NSA4

Definition Surface Plotter

A device generally constructed of plastic material having a rotating center sheet between two fixed identical outer sheets. A black azimuth circle, with markings on the outside of the circle, is printed on each of the outer sheets, and a red azimuth circle, with markings inside the circle, is printed on each side of the rotating center sheet. The azimuth circles have radial lines placed ten degrees apart and ten concentric rings, with each concentric ring 0.5 inch (12.7 millimeters) greater than the preceding one. This device is arranged to provide true-relative and relative-type bearing conversion for simultaneous plotting of true and relative bearings and to perform the functions of a standard maneuvering board on each side, permitting two plots at different scales.