Use.

The first thing you must learn, and which you can do on shore, are the points of the compass, to know them at sight and tell them quickly; for you see it’s of great importance to a pilot to know exactly how a ship’s head is; and the men at the helm, although good seamen and steering well, are not so ready at answering as a pilot wishes, and very often stammer at it — sometimes make mistakes. Now you see, when I’m piloting a vessel, if you stand at the binnacle, watch the compass, and answer me quickly how the ship’s head is, you’ll be of use to me in a very short time.

Frederick Marryat