“Do the subgirls live underwater?”
No? We live on land, just like everyone else.
I actually wanted to take this opportunity to explain a bit about the structure of the submarine force during WW2. One thing that made the US exceptional was its logistical capabilities. Basically, each submarine squadron (comprised of two submarine divisions) gets its own tender or submarine base.
These dedicated tender ships or the submarine bases do basically everything that’s involved in making sure a submarine run properly. This means providing spare parts and doing repairwork (short of a complete overhaul almost everything can be fixed on base), providing office space for the officers and their staff, billet maintenance and repair personnel, and the supplying of all foods, fuel, clothing, parts, munitions, medical stores, and the like.
From what I’ve heard of submariner’s recollections, even something like changing a propeller can be done on base. That being said, however, typically a submarine is sent back to the US after five war patrols, so I would say that in general, US submarines (especially towards the later end of the war) are very well supplied and maintained.
As far as Pacific goes, though, dedicated submarine girl bases are not currently on STEC’s radar. Subgirls aren’t submarines. It makes more sense for the girls to fix and maintain their own equipment with the assistance of fairies, and the fairies tend to be more skillful when there are more of them around each other. Thus, while it is possible to take all of the submarine related fairies and house them separately, STEC found it more sensible to just leave them all at Avalon.
What is being created, however, is an intricate system designed to funnel materials out of the deep-sea and into Avalon and the continent proper. STEC’s came a long way from its early days where subgirls are sent out to collect resources from beneath the ocean floor. That job can now be passed around and shared with the entire organization thanks to technological breakthroughs.
In addition, there is thought about creating strategic caches accessible to subgirls where they can replenish their weapons mid-sortie. That discussion is on-going, however. For one thing, STEC is a bit leery when it comes to leaving shipgirl weapons hidden (and unguarded). It’s safe to say that humanity still doesn’t understand shipgirl weaponry very well, and leaving that stuff sitting around is probably a bad idea by anyone’s count. For the other, it runs against the general principles in which STEC wages war. If a subgirl is determined to have sortied with an optimized load, then it makes better sense for her to return for R&R rather than attempting to continue on in a haphazard fashion.