Board Thread:General Discussion/@comment-104.51.53.50-20150415225527/@comment-26168103-20150423090454

imo the non-inclusion of WW II USN ships is because just like how the IJN is active on this side of the globe, they too are defending American waters from abyssal attacks (they have 2 sides to defend too, atlantic and pacific. probably defending Canada and Latin America as well. Europe is probably handled mostly by British, Dutch, French and possibly the Russians, leaving the Germans and Italians free to send reinforcements down to these waters). maybe they're too busy with their own problems to send reinforcements.

or maybe they don't even have shipgirls? take Strike Witches, for example. the one who developed a Striker Unit that allows witches to fight the alien invaders is a Fusoan (japanese), after which each country developed their own version of the Striker Unit based on their respective historical fighter planes. While there's no proof that only Japan, Germany and Italy has Shipgirl 'tech', but there's no proof that Royal Navy and US Navy has the 'tech' as well.

just my 2 cents on the matter.