HOW ABOUT THIS SIMPLE METHOD OF CHECKING YOUR COMPASS

This method is not affected by wind or current, knowledge of your Latitude or the azimuth of the Sun is not needed and nothing need be related to the boat lubber line. There must be a Sun that will cast a shadow and determine one initial heading; then with the protractor shown you are ready to check your compass. Print the protractor on this page and affix it to a flat board.  Drill a vertical hole through the center of the protractor for a thin tight fitting pin 4 inches long. From a chart of your boating area pick two known shore points and plot the course between them.

Pilot your boat along the plotted course, place the board on any level surface (or surfaces) on the boat, and rotate the board until the Sun's cast shadow is on the protractor degree mark that is equivalent to the plotted course (TRUE) heading. For example, if the course you plotted is 35 degrees the Sun's shadow must cast on the 35 degree mark on the protractor. Note: Sun's shadow on the 0 degree mark (on the protractor) is TRUE north. By swinging the boat in a circle you can record a COMPASS heading for a TRUE heading and knowing your VARIATION from the chart you can determine your DEVIATION AND MAGNETIC heading.