/jp/ - Otaku Culture

>>21164961
>Concentration Dial or Range Clock - In many ship photographs taken between about 1916 and 1940, there are what appear to be large clocks on the front and rear superstructures or masts. These are actually devices to tell the other ships in the formation at what range that ship is firing at. Together with Declination Marks (see below), these mechanisms allowed the other ships in the formation, whose view of the target may be obscured by fog, gun smoke or funnel smoke, to have their guns at the proper elevation and bearing when their view becomes unobstructed. This greatly reduced the time needed before they were ready to fire. The introduction of radar and better ship-to-ship communication methods in the late 1930s eliminated the need for these devices and they were removed from most ships by the start of World War II or shortly thereafter. For the concentration dial shown here, the small hand represents the range in thousands of yards, with 0 = 10,000 yards and 9 = 19,000 yards. The big hand represents range in hundreds of yards.
>Declination Marks - Scales painted on a turret to indicate to other ships in the formation the direction in which the turret is pointing. See photograph of HMS Emperor of India at right. See "Concentration Dial" above.
From navweaps