917. Historical.-The earlier turret designs in the U. S. Navy were two-gun turrets with what is known as a single-stage hoist. That is, the powder and shell were taken from the magazines and shell rooms and placed in an open car for each gun, which
was hoisted to the breech of the gun, traveling up and down in an open well. The guns were loaded, using rammers fixed in the rear of the turret so that the guns had to be brought to the horizontal position to be loaded.
When modern target practice was introduced in the Navy, about 1903, there occurred several very serious turret accidents, due to this open type of construction; and all turrets were modified by fitting them with automatic shutters, to seal the handling room from the turret chamber, except at the instant the car was passing the shutter. This was not entirely satisfactory, and new designs were made on the two-stage hoist principle; that is, the powder and shell were brought up from the handling room to an intermediate compartment in one set of hoists, and there transferred to another set which carried them to the guns. This permitted the introduction of a more positive flame seal between the turret chamber and the magazines as this intermediate compartment was fitted with
interlocks which did not permit doors to be open at the same time to both turret and handling room. Variable loading positions were also provided by putting the rammer on an arm from the gun slide, thus permitting the gun to be loaded at any angle of elevation.
In an effort to secure an increased rate of fire and increased reliability of turret gear, many turrets were converted to "hand loading." The ammunition cars were removed and tube hoists, power-whip operated, were installed for hoisting shell. The powder
was passed up by hand by men standing on fixed platforms at different levels. The telescopic rammers then in use were taken out and hand rammers used Hand loading required larger turret crews and required a larger amount of strenuous work by these crews.
918. Modern types.-Modern target practice created the demand for, and the Bureau of Ordnance designed, manufactured, and installed much faster and more reliable turret machinery that displaced hand loading for turret guns. All powder cars now in use are of the flameproof type. The pusher type of shell hoist has practically displaced the whip type. The chain type of rammer has displaced the telescopic type. Turret machinery is, in general, both fast and rugged. In the development of turret powder hoists, the maximum number of flame-proof Compartments, fitted with interlocking flame seals, compatible with an adequate ammunition supply have been installed between the magazines and the guns.
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