Ships and Sails 

Beginning about the 12th century, they increased maneuverability of their ships by building a rudder on the stern. Square sails enabled them to take advantage of following winds but triangular sails were good for any kind of winds.

Navigation 

The most important navigational instruments were the magnetic compasses and astrolabe.

Knowledge of winds and currents

This allowed them to know when it was the best condition to travel and what the best routes were for safety.

Technological Advancements