I don't know if this one's been mentioned here before (I skimmed the thread but didn't see it) but even if it has I'm gonna link it because it's so sad and wonderful (the bonus chapter will help take the edge off the pain tho)

The Last One Week by C-button

Featuring shipgirls who are more or less robots dealing with post-war depression, and the fatherly Admiral who tries his best to relate to his hostile new charges. It has a really cynical and callous Kitakami, which is an interesting change from the chill bro she's usually depicted as. This is probably the bleakest depiction of shipgirl life I've ever seen, not because their life is ultra violent and tragic, but just because it's dull, numb, and pointless after the war. 10/10, would feels again