Gyro compasses

A gyrocompass is similar to a gyroscope. It is a compass that can find true north by using an electrically powered, fast-spinning gyroscope wheel and frictional or other forces in order to exploit basic physical laws and the rotation of the Earth. Gyrocompasses are widely used on ships. Marine gyrocompasses have two main advantages over magnetic compasses:

- they find true north, i.e., the point of the Earth's rotational axis on the Earth's surface, as opposed to magnetic north, -an extremely important aspect in navigation, and

- they are impervious to external magnetic fields which deflect normal compasses, such as those created by ferrous metals in a ship's hull.