Why total cruiser tonnage constrained strategy

A cruiser balanced for scouting differed from one expected to protect a convoy against a heavier opponent. The Washington system limited individual ship size but initially allowed a navy to build as many cruisers as it could afford, so several fast ships could share escort and deterrence work. Later aggregate tonnage ceilings removed that ability to tailor ship numbers to missions. British insistence on changes for its light-cruiser requirements complicated later negotiations, while American concern centered on a naval race with Japan that Washington did not want to finance. In the convoy example, two cruisers draw off a battlecruiser while another keeps the merchant ships moving.