The Ame-chan in the translated note is correct. It's a short form of America-Chan. In this case, Ryuujou was referring to shipgirls from America.
OOOH!I always thought Ame-chan was full'a misers, but to think they had such a minimum gal...Yer a "have-not" too, arencha ♡Ya do that "rokken roll" stuff too, doncha?
As ya can see, I'm in charge of the bass (base)AAHAHHAHHAHAHAHA!!What's with this overly-familiar destroyer...?