Which naval battle of 1805 established British sea power for a century?

Trafalgar, where Nelson broke with two centuries of doctrine. Fleets fought in parallel lines exchanging broadsides, which was orderly and usually indecisive; he sailed two columns straight at the enemy line at right angles, accepting heavy fire on the approach in order to cut it into pieces and fight a melee his better-trained crews would win.

It worked completely - about twenty-two enemy ships taken or destroyed and not one British ship lost - and it killed him. He was shot by a marksman in the rigging of a French ship at close range, and died below decks about three hours later, after being told the battle was won.

The rate of fire was the real weapon. British crews could reload considerably faster than their opponents through relentless drill, which meant that at close quarters they simply delivered more shot per minute. The victory ended any serious prospect of invasion and left the Royal Navy dominant for a century - and Nelson's body was brought home in a cask of brandy, which is the origin of the naval slang for rum, tapping the admiral.