Weems & Plath Professional Protractor Triangle

The Professional Protractor Triangle with handle is larger than other navigation triangles on the market with legs that are 9.312 inches long and a hypotenuse (long side) 13.125 inches long. It has both 320mm & 1-80,000 scales and is constructed of heavy duty clear 5 mm thick acrylic for durability with a handle for ease of use. Both pencil and pencil sharpener are included with the Professional Protractor Triangle and this product is backed by our lifetime warranty.1. Slide two triangles to transfer course or bearing.2. Place protractor vertex over meridian of longitude to determine course or bearing3. Hole at the vertex of the protractor allows the point of the divider or pencil to be placed on a meridian for a quick accurate course measurement4. A string fixed through the hole can be used on a chart to determine a long distance course.5. On shipboard, a string through the hole with a weight can be used to determine a long distance course.6. Convert the protractor into quadrant to measure the altitude of Polaris to determine latitude at night. Use a string of fishing line tied to the vertex with a weight at the other end to determine the angle.7. Measure angle/altitude of on shore object (tower/lighthouse) to determine distance from your location. Add the bearing for a fix.