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For navigational purposes, the hack watch is synchronized with the ship's marine chronometer. The use of a hack watch makes it easier to take sights, as the chronometer is normally in a fixed position in a ship – below decks and suspended in gimbals to keep it level and protect it from the elements, while the hack watch is portable and can be ...
Hack watch and a marine chronometer Poljot Aviator caliber 3133 chronograph Founded in 1930 under orders from Joseph Stalin , the First State Watch Factory ( Russian : Первый Государственный Часовой Завод - 1ГЧЗ ) was the first large scale Soviet watch and mechanical movement manufacturer.
In typical use, the chronometer would be mounted in a sheltered location below decks to avoid damage and exposure to the elements. Mariners would use the chronometer to set a so-called hack watch, which would be carried on deck to make the astronomical observations. Though much less accurate (and less expensive) than the chronometer, the hack ...
Ships often carried more than one chronometer. Chronometers were kept on gimbals in a dry room near the center of the ship. They were used to set a hack watch for the actual sight, so that no chronometers were ever exposed to the wind and salt water on deck. Winding and comparing the chronometers was a crucial duty of the navigator.
A mechanical chronometer is a spring-driven escapement timekeeper, like a watch, but its parts are more massively built. Changes in the elasticity of the balance spring caused by variations in temperature are compensated for by devices built into it.
A boxed chronometer is mounted on gimbals attached to its box. A pocket chronometer is in the style of a pocketwatch. "Winding" refers to the number of days that a chronometer kept going before needing rewinding. However, they were all wound at precisely the same time every day, except for the eight-day chronometers which were wound weekly. [22]
Longitude by chronometer is a method, in navigation, of determining longitude using a marine chronometer, which was developed by John Harrison during the first half of the eighteenth century. It is an astronomical method of calculating the longitude at which a position line, drawn from a sight by sextant of any celestial body, crosses the ...
John Arnold (1736 – 11 August 1799) was an English watchmaker and inventor.. John Arnold was the first to design a watch that was both practical and accurate, and also brought the term "chronometer" into use in its modern sense, meaning a precision timekeeper.