How treaty limits encouraged larger destroyers

Why not replace one large warship with several smaller cruisers?

Treaty category limits could restrict that substitution, encouraging navies to pack cruiser-like capability into large destroyers such as the Tribal class.

Treaty rules could constrain both the number and aggregate tonnage of ships in a category, limiting a navy's ability to replace one costly capital ship with several cruisers. Designers then sought more capability from each permitted hull. The Tribal class illustrates the result. These destroyers were large and heavily armed enough to act like small supporting cruisers while remaining outside the cruiser category.