Things go back to a month ago.

After Zhengxin cooperated with Yishu Group to build islands in the South China Sea, the maritime patrol line in the South China Sea, which had been blocked, was fully opened. A certain Chinese submarine unit stationed near Sanya reformulated its cruising route and began its international sea patrol route from the South China Sea after a lapse of more than 10 years.

This submarine force in Sanya is subordinate to the South China Sea Fleet of the Chinese Navy. It is equipped with a Han-class nuclear-powered boat, a Xia-class ballistic missile nuclear-powered boat, and two Song-class conventionally powered submarines. In addition, there are more than a dozen R-class boats that have been in service for more than 15 years.

These submarines, except for the Han, Xia, and Song submarines, which are currently more advanced in China's independent research and development of the new generation of "national horn family" submarines, are all obsolete goods that have been eliminated.

In order to meet the increasingly complex international maritime environment, the fleet has recently introduced a batch of "Warsaw songs".

This submarine was originally the most successful conventional submarine developed during the Soviet naval era. It is mainly used for anti-ship and anti-submarine warfare in shallow offshore areas, and is known for its powerful firepower and low noise. After being modernized and modified by Russia, the Kilo-class improved version was formed, which is currently one of the quietest diesel-electric submarines in the world.

After adaptation, this batch of conventionally powered submarines was charged into the South China Sea Fleet to carry out cruise training missions.

On the day when Li Fanyu was flying in Japan, a scene that shocked the Chinese Navy occurred;

On the same day, one Han-class attack submarine and two Kilo-class conventionally powered submarines of the South China Sea Fleet's submarine formation 3 dived from the southern part of Apo Reef to international waters.

However, less than an hour after stepping out of the sea boundary and entering international waters, the Kilo-class 079 boat, which was responsible for piloting, discovered that there was a continuous active sonar to detect the formation.

Immediately, another Kilo-class 080 boat was also found to have its location exposed. Only two minutes later, in the Han-class 054 boat, the "da-da-da" sound representing the enemy's active sonar signal also sounded continuously!

After three hours of getting rid of it, the formation still did not leave the sonar detection range of the opposing side.

Among them, the 054 boat encountered a submarine cliff in the emergency diving evasion, although it escaped under the emergency treatment of the officers and men of the whole boat, and got rid of the tragedy of being crushed by force, but the hull still suffered serious damage.

During this time, three submarines were subjected to seven simulated attacks. That is, if it weren't for the fact that the other side didn't want to open fire, three submarines would have sunk seven times!

After the 054 boat reluctantly surfaced, it was discovered that it was only a maritime anti-submarine aircraft printed with the American flag that carried out active sonar detection of the formation and launched a simulated attack!

Although there is no fear of life, this incident has made the entire South China Sea Fleet and Xing Yaxin, who is stationed in the fleet to conduct submarine test and research and development work, fall into an ice cave.

You know, after entering international waters, the formation has already dived deeply. Under such circumstances, the formation is detected by enemy sonar, which means that all Chinese submarines will be under enemy surveillance.

This also means that the secrecy and suddenness on which the submarine force depends for its survival are gone!

It is very likely that the United States has set up the latest generation of active defense network in the international waters of the South China Sea, and has achieved all-round monitoring and blockade of the South China Sea.

Under such circumstances, in the event of a war, the submarines of the entire South China Sea Fleet will be useless. As long as you go abroad, you will be someone else's target!

The belief that had been held on for twenty years collapsed at that moment. Xing Yaxin stayed awake for more than three weeks, sticking himself in the R&D room.

Seeing that his state has been extremely poor, the whole person is in danger of sudden death at any time. The chief in charge of the entire Navy Bureau gave a death order, forcibly put him on a transport plane, and "transported" him back to the capital to visit relatives.

Although the person is back, Xing Yaxin's soul is still in the South China Sea.

The three submarines in formation at the time of the incident were all relatively advanced models among the submarines in service. Among them, the underwater noise of the Han-class and power submarines is only 85 decibels, while the noise of the two Kilo-type conventionally powered submarines is about 90 decibels, although they are diesel-electric conventional submarines.

The world's most advanced known military sonar detection network can detect the lowest sound source at 90 decibels. However, it does not mean that it cannot be detected below 90 decibels, but the noise inside the ocean is as high as 90 decibels. As long as the underwater noise of the submarine is around 90, it can blend in the sea and blend in with the heartbeat of the vast sea.

Therefore, there is a general consensus among experts in the field of submarines in the world - as long as the noise of the submarine is lower than 90, it has reached the "stealth standard".

After these days of hard thinking, Xing Yaxin deduced that the United States must have invented a sonar network that can detect and distinguish the noise of seawater and submarines, and applied it outside the South China Sea!

So this man in his forties had nothing in his heart from that day on. There is only one thought left - silence the submarine!

……

Xing Yaxin's home in the capital.

Although I haven't been home for a long time, my daughter must have come to clean it often, so the house is quite tidy. On the head of the bed in the bedroom, on the yellowed photo, the young Xing Yaxin was still smiling so brightly.

But Xing Yaxin, who was sitting on the bed, was already full of vicissitudes on his face.

Just as he was looking at the picture and getting distracted, his phone rang.

"Report to the chief, we have investigated the information of the motor mounted on the BMW 5 Series. The motor model is LS-551, which adopts the active noise reduction technology with completely independent property rights of Zhengxin, and the noise is as low as 15 decibels in the normal power output range.

Its production site is located in Zhengxin Industrial Base, Binhai New Area, Tiancheng City. At present, 7,721 units have been installed, mainly used in the three models of the 5 Series sedan of the BMW brand under Zhengxin.

According to our research, 32 kinds of raw materials are used in the production of this motor. Except for the production materials of the core component permanent magnet rotor, which mainly come from a rare earth mine in the Republic of Nanfei, the rest of the materials are supplied domestically. These suppliers have ......"

The report on the other side of the phone is very detailed, from the motor parameters to the supplier of a screw. After ten minutes of reporting, all the information of Zhengxin Permanent Magnet Motor has been displayed in Xing Yaxin's heart.

At this time, Xing Yaxin's tired face dissipated, and a hint of a smile appeared on the corner of his mouth.

"Help me contact the person in charge of the group, I need to meet with him. Immediately, immediately!"

Xing Yaxin ordered on the other side of the phone.

"Uh......" There was some hesitation on the other side of the phone.

"Is there any difficulty?" Xing Yaxin's brows furrowed, different from the previous Mu Ne, the majesty between the words made the person on the other side of the phone feel a lot of pressure.

"Report the chief, the target is currently in Level A protection status. We don't have the authority to find out exactly where he is. ”

"A-level protection?" Xing Yaxin hissed, of course he understood what the meaning of this code name was. As a senior national defense scientific researcher, he himself has been in this state all year round.

That means that the target is no longer in a normal city. It's in a place that exists in China, but never shows up on a map of China.

……

"Ahh

In a building where even the sun was missing, Li Fanyu sneezed fiercely.

"Dad, how many meters is this broken ground?"

Feeling the coldness around him, he muttered as he looked at the two guards in front of him who looked like zombies with gloomy faces like the environment.