Today what we’re going to do is learn how to use the E6B to calculate a Magnetic Heading and this comes from a question specific in the FAA knowledge test bank. We’re going to use that example to help us figure out how to use this E6B. So, the question we’re going to use today is this:
So over to the E6B and our first step is to set our wind direction under the true index. Our wind direction from the question was 215˚ and next it’s going to ask us to mark the wind velocity up from the center point. In this case, I have the center point resting on 100. I chose that just because it makes the math easier for me.
Magnetic declination. Magnetic variation on a nautical chart. Magnetic declination does not depend on the equipment of the vessel, but on its location, and also varies with time as does the deviation, but more predictably. The magnetic declination is indicated on the map, with the obligatory indication of the measurement year and ...
The arrow of a magnetic compass always points north. This feature of a compass needle was noticed in the XII century, after which people began to use a compass for orientation, especially at sea. This device is quite simple.
Those who read Jules Verne will remember that the cook Negoro had sinister plans for the ship Pilgrim and its 15-year-old captain and deliberately set them off course by place an axe under the compass binnacle. There are a lot of things on a ship that can affect a magnetic compass. To eliminate this effect, there are deviation charts for each compass that show the deviation for various courses. Over time, the deviation may be changed due to the installation of new equipment or the magnetization of the old iron parts, so tables are regularly updated. Using the value of the deviation table, it is possible to bring the compass course to the magnetic course. To do so, the deviation value for this compass course is added to the compass course if it's deviating east, or subtracted if it's deviating west.
There are two factors that influence your course ( compass course) from the course you drew on a map ( true course ): Compass readings deviations – magnetic deviation. Discrepancy of magnetic and true poles – magnetic declination. To calculate the compass course by the true course, or vice versa, you should set the values ...
However, if you draw a direct line from the point of origin to the point of destination and without deviating a single degree follow the plotted course, you will hardly reach your desired destination, especially if the distance is big. There are two factors that influence your course ( compass course) from the course you drew on a map ...
Offshore charts rarely show more than one or two compass roses and only show true direction. Look for magenta colored, diagonal dashed lines running across the chart. Scan along the line and find the variation. Use the variation indicated on the isogonic line closest to your position.
On the nautical chart, you use a protractor or course plotter to plot courses. Draw a line on the chart from your position to where you want to go. Measure the angle between any vertical line to the course to find true direction to your destination.
Complete 90% of your navigation--before you cast off the lines.
Simplicity and reliability are the hallmarks of any great compass.
If your compass read true direction, you could steer the true course you plotted on the chart. But because you use a magnetic compass, you must apply variation to true course to know the magnetic course.