The central strategic purpose was to prevent a French army from crossing to Britain. The British design worked as a layered defence: even if Villeneuve evaded one force, damage and delay would leave him facing further fleets. The forward vice admirals did not have to be Britain's only barrier because additional forces waited behind them. Victory mattered, but so did preventing the enemy from uniting its naval forces and creating the conditions for invasion.
Chapter · 51:24-54:36
Trafalgar's strategic aim: stop an invasion
Trafalgar was part of a layered system meant to slow an enemy fleet until stronger British forces could stop it.