A ship’s chronometer is a precision timepiece designed for use aboard a ship to enable the accurate determination of longitude at sea. It is accurate to within a few seconds per day and was essential for navigation during the Age of Sail. Ship’s chronometers are usually highly complex mechanical timepieces made of brass, steel, and gold, often with several hands and dials. They are usually constructed with a spring-driven movement, a balance wheel, and a mainspring. The movement of the chronometer is regulated by a pendulum and maintained in a temperature-controlled environment. Ship’s chronometers are also equipped with a number of additional features such as a removable winder and a ratchet wheel, which allow the chronometer to be adjusted while at sea.
