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History of Sea Navigation Before the GPS

By Sid Nair

Safely and easily getting from one point to another while at sea is known as the art of navigation. Long ago, during the 4th century B.C., people didn't have access to the technology that we know today. They had to rely on other methods to get from A to B while at sea. One of these methods was to stay close to the shore and follow the shoreline. Seafarers would detect prominent landmarks to determine their progress at sea. If a seafarer did sail out of the sight of land, the North Star and the sun would be used to determine the northern and southern directions during the night and day. Some seafarers would use major constellations or even the directions that the birds flew and the fish swam to find their way at sea. Others would determine the vessel's progress at sea by measuring time with an hourglass. They would then multiply the time by the vessel's speed, which was determined by counting the pieces of seaweed that were passed. Needless to say, these methods weren't very accurate.

During the Middle Ages, which spanned from the 5th to the 15th century, sea transportation flourished, partly because of the introduction of the compass. Although the Chinese knew about the importance of magnetic fields and invented the compass, it was the Europeans who initially used it for sea navigation. It took a while before seafarers regularly started using the compass because many though it was inconsistent and some thought that it was operated by black magic. Another navigational source was the so-called Portolan Charts. Mapmakers made these expensive charts during the 13th century, using compiled sail data that was recorded by seamen. The charts were still not reliable because they lacked latitude, longitude, and distance information. Other tools that were used for navigation during this time were the astrolabe and the cross-staff. Both of these tools were used to measure the ship's position using the sun or a star.

Sea voyages were prominent during the 1400s, when the Age of Exploration started. Traders were desperately trying to get spices from Asia. They used these spices to keep food from spoiling. However, attempting to get to Asia by land wasn't easy because often, routes were closed due to wars. Instead, traders decided to find their way to Asia by sea. Explorers from Portugal were sent out to find sea routes, but the progress was slow because they feared hot water and sea monsters that they believed were present at the equator. The Portuguese explorers used so-called caravel ships. The lateen sails of these ships were able to sail toward the wind and provided speed. In 1492, Christopher Columbus used this type of vessel for his first voyage. According to Columbus' logs, he mainly used dead reckoning navigation. Dead reckoning was a method in which the navigator would measure the distance and course from a specific point, such as the port. He would mark the day's ending point on a chart, and this point would serve as the starting point for the next day. Dead reckoning didn't determine the ship's latitude. To do this, Columbus used celestial navigation, which is basically using the moon, sun, and stars to determine your position. Other tools that were used by Columbus for navigational purposes were the compass, hourglass, astrolabe, and quadrant. The latter was a tool that measured latitude by determining the angle between the sun or a star and the horizon.

Navigating during sea voyages nowadays is a lot easier than back then. After World War II, the development of electronic navigation aids progressed quickly. Today, captains have access to electronic calculators and computers to perform necessary calculations, and they also use a satellite navigation system or global positioning system to determine their location at sea. With access to these advanced technological developments, you can imagine that it's much harder for a ship to get lost at sea.

Sea Navigation in the Ancient World

Sea Navigation in the Middle Ages

The Age of Exploration

Sea Navigation in Modern Times