Special Features:

Item is transparent and has a knob for handling

Properties:

An item generally constructed on a transparent plastic material. It embodies a standard inch scale, an inner and/or outer statue mile scale, a vertical statue mile scale, and may also include a nautical mile scale. The semicircular protractor portion may be offset or inset in forming a part of the item. It is designed to be used in plotting courses, measuring distances between two points on a chart or map, establishing meridians of references, solving wind angles, and determining bearing positions.