Master Gunner, Coast Artillery (670) Enlisted Personnel

Performs such duties as surveying, mapping, drafting, orientation, gunnery, and photography in a fixed seacoast defense area or in a mobile unit.
Plans, supervises, and executes field survey operations, using surveyor's instruments to locate gun positions, observation stations, and similar points by transit traverse or other survey methods. Measures base line between base end stations by running a line of levels to a point of known elevation and making necessary computations to obtain accurate horizontal distance between stations. Determines azimuth of base line by running a transit traverse. Checks directions by making solar or stellar observations, and computes direction by astronomical methods. Computes distances and directions from coordinates after they have been accurately established. Converts grid coordinates into geographical coordinates and vice versa. Prepares charts, maps, and tables. Makes sketches and detailed drawings, blueprints, and tracings of buildings, machine parts, or devices. Places local plane grids, standard military grids, and geographic grids on maps. Keeps post map and battery emplacement books current. Prepares charts and scales for all correction devices used for coast artillery fire control. Sets up and operates a meteorological station for fixed and mobile units to obtain wind velocity, direction, and temperature in order to compute correction factors for nonstandard weather conditions to be used in firing. Takes photographs during target practice. Develops and marks films to show deviation of bursts from target. Operates photo-laboratory, using ordinary darkroom procedures.
Must have good mathematical background and be able to solve computations involving plane and spherical trigonometry. Must be able to use slide rule and use such tables as logarithm, grid, firing, meteorological, surveying, ephemerides, and tables pertaining to projection of maps.