Compass
Gyro systems have long since been required aboard ocean going vessels. These units range from fully mechanical units that must be driven by servos, to liquid suspension units that seek north by virtue of their own dynamics, to highly precise ring laser units now employed by the military. In all cases these gyros are known as north seeking and by action of the earth’s rotation and clever circuitry, they all eventually point north. The advantage of using a gyro over a magnetic compass is its immunity to deviations caused by heavy metals in the earth’s crust. More accurate course holding and reduced transportation cost makes the gyro superior. Coupling this to today’s adaptive autopilots provides for a cost-effective fuel saving steering system.