Fun fact:
Yamato's shell caliber is actually BIGGER than on paper, which I think is pretty surprising given the accuracy of those babies in spite of the rule of thumb, bigger shell = more dispersion. Explains the penetration though.
This is modelled in the game where she appears flatter than she actually is; this is revealed when Yamato receives quite a bit of damage.
Even more fun fact:
Takatatsu Ayana, the voice of Yamato, is a Cute-type idol who is really embarrassed of her humongous E-class assets and often dressed in ways to make them appear smaller.