In Su You's words, this was a great voyage.

If you take the Ancient Tea Horse Road from Erlin Department to Meizhou, it will take about five days.

But if you take the water route, you must first enter the Minjiang River from the Glass River, and then go down the river to Yibin County, the intersection of the Minjiang River and the Yangtze River. Then turn around and go deep along the Jinsha River, passing through half of Dali, to the Anning River and the Yangtze River.

At the entrance of Jinsha River, turn into Anning River and go all the way north, passing Jianchang Mansion, and finally reach Erlin Department.

The entire voyage is like a huge U-shape. The two heads of the U are Erlin Department on the left and Meizhou on the right.

Drawing a straight line through the blank space between the two ends is the Ancient Tea Horse Road hidden in the mountains, and the entire U-shaped solid part is part of the waterway of the Southern Silk Road.

The whole journey is more than 1,600 miles, and the planned time is one month.

This is also a big cycle. Now when the Erlin Department goes to Meishan, the goods are mainly large livestock sent to Lingjing. At the same time, they also carry products from the southwest ethnic minority areas.

It is not cost-effective to go to Meizhou to exchange for Song Dynasty goods and then come back and take the Tea Horse Road.

To bring hundreds of tons of goods back by horse, thousands of horsepower would be needed, and the cost would be too high. With the Erlin Department's big ship, it would only take one ship.

So even though we have come in a huge circle, we still have to go.

Moreover, the only goods that ultimately went to the Erlin Department were salt, and most of them were sold when passing through Dali.

Two small boats were towed behind the big ship. Su You inquired and found out that after passing through the Song Dynasty, one had to be careful and live on the big ship if possible. External communication was mainly carried out by small boats.

The journey down the river was very fast. It only took three days for the ship to arrive at Yibin County. Jiazhou had already been passed by on the first night, and Su You was not even able to see the Leshan Giant Buddha.

After replenishing supplies in Yibin County, the ship began its journey upstream.

The speed suddenly slowed down.

The Jinsha River was still wild for a long time until the 21st century. Now it is almost completely primitive. Both sides of the river are covered with dense virgin forests. The real "apes on both sides of the river can't stop crying" reminds Su You of the documentary.

Views from both sides of the Amazon River.

Occasionally there are some tribal groups scattered along the open areas. Looking at the situation, they are still in the slash-and-burn cultivation stage.

Su You was bored, so he simply moved out the sawing machine and the foot-operated workbench and taught the soldiers how to operate and process wooden parts.

By the way, I picked some facilities on the ship to improve, such as adding a bearing sail pulley to the top of the mast, adding a winch to the anchor rope, etc. It was a combination of learning and practice.

The biggest modification is to add a watertight cabin and move the rudder compartment forward to the bow.

This ship looks mighty and majestic, with a streamlined style of battleship, and its speed is indeed very fast. At least in the Jinsha River Basin, except for the Song Army, the Erlin Department can rely on this ship to run rampant.

However, when Su You went down to the cabin, he was frightened to death. There was no watertight cabin, and his sister was tricked by the treacherous Song Dynasty shipbuilder!

For your own safety, this must be modified!

Although the boat boss thinks this is unnecessary, the freshwater river is so dangerous!

But Atunmi is very fond of this cheap younger brother now. The younger brother said that the moon rises during the day and the sun rises at night, which is correct, not to mention the small watertight compartment, change it!

Chen Zhen was squatting on the stern of the boat and drawing circles. Fanbang is a witch. I will fight you every time I show my sword. Now Su Mingrun is about to turn the bottom of the boat over and you are still clapping your hands happily. It is unethical! Idiot!

However, the boss of the ship absolutely supported the renovation of the helm house. A large steering wheel was erected on the bow of the ship. It used bearings and the transmission was extremely flexible.

The control gear set drives the fixed pulley to tighten the rope along the side deck of the ship, allowing the stern rudder to turn flexibly.

The stern rudder was not yet dared to be taken off, and the first mate was fearfully guarding the rear, fearing that if the bow steering wheel failed, he could immediately take over control of the ship.

There are many benefits to moving the helm forward. The boat owner can promptly determine the water conditions ahead without being blocked by the hull and sails.

Su You is also amazed at today's sailing technology.

The Chinese-style hard sail was not included in the four great inventions. In Su You's mind, it was really unfair.

This sail has been famous since ancient times for being able to handle the wind from all directions, being easy to sail and requiring less crew, which are all things that Western-style square sails cannot do.

Although there are mostly north-south winds in China's offshore waters, the wind direction changes rapidly, and the average annual wind speed is Category 4. Western square sails simply cannot adapt to such wind conditions.

When the Portuguese arrived in Macau, they replaced their sails with Chinese-style hard sails to adapt to the wind conditions in China's offshore waters. This type of ship with a Western-style hull and Chinese-style sails was called an old lock ship and was used by the Portuguese for a long time.

The biggest difference between Chinese sailboats, Western schooners, and square sailboats in the use of wind power is that they can all use static wind pressure, which is the lift of the airfoil. That is, the sail generates a sail arch in the wind flowing through the sail surface and flows over the upper surface.

The pressure difference caused by the different wind speed on the lower surface is the Bernoulli effect.

This kind of lift is much greater than the pressure generated by the wind blowing on the sail surface when the wind is downwind. Therefore, for Chinese-style hard sails and Western-style fore-and-aft sails, the ship speed is the fastest in crosswind, and the lift will not be reduced due to the increase in ship speed, so

Ship speed can sometimes exceed wind speed.

The square sail can only use the dynamic wind pressure when the wind is downwind. The higher the ship speed, the smaller the speed difference with the wind speed, and the smaller the thrust of the sail, so the square sail can never exceed the wind speed.

The stiffness of the Chinese hard sail is only compared to the Western soft sail that does not have stays. The Chinese hard sail actually divides the sail surface into many parts because of the stays, which plays a role in strengthening the sail surface.

Therefore, many non-"high-end" sail materials can be used for Chinese sails. Mats, canvas and even pockets can be used as sail materials.

Western-style soft sails can only use high-quality canvas because there are no supporting stays or ribs on the sail surface.

Moreover, the stays of a Chinese-style hard sail can prevent the holes in the sail from expanding, while once a hole is found in a Western-style soft sail, it will cause the entire sail to crack under the action of strong winds.

Therefore, Chinese sailors don’t need to pay too much attention to the holes in Chinese hard sails. Western sailors often laugh at the sails with many holes in Chinese sailboats, but they never notice that these ships with broken sails can still run briskly.

sailing, and if their own sails encounter such a situation, they must stop the ship and change the sails.

When encountering strong winds, the Chinese hard sail raises the sail from bottom to top, so the sail falls very quickly.

In an emergency, the sail can be instantly lowered by cutting the rope with a knife, and the center of gravity of the ship will drop at the same time, so it is much safer than a Western-style sailboat.

When matting is used as the sail material, the Chinese hard sail is certainly very heavy, but when cloth is used as the sail material, the weight is almost the same as that of the Western-style longitudinal sail.

The only disadvantage is that as a type of longitudinal sail, it rotates around the mast, so it cannot be equipped with a mast pull rope to increase the strength of the mast.

In addition, we missed the Age of Discovery, so we did not develop the high-mast system.

In fact, until the American Civil War, schooners were still plying the sea. The famous Wyoming was 100 meters long, with six masts and eleven sails, with a full load displacement of 9,100 tons, of which the cargo capacity reached 6,000 tons, and its maximum speed reached

An incredible sixteen knots, while a standard crew only requires fourteen people!

Later, after the development of steel masts, except for antique ships, the sailing world became dominated by schooners!

This kind of schooner is often used as a transportation ship, blockade breaking ship, and frigate due to its high speed and flexible steering characteristics.

It's a pity that China's rulers in the past dynasties, for various reasons, liked to ban the sea, and even banned the construction of pointed-headed sea-going ships, forcing China's navigation technology to die in its teenage years.

The large ship of the Erlin Division has many similarities with the Western schooners of later generations, so the crew responsible for operating it is actually only six people, and the rest are all Atunmi's quick reaction troops.

The leader of the team was Adun Chihuo, who was responsible for security and hunting. Several Meishan people were happy to see hunters. When they passed the Song Dynasty, after Adun Chihuo took out the crossbow from the bottom warehouse, they were even more happy.

Every day I go ashore in a small boat and play crossbow hunting.

Su You doesn't like to join in the fun, he likes fishing.
Chapter completed!