I like this because historically, Brits have been tsundere for Americans in the past (at least, they have been for one particular pairing...)
Plus, Iowa and Kongou are the youngest and oldest battleships in Kancolle, so it works too in a weird kinda age-gap way if you wanna look at it like that, especially considering Iowa acts like Kongou up to eleven, so it's funny to see Kongou getting weirded out by what's an essentially younger, more energetic version of her.