Purple Winds

The last few times I’ve presented The India Road, one question always pops up at the end.

“Have you read the book 1421?”

When I say yes, the follow-up is an enquiry about the theory that globalization was first achieved by the Chinese eunuch admiral Zheng He, in the early fifteenth century.

The premise, of course, is that the subsequent exploration of the Atlantic and Indian Oceans by the Portuguese is consigned to the irrelevance of second place.

I reply that a well-known pair of scholars, one of whom is a good friend, analysed the alleged Chinese voyages in detail and concluded that a good deal of the book is, to paraphrase King John’s Mathematical Junta, ‘a set of opinions uncontaminated by facts.’

The other scholar, Jin Guo Ping, is a Chinese Academician—The Middle Kingdom was apparently thrilled with the tales weaved by former Royal Navy nuclear submarine commander Menzies, until they discovered they were being sold a bill of goods.

Losing face is a terrible predicament in the East, and China dropped Menzies like a hot potato.

Perhaps the good commander spent too much time under water, but he succeeded in writing a pseudohistory book that made number eight on the New York Times bestseller list, and made a lot of money for Bantam and the author.

1421 has Zheng He departing from Calicut in June, headed for the Somali coast, at a time when the SW monsoon makes it impossible to travel west by sail. It also has the Chinese ships visiting Italy by sailing up the Red Sea and traversing the non-existent Suez Canal.

There is historical documentation of a narrow canal completed in the XIIIth century, but no record of regular use. By the time Napoleon’s army reached Egypt, only archeological evidence of a connection was found.

Even the XIXth century canal built by Ferdinand de Lesseps was initially only eighty-seven feet wide at the bottom—this contrasts with the one hundred-eighty foot beam of the largest ships in Zheng He’s armada.

So let’s leave pseudoscience behind, because the Red Sea is an oceanographic pearl.

Ocean water is heated at the surface by the sun, and the only way to heat the lower layers (down to hundreds or thousands of fathoms) is by transporting surface water to greater depths.

This happens, for instance, as two surface water masses meet, or when water collides with a continental mass. The convergence causes downwelling, and warmer surface water sinks. Alternatively, the surface water mass meets a less dense layer at the same depth and sinks below it—this typically occurs in estuaries, when denser seawater flows upstream below the river water draining out to sea.

In practice, these movements do not significantly change the temperature of the deep water—most of the ocean is cold and dark, with temperatures of 4ºC (39.2 ºF). Not so the Red Sea, where the water temperature at a depth of three thousand feet is higher than off most beaches in Portugal.

The Red Sea is in one of the hottest zones of the planet, and in some ways it works almost like a salty lake. At the head is the Suez, at the ‘mouth’ is the Bab el Mandeb, the Gate of Tears where the spy Pero da Covilhã arrived in 1488.

The boat was primitive, with no deck. The planks making up the hull were bound with hemp, the sails made out of matting.
“Rather indifferent naval construction when compared to our caravels,” Paiva said in a low voice.
The spy nodded. “All the better, all the better.”
The trip was long and tiresome, navigation was by line of sight, and the rudimentary vessel anchored every evening at sundown to avoid destruction on the madreporite coral reefs. At sunrise, prayers were said, and then the caravan would proceed. The voyage from Tor to Suakim on the African coast took over two months, as the small boat made its way past what is now Saudi Arabia, the holy cities of Mecca and Jeddah to port, and then across to the Ethiopian peninsula and Djibouti.

My description of the spy’s journey to Aden is based on the biography written in the late XIXth century by the Conde de Ficalho. The return journey took the spy to Jeddah. Although I wasn’t aware of it at the time, sailing north of Jeddah is no picnic.

Animation in 'Earth Wind' of the winds in the red sea on the morning of January 18th 2014.

Animation in ‘Earth Wind’ of the winds in the red sea on the morning of January 18th 2014.

My navigational guru, who commanded the Portuguese training ship NRP Sagres, introduced me to a wonderful site that calculates the surface wind pattern for the whole world based on isobaric surfaces, and then plots near-realtime animations.

What are isobaric surfaces? I smiled at the caveat ‘Warning! The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.’

We had all manner of fun, as I was told about the challenges facing the vessels racing Cape to Rio, because of the high pressure shift, and shown the video of the wind patterns. Then we wandered up to the land of the Vikings—I suggest you do the same, and you’ll understand how easy it is to sail west from Denmark to Greenland—it’s an island-hopping downwind run.

But if you look at the image I clipped for the Red Sea, it’s clear that one thing is sailing south to Bab el Mandeb from the Sinai, but sailing up the Mar Rôxo, or the Purple Sea, as the Portuguese called it, is a different game altogether.

In January the NE monsoon is in full swing—which is when Zheng He’s junks could have sailed to Africa—and a SE wind tunnels up the Red Sea, but this only blows as far as the holy city of Jeddah. On the African side is Port Sudan. From then on, sailing up to Suez is tantamount to torture.

The central channel of the Red Sea is deep, but the banks are shallow and full of coral reefs. The only way upstream is to tack against the NW winds, on a narrow sea that flows against you. When the monsoon reverses in May, the winds blow from the northwest all the way down to the Gate of Tears.

In the days of sail, Jeddah was as far as you could comfortably sail the Red Sea, and that is perhaps the reason why the ancient city is located there.

Atmos Fear and The India Road. Quick links for smartphones.

Atmos Fear and The India Road. Quick links for smartphones.


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