"So, this is supersonic speed..."
Jin, having boarded Pegasus 1, was flying through the upper atmosphere with Reiko.
At the moment, their top speed was approximately 3,600 kilometers per hour—roughly Mach 3. This figure was calculated from measurements taken by Laojun using a magi-radar.
In the vacuum created by the Breeze Barrier, it should have been possible to increase their speed indefinitely, but they had encountered a physical limit.
Specifically, it was the generation speed of the barrier itself.
Once they exceeded 3,600 kilometers per hour, the barrier could no longer be generated fast enough to keep up, causing the nose of Pegasus 1 to protrude beyond the protected zone.
"Even so, it's an extraordinary speed."
There was no doubt that being able to circle the planet Ars in just two hours was a staggering feat.
After enjoying the world of supersonic flight for a while, Jin decided to return to the ground and upgrade the rest of his aerial forces.
Once Jin crafted the necessary components and registered them in the memory control cores of the Smiths, the little golems could handle the mass production.
In this way, every aircraft was equipped with a force generator, rendering runways for takeoff entirely unnecessary.
"Of course, I can apply this to ships as well. And Golems."
He prioritized the modification of the Hydro boats and the Mermaid golems. Thanks to a specialized underwater version of the barrier that pushed aside water, the Mermaids’ top speed reached a blistering 500 kilometers per hour.
It was at this point that Jin fell into a state of deep reflection and self-restraint.
"Laojun, what is the status of the three aircraft carriers?"
These were the 20,000-ton class aircraft carriers whose construction had begun during the conflict with the Unifilar group. The first ship, the Hotaka, was already commissioned.
"Yes, My Lord. The second ship, the Myoukou, and the third ship, the Asama, are also complete. The Myoukou is currently in Tatsumi Bay, while the Asama is still in the dock awaiting its launching ceremony."
"Oh? Is that so...?"
Jin had just visited Tatsumi Bay for Reiko's testing earlier, but he hadn't noticed the ship. He had likely been too absorbed in the experiment.
"...That's fine, but Laojun, I have something to discuss with you."
"Yes, what is it?"
"It's about the necessity of those carriers."
They had built the aircraft carriers because launching aerial forces from Hourai Island every time was inefficient. However, before they could be used even once, the Unifilar group had been dismantled.
Furthermore, the completion of the transporters meant that while returning was one thing, deployment could now be done instantly to any arbitrary location.
"...It's my fault for acting on a whim."
"No, My Lord. Given the situation at the time, it was somewhat unavoidable. Besides, you do love creating new things, My Lord..."
Laojun offered a bit of support. Jin felt like the comment was slightly off the mark, but he decided to shake it off.
"Well, there's no use complaining about it now....So, what I wanted to consult you about is whether it might be better to remodel those three ships."
"What kind of remodeling did you have in mind?"
"I was thinking of a so-called 'universal ship.'"
From a military standpoint, highly versatile vessels are convenient, but they often lack a decisive edge. In other words, they tend to degrade from a universal ship into a mere general-purpose one.
However, since this was Jin’s creation, such concerns were likely to be minimal at best.
Laojun weighed the pros and cons, deliberated, and then replied.
"I believe the core idea is sound. What specific details were you considering?"
"That’s the difficult part... I was wondering if I could use the three ships to create a trimaran type..."
"Wouldn't that be too large?"
Combining the three ships would result in a 60,000-ton vessel; once the connecting decks were added, it might reach 70,000 tons. That would surpass even the super-dreadnought battleship Yamato from Jin's memories.
"As for me, I believe a flight deck large enough to launch and recover your personal craft, Pegasus 1, plus space for one or two other aircraft, would be more than sufficient size, My Lord."
"Yeah, I know. That's why I'm torn..."
"Father, why not simply build an invincible fleet?"
Reiko, who had been listening in silence until now, chimed in.
"Based on your memories, Father... I believe you had knowledge of destroyers, light cruisers, heavy cruisers, battlecruisers, battleships, aircraft carriers, repair ships, supply ships, submarines, torpedo boats... and the like?"
"No matter how you look at it, that's going too far."
Jin shot the idea down immediately.
He understood Reiko's sentiment, and part of him wanted to try building them, but he couldn't see a practical use for them. Even in World War II, the era of battleships had given way to aircraft carriers and planes.
If combat was the goal, it was more advantageous to focus on aerial forces. If there was no intention of fighting, then a fleet was nothing but a white elephant.
"Reiko, considering My Lord's personality, if he creates one vessel that is easy to use, he will surely cherish and employ it for a long time."
"...That is true."
Reiko herself was proof of that. Jin was the type of person who took great care of the things he grew fond of.
"In that case, putting aside the question of remodeling for a moment, perhaps we should outline the necessary specifications first."
Jin nodded at Laojun's suggestion.
"To begin with, it might be best to imagine the specific purposes and scenes where it would be used."
"Right, I see....For example, visiting Port Rock, or things like that?"
"If we take that into account, the ship cannot be too large."
That was the crucial point. In terms of aircraft, it would be the maritime equivalent of an airship. If it couldn't be shown in public, there wouldn't be many opportunities to use it.
"I’d like to visit Port Rock or Eckart's place. And then there's the Demon race's territorial waters. Another use I can think of is catching or transporting fish to provide relief during a famine."
"To traverse the northern seas, one would need a reasonably large vessel. A larger size is also an advantage for transporting fish."
"True..."
Jin fell into thought. He didn't want to do things halfway, yet he wanted to avoid creating something useless.
"I suppose I should make several ships of varying sizes..."
A boat under 10 meters offered virtually no habitability. Even 20 meters felt a bit half-baked.
"...Then, perhaps around 50 meters?"
The ship being built by Eckart Techles, the wealthy merchant from the southern Celuroa Kingdom, was in the 40-meter class. At 50 meters, it might just barely remain within the bounds of common sense.
"I see... In any case, a ship of that size won't be able to enter ordinary ports, so you would need to use a smaller boat for those occasions."
"A Hydro-class boat, then."
"If you use force generators for propulsion, there's no need to worry about balance, so there is no necessity to make them catamarans or trimarans either."
That meant at least two ships. Jin began to organize his thoughts, concluding that this was within the realm of common sense.
"Father, won't people wonder where you built such a large ship?"
"Ah..."
The base known as Hourai Island was a secret. He could claim it belonged to Deus Ex Machina, but insisting it was Jin's own property would be difficult.
"Ah—it's just one problem after another."
Unlike an airplane, a ship would be seen by many people, so there was a risk that any cover story wouldn't hold up.
"May I offer my opinion?"
Seeing Jin's struggle, Laojun decided to propose a plan.
"First, the three commissioned aircraft carriers will be converted into battleships and used for the defense of Hourai Island."
"That's not a bad idea."
"Since it is difficult to operate with battleships alone, we will construct several cruisers. The size will be in the 100-meter, 2,000-ton class."
On modern Earth, that size would be classified as a destroyer, but Laojun continued regardless.
"And for destroyers... no, as destroyer crafts, we will build a large number of vessels one size larger than the Hydro series."
Jin wondered what exactly Laojun intended to fight, but come to think of it, compared to their aerial forces, their surface naval power was certainly lacking.
"I'll... leave that to you. But what about my request?"
"Yes. I thought that if you were to see those vessels first, your own ideas might come together more clearly, My Lord."
Indeed, it might be easier to solidify an image if he had the actual ships in front of him. Jin gave his permission for that as well.
"Then, get started on the lead ship for each class immediately."
"Understood. How shall we handle the naming?"
"Hmm. Since we gave mountain names to the carriers-turned-battleships, maybe rivers for the cruisers and fish for the destroyer crafts?"
"In that case, shall we name the first cruiser Azusa and the first destroyer craft Carp?"
"Wait a second. Let's scrap the fish for the destroyer crafts. The image is too different."
While "Azusa" was fine since it was the river flowing through Kamikochi at the foot of Mount Hotaka, Jin felt that names like "Carp," "Sea Bream," or "Tuna" just didn't suit a ship.
"Let's use a series name and numbering for the destroyer crafts, just like the Hydro series. And for the series name... how about 'Stream'?"
Like the Hydro series, it was a fairly good name.
"Understood. The destroyer crafts shall be designated as Stream 1 and so forth."
Thus, the fleet to protect Hourai Island was officially established.
Meanwhile, Jin continued to agonize over the design of his personal vessel.
(If Elsa were here, I could consult her...)
Jin felt a certain sense of loneliness in the absence of Elsa, who was usually by his side.
As if to blow that feeling away, Jin immersed himself once more in his plans for the ships.