Minimum size for a modern presence ship

What is the minimum size or capacity needed for a modern presence ship?

A roughly 2,000-ton patrol vessel can show the flag globally if it relies on friendly bases. Fighting power pushes toward Type 31 size, while a self-sustaining general-purpose combatant is placed around 10,000 tons.

Presence requirements depend on combat role and access to support. A roughly 2,000-ton River-sized patrol vessel can make global policing deployments if it uses allied facilities and forward bases such as Bahrain. Useful fighting power pushes the ship toward Type 31 size. The Type 45 illustrates a larger, roughly 8,000-ton vessel optimized for air defence after general-purpose capabilities were removed to save money. A self-deploying, self-sustaining ship able to undertake a wider range of combat missions is placed around 10,000 tons, with further size buying endurance and deeper magazines.