The Indian Ocean - Michael Pearson [12]
It is fairly straightforward. The longitudes are roughly 20° E to 110° E. Southern Africa, more precisely Cape Agulhas, is one limit, and we then go around the coast, including the Red Sea and the Gulf, past South Asia and through the Bay of Bengal and so to what geographically is the obvious limit, that is the Malay peninsula and the Sunda Islands. Past this the monsoons change. Possibly the Sunda Deep of the Java Trench off the southern coast of Java, which is 24,442 feet (7,450 metres) deep, forms a bathymetric boundary which separates the southeast Asian maritime region from the Indian Ocean. From here we go south to Cape Leeuwin in southwest Australia.
So far we have followed the borders as recognised by the United Nations Oceans Atlas, and the International Hydrographic Organisation (IHO), but both these authorities then go past Western Australia to around Melbourne, the west coast of Tasmania, and then down to Antarctica. This opinion is not to be taken lightly, especially as it is congruent with those of Alan Villiers, who was a real sailor.4 Nevertheless, I would be inclined to stop at Cape Leeuwin, and go no further east. Certainly I agree with the International Hydrographic Organisation on the southern boundaries. In early 2000 the IHO delimited a fifth world ocean, the southern parts of the Atlantic, Indian and Pacific. This extends from the coast of Antarctica to latitude 60° S.5 We still have a lot of the Great Southern Ocean included in the Indian Ocean, including the peri-Antarctic islands on either side of 45° S, namely the Prince Edward Islands, Iles Crozet, Iles Kerguelen, Ile Amsterdam, Ile Saint-Paul, McDonald Islands, and Heard Island. From the late eighteenth century these islands provided places for sealers to winter, and today most of them have permanent populations of scientists, but they will play a small part in our history of the Indian Ocean.6 They will be of interest only when we have ships using the roaring 40s and the fearsome 50s as they go from one end of our ocean, south Africa, to another, western Australia.7 For most of history ships never went below the tropic of Capricorn.
One way to visualise what I think of as the Indian Ocean proper is to see it as a vast equilateral triangle. The base is the tropic of Capricorn, that is 23° 27' S. The two sides go north, the western one then including the Swahili and south Arabian coasts, up to north India, and then down from the apex through Burma, Sumatra and to northwest Australia. The only real problem with this is that it excludes the Gulf and Red Sea, and these were intricately connected with the Indian Ocean; apart from this it works quite well to depict the area of concern in this book. An alternative, perhaps even one to be preferred, is to see it as a vast letter M, with the Red Sea and Gulf on one side, and the Bay of Bengal on the other, divided by India.
The ocean proper, the vast wide expanse of water that we quoted Conrad on in the introduction (see pages 1–2), was well described by a Persian traveller in the eighteenth century:
It is not possible to measure the full extent of that sea except with the eye of fantasy. No one will ever delve to the bottom of that sea except by plunging into the waves of his wildest dreams. We were surrounded by a limitless desert of water. The days were white and the nights were black. You could not spy a single speck afloat on those fields of water, only the dark blue of the heavens reflected on the blue black of the sea.8
Opposed to this are the various bays and smaller seas and gulfs. Joseph Conrad saw the bays, in this case the Gulf of Thailand, as being rather different from the real ocean. One of his characters said that
from Bankok [sic] to the Indian Ocean was a pretty long step.... Extreme patience and extreme care would see me through the region of broken land, of faint airs, and of dead water to where