"It is hard to say when the wind is really against the wind." Xiong Jing naturally remembered a word: Bernoulli's principle of fluid. "The wind blows the sails, and sails push the boat. The real wind is not like this. Really against the wind is like... it seems..." Standing on the deck of the stern and looking at the seabird flying and singing on the side of the boat, Xiong Jing finally found an example and said: "It's like a seabird flying high. The bird's wings spread, and the air flows over the wings and flies down. The upward and downward are slow, and the bird's wings will generate lift, which will lift up the bird's wings.

To be honest, sails are used as wings, but bird wings are horizontal and boat sails are vertical. As long as the boat sail is aimed at the wind direction at a certain angle, like bird wings, and the wind passing through both sides of the boat sail is slow in front and fast in the back, the sails can push the sea boat forward."

"So that's it." The left and right Shi understood, but only understood. Their eyes kept changing between the seabird and the mainsail, as if they wanted to find out the similarities between the bird's wings and the mainsail.

"This sail cannot be really against the wind." Xiong Jing added. At this time, several second-year students from the aviation school who were listening to the deck of the stern floor stood. Xiong Jing had to say it more finely. "There are two kinds of sails, one is a horizontal sail and the other is a vertical sail. The horizontal sail is like a shield, square; the vertical sail..." He pointed to the triangular rear-mast mainsail. "This is a vertical sail."

"Horizontal sails are generally used for sea boats that transport cargo, or sea boats with a smaller aspect ratio. Such sea boats are heavy, so they must be pushed by cross sails. However, it is difficult to really go against the wind when cross sails. It is too slow to learn from crabs. It is better to wait for a good wind than to sail far away. Therefore, sea boats must wait for the monsoon and be able to sail only once a year. Sails are used for sea boats with a larger aspect ratio. The sea boats are narrow and have fewer loads. The sails can be really against the wind and can sail at any time of the year."

"Why... why can't this Hengfan really go against the wind?" The Right Shi looked at Hengfan, then looked at the Chengfan again, not understanding the meaning.

"Because the sail cannot turn over." Xiong Jing pointed to the front, back and side support cableways on the mast. "When it is really against the wind, the sail must be aimed at the wind direction at a certain angle. Because these ropes, the horizontal truss of the sails cannot turn to a suitable windward angle, so it cannot really go against the wind."

"Rope?" The masts are tied with ropes, and it is difficult for ordinary people to tell how many ropes there are. Although all the ropes are just a sail, a simple superposition of a mast can't be understood if you see them too much.

"Can you remove these ropes?" Zuo Shi asked again. The ropes were like spider webs, and his eyes were sharper than the right Shi, and he could not tell the ropes.

"Yes. But there is only one layer of sail left on the boat, and the mast is short, otherwise it will be broken by the wind. The boat can be feasible near the sea, but it is difficult to travel far sea. Because the sail surface is too narrow and the thrust is too small, you will still have to sail with the wind and cannot go against the wind." Zuo Shi actually said that Chinese sails. There is only one layer of Chinese sail. Because there is only one layer, the area of ​​the sail is not enough, and the thrust is not enough. Zheng He went to the West to sail with the wind, not against the wind, but Chinese sails are sails, and winds from all sides can sail, and sailing does not have to wait for the monsoon.

"It turns out that sails have their own strengths and weaknesses." Zuo Shi Ji said, and the Right Shi sighed easily.

"The cargo volume of sea boats, traveling against the wind and walking with the wind, must be made choices for the three." Unlike when building Shaosixing level, Xiong Jing has now understood the essence of sailing ship design. "This year, it will be launched to the water, which is really a sailing ship that is going against the wind, but this sailing ship cargo volume is less than half of the normal sailing ship."

"Not half?" You Shi said in surprise.

"Yes." Xiong Jing was talking about the fly-scissor experimental ship that was about to be launched this year. It was also a 29-meter-long keel (the boat was 35 meters long), a cross sailing ship that was more than nine meters wide, and a cross-scissor ship that was more than five meters wide. The actual drainage difference between the two was more than half. The cross-scissor ship had more than five hundred and twenty tons, and the fly-scissor ship was less than two hundred and fifty tons.

Keel bones are precious, and even if fly clippers can sail twice a year, it is not cost-effective. Historically, the main transport of fly clippers was tea or new tea. In addition, opium, both are lightweight and high-value items. Xiong Jing is not sure what to sell at that time, silk, porcelain, tea, spices? Or is it a giant iron, armor, paper, or even cement?

When he was thinking about trading goods, the acting captain Hong Mou Zheng ordered people to measure the speed, and the hourglass of the timing also began to count. Although the track is back down and cannot accurately determine the ship's position, it is not abandoned. It is often used as a reference for inference of the ship's position.

The sail was full and the smooth sailing was sailing eastward from Zhu Fangyi like an arrow, and the speed was so fast that two pawn-winged warships beat the drums. Two hundred and fifty slingers rowed with all their strength to lead the way in front. The speed of the Madam Xiang behind him was also not reduced, and she kept a distance of about five chains from the Madame Shao Si.

The sails whistled above the head, the sun was slowly rising, the sun was scattering on the sea, and the shimmering was golden. The river was still in sight, and the busy farmers in the fields were staring at the two sailboats carrying sails eastwards, while the curious children were running on the shore, but they were getting behind them as they ran.

"That's it." Xiong Jing smiled on his face. He enjoyed the feeling he was now. The sailors and students on the sea boat were also cheering on the other side. This time they were really going to go out to sea, heading towards the depths of the sea that they had never been to. Only Zhu Zhu and his followers, who had gone out to sea for the first time, grabbed a support on the deck, were worried, and there was no feeling of enjoyment.

"Please check the waterway." Wu Jieheng, who was in charge of navigation, walked over with the waterway he drew. He followed the map given by Xiong Jing, and his tracks were no different from those drawn by Xiong Jing himself.

"Do you know why this is the case?" He was already in the stern building, and Xiong Jing nodded and was about to explain the reason to him.

"Dahe travels north all year round. This time, he sails along the south wind and travels along the Dahe. He can reach the island in a few days." Wu Jieheng was the first in graduation score and was arranged on the Shaosi Ming No. 1. Xiong Jing had previously talked about Dahe in class.

"Well." Xiong Jing grabbed a pen, dipped it ink and drew a sketch of the East Asian sea area. The sketch cannot accurately display the latitude like the map, but the general position is good. "Remember! The currents within the big valley are so rotating," Xiong Jing drew a counterclockwise direction. "The big valley goes north and will divert it to the northwest and enter the Bohai Sea. The rest of the river goes south because of the coastal current. The wind direction alternates in winter and summer, but the current has not changed forever."

The king actually taught something new. Wu Siheng's face was full of excitement and kept nodding.

Before Xiong Jing finished speaking, he drew Dongzhou on paper and said, "It's so rotating outside the Great Valley," this time he drew a clockwise direction. "Go to Dongzhou and follow Daha to the south of Yingzhou, turn east at 40 degrees north latitude, and then travel east along Daha. It's best to sail in June every year. This is a westerly wind belt, and it takes six months to reach Dongzhou with the wind, rarely more than seven months.

The return journey is to go south along the coast of East China, at the end of January and early February, and sail westward at about 12 degrees north latitude. Monsoons and ocean currents will blow you back to Central China, and the voyage will only take three months. However, the place you return is here, Luzon, you must cross these islands and continue westward to go home.”

Urdaneta, a Spanish man in the 16th century, relied on his rich knowledge of navigation, currents and monsoons, took ten years to figure out the Pacific route, but now he easily painted it on paper. After Xiong Jing said that, Wu Shiheng's face turned pale, and he didn't know whether he was excited or afraid.

"The State of Chu urgently needs three valleys." Xiong Jing knew it was incredible to have an uncrowned young man guide a sailboat across the Pacific Ocean, but he was the best among the students, and everyone except him was one step short of it.

"The migrants in Jiangdong, all the fields are all down to the fields. Even if they plant millet, the yield of a small acre is less than one and a half stone, and the yield of rice is less than eight dou. A family of five needs to plant millet for a hundred and fifty acres to survive, and the rice is twice as good as that of growing rice. If the remaining two grains of the three grains in Dongzhou are not mentioned, the sweet potatoes must be found and brought back. Otherwise, the Qin army will attack Chu again in the future and the people..."

"I swear to bring back Sangu to death." Heng's pale face finally regained his blood. He bowed solemnly, and his determination was settled.

"Don't bring them all back." Xiong Jing instructed. "The yield of sweet potatoes is the highest, and there are enough sweet potatoes. The sooner you bring them back, the sooner you plant them in each county, the more food stored in Gaofu will be, and the harder the people will be hungry."

"I remember." Heng nodded heavily.

"There are three valleys wherever there are people." Xiong Jing added again. He didn't know what the situation in America is now, but since it was a crop, he naturally went to a place with a lot of people to look for it. "It is said that the Yin people traveled to Dongzhou hundreds of years ago. The Yin people often worshiped gods with outsiders. After seeing Yin people, it is necessary to think about how to get along with them."

"Yi." Xiong Jing once said about the Yin people's crossing the east, and remember it.

"Yeah." Xiong Jing just told him in advance. Seeing that he had finished speaking, he handed the chart to Heng and explained: "Remember and burn it."

It is March now, and the latest departure is June next year. It will sail from 40 degrees north latitude to Dongzhou. The six-month journey will arrive at Dongzhou just the end of the year. If you want to return in February, the ocean-going boat team will only have two months to find Indians and sweet potatoes.

Two months..., the vast East Continent, two months are obviously not enough, unless the Indians live by the sea. The ideal situation is to stay in East Continent for a year and spend one year and two months looking for the Three Valleys. You can always find something for such a long time. After finding it, it will be in June and July of the third year.

In the sixth and seventh year of the third year, what would Qin do in three years? Defeat Chu, attack Zhao, and endanger Han and destroy Wei?

After retiring from the army two years ago, Qin State restrained its minions and became extremely quiet. Although South Korea consumed 70,000 to 80,000 people in the Battle of Ao Cang, South Korea was not annexed by Qin State. Such a harmless Qin State is very uncomfortable and always feels uneasy.
Chapter completed!