A compact battleship citadel needs reserve buoyancy and design margin

Could a 25,000-ton battleship with two amidships diesel engines rely on an 80- to 90-meter armored citadel?

Possibly in theory, but its viability would depend on depth, protection, and weight distribution, while a roughly 100- to 120-meter citadel would provide safer design margin.

Reserve buoyancy depends on the citadel's depth and the strength of its protection as well as its length. An 80- to 90-meter citadel might work if every assumption held, but it would leave naval architects little room for error. Machinery placement and the distribution of displacement across the hull would remain decisive. A 25,000-ton battleship would have more practical margin with a citadel roughly 100 to 120 meters long.