You sure this kind of weirdness is a never build ship but designed for a navy?
I know the French submarine "Surcouf" of World War II with its two big guns of 203mm.
http://en.wikipedia.org/wiki/French_sub ... uf_(N_N_3)
But the turret, if it is clogged, could do the trick. Anyway, before 1950, most of the submarine had a gun on the deck, except that it is in the turret!
But we can always dream!
(sorry for my bad english, I use google translate)
State awareness of past precedent that justifies design decision
Link to precedent on Wikipedia
State justification for design decision through precedent without ability to understand how precedent relates (or does not relate) to design decision, or how infeasible or militarily unwise design decision is
Other rationalization goes here
That is the format of the average newbie Shipbucket post.