At Bridge level there are various different types of compass that were used on the Ross Revenge, but without doubt the most useful was the Gyrocompass located aft of the Bridge in the ships Chart Room.
Whilst first patented by Marinus Gerardus van den Bos in 1885, the first useable gyrocompass was developed in 1906 by Hermann_Anschütz-Kaempfe - principles of which are still used to this day.
The gyrocompass was different to the more common magnetic compass in that it was non-magnetic and based upon a fast spinning disc, together with the rotation of the Earth, to find a geographical direction. Gyrocompasses are widely used on ships as they have 2 significant advantages over their magnetic counterparts;
- They find True North determined by the earth's rotation, which is more useful than Magnetic North
- And they are not affected by ferromagnetic materials, such as the ships hull, which change the magnetic field
The gyrocompass could however be subject to errors if the ship needed a rapid change in course. The resultant speed and lattitude could cause deviation before the gyro could adjust itself. These days modern ships have overcome this problem by using computer based GPS systems electronically feeding into the gyrocompass to compensate any deviations.