To the British advance the allies opposed the traditional order of battle, a long single line, closehauled,—in this case heading north, with the wind from west-north-west. The distance from one flank to the other was nearly five miles. Owing partly to the lightness of the breeze, partly to the great number of ships, and partly to the inefficiency of many of the units of the fleet, the line was very imperfectly formed. Ships were not in their places, intervals were of irregular width, here vessels were not closed up, there two overlapped, one masking the other's fire. The general result was that, instead of a line, the allied order showed a curve of gradual sweep, convex toward the east. To the British approach from the west, therefore, it presented a disposition resembling a re-entrant angle; and Collingwood, noting with observant eye the advantage of this arrangement for a cross-fire, commented favorably upon it in his report of the battle. It was, however, the result of chance, not of intention,—due, not to the talent of the chief, but to the want of skill in his subordinates.
The commander-in-chief of the allies, Villeneuve, was in the "Bucentaure," an eighty-gun ship, the twelfth in order from the van of the line. Immediately ahead of him was the huge Spanish four-decker, the "Santisima Trinidad," a Goliath among ships, which had now come forth to her last battle. Sixth behind the "Bucentaure," and therefore eighteenth in the order, came a Spanish three-decker, the "Santa Ana," flying the flag of Vice-Admiral Alava. These two admirals marked the right and left of the allied centre, and upon them, therefore, the British leaders respectively directed their course,—Nelson upon the "Bucentaure," Collingwood upon the "Santa Ana."
The "Royal Sovereign" had recently been refitted, and with clean new copper easily outsailed her more worn followers. Thus it happened that, as Collingwood came within range, his ship, outstripping the others by three quarters of a mile, entered alone, and for twenty minutes endured, unsupported, the fire of all the hostile ships that could reach her. A proud deed, surely, but surely also not a deed to be commended as a pattern. The first shot of the battle was fired at her by the "Fougueux," the next astern of the "Santa Ana." This was just at noon, and with the opening guns the ships of both fleets hoisted their ensigns; the Spaniards also hanging large wooden crosses from their spanker booms.
The "Royal Sovereign" advanced in silence until, ten minutes later, she passed close under the stern of the "Santa Ana." Then she fired a double-shotted broadside which struck down four hundred of the enemy's crew, and, luffing rapidly, took her position close alongside, the muzzles of the hostile guns nearly touching. Here the "Royal Sovereign" underwent the fire not only of her chief antagonist, but of four other ships; three of which belonged to the division of five that ought closely to have knit the "Santa Ana" to the "Bucentaure," and so fixed an impassable barrier to the enemy seeking to pierce the centre. The fact shows strikingly the looseness of the allied order, these three being all in rear and to leeward of their proper stations.
For fifteen minutes the "Royal Sovereign" was the only British ship in close action. Then her next astern entered the battle, followed successively by the rest of the column. In rear of the "Santa Ana" were fifteen ships. Among these, Collingwood's vessels penetrated in various directions; chiefly, however, at first near the spot where his flag had led the way, enveloping and destroying in detail the enemy's centre and leading rear ships, and then passing on to subdue the rest. Much doubtless was determined by chance in such confusion and obscurity; but the original tactical plan insured an overwhelming concentration upon a limited portion of the enemy's order. This being subdued with the less loss, because so outnumbered, the intelligence and skill of the various British captains readily compassed the destruction of the dwindling remnant. Of the sixteen ships, including the "Santa Ana," which composed the allied rear, twelve were taken or destroyed.
Not till one o'clock, or nearly half an hour after the vessels next following Collingwood came into action, did the "Victory" reach the "Bucentaure." The latter was raked with the same dire results that befell the "Santa Ana;" but a ship close to leeward blocked the way, and Nelson was not able to grapple with the enemy's commander-in-chief. The "Victory," prevented from going through the line, fell on board the "Redoutable," a French seventy-four, between which and herself a furious action followed,—the two lying in close contact. At half-past one Nelson fell mortally wounded, the battle still raging fiercely.
The ship immediately following Nelson's came also into collision with the "Redoutable," which thus found herself in combat with two antagonists. The next three of the British weather column each in succession raked the "Bucentaure," complying thus with Nelson's order that every effort must be made to capture the enemy's commander-in-chief. Passing on, these three concentrated their efforts, first, upon the "Bucentaure," and next upon the "Santisima Trinidad." Thus it happened that upon the allied commander-in-chief, upon his next ahead, and upon the ship which, though not his natural supporter astern, had sought and filled that honorable post,—upon the key, in short, of the allied order,—were combined under the most advantageous conditions the fires of five hostile vessels, three of them first-rates. Consequently, not only were the three added to the prizes, but also a great breach was made between the van and rear of the combined fleets. This breach became yet wider by the singular conduct of Villeneuve's proper next astern. Soon after the "Victory" came into action, that ship bore up out of the line, wore round, and stood toward the rear, followed by three others. This movement is attributed to a wish to succor the rear. If so, it was at best an indiscreet and ill-timed act, which finds little palliation in the fact that not one of these ships was taken.
Thus, two hours after the battle began, the allied fleet was cut in two, the rear enveloped and in process of being destroyed in detail, the "Bucentaure," "Santisima Trinidad," and "Redoutable" practically reduced, though not yet surrendered. Ahead of the "Santisima Trinidad" were ten ships, which as yet had not been engaged. The inaction of the van, though partly accounted for by the slackness of the wind, has given just cause for censure. To it, at ten minutes before two, Villeneuve made signal to get into action and to wear together. This was accomplished with difficulty, owing to the heavy swell and want of wind. At three, however, all the ships were about, but by an extraordinary fatality they did not keep together. Five with Admiral Dumanoir stood along to windward of the battle, three passed to leeward of it, and two, keeping away, left the field entirely. Of the whole number, three were intercepted, raising the loss of the allies to eighteen ships-of-the-line taken, one of which caught fire and was burned. The approach of Admiral Dumanoir, if made an hour earlier, might have conduced to save Villeneuve; it was now too late. Exchanging a few distant broadsides with enemy's ships, he stood off to the south-west with four vessels; one of those at first with him having been cut off.
At quarter before five Admiral Gravina, whose ship had been the rear of the order during the battle and had lost heavily, retreated toward Cadiz, making signal to the vessels which had not struck to form around his flag. Five other Spanish ships and five French followed him. As he was withdrawing, the last two to resist of the allied fleet struck their colors.