In 1848, David and James Napier took out a patent for a type of compass which kept a permanent record of the direction of the ship's head, as indicated by the compass needle. A circle of squared paper was placed over the compass card and a clockwork mechanism cause d apin to make a hole in the card at three minute intervals, automatically recording the direction. This enabled an accurate record of the course to be transferred to a chart.

The compass bowl is held in a highly decorative brass gimbal with an elaborate sea serpent on each side.