The CompassThere were many devices in different parts of the world which pointed north. Many used lodestones (magnetic rocks) or needles which had been magnetized by rubbing them against a lodestone. The Venetians made the first practical compass in 1274.This compass was a magnetized needle with a compass card which showed four or eight points of direction. The compass was a valuable trade secret, and it was not shared with anyone. Before the year 1311, there are no recorded pictures of compasses.
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The AstrolabeThe Astrolabe is an angle-measuring tool, it is one of the oldest angle measuring devices. It was invented by the Greek astronomer and mathematician, Hipparchus. Its earliest use was for astronomy and astrology, not for navigation. The astrolabe was adopted for sailing when sailors learned that they could navigate by measuring the angle between Polaris (the North Star) and the horizon. The first documented use at sea is in 1481, on a voyage down the African coast by Portuguese explorers.
To work it the astrolabe must hang down so that it is perpendicular to the ocean. To keep it straight, the user holds it with a finger through a ring and lets the astrolabe dangle and then looks through two pinholes in a rotating arm. When light shines through both pinholes at the same time, the angle is accurate. The navigator reads the scale around the circumference of the circle. |
The CaravelThe Caravel was generally used for carrying cargo and fishing. Prince Henry the Navigator created the Caravel for long distance trade. Square sails were used to sail in open water while lateen sails were used to sail a;long the coast. It also had a rounded bottom, making it faster than other vessels of the time. Because of this they were also favored by pirates. Columbus’ ships, the Nina and the Pinta, were both designed as Caravels.
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