Or something that is bigger than the hole in the tool.Īdditional techniques for plotting a bearing. If your string is too short to make a loop, tie the end to a small twig, a button, Some folks like red thread, others prefer black, and some want a loop of thin elastic cord. Sewing kit, a thread from the core of a piece of para-cord, dental floss. Some field expedient string sources include, thread from a Line it up with the bearing on the edge of the protractor, and use the straight lineĬreated by the thread to follow the bearing away from the edge of the protractor. Longer that twice the distance you might want to extend a bearing.) Pull the string tight, String through the center hole and tie the ends together. Tools with protractors have a hole in the center. This is what we demonstrated in the above example.Īnother technique is to use a piece of thread to show your bearing line. Draw a line between these two points, and extend it asįar as you need to. Line up one side of the angle with 0 degrees on the. Now place a straight edge between the known point and the mark you How to use a protractor Line up the vertex of the angle with the dot at the center of the protractor. One of simplest techniques is to place a small pencil mark on the correct bearing at theĮdge of the protractor. Techniques for extending the bearing line The center of your protractor will be at the intersection of a line drawn between 0° and 180° and a line between 90° and 270°ĭetermine what lines to use to align your protractor with your north reference lines on your map.Ī protractor that is well suited for navigation will have numerous parallel lines aligned with 0° to 180° on the protractor. You will place the center of the protractor on the known point where you are plotting your bearing. Some protractors are numbered in four 90° quadrants,Īnd are a probably not a good choice for navigation use.įind the center point for your protractor. Make sure you use the correct set of numbers. You proceed in a clockwise direction? Many protractors used for drafting are numbered in both clockwise and counterclockwise directions. Is you protractor marked in degrees? Are the marks spaced at one, two, or five degrees? Is it a full or half circle protractor. 0° (and 360°)Īre aligned with our north reference, 90° is to the East, 180° to the South, and 270° to the West. Familiarize yourself with your protractorīefore you set you protractor down onto the map, take a good look at it and make sure you understand the markings.įor navigation purposes, we use an angular measurement system where a circle is divided into 360 degrees.
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