The Compass True North

Our charts are formed to give the lines of longitude to run parallel to each other, in truth they do not, as all the lines of longitude meet up at the north pole as this diagram shows. This is known as the TRUE NORTH.

Magnetic North

True North this is not the same place as the Magnetic North of the earth is, this at the moment is centered over North Canada and will differ as to where you are on the planet. In the Solent it is about 3 Degree West at the moment. In ALL the RYA questions it is 7 Degrees West. The difference between the True North and the Magnetic North is known as the VARIATION. To find your variation look at the nearest compass rose to you on your chart and adjust it to this year.

Deviation

Deviation is caused by metallic objects on your vessel such as the engine and is unique to each vessel. We can work out the deviation of a vessel if we know the True bearing of and object, the Compass Bearing and the variation off the chart. Be careful not to have metallic objects near the compass especially on bulkhead mounted compasses

Compass

This is the reading from the ships Steering Compass.

Converting from True the Compass and back again

Some people find this quite difficult to do, but by remembering the non PC saying below and as well as the CadeT (Compass to True Add East), it WILL be correct EVERY time!