Application of deviation 4

Let’s assume that your boat is on a Compass Course of 018 degrees, and you want to convert the course to a True Course so you can plot it on the chart.
The Deviation is 5 degrees East and the Variation is 3 degrees West.
To find out the True Course for plotting, follow these steps:
Firstly apply the Deviation to your Magnetic Course, using the formula: Compass to Magnetic add Easterly, subtract Westerly.
In our case 018 degrees Compass plus 5 degrees East Deviation equals 023 degrees Magnetic.
Secondly, calculate your Magnetic Course using the formula: Magnetic to True subtract Westerly Variation and add Easterly.
In our case 023 degrees Magnetic minus 3 degrees Variation equals 020 degrees True.
Thus, the Magnetic Course is 018 degrees, and the True Course you have to plot on the chart
is 020 degrees. Follow the same method if you want to convert a Compass Bearing to a True Bearing.