How developed was the navigation technology in Ming Dynasty?

In the third year of Yongle in the Ming Dynasty (1405), the great navigator Zheng He led a huge fleet to sail to the countries and regions west of the South China Sea in China for the first time under the order of Judy, the founding emperor of the Ming Dynasty, which was called "Zheng He's voyage to the West" in history.

6 10 years have passed. When we stand in front of the "treasure ship" model with a length of 15 18 m and a width of 6 1.6 m, we can't help sighing about the advanced shipbuilding and navigation technology in ancient China.

"Lucky boat" and sailing boat

From the perspective of technological development, Zheng He's voyages to the West demonstrated the brilliant achievements of China's ancient shipbuilding and navigation.

With the development of ancient shipbuilding technology in China in Ming Dynasty, three types of seagoing ships appeared, namely, sand boat, wide boat and lucky boat. Sandboat is a shallow draft ship with square head, square tip, flat bottom, many masts, many sails and large aspect ratio. The most distinctive feature of Guangzhou ship is the sail shape that unfolds like a folding fan. In addition, it also plays a certain role in slowing down the ship's swing by inserting the board deeper than the keel at the midline.

Lucky ship is a sharp-bottomed sea ship. The ancient lucky boat was "high in building, wide in bottom and high in fore and aft", with fenders on both sides. The whole ship is divided into four floors, the lower floor is equipped with earth-rock ballast, the second floor is for soldiers to live in, the third floor is the main operating place, and the upper floor is generally used for combat. The treasure ship used by Zheng He's voyages to the Western Seas adopted the form of a lucky ship.

In the era of sailing by the wind, besides ship type, ship power is also one of the symbols of highly developed ship technology in ancient China.

Zheng He's treasure ship has adopted a unique design in two important links of the power propulsion system: mast sail and paddle.

First of all, different from the segmented soft sails used by European sailboats at that time, Zheng He's treasure ship adopted longitudinal sail layout and rigid sail structure in its overall design, and the sail canopy was covered with stays, which was equivalent to ribs and could play a strengthening role. Although this kind of sail is heavy and hard to lift, it has high wind efficiency and can improve the speed of the ship. Moreover, the mast is not equipped with a fixed transverse truss, which can adapt to the sudden change of sea conditions, flexibly adjust its feet, and effectively use the wind from many sides.

Secondly, there are long oars on both sides and stern of Zheng He's treasure ship. This action is similar to today's propeller, with high propulsion efficiency. It can maintain a considerable speed when there is no wind, and is suitable for sailing in narrow harbors and crowded waters.

"Crossing the Ocean and Leading the Stars" and "Acupuncture at Sea"

Zheng He's fleet has further enriched and accumulated navigation knowledge and experience in observing astronomical climate, identifying azimuth and determining navigation route. It was by summing up these knowledge and experiences that people in that era further developed the navigation technology in the early Ming Dynasty on the basis of the Song and Yuan Dynasties.

In Zheng He's Navigation Chart, which records the navigation technology of Zheng He's fleet, a lot of rich information about navigation route, current along the way, water depth, reef distribution, berthing place, compass, astronomical navigation and so on has been preserved, which has become a valuable historical and cultural heritage left by predecessors.

According to Zheng He's Navigational Chart, Zheng He used the most advanced navigation techniques at that time, namely "crossing the ocean to attract stars" and "piercing the sea".

In ancient times, astronomical navigation was also called "guiding stars across the ocean", including observation direction and orientation. After the compass was used in navigation, the method of astronomical navigation was not abandoned, but continued to be enriched and developed. The cooperation with the compass pushed the navigation technology to a new stage.

Around the Yuan and Ming Dynasties, China began to observe the geographical latitude of ships by using the technology of pulling stars. Star pulling is done with a simple tool called a star pulling board. According to the book "Ancient Shipbuilding and Navigation in China" written by Jin Qiupeng, an expert in ancient shipbuilding and navigation technology, the star plate is made of ebony, and a pair of star plates includes a 12 square plate from small to large, and the smallest one is about 2 cm on each side. In addition, there is a small square made of ivory, about 6 cm long, with notches at the four corners. The lengths of the four sides of the notch are half-angle, one-angle, two-angle and triangle respectively, and the one-angle is 1/4 finger. When in use, hold the center of one end of the lead plate with your left hand and straighten your arm so that the lower edge of the plate is horizontal and the upper edge is aligned with the observed star, so that the height of the star and the horizontal plane can be measured from the position of the ship. After measuring the height of the stars, you can calculate the geographical latitude of the ship's position.

Observing and positioning with the "astrolabe", judging the position and direction of the ship and determining the course represent the world advanced level of astronomical navigation technology in that era.

Hai Dao Zhen Jing is a navigation compass used by China in Yuan, Ming and Qing Dynasties. This technology uses eight celestial poles (10 celestial poles minus "e" and "auspicious"), 12 earthly poles and four directions of gossip to divide the circumference of the navigation compass into 24 equal parts, which can accurately indicate the direction.

When Zheng He went to the Western Ocean, he marked the place with azimuth and time. For example, Zheng He's nautical chart states that "Taicang Port uses Yi Dan needle to level Wusong River, and Mao Yi needle to reach Nanhui Mouth", which means "sail from Taicang Port in the direction of 105 degrees, one class reaches Wusong River, and then sails in the direction of 97.5 degrees, and one class reaches Nanhui Mouth".

In addition, log, bathymeter and other navigation instruments, charts, needle road books and other navigation maps were all components of advanced navigation technology at that time.

Zheng He's fleet navigated with a compass during the day and kept its course by watching stars and navigating with a compass at night. By reasonably solving the problems of fresh water storage, ship stability and anti-sinking, Zheng He's fleet was able to "keep the Yun Fan high and the stars gallop day and night" under the sinister conditions of "Hong Tao meets the sky and the waves are like mountains", with few accidents. Hanging and waving flags of various colors in the agreed way during the day to form corresponding semaphores; Use lanterns to reflect the sailing situation at night; In foggy and rainy days with poor visibility, gongs, horns and horns are used for communication.

Standing at the starting point of history

Starting from 1405, Zheng He led his fleet to the Western Ocean for seven times, and the route was from the Western Pacific to the Indian Ocean, directly to the east coast of West Asia and Africa, passing through more than 30 countries and regions. His voyage predated Columbus's discovery of America by 87 years. As early as 92, Gamma developed a navigation route from Europe to India bypassing the Cape of Good Hope, which was 1 14 years earlier than Magellan's first voyage around the earth. In the history of world navigation, Zheng He's fleet opened a direct route across the western Pacific Ocean and the Indian Ocean. According to Dr. Joseph Needham, a famous British historian of science, there should be no less than 3,800 ships in the Ming Dynasty during the period of 1420, exceeding the sum of all ships in Europe at that time. For all countries in the world at that time, the scale and strength of Zheng He's fleet were unparalleled.

The length, scale and scope of Zheng He's voyages to the West are unprecedented. It not only reached the peak of world navigation at that time, but also made great contributions to the development of friendly relations between China and other countries.