On the Huofeng ship, everyone learned that the battleship had annihilated all five Japanese submarines, and immediately let out a cheer, but Abe Ichiro, who was sitting on the side, stared at the cheering crowd viciously, if it weren't for the two marines standing beside him, he would really pounce on him and beat Yu Feng hard!

At this moment, the sonar chief sent a message: "Report to the captain, behind the five submarines that we hit, there are sound signals from four more submarines." ”

Yu Feng was overjoyed in his heart, and thought, "There are four more?" Then we met ten Japanese submarines at once, and if we sank all of them, this result would be not small! Yu Feng immediately said: "Immediately track and calculate the target position, and the torpedo room is ready to launch the torpedo!" ”

The sonar chief said with some panic: "I can't track and calculate the location of the target, the interference is too strong!" ”

Yu Feng immediately asked, "Interference?" What interference? ”

"I don't know, the echo is messy, it must have suffered a lot of interference," said the sonar chief. ”

Yu Feng thought in his heart: "Could it be that the Japanese army is equipped with underwater acoustic countermeasure equipment?" ”

It turned out that the Japanese submarines were divided into two echelons, each with five ships, the five in the first echelon were all sunk except for the I-17 submarine where Hoshino Yasuwa was located, and the five ships in the second echelon, except for the one that was accidentally hit and sunk by the first torpedo, there were still four left.

The numbers of these four submarines are thirteen to sixteen, and the reason why these four submarines were not discovered by Lin Yuan's warships is not that they used underwater acoustic countermeasure equipment, but that in the attack just now, the torpedo explosion and the submarine explosion produced a large amount of gas, and the gas inside the submarine also leaked out, and these gases entered the water to form bubbles, and the bubbles rose rapidly in the water, invisibly playing the role of air curtain bombs.

Air curtain bomb is a commonly used underwater acoustic countermeasure equipment in the Lin Yuan era, and it is also the first underwater acoustic countermeasure equipment invented in the Lin Yuan era, this air curtain bomb is composed of a chemical agent that can produce a large number of bubbles, and a large number of bubbles can be formed in the water after the explosion, these bubbles have been pre-designed, some are large in size, some are small, the rise rate of large bubbles is large, and the rise speed of small bubbles is small, so that a "bubble wall" is formed in the water.

This "bubble wall" can not only reflect the quotation marks of active sonar, so that the torpedo mistakenly thinks that the "bubble wall" is the target, but also can block the sound emitted by the submarine and the ship itself, so that the passive sonar can not be traced, so that the enemy's torpedoes cannot hit the real target.

The torpedo of Lin Yuan's troops was interfered with by the bubbles, and either hit the bubble wall or deviated from the target, so the submarines of the second echelon of the Japanese army were spared, and the existence of the bubbles also interfered with the towed array sonar on Lin Yuan's warship, so the sonar chief could not detect the Japanese submarine according to the sonar signal.

Yu Feng thought in his heart: "Regardless of whether the Japanese army is equipped with underwater acoustic countermeasure equipment or not, I should not take risks, so let's let the warship drive a section into the distance to prepare for the Japanese torpedo attack, and let our unmanned underwater vehicles speed up and rush to the vicinity of the Japanese submarine team as soon as possible to conduct reconnaissance."

Yu Feng thought of this and gave an order, and the unmanned underwater vehicle immediately increased its speed, arrived near the Japanese submarine fleet, and sent the location and speed of the remaining Japanese submarine to the control room, and although the sonar soldiers in the Japanese submarine heard the sound of the unmanned underwater vehicle, he thought it was a noise, so he ignored it.

The captains of the remaining four Japanese submarines reported that they heard one explosion after another and understood: their submarine was attacked by Lin Yuan's warships, they were not as smart as Xiaoshan Shiji, they didn't think of a way to turn around and scatter and escape, but they thought of fighting Lin Yuan's warship to the death.

The captain of the Yi 13 submarine said loudly: "We were discovered by the warships of Lin Yuan's troops, the speed of the submarine is much slower than that of surface ships, so we have no hope of escaping, the only thing we can do is to launch an attack on the warship of Lin Yuan's troops, even if it is death, we must tell the group of people that we samurai of the Great Japanese Empire would rather be broken than destroyed!" ”

The captain then gave the order: "Empty the water of the fast diving tank, float to the periscope level, torpedo long, use the periscope to detect, and quickly attack as soon as the target is found!" ”

The torpedo commander replied in a loud voice: "Yes! Then they came to the periscope, grabbed the periscope, and at this time the submarine began to slowly float, and just as they were ascending, the submarine discovered the Japanese submarine and immediately reported the position of the Japanese submarine to the two warships.

After receiving the message from the submersible, the sonar chief reported to Yu Feng: "Captain, we have received a message from the submersible. ”

Yu Feng hurriedly asked, "Is it the location of the Japanese submarine?" ”

The sonar chief said, "It should be, but we're not sure!" ”

Yu Feng asked in surprise, "Not sure?" Why are you not sure? ”

The sonar chief said: "The sound waves used for communication are more complex than the sound waves used for reconnaissance, and the frequency and waveform of the sound waves need to be adjusted before transmission to load the information, but the sound waves are attenuated by the sea water in the process of propagation, and the information loaded in the frequency and waveform cannot be read for a while!" ”

Yu Feng said: "Isn't the towed array sonar still unable to determine the location of the Japanese submarine fleet? ”

The sonar chief replied: "The interference we have received is too strong, and it is not yet possible to detect the location of the Japanese submarines, and the submarines are our only hope." ”

Yu Feng thought for a while and said, "Increase the listening time for the sound waves of the submarine, and tell me as soon as there is a result." "Sonar is the same as radar, when the received information is inaccurate, increasing the reception time will make the information accurate, when the two battleships listened to the sonar message, the I-13 submarine floated to a depth of ten meters, and the torpedo chief gave various orders in a loud voice, and quickly completed the preparations before the torpedo was launched, and the torpedo chief said loudly: "Report to the captain, the torpedo is ready!" ”

The captain ordered: "Four salvos!" The torpedo chief then ordered the launcher: "Four salvos!" The launcher in the torpedo compartment in the bow then pressed the launch button, and the four torpedoes were fired together, and the launcher immediately said: "The torpedo has been launched!" ”

The torpedo commander immediately ordered: "Close the valve of the launch pipe to the sea and open the weight valve." "One torpedo on the Japanese submarine weighed 800 kilograms, and after the four were launched, the submarine lost more than three tons of weight, and if the weight of the three tons was not made up, the submarine would tilt, so the submarine needed to open the adjustment valve, introduce seawater into the submarine, and balance the weight of the four torpedoes that were fired.

The high-speed torpedo was quickly heard by the sonar on Lin Yuan's warship, and the sonar chief immediately reported: "Captain, the torpedo target has been found, and the speed is forty knots!" ”

Yu Feng thought to himself: "The Japanese submarine has launched a torpedo, and our anti-torpedo system is useful!" While thinking, he secretly glanced at Ichiro Abe, only to see that he was actually snickering, Yu Feng thought to himself: "Just laugh, you will have to cry in a while." ”