Navigation: The European Way

Sailors could figure out north and south easily because they could use the sun, stars, and other natural signs to measure latitude. But finding east and west (longitude) was much harder. They needed an accurate clock to know the time at home and compare it to the local time at sea. This difference in time helped them calculate how far east or west they had travelled.

How sailors used it:

1. The ship’s clock shows the time back home (e.g. London).

2. Sailors check the local time by watching when the sun is highest in the sky (midday).

3. They compare the two times.

4. Every 1 hour difference = 15 degrees of longitude.