For shipbuilding, Zhao Xin doesn't know much, if the simplest shipbuilding knowledge, I'm afraid it is in childhood, with a paper stacked boat, with an ordinary piece of paper, after a simple folding, you can float on the water, this is probably a lot of children, the most intuitive understanding of the ship.

Paper is heavier than the specific gravity of water, and only when folded into the shape of a boat can paper float on the water, which is already an application of average gravity, as long as you have a little knowledge of physics in junior high school, you can do this.

Zhao Xin is not an expert in this area, he doesn't know fluid mechanics, and he doesn't know what the ship needs to be built to be qualified, but he knows that an important reason why the ship can float on the water is the overall average buoyancy.

In the 11th century, the mainstream material for shipbuilding in the whole world was wood that was lighter than water.

The specific gravity of paper is about 1.25, which is heavier than 1 water, and the average specific gravity of wood is about 0.6, that is, in this world, except for a few woods, most of the other woods, their specific gravity is lighter than water.

In feudal society, and even in the longer world, the question of average proportions was not taken into account at all, and the development of ships was gradually developed on the basis of gradually expanding the volume.

Compared with steel, wood may be inferior to steel in terms of hardness and long-term performance, but it has a good characteristic, that is, anti-sinking.

Wood that is lighter than water has become the main material for shipbuilding, even if the ship is damaged with a big hole, it will not sink into the water for a short time, and even some with a large amount of seawater can be slowly driven back, which is the benefit of wooden hulls.

It also saves the design process, how convenient it is, how to make it look like, you can create what it looks like, because under the worst premise, the ship will not sink.

Even if it is a craftsman recruited from the navy, no matter how unconfident he is, Zhao Xin took the initiative to increase the weight of this big worker, although he only assisted the big ship of 800 materials, and only made 300 materials independently, and suddenly increased the size to 800 materials, on the one hand, a huge part of the material is wood.

Wood with only 0.6 specific gravity is much lighter than water, and a lot can be added when considering the specific gravity alone, and materials heavier than water, all solid wood, can carry a lot of things, not to mention the cabin that has been formed, the air is much lighter than water, as long as the cabin is formed, it must be able to hold a lot of things.

The natural characteristics of wood are only one of the aspects, the key is that Zhao Xin knows that Dingjun has mastered several advanced technologies.

The Northern Song Dynasty has begun to appear combined keel, which is the core technology for some large-scale shipyards, what kind of strength of materials and materials are combined, what kind of method is used to bond, what kind of method is used to dry and process, these are all summed up in the long exploration and failure, to put it bluntly, can make more than 2000 materials of large ships, almost all have their own unique technology.

In the early days of shipbuilding, the keel was not considered, and of course, the ship could not be built very large, and most of them were small boats.

On the river, the width of the river channel bothered the size of the boat, and in terms of flexibility, the small boat had an advantage over the large boat.

Faced with the prospect of going to the ocean, the boat is not so suitable, and the wind and waves at sea are more violent than on the river, so that the advantage of the boat is gone, and the boat is getting bigger and bigger from the beginning of the human journey to the ocean.

In the early days, a large ship was a huge cost, how big a tree was, which determined the size of the ship, and in Asia, where technology and history were most developed, there were not many common trees, giant trees.

In fact, in the whole world, the highest number is often the giant sequoia, which not only has a long lifespan, but the highest is even more than 3,000 years old, and the height is about 80 meters.

There are very few such giant sequoia trees in Asia, and most of them are in their twenties and thirties, and with the development of the times, there are fewer and fewer such giant trees.

Because not only shipbuilding will use giant wood, palaces, underground palaces, and even coffins are the biggest use of giant trees, the palace hall, under the premise that the masonry structure can not become the mainstream, giant wood has become the only material, which greatly accelerates the consumption of giant trees.

Compared with ordinary materials, although wood is the most common material, but the real giant wood, often accompanied by a long time, not to mention the American giant sequoia, a giant tree of more than 80 meters, more than 25 meters of wood, can not be grown in decades, compared with consumption, the output is too small.

China's skilled craftsmen, in the face of demand, chose alternative methods, and found a creative combination of combined keels, so that the demand for giant ships for giant wood has been reduced to the extreme, and the size of the ship is not determined by relying on materials, so that the cost of sea ships has been greatly reduced.

The shipyards of the Dinghai Navy do not have the conditions for combining keels, and they don't even know how to combine many wooden materials into a whole to jointly resist all kinds of forces on the ship, let alone what materials can be used to successfully connect all kinds of wood together.

They have a new alternative thing, which is wood instead of steel.

In the history of the whole world, until the modern industrial revolution, the development of iron and steel has been slow, even if the whole world, in 2500 BC, the world has appeared iron tools, and in East Asia, the recognized large-scale use of iron tools should be in China's Warring States Period, when Wu Yue's iron tools were the foundation of their rise.

However, in this era of large-scale appearance of iron tools, it was still bronze that occupied the main body of tools, and the first emperor who unified the whole of China, his army, used bronze crossbows and various bronze weapons, replacing quality with quantity.

From B.C., to the 11th century, the development of iron is very slow, even if it has been successfully used in many fields of production, but the output has not been large, iron in the eyes of the vast majority of people, is an ordinary kitchen knife, iron rod, or what iron rope and the like, these things, the longest is the iron cable, but also through the ring to combine, the longest alone, I am afraid it will not exceed 3 zhang, for the ship has already exceeded 10 meters long, no one thought that iron would be applied to the keel of the ship.

There is no problem with this for the Dinghai Navy, let alone the keel of iron, even if it is a whole ship built of steel, it is not a problem.

As the cheapest and easiest material to work with, it became an inevitable choice to build ships with steel at a time when the price of iron had dropped dramatically, and on the premise that it was cheaper than wood.

The steel of the Dinghai Navy is the source of his wealth, and it is also the basis of shipbuilding, under the premise of more than 30 tons, 50 tons, and even 100 tons of blast furnaces gradually established, the steel keel, there is no technical difficulty, even if the welding technology is not much developed now, direct pouring, it is not a difficult thing, at most it is the manufacture of molds.

Wood and steel, this is incomparable, not to mention wood, even if it is metal, it is already a historical leap.

Why is it called the Stone Age, it was the age of stone tools used on a large scale, in fact, in the earlier days, wood was the first tool.

Compared with the more solid and difficult to process stone, the wood that can be seen everywhere has become the earliest tool of primitive people, but the strength of wood and the performance of use, compared with stone tools, the difference is huge, and it has been gradually eliminated.

This is the natural difference between wood and stone, in front of the steel that replaces wood, stone, and bronze, this is a huge difference, in front of the steel keel, everything does not exist, no matter how strong the wood, its performance in all aspects, can not be compared with iron, let alone steel.

In the same way, what adhesive can compare with smelted metal, let alone seamless welding, even the most ordinary welding, even simple steel fitting, is much stronger than the sticking on wood.

As for a certain percentage of the increase in the weight of steel this heavier material, this problem is not big, the excellent performance of steel, in the use, far less than the use of wood, for a large ship of 800 materials, the weight of the keel may not exceed 30 materials, although this also reached the weight of 10 tons, but compared with the ship itself of more than 200 tons, it is only a very small part.

Steel is a very suitable material for large-scale production and use, under the premise that steel is used in the keel, some key parts, such as masts, bows, etc., key components, will also need to use steel, the overall use will not exceed 20 tons, and Zhao Xin also used the watertight cabin to the extreme, more watertight cabins, not only increase the stability of the ship, but also increase the buoyancy on the side.

The emergence of iron has made the ship's fault tolerance rate very high, even if it is a combined keel, if you want to reach 20 meters, 30 meters, or even 40 meters, and the combined keel that cannot be compared with natural wood, their strength will be weakened on a large scale, which is also a key to restricting the expansion of the ship.

In fact, in the era of pure wooden keels, few ships could exceed 1,000 tons, and larger tonnage would only reduce the strength and become a flashy thing, once it encountered wind and waves, it would fall apart and sink.

This point, for the steel keel, does not exist at all, compared to the wooden keel strength of several times higher than the steel keel, naturally has the basis for the construction of large ships, after undertaking some science and technology of the Song Dynasty, in the Ming Dynasty, Zheng He went to the Western Ocean of the big ship, terrible reached more than 30,000 materials, this is the large-scale application of iron keel.

Under the wooden material, the total displacement of the super giant ship of 10,000 tons, this is a myth, this is also the Ming Dynasty to show the force of the Laiyuan, small countries in Southeast Asia, and even tribes in Africa, in the face of 10,000 tons of terrible giants, they do not even have the courage to resist.

Now spanning hundreds of years of history, and even thousands of years of scientific and technological development, Zhao Xin has built a terrible steelmaking plant in Dinghai, a one-time smelting of up to 80 tons of steel, with an annual output of more than 2 million tons of steel, not to mention a steel keel, even if it is a warship made of steel, it is not impossible.

Of course, Zhao Xin knows that the steamships made of steel are far better than the wooden ones, and when the whole world is dominated by wooden ships of less than 500 tons, let alone super warships of 10,000 tons, even if it is some ironclad ships of 2,000 tons, it is also an inexplicable existence, and a simple collision is enough to sweep everything.

In the future, it is almost inevitable to develop towards a steamship made of steel, but at the beginning, Zhao Xin will not cross so big, the step is too big, it is easy to pull the egg, the appearance of a steel keel is enough to beat everything under the premise, rashly build a steel giant, the investment is too large, the cost is too high, and it is easy to recover.

Even if it is a wooden ship with a steel keel as the theme, Dinghai Navy also has some other technical advantages, aside from the keel, the processing of ship materials is also the key.

The traditional processing of ship timber is mostly after the trees are cut down, and then placed gradually, this time, at least two or three years, at most ten years, the principle is just through time, the moisture in the wood, gradually transpiring, and reducing the stress on the wood, so that he is gradually suitable for the construction of ships.

Relative to stress, moisture is the key, the ship is to be launched, water for most materials, is oxidized, not to mention the corrosiveness of seawater, salt, all kinds of aquatic plants and marine organisms, which has a huge impact on the ship.

Wet wood, soaked in seawater, will react quickly, will soon decompose and collapse, only dry wood, coupled with waterproof materials such as tung oil, can be large-scale ocean voyages.

A key point for new shipyards to enter the market is ship materials, without more than 10 years of accumulation, it simply cannot compare with traditional shipyards in terms of cost.

Stress this thing, put it for half a year, it's almost, as for moisture, it's faster, the emergence of the drying workshop, but also makes the processing of wood much easier, what kind of humidity you want, what level of ship materials, in addition to the stress reduction takes time, others, can be concentrated in a short time.

This greatly accelerates the development of shipbuilding, and some small aspects of the application, but also makes the processing of the ship a lot easier, the use of rivets and screws, greatly facilitates the combination of ship plates, as for heat treatment, the ship board processing into enough bending, these are not a problem for ordinary helpers.

With such an advantage, it seems that it is necessary to make a big ship beyond this era, but in fact, there is still a long way to go from building a shipbuilding base, and now, in the shipyard of the Dinghai Navy, the current construction is just an 800-material sea ship, the reason is very simple, the gap in technology.