Ocean, 100 km from Laiforia
Mu Empire's submarine, 'Tuna'
Most submarines owned by the Mu Empire patrol around Leifor to conduct a naval blockade against Leifor. The submarines move together in small groups to form a wolfpack. The submarines 'Tuna', 'Seabass', and 'Mackarel' are part of a wolfpack named Wolfpack 5 that patrols around Leifor's capital, Leiforia.
Voyage class submarine (idea from class 209)
Dimensions: 64 m long, 6.5 m wide
Displacement: 1,800 tons full load
Propulsion: Diesel-Electric: 4 x 1 MW Diesel, 1 x 7,000 SHP Electric Motor, 1 x 300 SHP Creep Electric Motor Driving 1 shaft, 15 MWh NaFePO4 solid-state battery
Speed: Maximum 25 knots submerged burst speed (2 hours)
Range: 12,000 NM @ 10 knots surfaced
Weapon: 8 x 550mm torpedo tubes, 14 torpedoes
Sensors: radar, sonar
Crew: 30
The submarine 'Tuna' and the other ships in Wolfpack 5 sail at periscope depth. A young captain named Captain Lantior is in charge of the submarine "Tuna." Captain Lantior was currently in his cabin doing some paperwork.
Suddenly, the ship's intercom beeped, "Captain to the control room, captain to the control room."
Captain Lantior immediately cleared the paperwork on his desk and headed for the control room of the submarine.
"Report!" said Captain Lantior after entering the control room.
"Captain, we detected multiple contacts on radar, range 22 km, they are moving at 8 knots towards Leiforia. Bearing 120." The XO said.
"Let's see it." Captain Lantior said this while heading to his workstation.
Captain Lantior pressed a button to raise the photonic mast to the surface. The photonic mast is a periscope replacement device, which is a mast outside the pressure hull, inside the sail, that can be raised and lowered equipped with a camera, either a regular camera, a low-light camera, or an IR camera, and also equipped with a zoom lens. The advantage of this photonic mast is that there is no need for penetration in the pressure hull, making the pressure hull stronger and smaller in size, thus reducing the wake that can be detected by the opponent and saving space in the pressure hull.
Captain Lantior looked through his monitor screen at the conditions outside the ship that could be seen through the camera on the photonic mast.
"Bearing 120, huh?" he asked for confirmation while turning the dial to point the photonic mast in the desired direction.
"That's right, now bearing 121." The radar operator replied.
There appeared on the monitor screen a number of dots with thin black smoke—a convoy of ships. He turned another dial to zoom in on the screen. Once the zoom reached a sufficient level, it appeared that the ships were a number of transport ships, mostly passenger transport ships. On them, he could see the Gra Valkas flag flying.
"Hmm, a convoy belonging to Gra Valkas, mostly passenger transport ships, possibly transporting troops. The escort seems to be a light cruiser, and there are probably 4 destroyers. The number of transport ships is approximately 18 ships." Lantior said.
"Are we going to attack?" asked the XO.
"Of course. Signal all ships to attack. We will attack on the starboard side, order 'Seabass' to attack the port side. 'Mackarel' will attack the rear." Lantior orders
"Yes, captain. Action station!" said the XO as he picked up the underwater telephone to notify the other ships. "Lower the radar mast. Use sonar and hydrophones only. Increase speed to 16 knots."
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A few minutes later,
"Captain, Our ship is already in reverse alignment with the Gra Valkas' ships. Range: 10 km. The other ships have already reached their respective stations." The XO said.
"Very well, load and ready all torpedo tubes. Flood all the tubes. We will attack the escort ships first. Target the light cruiser and one of the destroyers. We will fire at a range of 7 km, maximum torpedo speed." Lantior said as he looked at the monitor showing the image from the photonic mast once more before he lowered the photonic mast.
The entire crew of the 'Tuna' immediately prepared for the attack. The sonar crew marked the ships to be attacked for input to the torpedo fire control. Time seemed to pass very slowly while waiting for the distance to reach 7 km from the convoy.
"Captain, we are 7,000 meters from the lead ship!" said the sonar officer.
"Very well. Open the outer doors." Lantior orders
"The outer torpedo tube doors opened." Said the attack crew.
"Target using torpedoes 1 and 2." Lantior's orders.
"Torpedoes 1 and 2 are ready." Said the torpedo officer.
"Fire 1 and 2." Lantior's orders
There was the sound of compressed air pressing the torpedoes out of their tubes. The torpedo immediately extended the cable connecting the torpedo to the submarine.
"Torpedo is active, control is positive. Topedo is moving toward the intended target, accelarating to maximum speed. Sonar is in passive mode. Guiding the torpedo to target." The torpedo officer said.
After a while, the torpedo started moving at its highest speed. After a few moments, the torpedo began to rotate almost 90 degrees to begin attacking the ships it was targeting and began to activate its sonar.
"Sonar in active mode, target acquired. Torpedo control guidance is now transferred to local guidance on torpedoes."The torpedo officer said.
Moments later, the torpedo reached 2,000 meters from its target and approached the maximum length of the control cable.
"Control cable cut!" said the torpedo officer as the torpedo was over 5,000 meters from the submarine, the furthest distance using the control cable.
"Target the other destroyer and one of the largest transport ships on the starboard side!" ordered Lantior. "Use torpedoes 3 and 4!"
"Torpedoes 3 and 4 are ready!" said the torpedo officer a moment later.
"Fire 3 and 4!" Lantior ordered.
Two more torpedoes were launched at different targets. Although the fire control capability on the Voyage-class submarine could only control two torpedoes using cables, since the cables of the first two torpedoes had been broken, the second two torpedoes could be launched.
Two after two torpedoes were launched towards the targets, the ships of Gra Valkas.
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Since the torpedoes used fuel like the Otto II fuel on earth, they did not leave much of a trace in the form of air bubbles behind them. Additionally, the Gra Valkas ships did not anticipate that submarines would attack them. As a result, they only realized when the torpedo had hit its target.
The first ship to be hit was the light cruiser at the front end of the convoy, which was the closest ship to the 'Tuna'. The ship's aft section was where the torpedo hit it. The explosion equivalent to more than 1 ton of TNT destroyed the aft part of the ship, namely the engineering section, propeller shaft, steering equipment, and also up to the superstructure. As the ship was not in general quarters, all watertight doors were still open. Many did not have time to close the watertight doors on the hull, resulting in water flooding many compartments on the light cruiser. The ship quickly took on water and slowly tilted towards the hole in the hull. However, the ship did not sink quickly, so many crew members were able to save themselves.
The second ship the torpedo hit was the destroyer at the front of the convoy. The explosion was so powerful that it almost split the ship in two. Unfortunately, the explosion also ignited the gunpowder storehouse for the cannons located behind the ship. The secondary explosion destroyed the rear of the ship. But because the ship was seemingly split in two, the explosion at the rear of the ship did not affect the front of the ship much, in fact, it completely cut the ship in two, with the rear completely destroyed and sinking quickly, while the front was still afloat for a long time so that the crew at the front could save themselves.
Torpedo fire from other submarines hit almost simultaneously. There were six ships hit. Five of them were escort ships of the convoy. None of the torpedoes missed, and no one realized they were under attack. It was only after the six ships were hit that the entire convoy became frantic, trying to save themselves. The last two destroyer escorts also accelerated their speed and maneuvered to prevent being hit by torpedo fire. However, it was very difficult for them to find the torpedo that was fired because the torpedo trail was very thin and difficult to detect.
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A few moments before that.
"Increase speed to flank speed. Turn the course left, 45 degrees. Make the ship's movement into a zigzag. Any sonar contact?" asked the XO of the 'Tigras'.
"No, sir, we heard some high-speed propellers, it appears to be a torpedo approaching us." Said the sonar officer.
"Determine the bearing and approximate destination of those torpedoes!" ordered the captain of the 'Tigras'. "Ready depth charge."
"There are two torpedoes approaching our direction, captain. 1 torpedo is clearly in our direction, bearing 260, range 3000 meters, speed 65 knots!" said the sonar officer.
The captain immediately went outside the bridge and searched for the torpedo with his binoculars, but he could not find it.
"Turn course, relative, 45 degrees left of the incoming torpedo! We still have time to outrun that torpedo. Increase speed to maximum speed, add speed as high as you can!" said the captain of the 'Tigras'.
Destroyer 'Tigras' turned at high speed, and after that, her speed increased by 2 knots, reaching 38 knots, 2 knots above flank speed.
"Torpedo sighted, bearing 027!" said a spotter.
The captain of the 'Tigras' used his binoculars to search for the torpedo, indeed, there was a very thin line indicating the path of the torpedo.
"What kind of torpedo only produces torpedoes with such a thin trail?" thought the captain of the 'Tigras'.
It seemed that the distance between the arrival of the torpedo and the destroyer 'Tigras' was increasing.
"Good, we can make it. The distance is still large. Turn the ship back to 90 degrees in the direction of the torpedo's arrival!" ordered the captain of the 'Tigras'. "Increase our distance to the torpedo!"
"Yes, captain." Said the XO, who immediately ordered the helm to carry out the captain's orders.
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Mu Empire's submarine, 'Tuna'
"Captain, the entire enemy convoy is starting to maneuver to avoid the torpedoes!" said the sonar officer.
"Heh, a futile endeavor. Our torpedoes are sonar-guided." Said the XO
"But they are beginning to increase the distance between them to make room for maneuvering. Signal other submarines to keep their distance from the convoy. Don't allow them to approach the convoy too closely so that the enemy can detect them. Turn the course 20 degrees away from the convoy. Reduce speed to 8 knots," ordered Captain Lantior.
"Torpedoes reloaded, captain," said the torpedo officer.
"Good, standby, one salvo from all our ships should be enough to destroy all the opposing ships." Lantior said.
"Yes, captain," said the torpedo officer.
"Report from other submarines, they have finished firing their torpedoes. We're just waiting for the results." said the XO.
"Very good, that should be enough to destroy the convoy." Lantior said.
"Captain, more torpedoes hit their targets!" said the hydrophone officer.
"Good. Let's wait until all the torpedoes hit their targets and then go to periscope depth." Lantior said.
"Yes, captain," XO said.
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Gra Valkas Destroyer, 'Tigras'
"Captain, the torpedo is turning back towards us!!!" shouted a spotter.
The captain of the 'Tigras' looked back with his binoculars. There was a thin line of torpedoes veering towards their ship.
"How did they turn that torpedo?" said the captain of the 'Tigras'.
"Captain, we heard sonar beeping from the direction of the torpedo. The torpedo is carrying a sonar system!" said the sonar officer.
"No way! How can a torpedo carry sonar?" said the captain of the 'Tigras'. "Check again, there might be a ship behind the torpedo."
"Captain, there is no ship behind the torpedo. Range: 1,000 meters. Impact in 50 seconds!" said the sonar officer.
"Turn port 45 degrees away from that torpedo!" ordered the captain of the 'Tigras'.
"Yes, sir!" replied the XO.
But as the captain of the 'Tigras' rechecked the torpedo's course, it appeared that the torpedo was adjusting its course, following where the 'Tigras' was moving.
"Torpedo is still approaching us! Impact in 26 seconds!" said the sonar officer.
"There's nothing we can do to avoid that torpedo!" shouted the XO.
"Order all crew members in the rear to evacuate forward and aboard. Let the torpedo approach from astern. Close all watertight hatches. Hurry." The captain of the 'Tigras' said.
"Rotate the ship's course in the direction the torpedo is coming from. Let the torpedo hit the back of the ship."
"Yes, captain." The XO said
"All hands brace to impact and evacuate aft section! All engines, drive to as high as possible." Captain's orders from 'Tigras'.
They waited for an agonizing second before the sonar officer again announced, "Impact in 5 seconds!"
The torpedo approached from the rear and hit the rear of the 'Tigras'. A violent explosion occurred in the aft section that lifted the entire aft section of the ship out of the water. Due to the severity of the explosion, the depth charges placed at the rear flew in various directions, like empty barrels, but it saved the 'Tigras' because the depth charge explosion did not occur on the ship. The rear of the ship was completely destroyed by the powerful explosion, but the hull also acted as a shock absorber. The explosion filled the empty parts of the ship and destroyed them, reducing the force of the explosion. Therefore, although nearly 15 meters of the aft section of the ship were completely destroyed, the ship was still seaworthy, with no leaks in other parts. Also, by luck, the explosion could not penetrate the aft magazine. Of course, the ship was already immobilized as the rear main engineering was also destroyed.
Due to the captain's orders from the 'Tigras', the entire crew was rescued, but there were many injuries from the shock of the ship due to the explosion of the torpedo. Since the forward engineering was still undamaged, the power was still on, and the injured crew members were quickly brought to the sick bay that was still functioning.
"Damage report!" said the captain of the 'Tigras'.
"The entire aft section of the ship is destroyed, aft engineering, propeller shaft, propeller, and steering gear are destroyed. We are dead in the water. Because the aft engineering was open, water flooded the aft engineering, and the ship list aft 15 degrees." XO said
"Are the other compartments not flooded?" asked the captain.
"No, captain. All watertight doors are intact." The XO replied.
"Good, at least the ship's condition is stable. Send distress code." Captain ordered. "Also report what happened."
Before the XO could reply, there was another explosion, but it didn't come from their ship, the convoy was being hit by torpedoes one by one. Troops carriers or passanger ships that were not designed for combat simply broke in half if hit by a torpedo and sank.
"Lower the lifeboats and conduct SAR. Even though our ship is heavily damaged, we can still function as usual. Raise the white flag to signal surrender." The captain of the 'Tigras' ordered. "If possible, dump all torpedoes and flammables at the rear of the ship."
"Yes, captain," the XO said.
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1 km from that location.
Mu Empire's submarine, 'Tuna'.
"Our last torpedo captain has already hit the target. There are no more targets that have not been hit by torpedoes from our side." The XO said.
Captain Lantior immediately raised the photonic mast, and he and the XO looked at the damage caused by their wolfpack attack. The sea was full of debris, and many of the ships that were still afloat were severely burned.
"Captain, look, there's still a destroyer that didn't sink." The XO said this while pointing to the monitor screen.
Captain Lantior immediately moved the photonic mast in the direction the XO indicated and zoomed in on the destroyer, which still looked undamaged. That ship was the destroyer 'Tigras'. It was only after zooming that the extensive damage at the rear of the ship became apparent. Also, a white flag had been raised on the ship.
"Hmm, they're flying a white flag." Captain Lantior said.
"Oh, that's a sign of surrender, as told by the Myto Empire, huh?" said the XO.
"Yes, it seems that they are combat ineffective. It looks like they are conducting a SAR operation." Captain Lantior said as he pointed out a number of small ships that were unloaded from the destroyer, and some were already moving towards the rest of the convoy.
"It seems so, are we going to attack back?" asked the XO.
"Of course not, they've surrendered. Signal the other ships to cease the attack. We will gather at this point." Captain Lantior said, pointing to a point on the other screen showing the map.
"Yes, captain." The XO said this while moving to the communications room.
Captain Lantior pressed the button to lower the photonic mast of the 'Tuna'.
"Oh, yes. Contact the headquartes. Report this incident and inform them that we will be moving back to the rendezvous point with our supply ship to resupply the torpedoes. We need to replenish the torpedoes." Lantior said.
"Yes, captain," said the XO, who then continued walking to the communications room.
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Gra Valkas Destroyer, 'Tigras'
The captain of the 'Tigras' looked at the ocean around him. It seemed that the entire convoy was on fire and sinking, there were even some ships that were no longer visible, having sunk. The captain of the 'Tigras' felt the hairs on the back of his neck stand up. The enemy had only attacked for a few minutes, but the result was that the entire convoy was destroyed, and the escort ships of the convoy were unable to retaliate against the enemy. With this encounter, the possibility that the Mu Empire also had submarines during this time became confirmed.
"Can we detect the presence of an enemy submarine?" asked the captain of the 'Tigras'.
"No captain, sonar, or hydrophone reports are clear. We don't know where the enemy submarines are. But judging by the direction of fire, there is more than one submarine attacking us." XO said
Although 'Tigras' is dead in the water and heavily damaged, because the power generator is still functioning, the radar, sonar, and hydrophone are also still functioning. Even if needed, most of the weapons were still functioning, except for the weapons at the back of the ship.
The captain of the 'Tigras' sighed.
"It seems that the technology of either the submarine or the enemy torpedoes is above us. What an unpleasant surprise. How can we fight them?" said the captain of the 'Tigras'.
Not a single crew member on the bridge could answer that.
With that, the battle against the convoy of the Gra Valkas ended, which was a landslide victory for the Mu Empire. None of the Gra Valkas ships escaped the attack of the Mu Empire's submarines.
---oOo---
Gra Valkas Empire, Ragna
Office of Emperor Luke Berga Flüm Helia Regelstein Ghabart Von Granderia (Gralux)
Emperor Gralux had just arrived at his office, but a military aide immediately approached him and handed him a thick report. Emperor Gralux was annoyed at the thickness of the report. It appeared that the military aide was very agitated.
"What does the report say?" asked Emperor Gralux.
"Your Majesty's apologies, the report is the result of our battle at Cartalpas." The military aide said it in a trembling voice.
"Oh, then we can receive the report from there?" said Emperor Gralux.
"Yes, Your Majesty. The 'Grade Atlastar' ship was already at communication range with us last night." The military aide said.
"I see. How did the battle go? How many ships were we able to sink, and how much damage was caused in the city of Cartalpas?" asked Emperor Gralux.
"I apologize, Your Majesty. The Judgement Fleet and the Carrier Battlegroup escorting it are currently combat ineffective." The military aide spoke slowly.
"Combat ineffective? What does that mean?" asked Emperor Gralux while staring intently at the military aide.
"Both fleets have been destroyed, Your Majesty. Only 1 battleship, 1 carrier, 1 light cruiser, and 5 destroyers remain. Both the battleship and the carrier suffered critical damage." The military aide said.
"What? How did this happen?" asked Emperor Gralux.
"It seems that HME has reinforced its air force on Western Island. They can handle our airstrikes. Fighters from the carriers of the Mu Empire also assisted them. The Mu Empire fighters then moved to destroy the Judgment Fleet, and the Mu Empire battleship destroyed the carrier battle group." The military aide replied.
"How is that possible? They only have fighter ships equivalent to heavy cruisers, and the aircraft are still using biplanes." Emperor Gralux said.
Before the military aide could answer, a bodyguard came to hand a document file to the military aide.
"What is it again?" asked Emperor Gralux.
"Beging your pardon, Your Majesty. Mu Empire repelled our attack from Leifor. We did not manage to enter the Mu Empire's territory. Also, all of our fighter missions did not return, they were shot down by the Mu Empire. Currently, our troops are back on the Leifor side, regrouping and waiting until morning to attack again." The military aide said this while shaking his body.
"What's going on? Why can our fighting force be held back by the Mu Empire? Aren't they technologically inferior to us?" asked Emperor Gralux.
"I don't know that. This report is still incomplete. The main cause of our defeat is still unknown. We are still waiting for a full report from the battlefield." The aide replied.
Suddenly, a bodyguard entered carrying a colonel, who, by looking at his uniform, one knew that he served at the military headquarters of Gra Valkas.
"Your Majesty, I have come to report a very serious matter that we just received." The colonel said.
"What is it again?" asked Emperor Gralux.
"We report that since 3 o'clock this morning, the Mu Empire has been attacking our military forces in Leifor. Almost all border posts have been destroyed, and all radar stations close to the border have also been destroyed. The Mu Empire has destroyed many of our military installations. Currently, the Mu Empire rules the sky above Leifor." The colonel said.
"What exactly happened? Why are we losing to the Mu Empire?" asked Emperor Gralux, who felt confused about the consecutive defeats of Gra Valkas.
"We don't know your highness, but the Mu Empire's airstrikes, according to eyewitnesses, did use biplane aircraft, which is their hallmark." The colonel said. "We also have to report that currently two groups of Mu Empire troops have made it inside Leifor, and we also have indications that a number of cities and strategic positions in Leifor have fallen to the Mu Empire."
"Whaaaat!!! How did they get inside Leifor without being detected?" asked Emperor Gralux.
"We don't know yet, Your Majesty. We are currently gathering troops to attack those cities to reclaim them." The colonel said.
"How many of our troops are currently in Leifor?" asked Emperor Gralux.
"About 800,000, Your Majesty, half of which are at the border. We are sending more troops by sea." The colonel said.
"Those troops on their way are easy targets and will be attacked by Mu Empire ships. Signal all those ships to stay alert." Emperor Gralux said. "Why aren't all the troops at the border?"
"We are waiting until our troops can penetrate the Mu Empire's defenses. We deliberately put half of our troops on the inner defense to ward off a counterattack from the Mu Empire. Actually, this incident was calculated. But the speed of their troop movements is much faster than we predicted." The colonel said.
"All events are beyond the prediction of the military! Are you all incompetent to design a campaign?" Emperor Gralux said it angrily.
No one in the room dared to answer Emperor Gralux's question. Everyone was frightened by Emperor Gralux's anger.
Suddenly, a staff of Emperor Gralux gave Emperor Gralux a piece of paper. Emperor Gralux, who read the contents of the paper, became very angry.
"The Mu Empire has attacked the ships carrying our troops! Two convoys have been destroyed, who knows how many of our troops have become casualties in both convoys. This is completely unacceptable. Order all senior ministers and the military to meet with me. Now!!!" Emperor Gralux ordered angrily.
All the aides, including the colonel, immediately carried out Emperor Gralux's orders. They did not know that the situation in Leifor had become very critical for Gra Valkas...