I don't think you can say Villeneuve "accepted battle" at Trafalgar - he really had no choice. He was caught with Cape Trafalgar in his lee and the British fleet to windward in a very light breeze; he only had two real choices. He could keep going towards the Gibraltar straits, which is what the Emperor had ordered in order to land the troops on board in Naples to reinforce the French troops in Italy. Doing this held huge risks, however - his rearmost ships would probably be caught by the British, and reports of a British convoy heading for the straits suggested that he could be caught between two forces, a situation which would likely lead to total destruction of the French and Spanish Combined Fleet. His other option was to return to Cadiz; he took this option but took it so late that all it really achieved was to put ships with inexperienced crews into disorder just before battle was joined.
There is considerable evidence that Napoleon really did not understand sea warfare or maritime matters in general. He is reported as saying at one point "The Navy is always more willing to obey its barometers than my orders!", to which a well-judged response in the days of sail would be "damn right they are - wind and wave hold far more power over maritime warfare than you ever will!" An amusing example of the results of land generals trying to enforce operational timing at sea is the events of January and February 1805 in the Mediterranean. The French fleet is holed-up in Toulon; the British fleet is sheltering in Maddalena bay between Corsica and Sandinia, with an open blockade maintained by frigates and sloops outside Toulon (it's notable that Nelson is deliberately maintaining a loose blockade, here - he wants to entice the French fleet out to get a battle). For a few weeks there are Easterly winds, and the French fleet had shown no sign of movement. Then a north-westerly gale set in, and a dripping British fleet sees two blockade frigates incoming, firing signal guns and flying messages that the French fleet has put to sea. Nelson considers where the French fleet may be heading in a nor'wester and concludes that, since he knows they have troops on board, they must be heading for southern Italy, or maybe Egypt, again. He sets off in "pursuit". In fact, Admiral Villeneuve had been ordered to go west, to pick up a Spanish squadron at Cartagena. In a north-west gale. The French fleet found that going west in a north-westerly gale is hard (who knew?) What's more, when your ships have had no shakedown and your crews have been sat in port for weeks and have not had much experience sailing their current ships, trying to sail into a gale is dangerous and expensive. Well before Nelson realised that the French admiral had "fooled" him and returned to the blockade, the French fleet was back at Toulon with several injured men and broken spars, torn sails and lost rigging...
There is a larger point, here: it applies mainly to the "age of sail", but can be seen even in operations such as the Normandy landings in WW2. In sea warfare, you may have intentions, strategies and plans - and should certainly prepare for them as best you can - but the timing of your plan's execution is for neither Kings nor Emperors (nor even Admirals) to command, because it rests firmly within the province of the wind and the waters.
