Ship clock

The featured clock was manufactured by the German state-owned VEB Glashütter Uhrenbetriebe (GUB). The company traces its origins to Ferdinand Adolph Lange (1815-1875), who not only established the first clock manufacture but also a school of watchmaking in Glashütte in 1845 and encouraged the professionals he trained to establish their own businesses and through these efforts made the then economically depressed town into a well-known Saxon watchmaking centre. Today, the factory operates as a partnership under the name Glashütter Uhrenbetrieb as part of Swach Group SA, selling its luxury products under the Glashütte ORIGINAL brand. Ship clocks, also known as chronometers, were used to govern shipboard life, but were primarily used in navigation. Hence, they had to be impervious to temperature changes, and their airtight fitting was designed to protect them from moisture. They were mainly placed in the chart cabin, on the platform, wheelhouse or later in the engine room and on piers. They have now been superseded by electronic clocks and satellite navigation. The first clock with a measurement error of fewer than two minutes, which in navigation corresponds to half a degree of longitude, was built in 1759 by John Harrison (1693-1776), a carpenter and self-taught watchmaker. His H-4 chronometer weighed almost one and a half kilograms. With fluctuations of one second per month, it was a very accurate method of measuring longitude at sea. From November 1761 to January 1762, Harrison's invention participated in tests of measurement accuracy on board the British navy sailing ship HMS Deptford sailing from Portsmouth to Kingston, Jamaica. After 81 days of measurements in various atmospheric conditions, its fluctuation was only 5 seconds. Leszek Kocela