coatal navigation #2
December 27th 2006 18:00
A detailed but old style map
Coastal Navigation #2
Storms were the bane of all sailors and today not much has changed. Being at the will of the sea and the wind does not improve one’s temperament. It is difficult but not impossible to keep track of where you are when you can’t see land or feel the bottom. Once a storm has blown out and the vessel has survived the crew or navigator must decide where they are and which direction to travel next.
The sun of course will give an indication and at night recognisable stars, planets and the moon. The flight path of sea birds in the morning or evening and even the direction taken of migrating birds at certain times of the year. Recognising a sea swell as apart from wind waves will also give a good indication of where land is.
Of course getting to land can be just as dangerous as staying out at sea. Breakers on beach or huge swells and tides racing toward cliffs are a menace. Long before reaching the coast the navigator needs to know what is ahead of his vessel. From the deck of a boat the horizon is about three nautical miles away. So by climbing up a mast the view is naturally improved. Recognising the coast was important and many trading vessels hired or stole pilots that knew their way along shore lines.
People from time immemorial have known how to take the time of day by the sun. The sun moves across the sky at the same rate each day. Fifteen degrees for each hour. By holding the palm of the hand at full stretch and using five fingers pressed together it measures fifteen degrees or one hour of the sun’s journey. One finger equals three degrees or twelve minutes. Knowing the time meant that they could work out their speed and knowing these two factors the third actor of distance was easy enough to figure. Perhaps they did not have the mathematics to calculate as we do today but even stone age man could count and figure. {Primitive tribes in Papua showed anthropologists how they did this. Using five fingers of one hand was five. Touching the wrist was ten, the forearm twenty, the elbow twenty five. If he held up three fingers the count went three, six, twelve, eighteen.} who needs a computer?
So a lot of the guess work by now has been taken out of navigating along a coast. It stands to reason that the better you can do this the more reasonably you are going to be able to trade, make war or fish. The knowledge was first kept in the computer built into our heads. Then as it needed to be shared it became written down and of course maps became know. These were held secret in many instances and only trusted captains and navigators were allowed to have the information written on them. People of course have been selling secret maps and charts since they were first drawn up. Some real, some imagined, like the maps of supposed buried treasures.
Next learning to read maps and charts.
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