Navigation (Civ3)/Civilopedia

In the early days of seafaring, sailors operated solely through a process known as "piloting", in which the position and course of the ship was 
determined by referring to geographical landmarks. The need to stay in view of the shore severely limited the extent of sea voyages. Through 
experience, sailors learned to apply the science of astronomy to their profession, noting the positions and movement of particular stars. They 
realized that even when the shore was out of sight, they could steer by certain reliable stars. This crude, yet practical application of astronomy 
allowed the adventurous to sail into the unknown with a reasonable chance of finding their way. As a result, ship building technology quickly
improved, producing larger, more stable ships designed for longer voyages.