Ok, so my knowledge of naval history is woefully inadequate and I only recently read about Nelson and the Battle of Trafalgar. My understanding is that the common tactic of the day was to form up into a line parallel to the enemy line and blast away (hence ship-of-the-line). However, Nelson formed his fleet into two lines which he drove into the enemy formation in a perpendicular manner (relevant picture is relevant). The HMS Victory, his flagship, took a tremendous beating as it sailed toward the formation (as I assume the other ships did) but it paid off when the British ships broke into the formation and began to inflict raking fire on the enemy. Now, I understand that the Franco-Spanish navy that Nelson defeated was inferior and lacking in experience. Was this why Nelson's tactics worked? And if not, were his tactics replicated later?
Btw, sorry for any mistakes, I am intoxicated filled with holiday cheer.
In a word, maybe. In the documentary battleships, Naval Historian Eric Grove makes the point that the combined French and Spanish fleet was not nearly as skilled and competent as Nelson's and that allowed him to exploit their poor gunnery and seamanship. What Nelson did was very unorthodox and if used against a more competent adversary that could "shoot straight" it probably wouldn't have worked.
That's not to say that it would have been a British defeat, but the opposing fleet had as many ships of the line as Nelson had ships total so it would have been far bloodier at the best.
I wrote a very long reply to a similar question not too long ago, so I hope you'll forgive me just linking to it here. The short answer to your question is that the tactic of breaking the enemy's line, and concentrating on defeating a portion of the fleet in detail, was not Nelson's innovation nor was it unique to him.
But, he understood very well that the allied fleet would be beset by command and control problems, that its sailors were not as experienced as his, and that its leadership was varied in quality. He may well have adapted tactics differently to a different enemy.
A good command adapts to the conditions and that include estimates of the enemies abilities. Nelson set his plan based on what he thought the French and Spanish could do and would have had a different plan with a different estimate of the enemy.
