The Sagami-nada Sea was silent on the 12th of May, especially since it was in the middle of the night and the lone ship in this part of the ocean was still, motors cut in order to prevent it from being potentially picked up by any Abyssals in the area, and even though they were well within the Safety Zone, the submarines aboard the large ship still possessed a healthy dose of paranoia of being spotted as they performed their duties.
Iku looked up at the container-ship-turned-mine-laying-vessel while floating on the surface of the ocean, feeling at home in the saltwater which supported her and kept her afloat as the temperatures tonight were cool, and she was well aware that these temperatures would be considered freezing for a human, and that their submarine bodies and its various abilities helped them to survive and thrive in the depths, where no ship girl was capable of traversing.
She communicated with her fellow submarines in order to drop the next naval mine into the ocean for her to activate and plant, holding up her remote for Goya to see as she did so, the pink-haired submarine leaning forward on the ship's railing in order to look down at her.
"Yo, Goya! I need the next mine down here, asap!"
She could hear Goya's voice speaking to her over the shifting waves which surrounded her and the winds which whipped around her head and attempted to separate her drenched hair strands from each other with little success.
"Alright!"
And she could see that the converted container ship eventually ejected another naval mine through the side of its gargantuan hull, the naval mine plopping into the ocean as she felt the ripple of the ensuring wave gently push her to the left before she started swimming towards the naval mine.
The container ship's gigantic cuboid container on the deck contained a lot of the naval mines which were aboard the converted container ship.
And much like a gacha machine, the submarines who were on duty to watch over the ship's activities were tasked with working the system in order to drop another mine into the ocean through tubes which ran throughout the interior of the container ship and led to the large holes at the sides of the hull, which were elevated above water level.
Reaching the mine and lifting her remote, she scanned the mine as it bobbed up and down on the ocean as the air tank within it was fully filled in order to counteract the weights on the naval mines, which were installed in lieu of the anchor and chain on older naval mines.
Hearing the beep of the mine in order to signal its activation, Iku felt safe in its presence as she knew that the only thing which could set it off was a nearby Abyssal presence, so suffice to say, it wasn't going to detonate at point-blank range anytime soon.
She used the "Mark set-point" and then the "Down" button on the remote in order to set a reference point which was the surface of the ocean, and the mine was lowered into the frigid ocean as air bubbles seeped out of the small holes in the mine's shell.
Guiding the naval mine down manually as she kept a hand on a handle which was incorporated into the surface of the mine, she looked down at the pitch-black darkness of the ocean depths and heard Hachi's voice resonate in her head over the radio as it provided her company in the silent ocean which was the Sagami-nada Sea, population: 1.
"Alright, Iku. We'll be setting this mine down at these coordinates which I'm sending you."
Iku responded with a muffled,
"Aye."
As she received a series of numbers over the wireless radio, punching those numbers into her remote in order to enter the coordinates where they wanted to plant the mine, pressing the "Confirm" button as the six rotors on the naval mine started to whir, more air bubbles pouring out of the various "pores" in droves as Iku swam alongside it.
Scanning the naval mine with her remote meant that she temporarily paired them up as the mine was activated, and the mine would transmit its current coordinates to the remote and the distance to its intended target, being guided along by the rotors and the air tanks within the mine to move it in terms of coordinates and depth respectively.
Another naval mine popped into view amidst the relative darkness of the night sea, subtly making its appearance much like a nocturnal beast slipping out of the shadows where it belonged as Iku activated her night vision, her legs scissor-kicking slowly in order to keep moving.
The mine was primed and planted, and she could see another window pop up on her remote as she saw the coordinates of this other mine appear on the screen, and the relative distance of the moving mine and the planted mine as reference.
Another specter appeared from the darkness gracefully like a mermaid swimming to the surface, and her slightly grainy and radiation-green appearance in Iku's eyes was attributed to her night vision mucking up her vision despite allowing her to see better underwater.
Nimu was surfacing, and her long, light-brown hair was floating about in the ocean and trailed behind her not unlike a bundle of tentacles and oral arms swaying behind a jellyfish's main body while she swam upwards, meeting her halfway in the process.
Her swimsuit was identical to Iku's in that it was a blue school swimsuit with her name, "I-26" on a name-tag on her respectably-sized bosom which was struggling to escape the confines of her restrictive swimwear, and she wore a brown jacket with a white sailor collar on it, flaring out behind her as the properties of the ocean made it look as if she was weightless.
Her hair was held back by a white-blue headband and was tied up in two ponytails, and she gave Iku a warm smile and a small wave as she passed by Iku, and Iku reciprocated the gesture as they both knew that the ocean was a lonely place.
They often liked to greet and smile at each other while underwater in order to alleviate the boredom and the lack of human company deep underwater.
And save for the myriad of underwater animals which occasionally passed by them, there really was nobody down here who would converse with them, making the deafening silence and the overwhelming darkness of the abyss almost intolerable as they only had their thoughts and their wireless radio to entertain themselves with.
Now, as steel submarines back in the day, this didn't really affect them as they had their crew within them, and they were only able to feel these things on a rudimentary level, thus alleviating the feeling of loneliness felt then.
But as humanoids, these feelings isolated them and slowly eroded at their psyche the longer they dived underwater and heard the loud yet empty sounds of oceanic currents rushing by them as a piss-poor excuse for ambient noise replacing the noises of human civilization.
They constantly heard the metronome-like ping of their sonars reaching out into the nothingness and returning next to nothing, translating the titanic volume of the ocean which enveloped them and took up slightly over 70% of the Earth's surface, slowly feeling your steel body warping and compressing the further you stared into the abyss which all around you and fell further into it…
Iku shook her head out of her thoughts, wondering if she could ask for a break as submarines sometimes needed in order not to go insane from the isolation and danger of depth charges and torpedoes being rained from above, as other submarines unfortunately did when they cracked under the stress of war and far-from-ideal working conditions and had to be institutionalized.
In fact, the isolation was one reason why Iku felt like she had to act the way she did on land, being lewd, outgoing and completely unafraid of skinship with everyone else, because deep down, she felt as if she needed the attention as a human being.
Other submarines were content with simply being in the company of other ship girls when off-duty, and Iku could respect that, but for her, she craved the attention and interactions which she could receive when behaving like that, because when sortieing, she felt as if she were absolutely and completely dead.
Not in the conventional sense, mind you.
But in times like these, when you had no one to talk to and accompany you except the sound of your own breath and your thoughts, it was like being buried alive and left for dead, and she couldn't feel herself as anything resembling herself while sortieing as there was no "other people" for you to bounce your personality off of in order to affirm your identity.
The constant threat of being blown up by either depth charges or torpedoes didn't help either, and they sometimes had to play a game of "Catch The Sinking Teammate" and had to look into the dead eyes of their teammates.
If they even had them anymore, as Maru-yu once corrected Imuya and silenced the submarines for a good ten seconds with that horrifying image being seared into their minds.
That maddening isolation drove her to seek out everyone's attention with her developed body and loose attitude not unlike that of a harlot, since everyone would at least pay attention to her and help make up for the lack of human interaction in her sorties.
Was it the best way to deal with things? Maybe not.
But everyone was understanding enough to know that their job was tough, and even though everyone rolled their eyes at Iku's antics, she knew that they knew that it was her way of coping with things, and receiving any form of attention, good or bad, from her fellow comrades and her Admiral (who was easy enough for someone who was as well-endowed as her to please) was one way for her to recover from the soul-crushing work they had to perform on sorties.
She really felt as if she needed that break now, and Iku noted that the mine was nearing its intended destination as the rotors slowed.
It stopped as it reached its inputted coordinates and knew where it was relative to the other mines in the area, and Iku scanned the mine again in order to confirm its position and disconnect the pairing before letting go of the remote and allowing the retractable coil to reel the remote back onto the belt which they wore while on mine-laying duty.
Wouldn't want to drop anything into the ocean and waste time trying to search the ocean floor for it with the help of an Unmanned Underwater Vehicle, hmm?
She could almost see the dull hemispheres of other mines which were placed at depths which were lower than the mine which she had just planted, and those mines which were planted on the ocean floor or close to it were either of the traditional "anchor-and-chain" kind, or had one of the submarines use an extendable robot gripper toy to grip the handle on the mine.
They would then dive down with the mine to the maximum depth which they were comfortable with reaching, lest they implode from the pressure of the ocean acting on their bodies.
Using the gripper toy, they'd lower the mine to a depth which was beyond what submarines were capable of reaching, but was beyond what the "anchor-and-chain" mines were capable of reaching in order to prevent Abyssals from attempting to swim through the gaps in the naval mine formation, using the electronic interface on the electronic gripper to confirm the mine's coordinates before unpairing the mine from the remote.
Thinking back on things, perhaps submarines being chosen to be mine-layers was always meant to be, since they were capable of diving and priming the mines at depths which were dangerous to humans.
They could facilitate an efficient and fast system of planting mines underwater, especially the new batch which didn't contain an anchor and chain and were thus slightly harder for humans to plant.
And perhaps it was a slow, slippery slide down the slope of insanity that was war, but while submarines in the past were reluctant to do this job because of the risks involved, they were slowly desensitized to these matters as the war went on, partially because it gave them something else to do down in the depths, where boredom could drive them up the wall after prolonged periods of deep diving.
The detonation of a naval mine also produced one hell of an explosion, and the submarines eventually learnt to associate an underwater explosion with a dead Abyssal, and learnt to look forward to a bigger explosion which would kill more Abyssals who were attempting to sneak around underwater.
Perhaps this was them attempting to look for a passing and ephemeral beauty within a majestic and violent explosion, which annihilated and purged everything in the area in order to serve as a cleansing agent of sorts, amidst the bloodiness and ugliness that was war?
Perhaps.
Besides, they could help out some more with their diving abilities, so why not?
Diving back up towards the surface, Iku was a little excited to see how this battle was going to play out for real, because she knew that the Admiral had modified these mines so that their weights would come off and allow them to float up to the surface as their discarded weights wouldn't be there to hold the mines in place, and their air tanks would provide the buoyancy force needed for them to surface.
She spoke into her radio in order to talk to the submarines who were on the converted mine-laying ship in order to confirm with them what they likely already knew, double checking as they didn't want any miscommunication when it came to explosive hazards.
"Girls, we have this mine in place.
I'm coming up in order to plant the next one, and we'll rotate after that. Four hours of doing this crap gets to you eventually."
And she could hear Maru-yu speak up over the radio, likely getting ready for her turn at a dip as she spoke.
"Acknowledged. I'm on my way down now.
You can use the railing lift in order to hoist yourself up."
Turning off the radio, she headed to the surface as she saw that the gargantuan underside of the ship's hull had cast a shadow on the ocean itself, and couldn't be missed as she had already detected it as a fat blip on her sonar, allowing her ample time to avoid it and avoid smashing her head against the hull as she broke the ocean surface, her lungs clearing themselves of water as they tasted cold, fresh air entering them, enriching her cells with delicious oxygen.
Perhaps she was different from her fellow submarines, like Hachi, who preferred reading, and Goya, who liked going on more missions with her fellow ship girls in order to alleviate her loneliness, but for her, she felt at home while commanding everyone's attention in almost any way possible.
It was a constant reminder to herself, for herself, that she wasn't going to become an unperson anytime soon, to be forgotten by everyone as if she had sunk and had fallen back into the abyss, to fade from everyone's memory as her name was crossed out from a dwindling list of ships, which they were subjected to in the past.
Iku was Iku, but without everyone else being present underwater to see, hear, and acknowledge her in their minds as Iku, did being "Iku" matter anymore in the vacuum that was the ocean depths?
Was she reduced to nothing by the nothingness which enveloped her down there, as if she was no different than the sunken submarine which her name and past were derived from?
She had an inkling of what the answer to that question was.
And it frankly terrified her.