I like this version, whic btw is a very good drawing, not very unrealistic as a design, but quite unrealistic as an idea. Topredoes range during this period is a few thousand meters max, so by the time it is within range of a battleship, it is also under the sea, cause it is sunk.
Thanks.
You're right, the design is useful only if torpedoes gain a notable advantage against guns.
In reality the ship would simply get blasted away.