You may want to look into SpringSharp if you're actually interested in designing plausible
ships. It's not perfect, but it's much better than just eyeballing dimensions and
displacements.
Even with modern technology, the machinery needed to load 5-7 ton shells at a rate of
1/minute (especially if this ship had a tradtitional flashtight loading arrangement and
armored magazine) would be prohibitively large and heavy for naval use.
That's in addition to what others have mentioned about this being a lot of ship with no
real purpose. What would you use it for?
Although as far as unreasonable ship designs go, it's hard to beat this purportedly
historical one:
Also known as HIJMS This Is Why Commander Kaneda Isn't Allowed In The Shipbuilding Office
Anymore. 500,000 tons standard displacement, main battery of 100 40cm/45 (16") guns in
twin turrets backed by 200 single casemated 14cm/50 (5.5") guns and 200 submerged torpedo
tubes. Projected top speed of 42 knots!