Chapter 22 Chapter 22 "Zheng He's Nautical Charts"

Zheng He's fleet had friendly exchanges with Asian and African countries through ocean voyages with world-leading science and technology, which has a profound social, historical and economic foundation. Shipbuilding factories in the Ming Dynasty were spread all over the country, with Jiangsu, Fujian, Huguang, Zhejiang and other places being the most developed.Treasure ships were mainly built in Taicang and Nanjing, Jiangsu, and a part was also built in Fuzhou.Nanjing Longjiang is the first shipbuilding industrial base developed during the Hongwu period of Emperor Taizu of the Ming Dynasty.In the early years of Hongwu, the Longjiang Shipyard was built, and later there was the Bao Shipyard (located on the Sancha River in Xiaguan, Nanjing, Jiangsu).Zheng He’s voyages took Taicang and Nanjing, Jiangsu as home ports, and sailed from Taicang and Chongming to Wuhumen at the mouth of the Minjiang River in Fuzhou, Fujian.In addition to treasure ships, there are more than 200 ships or hundreds of ships every time they go abroad.Such as horse boats (medium-sized treasure ships, carrying horses and items), warships (riding ships, large warships), grain ships (transporting grain and logistics items), warships (escort ships) and other main ships.There are also auxiliary ships in the fleet, such as water boats (drawing fresh water), fishing boats, etc.The largest treasure ship was 44 feet long and 18 feet wide, while the middle one was 37 feet long and 15 feet wide ("History of the Ming Dynasty"), with nine masts and 12 sails.Horse ships have eight masts, grain ships have seven masts, passenger ships have six masts, and warships have five masts (Luo Maodeng's "Sanbao Eunuch Western Records").The treasure ship has 16 to 20 sculls, and the rudder weighs 4,810 kilograms (Zhou Shide's "Chinese Sand Ships"). In May 1957, a giant rudder stock was discovered at the dock site of Mingbao Shipyard in Zhongbao Village near the Sancha River in Xiaguan, Nanjing.It is made of iron wood and has a total length of 11.07 meters.According to the original tenon hole on the rudder stock, the height of this rudder is about 6.25 meters, which shows the hugeness of Zheng He's treasure ship.Treasure ships are several times larger than ordinary ships, and the cost is so high that "the money and grain of thirteen provinces in the world must be spent to be sufficient" ("Luo Maodeng's "Sanbao Eunuch Western Records").Wood for shipbuilding needs to be planted in Nanjing and other places, and collected throughout the country.To build masts, it is necessary to order the provinces of Fujian and Guangxi to search for timber for one or two years in advance.The mast is as big as ten feet one foot six inches long, one foot one foot around the root, and two feet nine inches thick when it reaches nine feet long.Every time a tree is obtained, the government will send a special person to re-inspect to see if it is suitable for use.The building of the treasure ship is magnificent, with "toumen, yimen, danji, dripping water, official hall, hallway, back hall, Kusi, side room, study room, office and so on, all of which are carved beams and painted buildings, elephant trunks, etc. Overhanging eaves", just like the handsome mansion ("Sanbao Eunuch Western Records").Treasure ships are "tremendous in size and invincible. Canopy, sails, anchors, and rudders can only be moved by two or three hundred people. There are so many people going around, how can they rest?" (Gong Zhen's "Western Fan Guozhi" ")

Zheng He's voyage to the West in 1405 was 87 years earlier than Columbus' arrival in America in 1492, 92 years earlier than Vasco da Gama's arrival in Guli, India in 1497, and 114 years earlier than Magellan's voyage around the world in 1519.When Columbus sailed to America, there were only three sailing ships and 88 sailors. Da Gama’s Portuguese fleet had only four ships and 160 sailors. Magellan’s fleet had five sailing ships and 260 sailors. When he returned to Spain, only one remained. The ship, with 18 sailors, is incomparable with Zheng He's fleet in all aspects. In Zheng He's fleet, most of the sailors driving the treasure ships were fishermen with decades of rich sailing experience along the coasts of Fujian, Guangdong, and Zhejiang.They are familiar with natural laws such as tides, monsoons, and ocean currents.During his voyages in Asian and African countries, he accumulated rich navigation experience and scientific knowledge, and compiled nautical charts and charts for crossing the ocean and drawing stars.

"Zheng He's Nautical Map" was originally called "Sailing from Treasure Shipyard, Out of Longjiang Pass and Directly Arriving at Foreign Lands".Fortunately, Mao Yuanyi in the Ming Dynasty compiled it into the 240th volume of "Wu Bei Zhi" and preserved it.It is the world's earliest precious document on navigation technology and navigation map, and it is also an important historical material for studying the history of transportation between China and the West in the 15th century.The original picture is drawn in a long scroll pattern unfolded in one word.When it was included in "Wu Bei Zhi", it was changed to a book style, from right to left, one page in order, 20 pages of pictures, and two pages of the map of crossing the ocean and stars.The picture starts from Nanjing, spreads all over the present-day South China Sea and the coasts of the Indian Ocean, all the way to the east coast of Africa.The map mainly focuses on the route, and draws landforms such as mountain shapes, islands, hidden reefs, and shoals.When crossing the Bay of Bengal and the Indian Ocean, due to the vastness of the sea and the uniformity of the water and the sky, there is no landmark navigation. Although there are compass on board to determine the course and orientation of the ship, astronomical navigation is still very important. "For three years, the economic sea is vast, the water and the sky are connected, and the surroundings are completely different, and there is absolutely no concealment. You can only look at the sun and the moon to distinguish the west and the east, the height of the stars, and measure the distance." (Preface to Gong Zhen's "Western Fan Guozhi").In "Yingya Shenglan" written by Ma Huan, there is a "Journey Poem": "I want to cast my eyes on the western regions, but I see the waves and the sky. And the fleet cannot do without celestial navigation.In ancient times, astronomical navigation was called "Crossing the Ocean and Leading the Stars". There are four charts in the appendix of "Zheng He's Nautical Charts":

1. "Guli to Hulumos Crossing the Ocean and Leading the Stars" (the title of the original picture is missing). 2. "Mount Ceylon Sumen crossing the ocean and drawing the stars". 3. "Map of Ambergris Islet and Mount Ceylon Crossing the Ocean and Leading the Stars". 4. "Churmos' Return to Ancient Li and Across the Ocean to Lead the Stars". A ship with three masts and three sails is drawn in the center of the map, and the positions, angles, and levels of the stars are marked around it to guide the ship's navigation.The upper right corner of the map indicates the map (title) from a certain place to a certain place.For the height of the stars, it is called a few fingers and a few corners.Li Xu of the Ming Dynasty said in "Jie'an Old Man's Essays": "A pair of star boards, twelve pieces, made of ebony, grew up from childhood, and the larger ones were more than seven inches long, marked with one finger, two fingers, and even twelve fingers. There are fine engravings, as if they were measured. There is also a piece of ivory, two inches long, with four corners missing, on which there are characters such as half finger, half corner and one corner triangle, facing each other upside down." This tells us that the utensils used for stargazing at that time were called "drawing stars". plate".It is a small square board made of ebony (hardwood), and there are 12 pieces. The largest one is more than seven inches long on a side, which is 24 centimeters today, and is called twelve fingers; Decrease by two centimeters, called ten fingers, nine fingers, eight fingers... The smallest piece is only two centimeters long, called one finger. "Finger" is the unit used to observe the height of stars in ancient times. One finger is about 1°34' to 1°36'. The unit below the finger is called "angle", and one "angle" is equal to 1/4 finger.Mastering celestial navigation is called astrology.When holding the star, the shipmaster threaded a small rope through the center of the star-holding board. The length of the small rope is about 72 centimeters from the distance from the human eye to the straight board held by the hand.Hold the starboard with your left hand, hold the straightened small rope with your right hand, and look at the starboard along the end of the rope with your eyes, so that the upper edge of the starboard is aligned with the star and the lower edge is aligned with the sea level, so that In terms of the height of the energy output star from the sea level, the star plate used at this time is a few fingers, and the height of the star is this index.If the observed star is the North Star, the geographic latitude of the measuring point can be obtained by obtaining the index of the North Star and then combining the degrees.These nautical scientific knowledge are extremely precious cultural heritage left to future generations.