Numbers create naval presence

Fleet size is an operational problem rather than a parade-ground comparison of individual ships. Replacing several third rates with fewer first rates reduces the number available for blockades, stations, refits, and sudden crises. A realistic rotation includes ships on station, returning to port, refitting, and sailing back out, so nominal totals cannot all be committed at once. In peacetime many hulls could be laid up in ordinary at a royal dockyard, while wartime mobilisation supplied the crews needed to activate them. This arithmetic helps explain how Nelson could have fourteen ships at the Nile while other British forces watched Brest and additional French ports. War, deterrence, and crisis management favour the navy able to show up.