The Indian Ocean - Michael Pearson [55]
How did captains find their way over the ocean? There is a contrast here between blue water sailing and finding one's way in more restricted waterways. In the treacherous Red Sea, Ibn Jubayr was very impressed with the navigational skills of sailors in these confined waters: 'We observed the art of these captains and the mariners in the handling of their ships through the reefs. It was truly marvellous. They would enter the narrow channels and manage their way through them as a cavalier manages a horse that is light on the bridle and tractable.'29 To a considerable extent, navigation was still like the way finding we described in the previous chapter (see page 56). It was a matter of the run of the water, experience, birds, seaweed, fishes, and sightings of known areas of land. Experienced navigators often wrote down what they had learnt. The most famous was Ibn Majid, who in the following passage, just like the Song source we quoted earlier, is using land sightings for guidance. When approaching Calicut, he says, 'look out for the hill between the mountains which are above the coast and there is no other such hill in these places and nothing so useful as a guide especially in the dark and its sides slope steeply.' When one is approaching from the north the ship should stay in about four and three-quarters fathoms of water until this hill is north-north-east of you, then approach the coast until the water is four and one-half fathoms and the hill becomes north by east and then north, and so on.30
Ibn Majid's work is an example of the pilot guides and navigational literature which were commonplace in the ocean. This geographical literature, from both the Chinese and the Arab side, showed that both knew the whole ocean, though Arabs found a limit at Madagascar. Ibn Majid wrote that 'to its south is the sea known to the Greeks as Uqiyanus which is known to the Arabs as the 'Ocean which encircles the world.' Here is the beginning of the southern Dark regions to the south of this island.'31 Tibbetts claims that there really was no exclusivity in nautical knowledge. Rather there was a common body of knowledge shared by Arabs, Chinese, Indians and Malays. It may be that practical navigational charts were not known before the Europeans, but there certainly were maps, as we will see. Charts may not have even been necessary, for navigation, apart from the use of wayfaring techniques, was done by observing the sun and the stars.32 In this the Arabs were simply following tradition, for the Beduin had long done this to find their way across the desert.
Again Ibn Jubayr tells us about this use. He was going on pilgrimage to Mecca, and embarked at Aydhab bound for Jiddah. They left on their jilabah, and on the evening of the second day there
rose a storm which darkened the skies and at last covered them. The tempest raged and drove the ship from off its course and backwards. The fury of the wind continued, and the darkness thickened and filled the air so that we knew not which way lay our course. Then a few stars appeared and gave us some guidance. The sail was lowered to the bottom of the mast, and we passed that night in a storm which drove us to despair....33
More usually either the North or Pole Star or the sun was used as a referent, and latitude was worked out from their height, measured in finger widths. The compass was apparently already known, as it had been long used by the Chinese, but it seems not to have been very widely used. In any case, it has been claimed that Arab empirical methods were more than adequate to determine latitude quite accurately. Based largely on a technical analysis