Figured. Okay, look at like this. You know what a familiar is, right? Like a witch's black cat and the like. In old days, a familiar like that was considered to be a demon or a fairy that had taken on another form to protect the witch. Now, in KanColle terms, look at the humanoid shipgirls. They're the souls of sunken shipgirls, and they have human forms. Fubuki, Kisaragi, Zuikaku, etc. All are human in form and have features that they share with their shipgirl counterpart. Now what of the non-human abyssal ships? In this theory, they're not actually sunken shipgirls. They're something else, something that spawned to protect the sunken shipgirls in the same way that a familiar protected a witch.