Would you even need a tank at an naval HQ? Especially one with magical transforming fleet girls? Unless of course that tank is actually a little girl as well, just transformed.
Funny story: the IJN actually had a tank stationed in front of the Navy Ministry building for most of WW2.
Not because they were worried about Allied commandos or anything, they just wanted to be prepared if the Army tried to attack them. Which seemed likely numerous times.
Yeah. According to Wikipedia the goat-headed things can mate with any species and produce kids, with the caveat that the children eventually EAT THEIR WAY OUT OF THE MOTHER. So, hope that image improves your fapping.