Hamilton Model 23 Chronograph

Discussion in 'Chronometers' started by Dano4734, Jan 5, 2013.

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  1. Dano4734

    Dano4734 Registered User

    My latest ... were these used as navigational watches in WWII or am I thinking on of the other Hamilton's. Just had a full Coa done on it. Watch is mint, I have some reflection on my photo's
    Serial number is P14144 I think 1942 is the year?
     

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  2. Jim Haney

    Jim Haney Registered User
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    Sep 21, 2002
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    Dan,
    Just read the similiar threads at the bottom for all the info you can digest on the Model 23.

    You have a super nice complicated watch.
     
  3. grtnev

    grtnev Registered User
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    Jan 18, 2009
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    Dan,

    A very nice acquisition indeed.

    In addition to Jim's comments, here are a few "cliff notes" from various sources that I collated into a couple of paragraphs when I picked up a Model 23 a couple of years ago.

    Richard

    "The Hamilton Model 23 Chronometer was used by all branches of the armed forces but predominantly used by the Air Force during WWII and into the 1950's Korean conflict. The Model 23 Chronometer had several uses.
    · It could be used as a traditional "Ground Speed watch" which would help the Air Force navigators correctly determine the ground speed while in flight. This is important for so many reasons such as properly determining where you are for navigation, safe drop speeds for paratroopers, fuel consumption and obtaining correct speed for bomb drop trajectory.
    · It could also have been used for artillery drills and on U.S. Naval vessels and submarines or any other circumstance where an accurate timeframe was needed to be measured.


    However, the Model 23 was most often used It was also used by the US Army Air Force during WW II in conjunction with the Mark III, Model 5 Octant or Pioneer (BendiX Aviation Corp) A-5 or A-7 sextant for navigational purposes while in flight over water where landmarks were not available.

    A sextant or octant was used to measure the “altitude” of a celestial body above a horizontal line of reference. (“Altitude” in this case is a special use of the word describing an angular measure, not a distance in feet above sea level.) A mariner can use the horizon as this line of reference, but when an airplane is flying above the clouds or flying at night, its navigator can’t see the horizon. The bubble sextant or octant solves this problem by providing an artificial horizon. It takes its name from an air bubble in a liquid-filled chamber that functions like a carpenter’s level, indicating when the sextant or octant is aligned horizontally.

    The navigator would look through the eyepiece of his sextant or octant and locate a star. With a drum on the side of the instrument (like a camera’s focus ring), he would adjust the angle of a rotatable prism until the star showing in the eyepiece is aligned beside the bubble. The prism and drum are geared to circular scales, marked off in degrees. From these scales he could read the star’s “altitude”.

    But just as importantly as knowing a reference star’s “altitude” the navigator had to know the exact time that the reading was taken. To do this, before taking the “altitude” reading, the navigator would start the Model 23 at some specific time, say 12:34:00 GCT. Once he had the star aligned beside the bubble in the sextant or octant, he would depress the pendant and stop the sweep hand and record the time of his observation along with the “altitude” reading from the circular scales. Since it was difficult to take a reading on a bouncing airplane, several reading of the same reference star were taken and averaged. To obtain a “fix” usually required observations of three different stars."
     

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  4. Dano4734

    Dano4734 Registered User

    Wow thanks so much I am excited to get it for sure. Thanks for pointing me to some great info
     
  5. Dano4734

    Dano4734 Registered User

    My watch maker friend lives for these, he said he loves working on them ... it is just so accurate ...I am thrilled
     
  6. Dano4734

    Dano4734 Registered User

    So I have to tell you this story. I could never afford one of these but wanted one for quite a while. My watchmaker went to an estate auction and found it . He paid 350 for it after checking it out. Took it back to his shop, did a full COA ... and sold it to me for 350. How nice is that.
     
  7. grtnev

    grtnev Registered User
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    Dano,

    Pretty neat deal to say the least - your watchmaker is a very good friend indeed.

    Richard
     

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