The Indian Ocean - Michael Pearson [17]
As for Gujarat, Terry wrote that the great ship going from Surat to Mocha
beginnes her voyage about the twentieth of March, and finisheth it towards the end of September following. The voyage is but short and might easily bee made in two months; but in the long season of raine, and a little before and after it, the winds are commonly so violent that there is no coming but with great hazard, into the Indian Seas.24
The matter was most pithily expressed by an Arab author, who wrote that 'He who leaves India on the 100th day [2 March] is a sound man, he who leaves on the 110th will be all right. However, he who leaves on the 120th is stretching the bounds of possibility and he who leaves on the 130th is inexperienced and an ignorant gambler.'25
Moving south to the end of the ocean, the west coast of Malaysia is a lee shore during the southwest monsoon, and at this time it is, just as on the west coast of India, very difficult to sail or land. This monsoon pattern also dictated that a passage from the far west of the ocean, say the Red Sea, to the far east, to Melaka, could not be accomplished in one hit; rather a stop over was necessary, probably in southern India, until the correct monsoon came to continue one's voyage.
Those who ignored the monsoons, or were ignorant of them, came to grief. In 1541 a Portuguese marauding fleet in the Red Sea set sail to return to India in early July. The headstrong captain refused to listen to the advice of his Muslim pilots, who, basing their views on centuries of experience, told him that by leaving at this time he would have no trouble getting to the entrance to the Red Sea, but that once in the Arabian Sea weather of such vileness could be expected that no ship could navigate. And this advice, of course, turned out to be correct.26 In 1980 Tim Severin, sailing on his Sindbad voyage from the Gulf to China, was becalmed east of Sri Lanka on the replica dhow Sohar for thirty-five days in March and April; earlier voyagers could have told him that this would happen.27
All this said, it is not quite as clockwork like as some accounts claim. For example, Severin picked up the southwest wind that he wanted in early April, which is much earlier than the books allow for. Thor Heyerdahl, in another replica boat, this one made of reeds, passed the Straits of Hurmuz and knew he was now in the monsoon area, which 'blows regularly across the Indian Ocean as if set in motion by clockwork, turning like a pendulum to move in opposite directions every half year.' However, what happened next showed how variable they can be. In January they picked up a faint south-southwest wind, 'and there was no sign of the strong northeast winter monsoon we could have expected in the middle of January'. The next day, before sunrise, the wind changed from south-southeast to north-northwest – in other words still coming from the wrong direction.28
For monsoon Asia the arrival of the rain-bearing southwest wind is vital, not only for maritime affairs but also for the much more basic matter of growing crops. In India, for example, there are monsoon ragas, they are a theme in miniature painting, and in some of the works of the poet Kalidasa. There are also methods to cope with any variability, again then showing that they are not totally predictable. Andrew Frater wrote engagingly about the problem if they are late, or fail altogether: