Zheng He’s sailing to West Ocean
2 THE EXPEDITIONS
2.1 Pre-sail preparations
In 1402-1424, during the reign of Emperor Zhu Di, the imperial court ordered the building and modification of 25 batches of sea-faring boats, totalling 2860. They included four batches of what is known as “treasure ships”, totalling 343, the sea-faring vessels especially for the voyages to the western seas. There still remain seven docks for building ships at the ruins of Nanjing Long Jiang Shipyard and the Treasure Ship dockyard.
Some historical records show that the sea-faring fleet under the command of Zheng He consisted of more than 200 vessels and 61-63 Treasure Ships. As the boats were built in different places, they varied in types, such as “FU” boats, “WU” boats, “GUANG” boats and “SHA” boats. The division of labour among the boats also varied according to different tasks they were assigned. There were large, medium and small sized treasure ships and boats for carrying water, soldiers, passengers, horses and foods. By “treasure ship”, it means exquisitely made boats for shipping official seals, official robes and all kinds of treasures to and from China. It also carried back rare animals, souvenirs and rare raw materials, spices, herbal medicines and crop seeds given to China as gifts from foreign countries. The king-size treasure ship measures 133.2 meters long; mid-size ones measure 111 meters long; and the smallest ones measure 60 meters long for carrying supplies. In Zheng He’s fleet, there were also eight-scull boats, which measures about 24 meters long, with two masts. It used masts in tailwind and when there was no wind, it used sculls.
2.1 Pre-sail preparations
From 1405 to 1433, Zheng He made 7 voyages down to the Western Ocean.
In order to avail the tailwind of the Northeast monsoon, Zheng He defied fatigue and completed preparations in less than one month and set sail from Liujia Port of Taicang. The second voyage, Zheng He visited Champa, Siam (Thailand), Java, Malacca, Nanwuli, Ceylon (Sri Lanka), Kayal (on the east shore of the southern end of the Indian Peninsula), Cochin and Calicut.
By the time of the third expedition, 1409 to 1411, Zheng He had established a settled program. The fleet used Malacca as its forward base and there the fleet was divided into squadrons that sailed independently to separate destinations.
The mission of Zheng He’s firth voyage was to escort envoys of 19 countries home and to procure all kinds of rare animals and spices from the Arabian Peninsula and East Africa.
Zheng He was order to go on the sixth voyage to escort the envoys of 16 countries include Mogadishu and Brawa in East Africa home. In order to sail directly to the eastern coasts of Africa, Zheng He used stellar diagrams to measure the height of the stars to position the fleet. Menzies (2003) suggested that the fleet had not merely rounded the Cape of Good Hope and traversed the Atlantic, they had been gone to explore Antarctica and the Arctic, North and South America, and had crossed the Pacific to Australia.
On the last voyage, when the fleet, carrying with rare animals and native produce, were sailing toward Calicut, Zheng He died of illness. According to the sea-faring tradition, he was buried at sea.
Figure 1 and Table 1 show some more information about the voyages.
Figure 1. Map of Ming China and Zheng He’s voyages
3 THE TECHNOLOGY
Various advanced technologies of the time were employed by Zheng He and his fleet to make the great feat. He successfully inherited the practice of former navigators in Chinese history and assimilated their ocean-going knowledge. He selected excellent sailors, made thorough preparations and built various types of seaworthy ships equipped with well-designed devices such as stabilization boards, watertight compartments, precise compass, and star boards. Based on the knowledge of his predecessors and the sea-going practice of his own, he prepared scientific navigation charts, which are of great value in history. He inherited and innovated the Chinese tradition of navigation through celestial observation. By inventing the technique of star board measurement for determining the height of celestial bodies and thus positioning, he elevated the navigation technology to a new level. He also had studied the general patterns of monsoon in the in the Chinese sea area, Indian Ocean and Arabian Sea and made effective use of these studies in his trip. The following subsections are contributed to part of the technologies employed by Zheng He and his fleet.
3.1 Ship building
China has a long history of building ships. The general design featured vertical sails, with neither horizontal sails nor fastening ropes. The sails were usually made of cloth or woven by bamboo chips stiffened by bamboo poles for wind-efficiency. With centuries of experience in building ship to sail storm-tossed oceans, the Chinese marine engineers had evolved a robust frame built in sections. Each section was contained by watertight bulkheads at either end, resembling the internal partitions of a bamboo. The watertight sections were bolted together with brass pins weighing several kilograms. Three layers of hardwood were nailed to a teak frame, and then the planks were caulked (made waterproof) with coir (coconut fibre) and sealed with a mixture of boiled tung-tree oil and lime. This hard, waterproof lacquer had been used to seal Chinese ocean-going ships since the seventh century, but so much tung-tree oil was required to build Zheng He’s treasure fleets that acres of land along the Yangtze banks were acquired to plant orchards of tung trees.
Marine engineers at the Longjiang shipyards designed their ships to survive the fiercest storms on the open ocean. Reinforced bows enabled the vessel to smash through the waves, and at either side of the bow were channels leading to internal compartments. As the square bow pitched in heavy seas, water was funnelled in; as the bow surfaced above the waves, the water drained out, modifying the pitching motion. A teak keel bound together by iron hoops ran the length of the ship, and specially cut, large rectangular stones – or composite stone and mud balls – were packed around it for ballast. Additional keels that could be raised and lowered were fitted at either side for more stability. In a storm, semi-submersible sea anchors could also be thrown overboard to reduce rolling. Even in the roughest weather and sea conditions, pitching and rolling were greatly reduced by these ingenious modifications. With the sophisticated technologies China was able to build largest ship of the world at the time. Some record noted the treasure ship is as large as 132m in length and 54m of width. Figure 2 compares the treasure ship to Columbus’s St. Maria.
The giant ship could survive typhoons and the sectional construction reduced the risk of sinking in case of a collision with a reef or an iceberg. They were designed to remain afloat even if two compartments were flooded after being punctured by coral or ice. To increase cargo capacity, the hulls of the junks were very wide compared with their length and they were float-bottomed. Their sails were balanced lugs, four-sided sails hanging from a yardarm set at an oblique angle – the characteristic sail of China. They were stiffened by a series of bamboo battens, so the design was extremely efficient when sailing before the wind. It also allowed the sails to be reefed, or lowered, quickly in an emergency.