Because the battle of Liaodong planned by Li Jing and the matter of Sichuan immigrants, they all involved inland river ships. Li Jing had to consider creating an inland river ship suitable for the entire inland area of the Ming Dynasty. The sheepskin raft can only drift along the water, and when it reaches the downstream, it is generally dismantled and transported back upstream by horse-drawn carts or horse-backed horses, because this kind of vehicle without fairing shape has great resistance in the chaotic shape. In fact, it can only be used one-way.

The sheepskin raft was far from satisfying Li Jing's needs. Therefore, it is necessary to design a special type of inland river that is suitable for most of the inland rivers of the entire Ming Dynasty. Li Jing decided to design a basic model first, determine the main structure, and then develop warships and cargo ships. After that, different specifications can be improved by scaling up and down according to the base type.

Inland rivers are different from the sea, the main thing is that the water is shallow, and it is necessary to have a shallow draft, so that the boat must be designed to be very wide, and it cannot be pointed like a sea boat. It is only possible to increase the amount of water discharged by expanding the planar volume. The aspect ratio must be between 2.5 and 5, and if it is too long, it will not be possible to turn in the river.

The second is the problem of propulsion, there are not many sails for inland river ships, if the wind is not good, the sea is wide and can go zigzag, but the inland river is narrow, and you can't go zigzag. Many of them are paddles or rows, and some are even poles, and the worst routes are simply pulled by people.

Take Chuanjiang as an example, the last time Li Jing went, he saw a lot of fiber-pulling, both men and women, all of them were the poorest and unemployed, and all of them didn't wear clothes, because the clothes would be worn out. Men and women mixed together, shouting trumpets while pulling heavy cargo ships across the Three Gorges. was so frightened that Li Jing's sister and the four maids hid in the cabin and didn't dare to come out.

The boat Li Jing bought on the two light curtains, the boat is small, the material is light, and it uses the most high-tech sails and control system, which can maximize the use of wind power through small range maneuvers. It is impossible to achieve a ship in this era.

Generally speaking, in terms of drive efficiency, the paddle is the lowest. Because, with each circular movement of the arm, half of the oars are in the air and half in the water, and the movement in the air is a waste of energy. The oars are generally located at the stern of the boat, and the oars are always in the water, and all the force can be used for propulsion, so the efficiency of the oars is three times that of the oars.

However, the oars also have the advantage that they can be arranged in multiple quantities on both sides, but only one oar can be arranged on one boat (except for large rivers and sea boats, which can be arranged on both sides of the dense oar). Even if more than one person is rocking together, it is not as convenient as paddling. The shortcomings of the rocking propel are also obvious, firstly, most of the rocking is in a standing position, and the long-term operation is more physically demanding. Second, the rocking oar occupies more space in the ship, which is not conducive to the deployment of multi-layer swaying.

There is also the paddle wheel, which was invented very early in China to propel ships with paddle wheels, and ships in inland rivers and oceans are propelled by paddle wheels. And it's very huge, and it's fast. This type of ship is a car ship.

As early as the Northern and Southern Dynasties, there were records of vehicles and ships in the history books.

In the Tang Dynasty, Li Gao played a role in the development of vehicles and ships. The cars and ships he built were moved forward quickly by human power. The structure is a wooden shaft across the two sides, and there is a wooden wheel with many paddles on each side, half of which is in the water and half is on the water.

The wooden shaft has a pedal inside the boat, just like a waterwheel stepped on by manpower, and a row of people hold on to the horizontal wooden pole and pedal it with their feet to make the wooden wheels outside the two sides rotate and paddle forward. There are many rows of wooden wheels from front to back of a boat, and there are dozens of rows, so the speed is still quite fast. The disadvantage is that it occupies the most valuable cabin space of inland waterway vessels, because of the shallow draft, inland waterway vessels often only have one cabin.

The vehicles and ships of the Song Dynasty were very prosperous, and the warship restored by Wang Yan in the second year of Shaoxing (1132) was set up next to 4 wheels, each round of 8 poles (oars). Carpenter Gao Xuan is also a famous craftsman who has created more than 10 kinds of large and small cars and ships, with a length of 20~30 zhang and a draft of about 1 zhang, which can accommodate 700~800 people; Medium-sized vehicles and ships generally carry 200~300 people. There are 2 cars, 4 cars, 5 cars, 8 cars, 9 cars, 23 cars, 24 cars, etc. This number is the number of axes of the paddle wheel shaft. The largest car in the Song Dynasty was 36 zhang long and 4 zhang 1 foot wide.

At the beginning of the Ming Dynasty, Chen Youliang also used vehicles and boats to conduct water battles in Poyang Lake.

After the middle of the Ming Dynasty, Lu Chongjun made various types of vehicles and ships called "Jingjiang Dragon Boats".

Until the beginning of the 20th century, there were still a small number of vehicles and ships in southern China. Although vehicles and ships have not been widely used in various water systems, they have a long history and have played a great role in the development of Chinese ships.

However, despite the great advantages of the car and boat, Li Jing still did not want to choose the car and ship propelled by the paddle wheel. One reason is that sooner or later you have to get on the steam engine, it is better to start using the propeller earlier. In addition, the propulsion efficiency of the paddle wheel is much higher than that of the oars and oars. After all, oars and oars are paddled with arms, vehicles and boats are pedaled with feet, arms are not as strong as waist and legs, the so-called arms can't twist the thighs, just like a bow and arrow can't shoot foot anger and waist crossbow is a truth.

However, there is a big problem with the paddle wheel. The structure of the paddle wheel is complex and greatly affected by wind and waves, and the maximum resistance on the water does not come from the friction between the water and the hull. It's the wave resistance. It's the resistance caused by the waves. If the boat encounters wind and waves, it will sway from side to side like a duck.

The density of air and water differs by 800 times, and the huge paddle wheel goes in and out of it, and the force is uneven, and it is easily damaged by long-term deformation. The exposed paddle wheels were also a good target for the enemy, and during the Crimean War in 1854, there were still a number of paddle wheels, and the batteries on the coast focused on attacking these paddle wheels with heavy losses.

The biggest drawback of the paddle wheel is whether it is efficient or low, and some people are determined to change it, and they think of Archimedes. Archimedes designed the spiral pump, which is to set up a shaft in a long cylinder, and there are many spiral-shaped blades on the shaft, as long as you shake it by hand, the curved handle on the shaft can pump the water up. It can be pumped for irrigation, and it can also be used for drainage in low-lying areas.

Inspired by the auger pump, the propeller was invented when it was completely submerged in water, with a propulsion efficiency of between 40% and 45%. In the past, the pulp and oar efficiency were in single digits, and even less than one. The bottom of the propeller can go through the stern, as long as it is waterproof.

In the era when there was no steam engine power, how to drive the propeller, Li Jing thought of two methods. One is to refer to the way of multi-person riding bicycles, using gear-to-gear transmission, and a row of people can pedal. It's like riding a bike. But such gears need to be strong, wear-resistant, and even precise, otherwise they will get stuck. This is difficult to do without math such as machine tools and involute equations.

This advantage is that the propulsion efficiency is super high, and the price of modern all-gear bicycles is five or six thousand yuan or even tens of thousands of yuan. The efficiency of the gear transmission is as high as 99%, and the chain can only reach about 80%. Pure gear bikes are really not for ordinary people to play. And it is also durable, will not drop the chain, worship the shared bicycle has been out of a batch, pure gear, hexagonal perforated non-inflatable solid rubber tire bicycle, is high reliability, not easy to break, maintenance-free.

Another method is very easy to achieve, that is, simply take the bicycle chain to drive, this flexibility is good, such as a good set, and the bicycle is the same as no two wheels, the chain directly drives the underwater propeller, and the handlebar should be used to control the steering gear behind the propeller. So that the propulsion and steering are there. This set of equipment is light and small, and can flexibly load any size of the original wooden boat on the river. Because this system weighs only a dozen catties, at most more than 20 catties. How much can a bicycle weigh without the wheels. One is a single-shaft single-paddle drive, and two are twin-shaft and double-propeller drives.

The installation is also simple, just screw it on with a large wooden screw. If you can make a gear that meets the requirements, you can make a simple device, install a lever on the handlebar, one forward gear, one reverse gear. It's so wonderful, Li Jing is going to worship himself, it's so thoughtful.

In the case of large, purpose-built inland waterway vessels, a spindle can be added to the cabin to run through the entire ship, and on the main shaft, from end to end, is a single bicycle mounted horizontally, and the chain is directly connected to the pedal wheel and the gear on the spindle. A drain rider rode horizontally on the main axle and pedaled the bicycle quickly, changing a group of people in half an hour, Li Jing roughly calculated that the inland river countercurrent can also reach a speed of 5 to 10 kilometers.

In this way, the surplus space on both sides of the ship can carry cargo, and it is also possible to install bulwark gun windows and install artillery for combat. Cargo can also be stacked on the deck, and of course masts can be installed as backups, so that if the wind is in the right direction, there is no need to tire the crew into dogs.

Chain production may be troublesome, these are fine parts, but it doesn't matter, Li Jing invited the goldsmiths, silversmiths and jewelers in Jinling City, they are used to using hammers, do these fine things, Li Jing has good steel is not afraid of not being able to get out, it really can't do a thick chain, enlarged chain, the difficulty is reduced in a straight line, the biggest problem of the chain is wear, at present, it can only be used carburizing and tempering to do surface hardening to resist wear. At the same time, add more lubricating oil, which can be replaced by animal fat mixed with graphite powder.

In the future, you can use manganese steel to make gears and chains, which is super wear-resistant. Manganese ore There are mines in the upper reaches of the Hanjiang River, and they have been mined in later generations, and it has to be said that the mineral resources of the Hanjiang River are too blessed, and there are all kinds of rare metals and minerals. Li Jing also knew the proven reserves and the location of the mine in later generations.

Li Jing arranged a group of people alone to make this propeller propulsion device, and after the steel pipe was burned red with plates, it was rolled up, wrapped around the square strip of the base, and the forging joint was made into a steel pipe. Different steel pipes can also be forged into various shapes. The chain is also developed by a separate group of people. Let's start with a few individual bikes to experiment. After it is done, find a wooden boat and install it for experiments.