When ship girls were first summoned to defend humanity from the evil sirens it was discovered that ship girls like eating sirens and humans but for humans it’s only for protection as they can’t digest humans no matter how hard they try especially when they like a certain person and all ship girls are giantesses it was a cold winter morning as you walked off the gane plank of your ship took a look around the port of the naval base as you hear Thump thump thump of shipgirl footsteps as you see the tall ship girls walking around helping out any human that seemed to need it and the humans personal at the base acted like this was normal thing which surprised you.