The boat itself is built using the technology of nailing and tenoning, the whole hull is connected by a combination of tenon and iron nails, the inner deck sleepers are connected to the left and right side tenons, and the side of the ship is made of four large wooden nails in rows of nails.

The wooden planks of the ship are filled with tung oil and lime. It is this strong combination technology that makes the Mulan boat extremely resistant to wind current impact and sinking.

It is said that in the same era in the Middle East and Europe, the shipbuilding industry there still used the primitive leather rope binding method to connect the shipboards.

Li Xiao made several changes to the ship, one is the watertight compartment, which divides the bilge into multiple compartments to make it have better anti-sinking ability. If a vessel runs aground or collides and damages a compartment and floods, it will not involve adjacent compartments, ensuring maximum vessel safety.

On the other hand, the bottom, side and deck of the ship are supported by multi-subordinate bulkheads, which can also make the whole ship have higher overall rigidity, which greatly strengthens the lateral strength of the ship and the ability to resist wind and waves and sinking, which make the ship have stronger ocean-going navigation capabilities.

In addition to adding watertight cabins, Li Xiao also improved the sails, and although during the Han and Han dynasties, the Han people were able to use the monsoon to sail to the sea, but they relied too much on the monsoon. During the Jin Dynasty, the high monk Fa Xian visited Tianzhu and returned by sea, but had to wait for the monsoon to reach Java for five months.

And Li Xiao improved the sailboat, with the rudder, so that the ship can be made in all directions, but the head is not feasible. Ships could go in seven other directions except for the direction of the wind, a technique that had not been mastered in the West until the sixteenth century.

Watertight cabin and new sails, this is the transformation of the new ship that Li Xiao asked Zhao Zhiman to make.

Zhao Zhiman went all the way to Hongzhou, found a large shipyard, bought three Mulan boats that had been built, and then remodeled the boats.

"I found three shipyards to renovate our ships to ensure that Saburo's improvement was not something that others could steal." Zhao Zhiman is very careful, after Li Xiao explained to him the role of these transformations, he kept a hand after buying the ship, and did not complete the transformation in the original factory, but found three shipyards to carry out gradual transformation, to prevent others from stealing this technology to the greatest extent.

Li Xiao smiled.

It's not so easy to learn secretly, but he doesn't plan to keep this technology forever, such advanced shipbuilding and navigation technology will definitely be handed over to the imperial court. If the sailors of the imperial court had this kind of technique, they would naturally be even more powerful.

However, when to take out the technology depends on the timing, and it always has to be exchanged for some benefits, and it can't be taken out for free.

Besides, new technologies always have to be tested, and it is more convincing to transform a few Mulan boats first, and then hand them over to the imperial court when they are used.

"Thank you, second brother, where is the ship now?"

"In Hongzhou, it is estimated that it will take another month to complete the transformation." Zhao Zhiman took out an account book, "This is the cost of buying a ship and renovating the ship, and it also cost some sailors and crews and some craftsmen on the ship, and also purchased a batch of grain after going to sea according to your instructions." ”

Li Xiao opened it and looked at it a few times, then closed it.

Sea ships are not as important as river ships and boats, they are the most skilled ships, and the cost of building a ship in this era is not low, even if there are many shipyards in the Sui and Tang dynasties, there are dozens of states in the world that can build ships, and even inland places such as Qizhou in western Beijing have large shipyards.

But the Mulan boat, which can carry five or six hundred people, is not small, it is a top-notch sea ship.

According to the conversion, this kind of ship is equivalent to the 5,000 material ship of the Song Dynasty, with a carrying weight of about 275 tons.

The river boats in the inland rivers even have those who can transport rice and stones, and the carrying capacity of this kind of boat can reach more than 600 tons.

The three Mulan boats, all of which were new boats, were bought at a higher price, each boat reached as much as 3,000 guan, and the three boats cost 9,000 guan, plus the cost of transformation, as well as recruiting crews, buying equipment, food, etc., Li Xiao handed over 10,000 guan to Zhao Zhiman, and there were not a few guans left.

"This money is worth it, everything is ready, only the east wind is owed, as soon as the ship is good, the second brother will drive the east ferry to Tushan Island!"

Li Xiao said lightly, but in fact, his heart hurts, this 10,000 yuan is not his, but borrowed to bite the gold, to be repaid, and the interest has to be calculated. Although Cheng Laomo lent him money, one yard is one yard, and interest is indispensable. Fortunately, this ship is big, one boat can carry six or seven hundred people, Li Xiao only needs one boat now, and the remaining two Li Xiao can be resold to the Cheng family and the Xue family as agreed.

He spent more than 3,000 yuan on a boat, and it should be about the same to sell them two families for 5,000 yuan, this ship is an improved Mulan boat, which is much more advanced than an ordinary Mulan boat. The sailors of the imperial court could only start from Dengju, first to Liaodong along the Miaodao Islands, and then all the way south along the coast to Liaodong to Goguryeo and Baekje.

From Dengju to Baekje, it only takes two or three days to reach it in a straight line, but the imperial court's ships do not have this technology, unless it is in the right monsoon season, and they can sail directly eastward by the wind for two or three months a year.

It's the same with coming back from Baekje, and there are only a few months a year to wait for the monsoon direct flight back.

And to go back and forth, you have to wait for two monsoons, and one wait is half a year. Go with the wind, there is no tailwind back, unless you sail around the shore, you can only wait for half a year. It would have taken a month or two to circumnavigate the shore in a straight line for three days.

Li Xiao's transformation of the Mulan boat is a mature ocean-going navigation technology in the Tang and Song dynasties, using advanced sail technology, it can come from all directions, and it can also sail in the ocean without relying on the monsoon.

In addition, he still has a nautical compass in his hand, which is a real weapon, and he is not afraid of losing his way if he does not sail along the coast. As long as you don't lose your way, the danger of a two- or three-day voyage is greatly reduced.

Sell two ships and keep one, and sell two ships for 10,000 yuan, and it just so happens that the cost of your own ship will be passed on to those two heads.

Li Xiao's abacus is still good, it's not that he can calculate, this is the embodiment of value. Friends belong to friends, business belongs to business. If it weren't for these two, other families would want Li Xiao's boat, and it wouldn't be a show.

It doesn't matter, if you spend 10,000 yuan, I won't sell it to you.

Zhao Zhiman recruited a full two hundred idlers and fierce men for Li Xiao, and these people were about to become the first maritime colonial mercenaries in the Tang Dynasty.

"Everyone is very good at riding and shooting, and they are not afraid of wind and waves and do not get seasick."

Don't get seasick, this is also the basic condition that Li Xiao put forward for recruiting mercenaries, if you are seasick, then you will go to sea to have a good time. As soon as the ship docked, people were dizzy and couldn't stand on their feet, so how could they go ashore to rob and arrest people?

Fortunately, there are still a lot of people who are strong and not seasick, and the team of 200 people was quickly assembled, all of whom were outlaws who dared to fight, who liked to take risks, and were very willing to go to the east of the sea to do a hard job.

With two hundred mercenaries, plus a crew of dozens of sailors, a ship can accommodate three or four hundred people, which is just enough to hold prisoners.