After inspecting the dry dock site, Li Jing and others continued to visit the workshop on the shore, which is mainly engaged in the production of ship components. The timber is processed in the workshop, made into components and then assembled into sailboats in the dry dock. After launching, it continues to outfit, install locks and sails, power winch, etc.

You may wonder why wooden sailboats are generally no longer than 60 meters long, and the longest Victory is only 67 meters. This has to do with the properties of the wood. In order to be able to build wooden warships to the "limit" of more than 60 meters like the Victory, Britain and France developed new shipbuilding technology in the 19th century to maximize the use of the characteristics of wood, and almost exerted the ability of wood as a material to the extreme.

So if you use wood to build a ship, what are the disadvantages that limit the length of the hull and the problems that must be overcome? Compared with steel, wood is naturally a much less plasticized structural material, first, the strength of wood is low, and second, the components are not easy to connect. 3. The wood is difficult to deform, or the internal fiber integrity is damaged after deformation, and sufficient strength cannot be maintained. These three problems together constrain the wooden battleship from being built for too long.

In particular, a lot of wood needed for ship construction is not straight, and the wood that is cooked and bent will cause internal fiber fracture and loss of structural strength. In order to obtain naturally occurring curved trees, naval architects traveled almost all over the forests the size of Europe.

In the mature period of the 18th century, what was the difference between a sail warship and a sail merchant ship?

The biggest difference is in the keel and boat ribs. The keel of the battleship was specially reinforced design. And the rib of the ship, the battleship was a whole log thirty centimeters square. The ribs of the ship were next to each other, almost densely arranged next to each other, except for the gun window. The outer ribs are usually made of European oak and Burmese teak. Of course, these timbers are also produced in China. In this way, the battleship formed a half-meter-thick armor belt of the ship's walls, which was used to defend against shells.

The keel of a merchant ship is relatively simple, and a merchant ship generally does not need to do drastic maneuvers and bears much less stress. And the ship's rib does not need to be so thick, usually only one is only a few meters. The planks are also very thin, usually less than 10 centimeters. The Flame Phoenix, a two-in-one type of Dutch warship merchant ship, was actually built according to merchant standards. In order to resist the shells, Li Jing had to cover the waterline and gun compartment with steel plates on the premise of losing the load performance.

Accompanied by Zhang Cheng and other senior foremen of the shipyard, Li Jing walked into a very tall and spacious workshop made of bamboo, and the timber processed by other woodworking workshops was transported here. Inside, there were long large cast-iron troughs steaming hot, boiling water and coal burning under the iron troughs. The crane on the roof boils the whole dried wood in boiling water, and when the fibers of the wood soften, it is bent in a cast iron mold.

When bending, you can't press to the required bend at once, like taming a bow, inch by inch, and then recover back, try not to break the internal wood fiber, in order to maintain the tension and toughness of the wood to the greatest extent. Both the board and the rib need to be machined to the right bend according to the design.

The little senior sister has been following Li Jing all the time, and she didn't lock her up this time, but she knows very well that what Li Jing is showing him now is the core secret of Li Jing's family. This made her even more curious, what Li Jing was doing in those days.

She listened carefully to the dialogue between Li Jing and these engineers, and Li Jing discussed with everyone a lot of technical difficulties that are currently involved and will be involved in the future. Since these people are all masters and proficient in their professions, the discussion is more in-depth.

When the ship is sailing on the sea, when it is stressed, it is a force in six directions, up and down, east, west, north and south, there are waves and strong winds, and the force on the hull is more complicated when squeezing and pulling the hull, mast and sail lock. The ship swayed, heaved and heaved, and the large waves crashed on the side of the hull, and the wooden structure of the wooden shipbuilding was more prone to deformation. No matter what material, if the force is not large, it is only a temporary deformation, if the external force can be withdrawn and can bounce back, this is elastic deformation, not a big problem.

If there is a sudden large force, or a "load" that is not removed for a long time, the material deformation cannot be returned, and even the material cannot resist the external force and cracks occur. The former is "plastic deformation", such as the deformation of the car shell in a crash, if the latter material is completely wasted, how big and terrifying this deformation is, for example, it can be seen very intuitively. Usually there will be several hatches on the deck. In the case of huge waves, the hatch cover must be nailed with a wedge, otherwise, the waves will squeeze the hull, and the deformation of the hull will squeeze the air in the cabin, and the air will collapse and fly over the hatch cover on the deck.

The lower the strength of the wood, the more serious the problem, the larger the cargo load the ship carries, the coarser the shipbuilding wood will need to be. However, with the passage of time, large sailing ships have been built in Europe for more than 150 years, and natural large timber is difficult to find; Daming is better, at least Sichuan giant trees are still preserved a lot.

Secondly, the weight of coarse wood is also larger, so the coarser the wood, the lower the load-bearing efficiency, and in the end, the weight alone may bend itself. It was even crushed.

It is not easy to connect the wood components between each other, and the "connection" is that the force of one wood member needs to be transmitted to the other, so that the hull structure can become a truly coherent and stressed whole, and all the stresses can be as average as possible, so as not to let some local structures bear more than their own strength and toughness. Rapid fatigue, breakage. Even before World War II, rivets were the main shipbuilding technology of mankind.

The steel deformation is small, and the force can be easily transmitted to adjacent components, whether riveted or welded. Wood is very different, generally visible to the naked eye, through the texture of the material - "wood heart rings". Wood, like meat, is made up of many fibers arranged in parallel. The strength of the connection between these wood fibers is far from catching up with the inside of a single fiber, as the saying goes, "chopping wood does not follow the pattern, and the woodcutter is tired to death". The strength of the wood varies greatly in different directions.

In this case, the nail is driven into the wood, which originally destroys the coherence of the timber structure, and the fastening pressure of the nail on the timber can only affect the wood fibers in a small area near the nail, and the farther ones are irrelevant to this, because the wood fibers are not as tightly connected to each other as the steel microstructure.

Two or even several wooden members are fastened together by a rivet. At this time, if the battleship is sailing in the wind and waves, then the hull will be stressed, and the various components will be elastically torsional and bent under the force. If the battleship rolls sideways in the wind and waves, the cannons and superstructure parts on the right side will all be pressed against the hull below the waterline, and if the cannons and upper hull members on the windward side on the left side have a tendency to pull apart from each other.

In this way, between the wooden components that have been deformed by force, the rivets that fasten them are pulled back and forth, frustrated. Each piece of wood is very thick, and the rivet can only be made as thin as possible in order not to destroy the overall structure of the wood, so that the pressure generated by the whole wood pulling the rivet is concentrated in the wood near the rivet, and the rivet and the wood are not tightly combined, but form a cavity. Soon these wood fibers are compressed and deformed by the rivets, and the nail holes of the rivets are loose and wide. In this way, the timbers can be staggered from each other. In the case of high sea conditions, the beams and various components of the entire ship can be observed in the cabin of the whole ship writhing like maggots, which are subjected to stresses, wood deformation, and nail movement.

Riveting this very unreliable structure will first produce various loosening in the wind and waves; Secondly, there is a big problem as a whole, that is, the problem of the deformation of the entire hull, which has always plagued the craftsmen and designers of the sail era, which limits the maximum length of the sail battleship. And the maximum length does not increase, you can only widen the width to increase the volume, so short and thick design, the length to width ratio of the small ship, the resistance is huge, and there are not too many masts, the mast is less, the sail area can not go up, the efficiency of using the wind is low, and the speed is seriously dragged down.

The little sister listened to Li Jing and the shipbuilders discussing technical problems, and also had a certain understanding of sailing ships in this era. After continuing to visit the casting workshop, rivet forging workshop, and paint workshop, the little sister found that it was so complicated and difficult to build a sailboat.