This watch

This Hamilton pocket watch really is very special, featuring a black 24-hour dial and the marking G.C.T., is a specific type of high-grade military navigation watch, dating to the 1940s. due to its specialized features. It is a prized collector's piece that reflects Hamilton's critical role in American military history. a variation of the military issue Master Navigation Watch with the Hamilton Grade 4992B movement, a 22-jewel version of their railroad movement. G.C.T.  Stands for Greenwich Civil Time. This was the military time standard used for navigational purposes and the master reference time for the U.S. military from 1924 to 1952.
 A 24-Hour Dial The dial is configured for 24-hour time (military time), with the hour hand completing only one full rotation per day. This aids in reading time without ambiguity for navigation.
The dial is matte black with white numerals and hands, designed for maximum visibility and contrast in poor light conditions, such as inside an aircraft cockpit.

Extra Points

The Hamilton Watch Company was established in 1892 in Lancaster, Pennsylvania.Hamilton quickly developed a reputation for creating pocket watches of the highest quality and accuracy, exceeding the stringent requirements for "railroad grade" timepieces. They manufactured the "Watch of Railroad Accuracy" and maintained a majority of the railroad watch market.

During World War I and especially World War II, Hamilton retooled its operations to exclusively serve the military, supplying over one million watches. This shift solidified their reputation for precision in military applications, including marine chronometers for the U.S. Navy.

The G.C.T. Navigation Watch
High Jeweled (22 Jewels)    The high jewel count (22 jewels in the typical movement for this model) signifies a high-grade, highly precise movement that was adjusted for multiple positions and temperature. Accuracy was critical for the navigational function.
Sweep Seconds    The watch features a large central seconds hand that sweeps across the whole dial, rather than a small subsidiary seconds dial. This, combined with the hacking function (the ability to stop the seconds hand by pulling the crown), was essential for synchronizing time among flight crews down to the second.
This pocket watch was a key instrument for the navigators on U.S. Bomber aircraft (like the B-17s) during World War II. It was used as the master time indicator, earning its movement the nickname, "the watch that won the war".

 

What We Think

This exceptional piece is a genuine 1940s Hamilton U.S. Air Force Navigator's pocket watch, a testament to American watchmaking excellence during a critical era. Commissioned specifically for military aviators, this watch features the legendary Hamilton Caliber 4992B movement. With its 22 jewels, high-grade finish, and precise adjustment for Temperature and 6 Positions, this mechanism was built for reliable accuracy in the demanding environment of airborne navigation. The unmistakable black 24-hour G.C.T. (Greenwich Civil Time) dial is a classic design chosen for rapid, error-free reading, a vital feature for the pilot or navigator relying on celestial navigation. Owning this watch means holding a significant piece of horological and military history—a tool trusted by those who flew the missions that shaped the world.

Spec Stuff