Judging from the official calander 2017 she is decently sized, probably on par with Umikaze
By game CG, Yamakaze has around a large B cup or C, I don't know. While Umikaze has much bigger, at around F. I mean, damn! That's big. Well, it's not very consistent through every medium though.
Edit: Yamakaze has a solid B cup according to kancolle-pai.com though.
You know shit's totally serious business when we have a dedicated website for keeping track of shipgirls' bust size.
Well, it doesn't help that all the different official artists have their own preferences and styles when it comes to body types. What might be busty and thicc for one artist might be normal to another. It makes getting an accurate reading on sizes a bit fiddly. There's a certain art behind it is what I'm trying to say.
