While I'll acknowledge that we're talking about real-world versus in-universe reasons, it still feels a bit disingenuous when the characters discuss why all the living warships in Arpeggio of Blue Steel are personified as female.
While the given reason-that ships are given female pronouns, so they should be girls-is pretty logical, and is why many, many ships with personalities are personified as female in science fiction, the other obvious reason-because the series creator(s)* felt like occasional fanservice-is definitely a factor in this case, though the series is relatively tasteful most of the time.
(I still think it's a pretty decent series, overall... even if/partly because it's a series that uses the phrase "tsundere heavy cruiser.")
*Arpeggio of Blue Steel is both a manga and an anime adaptation. I know very little about the manga and it's possible it has very little fanservice (though I doubt it), but the anime, erm, flirts with fanservice a fair bit, especially in the intro sequence and a couple of random episodes.