World War Two Hamilton Model 21 Two Day Marine Chronometer in Original Case

A World War Two period Hamilton Model 21 Two Day Marine Chronometer in original mahogany case.

This super example of an American made chronometer has a silvered dial engraved with “Hamilton Lancaster. PA. USA”, the serial number “N4149” and the date of 1941. It has two further dials for minutes and state of wind.

The movement is housed within a gimbal inside a three tier mahogany case. The top lid reveals a glass plate which was used for general observation of the chronometer whilst keeping the movement safe, the second lid for undertaking winding. The inside lid bears its original label providing information relating to the safe transport methods for the chronometer. It reads, “Cork as shown before shipping (with diagram). See Ship’s chronometer record book (form NBS 702) Transportation Paragraph 2”. The exterior of the case has a brass drop handle mounted to either side and two brass slide catches for opening the lids. It has a further label stating, “Hamilton Watch Co, Lancaster PA. USA”.

The Hamilton Watch Company were invited by the US Naval Laboratory in 1939 to create an American made marine chronometer. The US Government was plagued by shortages throughout the First World War and had to rely solely on European made instruments. Hamilton agreed in 1941 to undertake the work and thirteen weeks after Pearl Harbour in February 1942, the company delivered two prototypes for review to the Naval Observatory. The Model 21 was warmly received by those who observed its accuracy and ingenuity which was improved in a number of areas from its European counterparts. Even more effective, the Hamilton chronometers were capable of being manufactured using assembly line techniques and were therefore quicker and easier to produce in numbers. Within eighteen months, Hamilton had produced 400 chronometers for the war effort and production rose sharply to around 500 pieces a month by 1944, they had delivered 10,902 chronometers by the end of the war. Production continued after the war until 1970 when a final total of 13,984 Model 21 chronometers were manufactured.

This model with an early serial number 4149 confirms that this is a wartime version of Hamilton’s famous chronometer and given the above is likely to have been manufactured in late 1943 to early 1944. A fine instrument with some great historical interest.