Just when Xia Yu found the atlas that could decipher the structure of the submarine from the slain maintenance technician, countless ships, submarines, and planes were patrolling back and forth in a large area of the East China Sea.

Compared with the planes in the sky, the only ones that can really play a search role are submarines and surface ships. But this area is too big, enough to be described as vast, dozens of ships and submarines can search for a limited range, especially when you want to search for an extremely quiet submarine in the sea, the passive sonar system can do is really limited, so under the orders of the superiors, whether it is a surface ship or an underwater submarine, all the ships involved in the search mission have turned on the active sonar detection to search.

But once the active sonar is turned on, it is equivalent to telling the submarine its own position hidden underwater, and the sonar system is very vulnerable to interference underwater. The most direct is the multipath effect, reverberation, ocean noise and self-noise interference, as well as the density of the water, the undulating seabed environment, these factors will produce refraction, scattering, reflection and interference, so that the feedback back of the sound is bent, signal distortion, etc., which affects the efficiency of the sonar system.

Once the active sonar system cannot detect the enemy, and at the same time tells the enemy his own position, it is undoubtedly an act of death when fighting underwater. Even if it is like now, multiple submarines support each other to form a joint defense to conduct an area search, and it is impossible for the enemy to launch an attack on their own side, but the location information fully exposed by their own side can also allow the enemy submarine to better choose the lurking position, or use the gap between the search areas to shuttle through, and all of them must be judged according to the actual situation.

The order given by the superior to take the initiative to turn on the active sonar search is also a helpless thing. At least under the search of dozens of active sonar detection sources, the American submarine did not dare to be too careless, not to mention anything else, at least the American submarine could not sail underwater at full speed, otherwise it would be very easy to be detected, so the American submarine could only slow down and detour.

In this way, it can delay the time for the other side to escape from Chinese waters, thereby increasing the success rate of the search mission on its own side. It can be said that this also bought the foreshadowing for Xia Yu's escape plan to succeed, otherwise once the US submarine enters the Sea of Japan, or returns to the escort range of the USS George Washington aircraft carrier formation, even if it is unwilling, the Navy General Staff can only declare the operation a failure.

In the command tower of the US nuclear submarine, almost everyone's attention is focused on the position of the sonar, because the search formation that is gathering from the rear has as many as dozens of targets, and the active sonar detection wave continues to echo, which has been stirring the nerves of all the personnel in the command tower, even the agents who are responsible for capturing Xia Yu can't help but pay attention to the sonar detection at all times, after all, in a closed underwater ship that is going to sink nine times out of ten once hit, everyone's fate is tied together.

The large-scale search activities on the surface and under the water attracted the attention of the vast majority of the people in the command tower, which also made the American submarine enter the combat state from the time the search team was discovered, not only can the submarine not make too loud noise to attract the attention of the search team, all the people on duty must be in their posts, even if they are temporarily unemployed, unless necessary, they cannot move at will, which creates favorable conditions for Xia Yu's actions in the second half of the submarine. However, Xia Yu didn't know what was happening now.

Sneaking close to the hatch outside the monitoring room of the nuclear reactor, Xia Yu knew that he could enter directly from the hatch, because the working panels of the monitoring room were installed in the recesses of the walls on both sides of the aisle, and the three staff members on duty sat there, responsible for the control boards in front and on the left and right sides, although as long as he moved his body slightly, he could see the situation in the aisle, but under normal circumstances, no one would do that, because it was very likely to be hit by other people who were passing by.

Lifting the maintenance toolbox, Xia Yu lowered the brim of his hat, although no one in the submariners, especially the submariners in the engine room, would wear a hat when they were working, but in order to hide his conspicuous oriental face, Xia Yu still had to do this, for the same reason as before, delaying the first reaction of the other party when making contact.

Holding the maintenance toolbox in his left hand and moving forward, his slightly sideways body made it impossible for the person in front of him to see his right hand, Xia Yu slowly approached the monitoring table, and the slightly slight voices of the three people in front of him could already be heard very clearly. The dagger clenched in his backhand shone with a piercing cold, and when he walked to the monitoring table, Xia Yu gently threw the maintenance toolbox in his hand forward, "Boom, boom", and all the things in it were suddenly scattered all over the ground.

"Oh, damn it." The huge movement immediately attracted the attention of the three of them, and the three people who turned their heads didn't look at Xia Yu for more than a second, and they were all attracted by the pile of scattered maintenance tools on the ground, and the person closest to Xia Yu wanted to raise his head and scold Xia Yu after seeing the pile of tools, but at this time, Xia Yu moved.

Within a second, Xia Yu was like a cheetah that suddenly attacked, and the dagger he held behind him moved forward with his body, directly cutting the throat of the person closest to his right hand, and then his body took advantage of the situation and pushed forward, his left hand covered the mouth of another person who was responsible for monitoring the left control panel, and the dagger held in his right hand pierced his lungs, and then his body quickly rotated to the left and leaned sideways, the dagger stirred with the movement of his body, and the sharp M9 multi-functional saber directly cut off two ribs and pierced the opponent's heart at the same time, The left elbow pushed back with the rotation of the body, just hitting the throat of the last person in the middle who had just reacted to the situation and raised his head to confirm it, and then what was waiting for him was the dagger that Xia Yu delivered again, and the warm blood of the other two people was still sticked.

In less than a second, almost no one could react to the rapid attack, Xia Yu directly solved all three people in the nuclear reactor monitoring room in one breath without causing any huge movements, but the sound of the pile of tools thrown on the ground was directly monitored by the sonar in the command tower, which frightened everyone in the command tower.

There are search teams almost everywhere behind them, and the officers of the ship are eager for the submarine to fly directly in the air at the moment, and even the voice is much quieter, for fear that the sound will be heard by the search team outside, this is good, a crackle sounded in a quiet environment, it is no different from firing a cannon in the ear, the sonar officer was so frightened that he listened to the sound in the headset, for fear that the search team heard the sound just now.

Everyone in the command tower unconsciously held their breath, looked at the sonar with a stern face nervously, and after half a sound, they saw the sonar man exhale deeply, and then heard the sonar man say: "It's okay, no one has found us, and all the targets have not changed their course to come to us." ”