In order to find the route in the open sea, the sailors referred to the pole-star, which indicates the North. If the clouds or some storm did not permit visibility, sailors had to sail blindly. The problem of bearing was solved by the compass, probably a Chinese invention which was brought into the West by the Arabs and which was commonly used on the European seas about the year 1300. The compass consisted of a magnetic needle mounted on a fine pivot. The magnetic needle always points towards the magnetic North. In this way bearing was possible even at night, in the winter and with an overcast sky. Later, at the end of the Middle Ages, the astrolabe was used. It is an instrument already known by the Greeks which the Arabs improved and spread throughout the Mediterranean. It permitted the measurement of the latitude of a ship at sea, calculating the height of a star on the horizon. In order to map out a route, the sailor had the “portolani”. They are nautical maps in which the line of the coast, ports and landin are drawn exactly. There were no meridians and parallels, but there were some compass cards put in different places of the map. Their directional points extended and crossed forming a net which represented the maritime routes. These innovations not only made the navigation safer and faster, but they permitted to shorten the time of inactivity for the ships during the winter. Streets and bridges were often impassable because of bad maintenance, consequently navigation was generally favoured. With fair winds people could cover distances which were unthinkable for people who travelled by land and it cost less. Contrary winds or dead calm made the voyage endless and painful because sometimes people suffered thirst.

 

                                                                                                                                    © S.Lannino 2001