Seaport's nickname "Wanko" is because of the first part of her name "港湾", or "Kouwan". Specifically to this comic, her twintail hairstyle earlier and Airfield-chan's pun probably had something to do with it too.
So the I-class destroyers are stray cats then? kinda cute way to think about it.
Onee-chan, Onee-chan!Ii...Th... Thank you... I'll take good care of it...I love you, Wanko!You can have this one too...!Yuzuki GaoWanko—!I-class...And this!This one too!Onee-chan!Thank you, Wanko!I found this over there... I'll give it to you, Onee-chan!Ah... erm...Onee-chan!*noisy commotion*Onee-chan! Onee-chan!Here!Oh...? Going for a victory in numbers, Wanko?