I copied 209?

  Zhou Tianlei and Long Meier sat down in a relatively quiet café.

  Zhou Tianlei remembered the Battle of El Alamein and thought it necessary to remind Rommel. That battle had almost ruined Rommel's reputation for life.

  At that time, the British intelligence work was done very well, and the German army did not know the performance of the Matilda tank at all. The 37 anti-tank gun, which was called "military door knocker" by the German army at that time, performed poorly in combat. It wasn't until the 88 high-altitude cannon joined the battle that the situation was reversed.

  This battle, to some extent, influenced the outcome of Dunkirk. Without this battle, the German army might not have been afraid of losing its armored forces and could have annihilated the British Expeditionary Force and French troops. They would not have allowed them to retreat from Dunkirk. The Great Retreat at Dunkirk was also a major reason for the German defeat later on.

  Rommel listened with a puzzled expression as the hero of Spahk Bay spoke to him in veiled terms, saying that in future battles he might encounter an enemy heavy tank that was impervious to the 37mm anti-tank guns currently used by the German army, but which moved slowly and could be penetrated by the current 88mm high-velocity gun.

  "Long Mei'er asked in confusion: 'How did you know? Our army didn't even know the enemy had this equipment, how did your navy know?'"

  Luckily Zhou Tianlei had a draft ready. He mixed it up with a combination of coaxing and deception.

  Zhou Tianlei received a notice from the Navy Command in the afternoon, asking him to go to the Hovats Shipyard to participate in the development of new equipment. He arrived at the Hovats Shipyard and met Walter, who had designed a new type of submarine as early as 1934.

  Walter didn't think much of Zhou Tianlei after meeting him, in his opinion, this was just the navy letting him come for their own purposes. The submarine commander didn't understand submarine design, he could only propose certain requirements for some components.

  Zhou Tianlei also saw it, but he didn't show it on his face.

  He smiled at him: "Hello, I'm Gao Te. Prion, you can call me Gao Te."

  Zhou Tianlei then asked Walter: "Do you know why your V.80 was vetoed?"

  "Walter said: "At that time they thought I was impractical."

  "That's true, but the submarines you've produced also have many problems." Zhou Tianlei took out a drawing he had prepared long ago - the overall layout of Germany's famous Type 209 submarine.

  "Take a look at this?" Walter asked Zhou Tianlei with confusion after carefully examining it; "Why is there no deck weapon on this, and the shape of this boat is completely different from our U-boat."

  Zhou Tianlei said: "It's not just these places that are different, there are many other places that are also different."

  "The engine you're designing now should be firmly installed on the hull, right?" "Yeah! What's wrong with that?"

  "This would expose our submarines to the enemy, who could locate them with their advanced underwater detection facilities."

  "Aren't we now using surface attacks? Can weaken the sonar's working effect."

  "It won't work like this in the future, the enemy will invent advanced detection instruments, and attacks on the surface will be discovered by them. But those instruments have no effect on underwater objects. So from now on our submarines need to lie in wait underwater for a long time. Therefore, we must try our best to reduce the noise emitted by the submarine underwater."

  "What you're saying opens up a whole new line of thinking for me," Walter said. "So how do we reduce the noise of the submarine underwater?"

  "There are many methods, for example, the installation of submarine main engines you mentioned earlier is a rigid connection, while I use an elastic base to install the main engine, and then connect the base to the hull. From this, it can be inferred that many devices on submarines that produce large noise cannot be directly connected to the hull. All need to take vibration reduction measures. This I call it noise closure management (Zhou Tianlei dissatisfied with the shout: "I just want to keep my life safe, I don't want to die in 41 years, so of course, I have to design advanced submarines")

  "What else could you be considering if not installing weapons on the deck?"

  "This way can reduce the resistance of the submarine underwater, increase the speed of the submarine underwater, and also reduce the noise of the submarine underwater."

  "The design of this submarine is different from the current design. The current submarines focus on increasing surface navigation speed, but do not pay attention to underwater speed. As the time spent by submarines underwater becomes longer and longer, it is necessary to change its shape design.

  As we spend more time underwater, our observation methods have also changed naturally. In the past, we often navigated on the water surface and observed targets through binoculars before diving down to attack the enemy. Now we need to find and destroy enemies while underwater, so we also need to develop advanced underwater reconnaissance equipment. We want to install the submarine's sonar sound receiving array along its hull, leaving a certain distance between them. This can ensure that we can detect enemy situations without making a sound on the water surface.

  The sonar should be installed at the bow of the submarine, which is the quietest place on the entire submarine. The sonar has the highest efficiency there."

  Walter heard Zhou Tianlei say that it seemed like a new world had appeared before his eyes, and many things he hadn't thought of or dared to think about were all appearing in his mind. He excitedly said: "This way, the submarines we manufacture will be invincible in the world."

  Zhou Tianlei stretched out his right hand to him, and the two men's hands were tightly clasped together.

  In the following months, Zhou Tianlei and Walter lived in the factory, eating and sleeping there. The two men worked closely together to solve many problems related to the design of new submarines, parts processing, and overall assembly. Under Zhou's guidance, they applied a segmented assembly method that was not used by Germany until 1942, but was already being used in 1939, greatly increasing the manufacturing speed of the new submarine.

  Zhou Tianlei knew that he had to speed up the production of new submarines, otherwise they might be disrupted by external factors in the later stages. The ventilation pipe, a device that was installed only in the later stages, was also installed on the submarine. Its appearance greatly increased the underwater activity time of the submarine. However, Zhou Tianlei knew that it was impossible to develop fuel cells for submarines at this time, so he didn't bring it up.

  At the end of '39, the new submarine was finally fitted out. It's time to go to sea for experiments, Zhou Tianlei looked at the new submarine that resembled the famous Type 209 submarine in the future and thought: I stole the design of the Lübeck Engineering Institute's Type 209 project, what should this be considered?

  On a gloomy morning, Zhou Tianlei led the submarine experimenters, many of whom were his subordinates from Submarine No. 47, onto the new submarine. D?nitz gazed at them from the shore, with tears welling up in the corners of his eyes. After the submarine sailed out of the harbor, it arrived at the designated experimental sea area.

  "Contact established with Zhou Tianlei and the experimental ship. Starting experiment program. 'Fill main ballast tank, maintain one-quarter speed, dive to 25 degrees down angle, dive to periscope depth.'"

  A string of orders was given, and the submarine began to slowly disappear from the surface. "Raise the periscope." The periscope rose, revealing a small head above the water's surface, which was seen by the ships on the surface.

  "Continue with the experiment, deep dive experiment." "Yes, Captain." "Dive to maximum depth, speed unchanged." Zhou Tianlei watched as the depth gauge slowly rotated towards the maximum depth on the instrument panel.

  As the submarine dived, strange noises began to emanate from within, and it seemed as if the seawater was trying to crush the monster that had appeared in the deep sea. When they reached a depth of 150 meters, all the crew members except Zhou Tianlei started to show signs of change on their faces. No wonder, they had never dived to this depth before. But the submarine continued to dive, and when it reached 200 meters, the strange noises inside grew louder. The simple devices installed by the old soldiers in the submarine also began to reveal the extent of its deformation.

  The faces of the crew members were getting uglier and uglier. But Zhou Tianlei still didn't stop the dive. His face was smiling. Some crew members made the sign of the cross on their chests, muttering something to themselves. But without the captain's next order, no one dared to say anything. This shows the quality of German soldiers, but asking about Zhou Tianlei's family is inevitable. Until they dived to a depth of 280 meters, the maximum safe depth of the submarine, only a small pipe in the command cabin burst with a loud noise, and water splashed everywhere, but nothing else unusual was seen.

  "Report the status of each cabin." After all cabins reported back that everything was normal, Zhou Tianlei finally burst out laughing: "Haha, success! Main water tank draining, maintain half speed. Dive to 100 meters, let's do the next experiment."

  Experiment one by one, underwater maximum speed, quiet speed. Surface maximum speed, underwater using snorkel maximum speed...

  It had been going on for several days, and finally it was time for the simulated confrontation. Zhou Tianlei's new submarine was able to catch the destroyer every time, but the destroyer's sonar had a hard time finding Zhou Tianlei. After the sea trial ended, when Zhou Tianlei and his team returned to the dock, they were surrounded by an excited crowd...