Hamilton "Pilot's Watch"

[Tuttebenne]

A friend had what looked like a pocket watch on his bench but it had a very different dial. It has a black 24 hour military style dial with white hands and a sweep second hand, and he called it a Pilot's Watch. The exterior of the case back had some info about a contract number, serial number and the words "Hamilton Watch Company on it. On the dial, in the location where the manufacturer's name is usually found are the letters "GCT" What do the three letters stand for and can anyone supply any information on these watches?

Thanks,

Andy

[Tuttebenne]

A friend had what looked like a pocket watch on his bench but it had a very different dial. It has a black 24 hour military style dial with white hands and a sweep second hand, and he called it a Pilot's Watch. The exterior of the case back had some info about a contract number, serial number and the words "Hamilton Watch Company on it. On the dial, in the location where the manufacturer's name is usually found are the letters "GCT" What do the three letters stand for and can anyone supply any information on these watches?

Thanks,

Andy

[doug sinclair]

Andy,

That is a 4992B. Basically a 992B with a modified dial train to read a 24-hour day. It was also modified to accomodate the seconds hand, and it is equipped with a "hacking" feature which stops the watch in a hand setting position to allow for setting to the second. The GCT stands for Greenwich Civil Time. These watches were made both in steel cases, as well as sterling silver. Which one does your freind have?

According to Art Zimmerla, there were about 114,000 of these made, in total. Zimmerla notes that "The 4992B was the principal navigation watch used by the U S military during WWII." I would think it might have had some use by Air Force navigators, although I'd have thought a wrist chronograph might have suited them better.

[Tuttebenne]

Doug,

The owner's Dad was the WWII pilot. I thought the same as you - why not a wrist chrono? The case appears to be steel but I will look closer the next time I see him. Thanks for the information; I will pass this on to the owner.

I am looking forward to when we can post photos on the site because I had a couple of this particular watch to share.

Andy

[Don Dahlberg]

As of Dec 31, 1957 the official production of the 4992B was 119,739, but it was still in production at this time. There were 2,394 of the 12 hour 3992B models produced terminating in 1945.

During WWII there were 2000 produced for the British Navy, 312 for the Canadian Navy, 73,285 for the US Army (mostly for the Army Air Force) and 21,521 for the US Navy. These numbers do not distinguish between the 4992B and the 3992B.

The Navy prefered the silver cases, my records show all of the silver cases as well as some base metal cases going to them.

It was called a Master Navigational Watch. The intended purpose was for celestial navigation, which required accuracy within a couple of seconds per day. Even the civilian airlines purchased them during and after the war.

Take a look at the metal case used in the later years to shield the watch from vibration and magnetic and electrical fields. http://www.chronometer.net/nav.htm

The Navy often used a wooden box for use on boats. See http://www.shipsclock.com/ProductCatalog/PCDetail.htm

Don

Don