Using a Compass
This is a one of the three compasses found on the Mary Rose. The compass had an iron needle in it which was magnetised. The pilot made the needle magnetic by stroking it with a piece of magnetic rock called a lodestone. The needle was balanced on a spike, and it would point to the Magnetic North Pole.
The card inside the compass would have looked something like this. North is at the top of the card; the other directions weren’t shown on many compass cards.
When it was being used, the compass would be held in a wooden stand called a binnacle. No iron was used in the construction of either the compass or the binnacle, because iron affects the accuracy of compasses.