Design fleets from commitments and force-generation math

A balanced fleet cannot be designed only by maximizing weapons on each hull. Planning begins with standing patrols and alliance commitments, then applies a rule of three for routine force generation or four for a continuously guaranteed capability. Larger classes create additional resilience because maintenance, training, and recent return from operations do not fall into perfectly rigid thirds. In the example, nine destroyers for two carrier groups often leave four or five usable hulls, allowing a second group to form in an emergency. Enough aggregate hulls let refits, training, presence, and sudden combat requirements coexist instead of competing for the same single ship.