Why heavy spinal guns would break a Tribal destroyer

What would Tribal-class destroyers do with 10- or 12-inch spinal gun mounts?

They could menace battleships, but firing the weapons would likely break the ships unless the hulls were comprehensively redesigned.

Tribal-class destroyers with 10- or 12-inch spinal guns would try to attack battleships, with Bismarck imagined taking hits around the waterline. Firing such weapons would also threaten to break the destroyers' own hulls. The ships would need extensive structural rebuilding to make the proposal workable.