de

    sticker (Chris at chronometer.net)

  4. #4

    Default

    Quote Originally Posted by kfranzk View Post
    Thanks Lysander for this additional info!
    Astonishing how expensive these supposed simple electronic clocks were in 1975! But the Imhof movement was really hightech.
    ==> Can anyone provide me with a scan of the original specs: MIL-C-24523?
    Would be great, thanks Konrad Knirim
    konrad.knirim@t-online.de

    sticker (Chris at chronometer.net)
    A copy of the spec is on its way.

  5. #5
    Senior Member lysander's Avatar
    Join Date
    Mar 2007
    Posts
    2,961

    Default

    If you get it running the two terninals on the back should provide a make-break circuit every even second (except second 58).

    And an correction:

    There where two contracts to Marathon for MIL-C-24523 chronometers. One in 1987 (N00104-87-C-6527) for 1456 clocks and one in 2003 (SP0440-03-C-1042) for 358 clocks

  6. #6
    Member kfranzk's Avatar
    Join Date
    Feb 2007
    Location
    Dusseldorf/Germany
    Posts
    221

    Default

    Thanks Lysander and thanks to hq_sandman_ute for the milspecs,
    the two contacts are for the two LR50 batteries outside the brass movement case. So there are no switched contacts. Sorry!
    There must be changes to the MIL-C-24523 specs as they mention a black dial while mine and Chris's has a white dial and little changes on the box, or is there another milspec?
    Greetings Konrad Knirim

    See extract of MIL-C-24523 and the tag on Chris's chronometer:


  7. #7
    Senior Member lysander's Avatar
    Join Date
    Mar 2007
    Posts
    2,961

    Default

    According to the federal supply catalog, NSN 6645-01-067-0780 has a part number of MIL-C-24523, but that specification was cancelled in 1991 without replacement. So, that clock, made in 2003, is not, strictly speaking, made to any specification. And the procurement contract can modify the requirements...

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •