Why a more powerful Hood needs hull work

Would about 151,000 shaft horsepower be too much for a worn HMS Hood to accept?

It could be fitted, but only with extensive hull strengthening, replating, and inspection.

The proposed machinery would give Hood about 151,200 shaft horsepower, substantially above her original plant. That power would be usable only after significant supporting work. The hull would need reinforcement, selected plates would likely need replacement, and the keel would require careful inspection. The exchange makes higher propulsion output a structural-life problem as well as an engine-room calculation.