Why invasion planning needs tonnage as well as capability

How should individual ship capability be balanced against the tonnage required for a naval invasion?

Maintain capable ships, but also enough aggregate displacement to meet the invasion threshold; very large battleships contribute heavily to both needs.

A viewer's campaign-design point raises the balance between individual capability and aggregate tonnage. A 90,000-ton battleship contributes heavily through its combat qualities and its share of a two-million-ton invasion requirement. A fleet composed entirely of individually efficient ships may still struggle to assemble the displacement demanded by a major operation. The answer makes force structure a quantitative as well as a qualitative problem.