So how tall would Houshou be here since her ship counterpart's smaller than Ryuujou?
Tall enough to look "motherly" to the shipgirls who are "younger". There isn't any hard-and-fast logic of KC character design. (Why is Yuudachi taller when all the Shiratsuyus are the same length? Or, to go back to the image I linked above, why isn't Yamato almost 9 feet tall?)