Why fleet composition cannot be reduced to one ratio

How should a navy determine the useful combination of destroyers, cruisers, and battleships?

Start with missions, geography, allies, and the peer threat; globally dispersed navies need proportionally more escorts and cruisers than fleets operating close to home.

A fleet's useful mix depends on its likely opponents and how widely its interests are dispersed. A navy operating close to home can concentrate on supporting its capital ships, while a smaller navy may rely on an ally to provide those assets. Worldwide Royal Navy commitments call for more cruisers and destroyers to provide screens in different theatres. The suggested British ratio is two capital ships, six cruisers, and twelve destroyers. France and Germany provide contrasting examples with fewer overseas escort commitments and different resources.