The Good Old Magnetic Compass
![](https://sailspiration.com/wp-content/uploads/2012/08/Sailing_Navigation_Compass_1-670x216.jpg)
The Chinese invented the compass by around 1110. It improved the safety and efficiency of sailing greatly. The dry mariner’s compass was invented in Europe around 1300. It consists of a freely pivoting needle on a pin enclosed in a little box with a glass cover and a wind rose.
The GPS (Global Positioning System) has succeed the compass in certain areas but remember:
A compass won’t run out of batteries and a map will never lose its signal.
How to convert the magnetic compass course to the true course
Compass Course (magnetic).
+ Deviation
+ Variation
= True Course
The true course = the course plotted in the chart,( i.e course over ground)
The deviation = caused by nearby iron and steel
The variation = the angle between the magnetic north pole and the geographic north pole.