Free The River at the Centre of the World by Simon Winchester

Admiralty Pilot explains: ‘When the number of junks manoeuvring in the channel at Wusong Kou is such as to make navigation difficult, a red flag shall be hoisted.’ And as if to underscore the flag's warning, there were scores of black dots on the waters ahead, like a vast floating business of flies. Some were large ships that moved slowly across my field of view; the others, the smaller vessels, darted almost furtively back and forth on their appointed business.
    They dart where once they glided. The junks on nearly all the reaches of the Lower Yangtze have motors these days, not sails. It is a rare delight to see the distinctive shape of a classic Chinese junk – the peaked lugsail with its die-straight luff and sinuous leech and with the heavy bamboo battens jutting from the edges. But the bewildering variety of craft that scuttle between the riverbanks today performs much the same functions as the sailing junks did half a century ago – there are almost as many different designs of power vessels as there were of the old and much-loved sailing junks. Captain Zhu had a book of charts on the bridge that showed silhouettes of the different types – and at the back of the book, on pages that were less well-thumbed, were silhouettes of sailing junks as well.
    Scores of subtly different designs were to be found on the pages, dozens of sizes, boats bent to innumerable tasks, a nautical bestiary. Flipping through the pages was like seeing a shadow play, the boats the cut-paper figures from a Javan wayang show. There were outlines of the long, low cotton boats from Chongming, which take raw cotton out to the markets of Shanghai, and return with what is politely called night soil, still the principal fertilizer on the great tongue-like mudflat. There were silhouettes of the pig boats also from Chongming, but larger and fatter and with a bulk that was easy to recognize. They had to be sturdy, since their business was with pigs * taken to market, people brought back. There were pictures of ice carriers that transport blocks frozen in the fields in midwinter – and which are kept insulated through the warmth of early spring by ingenious arrangements of straw and soil. There were broad-beamed fish carriers, made stoutly of pine to weather the estuary's storms and heavy seas and tide rips. It is said that the game of mah-jongg was invented by the crew of a Ningbo fish-carrying junk, who believed that by making up a game on which they had to concentrate their minds they might forget a discomfort which they couldn't understand, which we now know as seasickness.
    But you don't see too many of these special craft. More often than not the smaller boats on this reach of the estuary would be the tiny stern-poled (and sailless) sampans, so called because they are made of three pieces of wood, compared with the five of the wupans – and on the day I arrived they seemed to be everywhere. I knew that once in a while one might see one of the larger vessels – like a long-distance coastal trading junk, or one of the special light-wood junks built so they can ride up and over the deadly bore that sweeps down into the funnel of Hangzhou Bay, on the far side of the Yangtze herself. But on this morning I saw neither of these bigger craft. Still, with all the activity that I could see from where I stood on deck, it was small wonder that the red warning flag was flying. Small wonder, too, that inspection cruisers like this one patrol the river ceaselessly, helping, watching, guarding.
    On the left side – technically the right bank of the river, reckoned from the point of view of the water flowing downstream – there was a sudden burst of industry. Cooling towers exhaled tall florets of white cloud, cranes swung containers up from the decks of waiting ships, black rubbery umbilical cords sucked oil from waiting tankers, there was what appeared to be a mine building with two winding wheels rotating at speed, an array of great chimneys with strobe