Republic of China: Ace Pilot

As dawn broke, the deck of the Hetu aircraft carrier was already bustling with activity. Mechanics were inspecting P-40C fighter jets, refueling, tuning engines, and checking machine guns, meticulously performing every step.

This was part of the preparations made by the fleet after it passed Majuro Atoll, in preparation for Fang Wen's daily takeoffs and patrols.

The sea breeze was still biting, but it was especially hot because we were in the equatorial region, and the crew members' skin was tanned dark by the scorching sun.

Wearing a flight jacket, Fang Wen calmly boarded the fighter jet and began a new day of patrol.

The engine roared to life, the propellers whipped up a whirlwind, and Fang Wen once again used his mechanical perception ability to first check the aircraft. After confirming that there were no problems, he precisely controlled the fighter jet to complete a 100-meter short takeoff. The fighter jet skimmed the sea surface and climbed up to begin reconnaissance at high altitude.

The lack of discoveries in the past few days made Fang Wen even more cautious. He spread his mechanical perception ability to its fullest extent, while his fingertips rubbed the vertical eye gem on his neck, ready to activate his X-ray vision ability at any time.

They were trying to use this method of observation, which could penetrate the sea surface, to discover submarines lurking underwater.

The fighter jet maintained an altitude of 1000 meters and cruised slowly along a range of 100 kilometers ahead and 80 kilometers to the west.

Fang Wen's supernatural perspective was fixed on the sea below. His supernatural ability was like an invisible net, covering the entire sea area and not missing any slight anomalies.

The seawater was a deep, clear blue, and amidst the undulating waves, one could occasionally spot the enormous figures of a few whales chasing schools of fish.

After patrolling for about half an hour, just as the fighter jet flew to a point 70 nautical miles west of the fleet, he suddenly spotted a faint trace on the sea surface.

It's definitely not a whale; it's much bigger than a whale.

With that size, it could only be a deep-sea monster if it weren't a submarine!
Fang Wen felt a chill run down his spine and instantly tensed up. He immediately controlled the fighter jet to circle over the sea area while simultaneously enhancing the penetrating vision of the Vertical Eye Gem.

As my gaze pierced through the layers of seawater, the underwater scenery gradually became clear.

A gray Japanese I-15 submarine was quietly lurking at a depth of more than 40 meters.

Compared to the Haida 6 medium submarine that was previously sunk, this submarine is significantly larger.

This is a Japanese submarine model capable of independently conducting long-range reconnaissance and interception operations.

"There really are submarines lying in ambush!" A cold glint flashed in Fang Wen's eyes as he instantly understood the Japanese army's plan.

Clearly, after losing intelligence support from spies, the Japanese military was unable to obtain the convoy's route, so they dispatched patrol submarines to deploy in this dangerous sea area in advance, relying on the submarines' stealth to wait for the enemy to come to them.

If the fleet continues on its original route, it will enter the submarine's reconnaissance range in less than an hour, at which point the fleet will have a hard time avoiding submarine torpedo attacks.

Without delay, Fang Wen dared not hesitate and immediately maneuvered the fighter jet to climb to a higher altitude and return to base.

After flying back over the fleet, before even landing, he picked up the Taishan walkie-talkie on the right side of the instrument panel and issued a warning to the fleet: "Attention all ships! Attention all ships! Japanese submarine spotted 70 nautical miles to the west. Immediately turn southeast and abandon the original Fiji route!"

The instructions were quickly transmitted to the captain's cabin of each ship via the internal communication network.

Without the slightest hesitation, the captains of each ship immediately adjusted the rudder, increased the throttle, and the entire fleet turned southeast in an orderly manner, instantly increasing the speed to the maximum, and sped away from the submarine's lurking area.

At this moment, Fang Wen still did not land, but returned to the airspace where the submarine was discovered and continued to reconnoiter the submarine below.

The result is even more dangerous.

It wasn't just one I-15 submarine; there were two other submarines patrolling in the adjacent waters.

This distribution indicates that a large area of ​​sea has been controlled, making it difficult for ships on the Majuro-Fiji route to evade underwater submarine detection.

To avoid alerting the enemy, Fang Wen continued to observe, then climbed higher and returned.

Twenty minutes later, Fang Wen piloted the P-40C fighter jet to land on the deck of the Hetu semi-carrier. With a screeching sound, the fighter jet came to a stop at the end of the deck.

The mechanics on deck immediately surrounded him.

The cockpit canopy opened, Fang Wen stood up, stepped down the boarding stairs, took off his flight helmet, and his forehead was covered with fine beads of sweat.

Flying at high altitudes in such a hot environment is an extremely arduous task.

He took the towel that Gong Xiuneng handed him to wipe his sweat, and then drank a big gulp of warm water.

"Notify all ship captains to immediately conduct a wireless conference using the Taishan walkie-talkie."

"Yes, sir." Gong Xiuneng picked up the walkie-talkie and spoke to the ships. "Attention all captains, convene a radio conference immediately. All personnel must attend and no one may be absent."

Just a few minutes later, the voices of the captains of each ship came through the walkie-talkies one after another. Everyone's tone was tense. The sudden appearance of the Japanese submarine broke the previous calm. Everyone knew that the Japanese had already laid a trap in this sea area. If they were not careful, the entire fleet could be buried at sea.

Fang Wen picked up the walkie-talkie and pressed the call button: "Everyone, please be quiet. I just spotted Japanese submarines on the west side. After careful reconnaissance, I confirmed that there are not one, but three Japanese submarines, arranged in a triangle, which have blocked our original route. Moreover, this time the submarines are much larger than the last ones. If we continue to Fiji according to the original route, we will enter their reconnaissance range in less than an hour. At that time, once the submarines launch their torpedoes, we will not have time to dodge."

No sooner had he finished speaking than a commotion broke out on the walkie-talkie, and someone asked anxiously, "General Manager, what do we do now?"

"Don't panic, everyone. I've already planned a new route. We're currently sailing southeast, heading first to French Polynesia. There are many islands and reefs there, and the underwater conditions are complex and unfavorable for submarine navigation."

Fang Wen's words gradually calmed everyone down. One of the captains asked, "General Manager, should we increase our vigilance while we are sailing? What if the Japanese submarines discover our course and catch up with us?"

"We must strengthen vigilance," Fang Wen said firmly. "All ships must maintain a reasonable distance and constantly monitor underwater activity. I will take off in fighter jets every three hours to patrol and search the surrounding waters. If any Japanese submarines are spotted, I will notify everyone immediately. In addition, all ships' walkie-talkies must be kept fully powered and must not be shut down during communication."

The call ended there.

Gong Xiuneng asked, "Commander, is it really possible to avoid Japanese submarines by going to French Polynesia?"

"Not necessarily. We need to keep a close watch on things, and if anything unexpected happens, we'll have to take appropriate action," Fang Wen replied.

He looked at the nautical chart. According to the current route, he would head southeast to French Polynesia, then turn southwest through the southern waters of the Cook Islands, and finally arrive in New Zealand.

This route represents the option that best ensures the safety of the fleet.

Meanwhile, in the waters 200-300 nautical miles south of Majuro.

Three submarines were slowly cruising underwater.

For several days, they deployed multiple submarines near the Majuro-Fiji shipping route, waiting for the Taishan fleet to appear, in accordance with the original plan.

But so far, not a single submarine has reported finding the convoy, which has made the submarine fleet commander increasingly anxious.

"Commander, reports from the submarines indicate that no ships have been detected," the communications officer said cautiously, head bowed. "The I-15 submarine flotilla reports that they have been lying in wait in the designated area for three days and three nights, but have not detected any trace of the fleet. I'm afraid... I'm afraid the Taishan fleet has changed course."

The Sixth Fleet commander slammed his fist on the nautical chart, his face contorted with rage. "They must have changed course."

The staff officer next to him quickly advised, "That's not necessarily true. The sea area is very large. What if we're in a blind spot for the submarine's search? If they want to return to Asia, they can only pass through that area. We can't change the submarine's patrol layout arbitrarily."

The commander paused for a moment, then slowly nodded: "You're right, but we can't just wait around. Leave two of the three I-15 submarines that are already lurking in the designated area to remain in position and closely monitor the surrounding waters. If they spot the convoy, report immediately and do not act without authorization. The other submarine will head south. There is no specific search area specified; just find the convoy."

"Hail!" The communications officer immediately saluted and turned to relay the order. At that moment, the I-15-class submarine No. 17, which was lurking in the western waters, received the order, immediately started its engine, slowly surfaced, adjusted its course, and sped south.

Inside the submarine, the captain stood in the command center, looking at the navigation instrument with a serious expression: "Attention all crew, full speed south. Once the Taishan fleet is spotted, immediately begin covert tracking. Do not reveal your position and await fleet support."

The submarine was traveling at a high speed of 20 knots on the sea surface, aimlessly searching for the whereabouts of the Taishan fleet.

Time passed day by day.

The fleet, which turned southeast, successfully avoided Japanese submarines and finally arrived in French Polynesia.

Here, the fleet did not stop for resupply, but instead turned directly southwest towards the Cook Islands.

Every day, Fang Wen took off and patrolled in his fighter jet four times. He was extremely cautious during each patrol, activating his mechanical perception ability and the X-ray vision of the Vertical Eye Gem to the fullest extent, not letting go of any slight anomaly.

During this period, he also discovered several underwater anomalies, but after careful investigation, they were all whales or other large marine creatures, and there was no trace of Japanese submarines.

As night fell, the sea gradually calmed down, and a bright moon hung in the night sky, casting a soft silver light that illuminated the sea.

The fleet continued to travel at full speed, with all the ships' lights dimmed to their lowest setting, except for the navigation lights which were flashing faintly.

Fang Wen sat in the lounge of the Hetu, not sleepy at all.

Although no trace of Japanese submarines was found for several days, he always felt that things were not so simple. The Japanese would definitely not give up searching for the fleet easily and would most likely send submarines to search along the surrounding waters.

"We must prepare in advance," Fang Wen thought to himself. "Once we discover Japanese submarines, we can no longer just hide like before; we must take the initiative to attack."

What can be used to deal with a submarine that is 50 meters underwater?
Ordinary bullets and shells lose their firing rate underwater due to the resistance of the seawater, greatly reducing their effectiveness.

However, not all weapons are useless against underwater submarines; depth charges are one of them.

Fang Wen searched his memory for information about depth charges.

This device utilizes the physical law that hydrostatic pressure increases with depth, and controls the timing of the explosion through a water pressure fuse to ensure that it detonates near the depth where the submarine is located, rather than exploding upon contact with water.

The incompressibility of seawater allows for the almost lossless transfer of explosive energy, which can generate shock waves, bubble pulsation, and fragmentation.

Shock wave: The instantaneous high pressure directly compresses the submarine's pressure hull, causing deformation and rupture.

Bubble pulsation: The expansion and contraction of bubbles generated by the explosion create secondary or even tertiary impacts, causing the shell to repeatedly bend and fracture due to fatigue.

Fragmentation damage: Projectile fragments penetrate the submarine's hull at high speed, damaging internal equipment and personnel.

However, achieving this effect requires a dedicated underwater bomb production line.

No weapons were purchased this time because they were not on the U.S. list.

Of course, it's not entirely impossible.

It is also possible to modify ordinary bombs into underwater bombs.

In this regard, Fang Wen, who possesses mechanical perception, could do it.

He was prepared to give it a try; if it succeeded, he would have a secret weapon to deal with underwater submarines.

Immediately, Fang Wen got up, went to the armory, personally opened the sealed door, and took out a batch of aerial bombs.

Then they went to another warehouse and took out some small lathes, drills, and precision gear sets that had been purchased in the United States and were made in the US.

Several of the best mechanics and ordnance engineers were called over. Looking at the bombs scattered all over the ground, they all guessed that they were building a weapon to deal with underwater submarines. No one asked any questions and just waited quietly for instructions.

Fang Wen reached out and touched the bomb casing. His mechanical perception ability had already been activated, and the internal structure of the entire bomb appeared in his mind like a cross-section: the explosive compartment and the detonation tube were clearly visible.

“We don’t have specialized depth charges, nor do we have water pressure fuses.” Fang Wen’s gaze swept over everyone. “But ordinary bombs can be modified.”

He pointed to the bomb's nose cone: "This kind of aerial bomb, equipped with an impact fuse, will explode upon contact. If dropped into the sea, it will only explode in the air on the surface and will not damage submarines tens of meters underwater. What we need to do is replace it with a mechanical delayed fuse. The bomb will not explode when it hits the water; it will sink first and then explode precisely when it reaches the depth of a submarine."

An American mechanic he had hired frowned: "Mr. Fang, the sinking speed is unstable, and the ocean currents are having an impact. How can we time it precisely?"

"I'll calculate it, I'll calibrate it." Fang Wen squatted down and quickly wrote and drew on the wooden board.
"This bomb weighs about 50 kilograms and has a cast steel casing. Due to the resistance of the seawater, its sinking speed is approximately 2.8 meters per second. Japanese submarines often lurk at a depth of 40 to 50 meters. We need to detonate the bomb at a depth of about 50 meters underwater. Taking into account the water entry buffer, a delay time of 18 to 19 seconds is the safest."

Once the principle was explained, everyone immediately understood.

This method doesn't rely on water pressure to sense depth; instead, it uses time to gain depth. It's an unconventional approach for maritime emergencies, but it's currently the only feasible method.

The first step in the modification process, which is also the most dangerous, is to modify the original fuse.

The instantaneous firing pin of an aerial bomb is extremely sensitive; it can be detonated by the slightest vibration.

Fang Wen told everyone to step back, leaving only himself to operate the equipment.

He pressed his palm against the fuse casing, his mechanical senses fixed on the positions of the internal spring and firing pin. He loosened the fixing nut little by little, and removed the firing pin, detonator, and detonation rod one by one, his movements as light as if he were unraveling a taut string.

After all the original fuses of the aerial bombs were safely removed, the manufacturing process officially began.

Fang Wen directed the group:

"Use spare gears, springs, and delay caps to assemble a mechanical delay mechanism. After being submerged in water, the seawater melts the safety wax, and the springs only start running then, preventing premature detonation in the air."

The mechanics were turning parts, grinding gears, and assembling springs; Fang Wen, on the other hand, used his supernatural abilities to check each item one by one. He could find the problem as soon as he touched a spring to see which one was not strong enough or which gear was too tight.

Without precision instruments, his superpower is the most accurate measuring tool.

After the delay mechanism is formed, it is reinstalled into the bomb head, resealed, and waterproofed.

The aerial bombs that were originally designed to be dropped in the air have now been transformed into simple depth charges that sink over time and detonate at set times.

After nearly two hours of work, all ten modified missiles were completed.

But Fang Wen did not stop there.

Theoretical calculations are ultimately just on paper; sea conditions, bomb attitude, and seawater salinity all affect the sinking speed.

If it had been just one second off, the explosion would have been nearly three meters away from its depth, and the force would have missed its target.

"A water drop test must be conducted."

He decided to personally pilot the plane to drop the bombs, and then use his supernatural abilities to observe the live-fire data. (End of Chapter)