Chapter 9 Chapter 9 The Maturity of Shipbuilding and Navigation Technology in the Han Dynasty

In the Han Dynasty, my country's shipbuilding and navigation technology had matured.Its symbol is that in addition to the tall "building ships" with a height of more than ten feet and three floors and various types of ships mentioned above, there are also many inventions and creations, such as oars, sculls, stern rudders, sails and other ship propulsion. The increasingly perfect and widely used tools, the major contribution of the shipbuilding structure of the transverse compartment, etc. As far back as the Neolithic Age in our country, we have already known to use pennies and wooden oars to row and control the direction of the boat.Later, with people's long voyages to the deep water area, the use of pennies is not so convenient and not very effective, and the role of wooden oars is increasing day by day.The early oars were mostly short oars, called "Ji".On the wooden ship model of the Western Han Dynasty unearthed in Guangzhou, there are four wooden figurines, each holding a short oar, sitting and rowing the boat, that is the oar.However, due to the shallowness of the oars and the small driving force, people continue to improve, lengthen the paddle board and widen the blades, and the short oars for sitting and paddling are increasingly becoming long oars for standing and paddling.The long paddle was called "棹" in ancient times.Because the long oar is heavy and it is inconvenient to paddle, a handle hole or a fixed fulcrum for placing the long oar is made on the side, called the oar seat, to exert leverage.The paddle board pushes the water backwards, and its reaction force pushes the boat forward through the oar seat.In the wooden ship model of the Western Han Dynasty unearthed in Changsha, we can see that there are 16 long oars, namely "棹". When paddling, the strength of the arm can be reduced, and the effect of the wrist and arm is brought into play. The weight of the oarsman also produces the effect of doing work, and the efficiency is greatly improved.In order to increase the speed of the boat, paddlers often row and sing together to unify the movement and reduce fatigue at the same time.In Emperor Wu of the Han Dynasty's "Ode to the Autumn Wind", there is a description of "Xiao Drum Ming Comes Out of the Song", which describes this situation.

The scull is a tool for propelling a ship by manpower evolved from a long oar, and it is also a tool for controlling the course of the ship.Oars are often inconvenient in rowing.Every time the paddle enters the water to do work, it will immediately leave the water to prepare for the second time to enter the water to do work. In this way, what is done in the water is "virtual work", which affects the efficiency of rowing.Therefore it works intermittently, and the boats and ships can only be propelled intermittently.So people improved the long oars and invented sculls.The shape of the scull is very similar to that of a long oar, but larger, and the handle and board of the scull are curved.The cross-section of the end entering the water is bow-shaped, and the other end is tied to the boat. A rope called "scull rope" is tied to the top of the scull handle, and the lower end of the scull rope is tied to an iron ring on the deck.The scull rope can not only fix the scull, but also can be stretched to adjust the depth of the scull board entering the water.Liu Xi's "Explanation of Names" pointed out the operating position and function of the scull: "It is called a scull next to it, and the scull is also used to use the brawn force to move the boat." The operation method of the scull is "shaking", which is called "shaking the scull".After entering the water, the scull continues to shake, and the scull blades in the water swing from side to side, and the difference in water pressure between the front and back can generate thrust.Its thrust is more efficient and less labor-intensive than long oars.Because the scull lengthens the handle and blade of the long oar, and bends the tail of the original blade upward, the scull is also called a new type of long oar.The scull is placed on the side, and the scull is held by the handle and shakes back and forth to continuously propel the boat. This is an epoch-making major invention in the ship propulsion tools of the Han Dynasty.Later, the scull gradually evolved from being placed on the side of the ship to being placed at the stern. It can not only play a role in propulsion, but also control the turning of the ship, adjust the direction, and control the course.Due to the simple structure of the scull, one device can be used for multiple purposes, and it still works today.The scull is China's outstanding contribution to the world's shipbuilding and navigation technology.

my country is the first country in the world to invent the rudder.The invention and use of the rudder is a major achievement in my country's shipbuilding and navigation technology.The function of the oar is to row and control the direction. The oar that controls the direction is called the rudder oar, and its position gradually moves from the side of the ship to the center of the stern to become the tail oar.The tail rotor changed from paddling to swinging without leaving the water surface. The tail rotor played the role of a rudder and was renamed the rudder oar. The rudder oar is the ancestor of the rudder.From the wooden boat model unearthed from the Western Han Tomb in Jiangling, Hubei in 1974, it can be seen that there are five long oars on the boat, all of which have oar forks. Four of them are used for rowing on both sides of the front of the boat, and the other is near the stern The sides are used as rudder oars.The rudder and oar are not easy to operate when encountering shoals or docking, and the blades are not easy to operate when the size of the hull increases, so people changed the installation method and produced the rudder.

The rudder was invented and used at the latest in the Eastern Han Dynasty. The rudder of the pottery ship model unearthed in Guangzhou in 1955 has an early stern rudder.The rudder surface is an irregular square shape with a large area, which is completely different from the shape of the rudder oar.The rudder stock is fixed in a cross-shaped structure and extends obliquely from the stern to the rear of the ship. There is a hole at the top of the rudder stock for installing the rudder handle. Turning the rudder handle can make the rudder surface rotate on a shaft, and the direction of the ship can be adjusted freely.This is a major innovation in heading control tools.

In the Han Dynasty, the technology of using sails in our country was mature.During the Qin and Han Dynasties, my country was already able to conduct large-scale navigation by virtue of the monsoon.This is impossible without mature sailing technology.Liu An of the Western Han Dynasty said in "Huainanzi": "If you see the wind when you see the wind, it doesn't take a moment to decide." Chu people call it Wuliang." Ni is an ancient device for measuring wind and observing wind direction. Later, some people also called it Wuliang. The "伣" wind measuring instrument existed in the Shang Dynasty.It was used in the Han Dynasty.This is actually a silk ribbon (or feather) tied to the top of the pole for wind measurement.When there is wind, it swings with the wind, and the direction of the wind can be known according to the direction in which it swings.On the Jianzhang Palace built by Emperor Wu of the Han Dynasty, there are two copper phoenixes that look at the wind (observe the wind direction).The ancient geography book "Sanfu Huangtu" said: "The bronze phoenix is ​​five feet high, decorated with gold, and there are pivots on the top and bottom of the house, flying towards the wind."Of course, this is all grand.Why is it called "five liang" again?Because the weight must be more than five taels and less than eight taels, if it is too heavy, it will be difficult to blow up, and if it is too light, it will be easy to rotate, and it will be difficult to grasp the direction of the wind.Due to the simple and practical structure of this wind measuring instrument, it can be easily moved to the ship for use in navigation.Li Bai, a poet of the Tang Dynasty, has a sentence in his poem "Sending Cui's Kundi to Jinling" that "the water guests return to the boat, the clouds and sails curl up with light frost, and the flat boats come down to the pavilion, and the five liang are flying first", which illustrates this problem.Later generations still hang the "carp streamer" on the top of the mast, which is developed from the beautification of "伣", and it is also a wind measuring instrument.

The structure of the sail and the technology of controlling the wind were completed in the Eastern Han Dynasty at the latest.One type of sail is made of silk fabric or cloth, called "cloth sail"; the other is made of bamboo strips or other plant fibers, called "Xi Fan".From a structural point of view, one type is soft sails, such as cloth sails and cattail grass sails, which have no horizontal bamboo support and can only be hung with a gable mast when the wind is down, and cannot be moved obliquely or rotated.The other type is hard sails, which are supported on one side of the sail by several bamboo poles of the same length as the horizontal plane of the sail, or alternately interspersed on both sides of the sail. This kind of horizontal bamboo poles is called sail bamboo, which can support the sail surface. Making it flat allows for more efficient use of wind power.Rigid sails can be hung on a separate mast, and can be turned around the pole to form a balanced schooner.

Wan Zhen, the prefect of Danyang in the Eastern Han Dynasty, wrote "Nanzhou Foreign Objects", which described the sailing and wind-controlling skills of the South China Sea navigators at that time.The book explains the role of the position of the sail surface in controlling the wind and the relationship between the style of the sail surface and the wind: "The four sails, if they are not facing forward, are inclined to move and gather to catch the wind. The wind is the latter. If it is in a hurry, it can be increased or decreased as appropriate. Obliquely stretched to capture the wind, without worrying about high danger, so you can't avoid the swift wind and shock waves when you walk, so you can be sick." This makes us understand. The sailing technology used for the sea-going ships of the Han Dynasty.When a sea-going ship sails in the wind, it adopts different sail position arrangements depending on the direction of the wind.This method is still used in modern wooden sailing ships.There is a saying among boatmen that "a boat sails in all directions".That is to say, sailing boats need to use various wind directions to sail with the wind.Eight winds refer to eight wind directions relative to the course of the ship, namely downwind, headwind, left and right wind (ie left and right crosswind).Left and right slant downwind, left and right slant against the wind.When all kinds of wind blow, they form an angle with the longitudinal centerline of the hull.When the wind is downwind, the wind direction is consistent with the longitudinal centerline of the hull to form an angle of 0°, when the wind is across the wind, an angle of 90° is formed, and when the wind is headwind, an angle of 180° is formed.The heading of the ship and the wind direction are between 0°-180°, so that different angles will be formed due to the different wind directions, and this angle is called "wind angle".When the wind angle is 0°, the course of the ship is consistent with the direction of the wind, and the sails of the ship are fully facing the wind, which is the best position to use the wind force.At this time, the sail surface and the longitudinal centerline of the hull form a 90° angle, which is called "sail angle". In general, the wind angle is inversely proportional to the sail angle.In fact, sea-going ships often sail in various crosswinds and oblique winds, and there are very few cases where the wind angle of 0° and the sail angle of 90° are downwind.No matter what the wind direction is, the boatmen will adjust the sail surface to the best position as the wind direction changes, forming the most favorable sail angle.Always pitch the sail to face the wind.On a ship with many sails, the slanted sails face the wind separately, and the rear sail will not block the front sail from the wind.This is also the mature experience of using sails to sail a boat that had been formed as early as the Han Dynasty.The article "Ode to Guangcheng" written by Ma Rong in the Eastern Han Dynasty in the second year of the Yuan Dynasty (AD 115) gave a vivid description of Fengfan: "Then Fang Yuhuang, Lian Qizhou, Zhang Yunfan, Shi Niyi [chou silk], Ling Xun Flow, send out songs, come out of the water, and fish come out, yarrow [shi poem] Cai (yarrow stem, used by the ancients for divination, "yarrow Cai" means yarrow turtle, yarrow and tortoise shell, all used to predict good and bad luck) float, Xiang Ling (God's name, Concubine Yu Shun, that is, Mrs. Xiang) descends, and Han women travel." ("Book of the Later Han·Ma Rong Biography")

From archaeological discoveries, it can be known that the Han Dynasty in my country used advanced shipbuilding technology and adopted the shipbuilding structure of transverse compartments.From the Eastern Han pottery ship model unearthed in Guangzhou in 1955 and the ship model unearthed in Jiangling, Hubei in 1974, it can be seen that there are three cabins under the deck of the ship in the front, middle and rear.From the Guangzhou pottery ship model, it can be clearly seen that there are eight beams from the bow to the stern. There are wooden planks laid along the longitudinal direction of the ship on both sides of the ship, which are used as left and right walkways for punt poles.With rudder anchor.Since there is a cabin built on the deck, the left and right walls of the cabin are pressed on the two sides, so there must be beams under the front and rear walls to support its weight.The front and rear walls of the three cabins are each pressed on a beam, which uses six beams. Among the remaining two, according to the general construction mode of wooden ships, one of them is the dragon beam of the bow, and the other is the stern. broken water beam.This shares exactly eight beams.Below each beam is the frame to reinforce the transverse strength in the construction of wooden boats, on which the bulkheads composed of transverse planks are attached.Eight beams indicate that there are eight bulkheads, which divide the hull into nine tight subdivisions (cabins).Here it is the shipbuilding technology of the compartment structure formed by beams and bulkheads.When the ship is sailing, even if one or two cabins are damaged and flooded, the water will not flow into other cabins, and the ship will not sink immediately.The flooded cabin can quickly pump water, plug holes and make other repairs without affecting the continued navigation of the ship.The bulkheads and shell plates are tightly nailed, the gaps are sealed with tung putty, and the hull is reinforced, which increases the firmness and safety of the ship when sailing in strong winds and waves.

The bow cabin is mostly used to store sails, cables and other nautical tools and items.The aft cabin is mostly used as a galley.There are also seven formal cabins available. The shipbuilding structure of the transverse compartment is a major invention of my country's shipbuilding technology.In later generations of shipbuilding, no matter how the hull was subdivided, the ancient Chinese shipbuilding design principles of anti-sinking and reinforcement of lateral strength were followed.