Why Fritz X sank Roma but not Warspite

Why did Roma sink after Fritz X hits while Warspite survived?

Hit location, resulting damage, luck, and Roma receiving two weapons produced different outcomes.

Torpedo attacks offer a useful comparison because small differences in impact point can radically change flooding. Roma's two hits further increased the chance of catastrophic damage. A guided weapon's name and nominal performance do not determine which compartments, magazines, or machinery its blast reaches. Warspite's survival and Roma's loss therefore illustrate the combined effects of placement, damage path, redundancy, and luck.