So i got thinking today about big ships and big guns ( this is relating to my post yesterday). I did a bit of digging and found out which ship/class was the biggest of the battleships(Yamato Class; Japan), what was the largest caliber gun used in combat (Schwerer Gustav; Germany), and what cannon had the farthest range of fire (V-3; Germany, debatable). The reason for this is that i had the idea to make(with some assistance) to make a even larger battleship than the Yamato Class with bigger guns that could fire farther than most battleships.

But being relatively lacking in the mathematics department i decided to ask the community for help. I wanted it to be as accurate as possible so that's why i didn't try guessing the right length and stuff. Keep in mind this is all impractical (but most super weapons were) so this isn't all that serious but i do intend to try and build( with assistance) this and its accompanying fleet. I don't know any website or what kind of calculations are needed so that's why i'm asking.

This new class of battleship is very large (which is obvious)

Measurements and Such( its going to get very impractical)

Caliber - What caliber round would be needed to sink a battleship in once shot (told you it would be impractical) no matter where its hit. i'm thinking something along the line of 26" or more but i'm not quite sure.

Naval Artillery - How long of a barrel / what kinda force is needed to fire said round to about a rang of either 50 to 100 miles away (80.4672 km to 160.934 km)

Armor - how thick/ and or what type of armor is need to survive to take on 2-3
Carrier battle Groups( or at least 5- 12 warships to be somewhat precises) along with multiple torpedoes hits)

The impracticalities continues.

Ship length(or Hull Length)
Ship Displacement
Propulsion

Armament
Main Guns 12 x C(calculated caliber) guns (3 x 3) or 4-6 x C guns (2 x 1)
? x 50 mm AA guns (4x4)
other armament can be suggested

Other details can be suggested.
I've already thought of the name for the first Ship (probably the only one in the class)

Leviathan Class Battleship: The Marina

I'm thinking this can be a Community Project with everybody involve could help in with the design and such.

Thank you for the help ( ^~^)b
I'm going to try to start of with the bottom of the hull and then upload it.