There were many Minoan ship masters that travelled the open sea routinely on busy, especially in summer, well-established trade routes throughout the entire Mediterranean Basin and into the Atlantic. They used every available indicator in nature and compared it to a mental navigational map stored in their mind to plot a course. They focused on the sun, moon, stars, the predictable seasonal winds, and other indicators to guide them.

Navigating by the Sun

The Sun at Noon in a Haze

On a clear day when the sun’s position can be observed, the sun arcs in the sky relative to the horizon from the northeast at dawn to rise to its midday zenith and then arcs down toward the northwest to set in the evening. The position of the sun at it's noonday zenith indicates north by sighting a line from the horizon through the center of the sun. The north-south position of the sun's arc across the sky changes with the seasons. With this in mind, they could dependably deduce directional information from its position in the sky at any time during the day.

Using the Moon to find North

The light we see from the moon is the light it reflects from the sun. Whenever a crescent shape, either light or dark, can be seen on the moon's surface it gives an observer the ability to determine a northerly direction. By sighting a line that connects the endpoints of the crescent it indicates a northern heading. Also, if the moon rises before sundown, the illuminated side indicates the west. If the moon rises after midnight, the illuminated side indicates the east. This provides a navigator with a rough east-west reference in the night sky.

Using the Moon's Crescent

The Moon's Libration

The Celestial Navigation of the Ancient Minoan Mariners

On a clear night, the countless stars gave the mariners many more points of reference to help them navigate more precisely. There were stars in all quadrants of the night sky moving in a predictable, orderly way from dusk to dawn and season to season throughout the year. They used two groups of stars that were always visible above the horizon and rotated about the bright unchanging North Star. They called them the "Two Bears". In the northern hemisphere the direction of north can be found by sighting the North star. The North Star (Polaris - 430 light-years away) stays in a fixed position in the night sky throughout the whole night. The Bears rotated about the North Star and changed their orientation to it as the seasons changed. They could tell what season it was simply by looking at the orientation of the Bears relative to the North Star in the evening sky.

The Movement of North Star and Stars in Night Sky

The Two Bears and the North Star

The Big Dipper and the Seasons

Polaris also gave them their north-south position (latitude) by observing the angle it made with the horizon. The North Star is significantly higher in the night sky in the far northern Aegean and lower in the sky if they were well south near the coast of Egypt on any given night.

The North Star and Latitude

They probably used a simple tool to more precisely measure the angle of the North Star relative to the horizon. It was composed of two cleanly sawn, thin sticks of wood that were about a half meter long. The two sticks were joined together on one of their ends into a hinge that pivoted on a small peg. The free end of the top stick pointed to the North Star, and the bottom stick pointed to the horizon. A string with a lead bobbin hung from the top stick. By opening and closing the sticks, the length of the string from the top one to the bottom one could be measured. They could get a good measure of the angle of the North Star from their position with this simple instrument. With a good initial angle measurement (fix) as a reference, if they knew what the difference of the angles was between the angle of their starting point and the angle of their destination they could deduce their destination’s north-south position at any time of the year; no matter where they were in the open sea.

Other Navigational Indicators and Tools

To this they added the information gathered from the direction of the seasonal winds. If the wind died down, they would look at the swells on the sea. The direction of the wind could be estimated from the swells long after the wind had ceased. If the winds died completely or were confused, they would look for birds, like the terns, that fed at sea during the day and flew back to land with the approaching sunset to indicate a nearby landfall.

They took a measure of the ship’s speed in the water using a large piece of cork with a light line of rope attached to it. A mariner at the stern of the ship would drop the floating cork into the sea and count the number of heart beats it took before the line tightened in his hand. Another instrument they found useful in coastal areas, especially in the perilous shallows near the mouth of the Nile, was the sounding lead. It was a weight of lead tied to a rope used to determine the depth of the water when thrown overboard. It could also be used to detect the composition of the seabed and give them an indication of how much anchoring would be required to hold the ship in position in the current.

The Miniature Frieze - Akrotiri, Thera

Knowledge of the predictable seasonal winds aided them greatly in navigation. For example, the predominant winds in the Aegean Sea are the north and northwest winds. The north winds of winter and the northwest winds of summer can sometimes grow into strong gales that can easily blow a ship out of control downwind. The other important winds are the East wind that blows in summer and fall, the West wind of late spring and early summer, the stormy South winds of late summer and autumn, and the Southwest wind of spring and late fall. They categorized each of the winds with its own set of attributes such as dry, wet, hot, cold, dusty, clear, strong, weak, etc.

The sun, moon, stars, winds, and their instruments provided the ancient Minoan mariners with reliable information they could compare with their navigational mental map to dependably get a reasonable fix on their position and determine their ship’s heading in the open sea far beyond the sight of land.

Copyright © 2007, 2008
W. Sheppard Baird
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