Liu Bei sent Sun Wei to Xu Duguan, rushing back and forth, plus the mediation of hospitality and gifts in the imperial court, it would take a month and a half to see the results.

And in the past month and a half, Zhuge Liang obviously has no time to be idle. Before Sun Wei was sent out, he had already been rushed by Mi Zhu and Chen Qun to solve difficult problems.

Fortunately, the problems to be solved this time are very fresh, and they can allow Zhuge Liang to apply the arithmetic and natural principles he just learned from his eldest brother, so he doesn't feel hard, but it is very interesting and fulfilling.

After sorting out the difficulty of the problems on both sides, Zhuge Liang chose to spend two or three days first to point out the Mizhu family's sea ship craftsmen, how to modify the original sea ship with keels, and add some other small technical improvements to increase navigation safety.

Chen Qun was very depressed at first, and sincerely asked for advice, begging Zhuge Liang to tell a reason, why should he favor one over the other.

Zhuge Liang also pointed out very bluntly: "Brother Zizhong's side is easy, it can be solved in two or three days, and then the sea ship craftsmen can start work." Brother Changwen's side of the matter needs on-site investigation and survey before giving a construction plan, so it is easy first and then difficult. ”

Chen Qun thought about it, accepted this explanation, and did not come to harass again.

After all, how to renovate the canal and how to build the gate in Guangling, these engineering measures are bound to the geographical environment, and Zhuge Liang and Zhuge Jin have not been able to plan and design remotely in Yuzhang in the past three months.

And shipbuilding and ship change and geography is not strongly bound, Zhuge family get a few ships to Yuzhang, these months have time to ponder, experiment, and wait back to Guangling, directly technical disclosure of the answer.

It makes sense.

The craftsmen of the Mizhu family quickly learned how to temporarily install the keel, and tried their best to figure out the details of the streamlined shape of the keel.

Trying to sharpen the keel as little as possible to increase the navigation resistance, as for the ship's maneuverability and slower rudder turning, there is no way. Increasing the underwater roll resistance will definitely inhibit the rudder.

In addition to the keel, the Mijia craftsmen also learned a strengthened anti-leakage technology of "beating hemp and soaking tung oil" that was not available in the Han Dynasty -

This thing was also casually brushed on Douyin in Zhuge Jin's previous life, and some bloggers sold "traditional handmade shipbuilding technology", and Zhuge Jin also watched it casually at that time, but he didn't expect to use it after crossing, so he taught it to his younger brother.

The specific method is nothing more than to wedge materials such as flax / flax fiber with a chisel into the gap between the planks and planks of the hull, and the hemp fibers should be soaked in tung oil. In this way, after the tung oil is dried, the waterproofing effect of the joints of the wooden board can be improved by an order of magnitude.

Originally, the ships of the Han Dynasty were difficult to achieve absolute leakage prevention, and if they went to sea, they often found that the inner wall of the bilge and the bottom of the ship were very wet, and even slightly accumulated water. After beating hemp and tung oil, the situation can be alleviated a lot.

Although it is simple to beat hemp with tung oil, it cannot reach the technology of watertight compartments in the later Song Dynasty, but it is much better than the original use of Mizhu, and it can be improved to the level of leakage prevention in the early Sui and Tang dynasties.

In a word, it took Zhuge Liang three days to improve the leakage prevention performance of sea ships for about three hundred years, to the end of the Sui and early Tang Dynasties. It also improved the ship's anti-roll wave measurement performance for 800 years and reached the level of the Northern Song Dynasty.

Mi Zhu harvested these improvements, and was immediately overjoyed, which could not only serve the great cause of the Lord, but also serve the Mi family's own maritime business.

Out of gratitude to the Zhuge family, and realizing the huge potential of the Zhuge family to hug their thighs. Mi Zhu couldn't help but propose that he wanted his family's maritime merchant fleet to give the Zhuge family a profit of one percent of the dry shares, and in the future, the Mi family's maritime trade profits would be distributed every year.

Zhuge Liang was embarrassed to take it at first, but after all, he was influenced by the thoughts of his eldest brother in this life, and the eldest brother has often taught him in the past few months that it is appropriate to rely on technical improvement to receive money, which is not against the way of a gentleman, and maybe it can also inspire the people of the world to work together and come up with new things to benefit the people.

In addition, Mi Zhu even began to inquire about Zhuge Liang's "whether he is married and whether he is married", Zhuge Liang was afraid of long nights and dreams, but he still calmly accepted the dry shares, and said that he would not take it in vain, and the Zhuge family will have new improvements in navigation and shipbuilding technology in the future, and will take the initiative to cooperate with the Mi family.

As for Mi Zhu's question, Zhuge Liang only said:

"I was able to escape from Jingzhou, thanks to the help of an old friend, I have made a marriage contract, and the gentleman should be true to his word.

Moreover, my eldest brother is twenty-two years old and unmarried, so how can I talk about this matter and disturb the order of the elders and children in the family? ”

This reason is upright, and Mi Zhu didn't say anything more.

……

After spending three days to get Mi Zhu and letting the Mi family shipbuilders build and tinker with it themselves, Zhuge Liang took a break from Chen Qun's side to fill another pit dug by the eldest brother last year:

Hangou water control and solve the problem of saline-alkali land in Guangling County!

The two sides were not polite and humble, and as soon as they came up, Chen Qun reported that in the past winter, he used the 40,000 soldiers and family members who immigrated from Xiapi County to work for relief.

How many polders have been built and how much irrigation reservoir capacity has been added to the area near the canal in Sheyangze during the dry season.

These situations are similar to Zhuge Liang's measures to govern Peng Lize on Yuzhang's side.

Because of Chen Qun's governance, last winter, at least Guangling County added hundreds of thousands of acres of fertile polders (Han acres, equivalent to about 0.3 acres in later generations), which is enough for tens of thousands of strong laborers to cultivate. The irrigation conditions are also very good, and if the saline-alkali land can be treated well, it is a high-quality paddy field.

Zhuge Liang spent three or four days on the road, running from Guangling County to Sheyang County, and after inspecting all the way, he also knew what to expect.

"River improvement, silting polders, and dredging reservoir capacity have been done very well, and there is no problem.

Therefore, the remaining difficulty is just that I don't know how to build a sluice gate for the Hangou Canal and block the seawater backflow of the Yangtze River at high tide? ”

After Zhuge Liang finished his investigation, he summarized the difficulties that Chen Qun still couldn't solve.

When Chen Qun heard this, he couldn't help but smile bitterly: "Don't say it so lightly, what do you mean by 'just not being able to repair the floodgates', the difficulty of this matter is really beyond my expectations."

Last year, I also thought about it, thinking that I could consult skilled craftsmen and water control officials to build a canal gate. But after starting it, I realized how hard it was. ”

Zhuge Liang casually investigated: "Is the built gate not easy to open and close?" Or will the gate leak? Or will it not be able to withstand the water pressure of the drop on both sides and will be washed away? I don't think it should collapse, so many dikes and cofferdams will not collapse, and if you want to reinforce, it should still be easy to do. ”

Before the Han Dynasty, it was not uncommon to build dikes to contain large waters, so Zhuge Liang felt that it could not be a problem of not being able to block the water.

Chen Qun really responded: "It's really not a matter of collapse. After consulting with skilled craftsmen, I tried various reinforcement techniques, and it was still possible to make the gate withstand the flow of water.

Moreover, after the gate was closed and the water began to be stored, but in a day or two, the water level at the gate rose as high as the water from Huaiyin upstream, so it turned into still water, and there would be no more impulse.

However, once the gate is too strong, it will be difficult to open and close. Every day after the peak of the tide, when the gates are to be opened for navigation, it is labor-intensive, almost as laborious as digging a dike.

When the gate was to be closed the next day, it was not closed tightly, so it had to be refilled with sandbags to plug the joints and try to do everything possible to prevent water leakage. Over time, the river was repeatedly silted up, and it became a problem for boats to enter and exit the canal, and the gains outweighed the losses.

But if you don't build the gate so strongly, it will leak again and will always be closed loosely. I've been trying for four months, trying all the tricks, maybe Ziyu thought the problem too simple at the beginning, and I've never heard of anyone who can repair the sluice gates for the canal since ancient times. ”

Zhuge Liang listened to Chen Qun's detailed statement, but he was not worried at all, but a stone fell to the ground in his heart.

Before he came, in the past few months in Yuzhang, he had discussed a lot of expected situations with his eldest brother, and he was really afraid of encountering some strange troubles.

But Chen Qun seems to be working very hard, and the work has not been wasted in the past few months, and other small problems have been solved, leaving only the ultimate big problem of "the gate is leaking, or it is not easy to open and close".

This is like a student making a paper, not afraid of difficult questions, but afraid of cumbersome questions and testing your carefulness.

If there is a clumsy but diligent and careful Xueshu who partners with him, checks and eliminates all the small and low-level mistakes, and only leaves the final question to ask Xueba to help, it will be very comfortable.

Zhuge Liang said confidently: "Since there is only such a major problem, I will go to the gate construction site tomorrow to take a closer look, and then gather all the original craftsmen and work together." ”

Chen Qun had no other way but to agree.

……

The next day, the group came to the gate construction site more than ten miles southeast of Guangling City, by the Hangou Canal.

Chen Qun recruited thousands of laborers who were responsible for the specific work, as well as dozens of city builders and carpenters, as well as technical officials of Gongcao. Among them, there are many old people who are old and know how to build walls and dams.

A large group of people surrounded the construction site, comparing and surveying the scene little by little, and working together to find a way.

Zhuge Liang took a closer look and saw at a glance that there were two obvious problems with the experimental gate left by Chen Qun.

Zhuge Liang first asked: "How did you open and close this gate?" Is it along the axle of the door? Or is it pushed and pulled left and right? ”

Chen Qun gave him a look, and immediately an old official from Gongcao came over and answered:

"This is a swivel opening and closing along the axle, but I have tried pushing and pulling left and right before. Both of them leak and do not close tightly, even if they are closed tightly at the beginning, the water pressure will wash all day, and it will gradually collapse and leak. ”

Zhuge Liang nodded: "In fact, if you want to say that the opening and closing is the simplest and most reliable, it is still to hang the Wanjun gate and lift the door up and down." However, the canal was too wide to be compared to the city gate, and it was impossible to build a tower across the canal and hang the gates.

The remaining two methods are more reliable to push and pull, if you rotate to open and close, once the fan riverbed through which the gate passes is blocked by silt, boulders or wrecks, it will not be able to open and close. Push and pull left and right, only need to clear the space of the two chutes, and it is also convenient to slightly stack and strengthen the inside and outside of the door. ”

The old officials of Gongcao didn't have much opinion on this issue, they were originally out of tricks, so they tried everything. This young man has a big mouth, and although it sounds a bit iron-clad, it seems that the basic skills are still very solid.

The old craftsmen and officials next to him have also slightly established trust in Zhuge Liang.

Zhuge Liang struck while the iron was hot, and continued to point out the key issues: "After determining the use of push-pull gates, you still don't block them tightly, I think the key is that your two gates are too flat, so you can't bear the pressure."

These left and right doors are almost parallel docking, even if the middle is reinforced with a rung-like latch, how much compression can there be? It is not surprising that under the washing of the tide of the river, it was immediately washed loose and leaking.

Have you not built an arch bridge? I don't know that the bridge must form an arch coupon in order to let the carriage and horses press on it without collapsing. If it is a bridge with a large span, built completely flush up and down, how can it withstand the heavy pressure?

Therefore, this gate should also learn from the arch bridge in general, so that the chute of the left and right doors forms an angle, and finally when the door is closed together, the left and right arches up, and the top angle of the arch coupon should be on the side with higher daily water pressure.

And once the angle is made, the side of the two doors touching each other is not necessary to be completely smooth and flat, it can be made into a dog's tooth staggered shape, and after being put together, the mortise and tenon joints are wedged together, and then the brake latch of the tight hoop is set. The more the tide washes, the tighter the gate will be, and unless it is actively pulled open to the sides, it will not leak easily. ”

Zhuge Liang said as he drew a "V" shaped structure on the land with a tree branch, and the gate originally built by the craftsmen was in the shape of a "one", and the two sides had no angle.

Several craftsmen who are relatively not so knowledgeable, after listening to Zhuge Liang's explanation, their eyes lit up: yes, why didn't we think of borrowing from the compression-resistant structure of the arch bridge? If a two-stage V-arch is created, it must be able to withstand the water pressure of the tide, right?

However, the oldest, gray-bearded old official was not easily frightened by Zhuge Liang's suggestion.

I saw that he shook his head helplessly, revealing an expression of "the young man is really unreliable", and said with a smile: "Haven't you ever seen the scene of Guangling tide pouring into the ditch?" This method is just a matter of course, if the gate is made into two sections of each other's arch tenon, it is not difficult.

But have you ever thought about which direction this arch is heading? If it is low tide, the water level of the Yangtze River is far lower than the water level of the Huai River and Sheyang Zelai in the upper reaches, high in the north and low in the south, and if it is high tide, it may be high in the south and low in the north.

One of the prerequisites for building bridges with arch compression is to ensure that only the direction of the arch back bears pressure. If the pressure direction is suddenly to the south and suddenly to the north, once the soffit is compressed, this gate is afraid to collapse immediately!

Just like a chicken egg, when holding the eggshell in your hand, it is not easy to break the eggshell if you hold it tightly, just because the eggshell arches outward. But when the chick breaks the shell, how weak is the strength? Because of the hard chiseling from the inside of the eggshell, the shell can be easily broken. The gate repaired with this method, when encountering soffit pressure, I am afraid that it will be as brittle as chicken eggs! ”

The old official is obviously a man who has been controlling water for many years, has a lot of experience, and is also quite prestigious among the Guangling Gongcao. Listening to the questions he pointed out sharply, everyone, including Chen Qun, couldn't help frowning again and became worried.

However, Zhuge Liang was still prepared, and in the face of everyone's doubts, he still said in his hand: "This problem is very good, but it is not impossible to solve it - in fact, it is completely possible to connect the estuary of the canal and the Yangtze River from one to two, and dig an additional river next to it.

In this way, in the future, it will be ensured that the water level of the Yangtze River is higher than the water level of the Huai River/Hangou in the future, and the sluice gate on this opening can only carry the heavy pressure from the Yangtze River to the Hangou from south to north.

On the other hand, the water level of the Huai River/Hangou is always higher than that of the Yangtze River, even when the Yangtze River is at high tide, it can be at most flat. For most of the time, the gate is under pressure from north to south.

The water pressure from the south to the north of the estuary, in the future will only be allowed to navigate from the south to the north of the boat, so that the boat can float down the river, even without paddling, pulling fiber, after the water level rises, but also let the river boat directly into the ditch, no need to change boats, but also save loading and unloading manpower.

The estuary with water pressure from north to south will only be allowed to sail from north to south in the future, and the same principle will be true. ”

Zhuge Liang said while drawing a schematic map on the soil, the current canal estuary is in the east of Guangling City, and Zhuge Liang casually drew a line,

The ditch is led to the west in the north of Guangling City, and a fork is divided, which is connected with the moats on the west and north sides of Guangling City, and then all the way to the southwest, and finally about twenty or thirty miles away from the upstream, drawing to connect with the Yangtze River.

When Chen Qun and those old officials saw this plan, they were immediately shocked.

What is this line of thinking? Is this to dig a 30-mile fork in the 280-mile-long Hangou Ancient Canal? It takes a lot of work, right?

However, Chen Qun reacted quickly, and he quickly realized that when Zhuge Liang signaled, he borrowed a part of the moat on the northwest side of Guangling City, and if the overlapping part could be omitted, it was estimated that more than ten miles of road would be dug, and this amount of construction was still acceptable.

Digging more than ten miles of rivers is equivalent to digging the moat of Guangling City again, and you can achieve a small success by getting tens of thousands of conscripts and working for a few months. If you confirm that the method is feasible, you can slowly expand it in the future.

And if it is really possible to divert the canal boats from the south to the north, and the water level of the estuary is also diverted, to ensure that each estuary always only needs to carry the water pressure in one direction, and there will be no "high water level in the north and high water level in the south for a while", then the arched gate connection method seems to be really feasible.

Chen Qun thought about it, and hurriedly grabbed the old official Cao and asked, "Old Qin, do you think this method is feasible?" If the estuary is really diverted, can the arched gate hold any estuary as long as it is subjected to one-way water pressure? ”

The old official only felt that his lips were dry, and his mental pressure was huge, so he didn't dare to jump to conclusions, and finally just struggled and said:

"The key is to see if anyone in the world can measure it so accurately, and really make sure that after changing the estuary, the water of the Yangtze River at the new estuary is always higher than the water of the Huai River! And you can't leave too much margin and deliberately make the Yangtze River too high, then it will not be closed after the door is opened! The Yangtze River can only be allowed to be just a little bit higher, and someone can guarantee this, and it is not difficult to repair an arched gate itself! ”

After the old official finished speaking, other workers and old craftsmen also echoed it, saying that the difficulty of this idea was not in construction, but in measuring the "altitude" of the water level - although the Han Dynasty did not have the word "altitude", but they expressed that meaning.

After collecting everyone's opinions, Chen Qun returned to Zhuge Liang's side and spread his hands: "Mr. Kong Ming, you have a good strategy, but no one in the world seems to be so clever as to measure the water level between two rivers and two points that are far apart. ”

Zhuge Liang didn't have much nonsense about this question, but just left a sentence: "I'll leave this to me, but you still need to give me a few compass stones to use to measure the level." These stones are too heavy, I didn't bring them from Yuzhang, and I have other tools. ”

Chen Qun looked confused, so he had to go to a professional again: "What is a compass stone?" ”

Many craftsmen next to him were also confused, and in the end, the old official surnamed Qin remembered it, and suddenly realized:

"Isn't it the kind of cross carved groove stone that should be used in the middle of the cross tomb road and at the level of the four directions when repairing the emperor's mausoleum? As long as the tomb is higher than the direction along the compass stone cross trough, it can be ensured that it will not be flooded after it is caused? ”

When Zhuge Liang heard this, he was a little surprised, and nodded approvingly: "Do you still know the specific use of this thing?" Then why didn't you think of using it to measure altitude? Just a slight change. ”

The old official surnamed Qin was stunned when he heard this: How can this change slightly? It's too simple, isn't it? I can't imagine it!

However, Zhuge Liang was able to say this, he believed it at least ninety, and he hurriedly whispered to Chen Qun:

It seems that what Mr. Zhuge said is most likely really sure. Although I don't know what he did, I have never heard of a craftsman who measured the level of the tomb and the water table for the emperor's tomb could make a mistake and cause the emperor's tomb to be flooded. The method of the gentleman has evolved from this, and with the addition of the magic method, it may really work. ”

Chen Qun: "Then don't you prepare tools for Mr. Kong Ming!" ”

For a while, the resources around Chen Qun were really mobilized, and he decided to gamble with Zhuge Liang.

The whole project has been pushed forward from the survey stage.

And Zhuge Liang's plan, to put it bluntly, is not much difficult to go against the sky - the Grand Canal of the Sui Dynasty in later generations, in the Tang and Song dynasties, the connecting ports on the north and south banks of the Yangtze River were all made into this bifurcated state of "two-way waterways are independent".

In order to facilitate the repair of the one-sided anti-pressure gate, it is also convenient for the boat entering and exiting the river mouth to drift on its own without pulling the fiber chaos.

After the deed was completed, it benefited the people for thousands of years, and it was still benefiting until the Ming Dynasty. In later generations, when I went to Yangzhou and Zhenjiang to travel to see the scene, I knew that the ancient Grand Canal was bifurcated and connected to the Yangtze River.

All this does not require any construction technology against the sky, but the people of the Han Dynasty are still too poor in mathematics, the survey level is too poor, and the optical geometry is too poor, and they cannot find the water level of the Yangtze River that is slightly higher or slightly lower than the water surface of the canal.

If the water level difference is not well grasped but forced to do so, once the water level of the Yangtze River is too high, the result is that the Yangtze River surging into the ditch, turning Huaiyang into a Hongze Lake. If the water level at the connection point of the Yangtze River is too low, the ditch will be directly drained by the Yangtze River and become dry and scrapped.

However, any ordinary surveyor who traveled through the past of a water conservancy department from later generations, as long as his professional level was not too inferior, measured the relevant geological data and provided it to the people of the Han Dynasty.

Then the contribution of this surveyor can save 100,000 workers from repetitive work for hundreds of years in the future, and by the way, it can also take care of the saline-alkali land around Sheyangze. (However, before the construction is completed, the surveyor and his family members are usually hoisted until the final construction is completed to confirm that he has made a correct measurement.)