Being in a rocky boat, wearing headphones, closing your eyes, reducing the connection between your five senses and the outside world to the limit, and listening attentively to the sounds from the bottom of the sea, the whole person seems to slowly sink to the bottom of the sea, surrounded by bottomless darkness, and it is like returning to the mother's womb, and the body is suspended in chaos.

The darkness makes people more focused, and the beauty of the underwater chant makes it impossible to feel the passage of time, but when the strange sound sounded around him, his eyes opened involuntarily, and he returned to reality in a cold sweat, glad that he was not really at the bottom of the dark sea, and he didn't have to think about what kind of monster made the sound just now.

If experienced teachers and graduate students of the School of Underwater Acoustic Engineering are here, using two or more underwater pickups, they can judge the swimming speed and direction of the target through the triangulation method, and I have heard that the senior officers and men of the submarine listening system can even identify the real body of hundreds of noisy targets in a relatively short time.

Zhang Zi'an didn't have such outstanding skills, he could hear that this was the song of a minke whale, because the sound of a minke whale was very distinctive, and he knew that there were minke whales nearby, if it was replaced by a relatively rare whale, he would not be able to hear it for the first time.

He listened for a while, and then heard what appeared to be other cetaceans, but they were too far away to distinguish them.

So he took off the headphones and hung them around his neck and sank the underwater speaker into the water, but not as deep as an underwater pickup because the line wasn't long enough.

He turned on the speaker and began to play Shihua's singing.

After playing for a few minutes at a time, he paused, put his ears back on, and listened to the sound of the seabed, if he didn't, because the speakers were too close to the pickups, Shihua's singing would drown out all other sounds, and as a result, nothing could be heard.

Yesterday he used Shihua's singing to appease the male minke whale, but unexpectedly the song attracted the giant whale, and today he plans to do the same to see if he can lure the giant whale over again.

This time, he was mentally prepared that he would never be attacked by the giant whale again.

Yesterday the whale surfaced without warning, almost making him think it was a submarine of some country, because it must have swam in one breath, and there was no trace of it on the surface.

The whale was not very easy to get along with, and if he was to be approached by it again to a dangerous distance, there would be no minke whale to save him today - it was a small matter for him to capsize and fall into the water, and if these valuable instruments fell into the water, he would have to send his pants to the pawnshop.

However, he has an underwater pickup, and as soon as the whale comes within a certain range, he can detect its arrival in advance and take countermeasures - escape.

For example, it's like a cat-and-mouse game between a destroyer and a nuclear submarine, except that this destroyer is more cowardly.

This kind of thing is a test of patience, think about the submarine sonar in the war movie who often sits for half a day when on duty, listens to various sounds coming from the headphones, and tries to spot the enemy submarine sonar before he finds himself, what level of concentration is required? As long as the mind wanders slightly, the entire submarine may be sunk by the enemy submarine.

Zhang Zi'an didn't have that patience and focus, but fortunately he didn't need to listen for too long.

About the third pause, there was a sudden strange sound in the monitor-grade headphones, mixed with the brief pop of minke whales, which he would probably miss if he hadn't been focused.

There seemed to be more than one minke whale nearby, and the sound was chaotic and noisy, similar to bargaining in the vegetable market, I don't know what they were talking about, but as soon as this strange sound appeared, the sound of the minke whale was like ringing the bell of a class, and it suddenly fell silent. Immediately after, minke whale voices erupted at a higher density, as if warning each other about something, say—the wolf is coming.

There is no way, although cetaceans have a certain degree of intelligence, they are still stuck in the era when communication is basically based on roaring.

Zhang Zi'an cheered up, listened more intently, nervously wiped a handful of sweat from his palms on his pants, took a deep breath, and glanced at the handle of the motor.

He couldn't be sure if the sound was coming from the whale or something, so he had to wait.

About half a minute later, the voice sounded again, closer and more real than the last time.

The target was swimming very fast, and with rumbling echoes, a huge object like a train was rapidly approaching.

Zhang Zi'an can almost imagine the posture of a giant whale opening its mouth, swallowing all the small fish and shrimp along the way indiscriminately, and then expelling the seawater from the whale baleen.

On the contrary, the sound of minke whales is weakening and their numbers are decreasing, as if they are moving away from the mysterious beast, not necessarily because they are afraid of it, but because they have eaten all the food nearby, leaving the other whales hungry.

The sound was getting closer and closer, like a periodic flute, sometimes loud and sometimes small, and even his eardrums were vibrating with it when it was large, and it was almost inaudible when it was small.

Zhang Zi'an frowned again and again when he heard this, what is the sound made by this thing? Is it the giant whale?

He glanced at the LCD of the meter, which was automatically recording and plotting the waveform of the sound, but he didn't have time to look at it closely, the target was coming very quickly. He wasn't sure if he had recorded a long enough sample, but he had to leave right now or he might repeat yesterday's scene.

He took off his headphones and quickly rolled the fiber optic cable to carry the underwater pickups up from the bottom of the sea. The 50-meter-long fiber optic cable was not so quick to get ready, and he stared nervously at the calm sea as he curled it, fearing that a submarine-like body would suddenly emerge somewhere.

The underwater pickups were finally lifted out of the water with a thud, and some dark green seaweed was entwined around them.

He lowered the pickups, started the motor as fast as he could, adjusted the bow to the direction of land, turned the power to the highest, and the propeller spun at high speed.

The assault boat galloped towards the shore.

At this time, he was still not completely reassured, and looked back as he drove away.

Burst!

Barely a minute before he left, a huge column of water erupted from where he had been, reached its highest point, and then crashed into the water like a torrential rain.

The sea was divided on both sides, and huge bodies surfaced.

Zhang Zi'an estimated that he had probably come to a safe area, so he slowed down the speed of the ship and picked up a telescope to observe.

The whale flicked its tail and swam on the surface of the sea for a while, as if it had not found anything of interest, and after a few breaths, a fierce man plunged into the water and disappeared again.

Zhang Zi'an finally breathed a sigh of relief, firstly because he "did" and retreated today, and secondly, because he confirmed that the source of the sound was the giant whale, not anything else, and it was not a trip in vain.