Navigation and Seamanship (1+1)

True Course to Compass Course and Vice-Versa

Ture North: This refers to the geographical North Pole. This is a physical pole since the axis of the earth passes through the same. All charts are aligned to this pole and the co-ordinate system refers to this as the North Pole.

Magnetic North: This is the south-seeking pole of the earth when considered as a giant magnet. All magnetic compasses point to this pole as North. The physical and the magnetic north pole do not coincide. The magnetic pole shifts over time as the earth cools down and also due to other various reasons. The physical pole remains stationary.

Compass North: This takes into account bothy variation and deviation experienced by the compass while pointing the direction of North. It is not possible to have two ships compass point at the same direction as North.

Magnetic Course: The angle between the magnetic meridian and the direction of the ship's head. It defines the direction of the ship's head relative to "Magnetic North".The difference between the two is the variation.

True Course: After allowing for Deviatin and Variation to the Magnetic Course/bearing.