Fleet Tactics and Naval Operations starts with “the Age of Fighting Sail”:
Since it was natural for sailing ships to fire abeam, the practice of positioning ships in a straight line in order to fight an enemy was entirely logical for that day. At the same time, because the admiral’s signal flags—then the only effective way of communicating orders within a squadron or fleet—were difficult to see for vessels arrayed in a single line, command-and-control was more reliable if the admiral placed his flagship in the center of the column.
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His objective was to bring all of his force against the enemy, “well ordered, well knit, and simultaneously,” and with no unengaged reserve. Training at sea improved captains’ seamanship skills, enabling fleet commanders to place a tightly spaced column alongside a raggedly disposed enemy line—a step that could significantly bolster the squadron’s collective firepower, especially in cases where enemy ships were spread thinly or where they overlapped and masked each other’s fire.
Indeed, it took skillful seamanship to bring the firepower of even two ships simultaneously against a single enemy. To be fully effective, guns had to be well within three hundred yards of the enemy, firing essentially at point-blank range. The maximum significant range for naval guns was eight hundred or nine hundred yards; beyond this the probability of hitting the enemy was remote and round-shot would barely be able to penetrate a hull. The firing arcs of broadsides were limited to about 25 degrees forward and aft of the beam. Training a gun was a slow and awkward process, so that, by and large, it was easier to train a ship’s guns by maneuvering the ship herself than by trying to turn her cannon to one side or another. As a result, it was rare for two consecutive ships in a column to enjoy the advantage of directing fully effective fire at a single enemy simultaneously.
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The most effective method of massing force and increasing the density of firepower was to stack cannon vertically—hence the logic of building two-deckers and three-deckers.
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In 1697 the highly respected Jesuit priest and French naval tactician Paul Hoste would write that the size of vessels contributed more than numbers to the strength of the fleet. Hoste cited two reasons—first, that larger ships had more and heavier guns, and, second, that a fleet of large ships would bring more and larger guns to bear in the same length as a column made up of smaller ships that were spaced more closely together.
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From combat experience the two-decker was known to have more than a two-to-one advantage over a single-decker (which later would be known as a frigate).
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Barring a lucky shot that landed in a magazine, ships were not often sunk by gunfire (although they later sank from hull damage, which is a separate issue). Ships were defeated by what today we would refer to as a firepower kill—by knocking out their guns and gunners and crushing the ships’ morale and their will to fight. As many ships were captured as were sunk. Since British seamen fought better and French ships had excellent sailing qualities, many of the ships sailing in the Royal Navy were rehabilitated French vessels.
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According to the computation, with simple continuous fire on both sides and no hull strength advantage for either, the two-decker would lose only five guns, at the same time destroying the frigate’s entire broadside of eighteen.
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If a two-decked seventy-four were matched against a three-decker rated at one hundred guns, then, using the same model and assumptions as before, the two-decker would be forced to capitulate before the three-decker had lost twenty guns.
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Admirals also learned, however, that keeping a close interval between ships could provide them with increased mutual support, so the distance specified in their Fighting Instructions could be almost unattainably short—as little as three ship lengths between vessels.
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A second reason for tight spacing was to prevent an enemy from breaking through the column and raking ships on either side with entire broadsides at pointblank range, and from an angle where the target ship was unable to return the fire.
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As a result, the tactician’s primary problem during this era was to concentrate firepower at sea at a time when effective gun range was very short—less than five hundred yards.
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The eighteenth-century French were such a reluctant enemy. Seeking to avoid a decisive action, they concentrated on improving their accuracy instead of on increasing the volume of their fire, arming their ships with more long-range guns, positioning themselves to leeward, and firing high into the rigging to cripple English ships, forcing them to slow, drop back, and weaken the line.
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Nelson stands out in memory because the Battle of Trafalgar, fought on 21 October 1805, was the last big fleet action for more than a century. Yet, his fame does not rest on an accident of history. The reason that there were no more fleet actions was that Nelson did what no one else had been able to do: he eliminated the enemy fleet, ending the need for further fleet actions and setting the stage for a hundred years of British naval dominance.
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The order of sailing will be the order of battle, he said. This notion, now a pertinent watchword for a modern fleet, was a stunning innovation in 1805.
One can learn the wrong lesson from Trafalgar. Had Nelson used his Trafalgar tactics against, say, Dutch Admirals Maarten H. Tromp or Michiel de Ruyter or France’s de Suffren, the result would have been disastrous. Every one of his ships in those light winds of October had to run a gauntlet of three or four unanswered broadsides, which would have guaranteed his defeat had his opponent been firstrate.
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For the Dutch, commerce via the English Channel was survival. With it they would prosper; without it they would wither into nothing. Neither side could decline battle and still achieve its purpose in the war. It either built up its navy and fought, or made peace and lost its objective. The wars had limited objectives, so the winner could indeed anticipate a net financial gain and the loser could anticipate financial and national ruin. As a result, the motivation to fight and fight to win was strong.
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It suited France’s strategic objectives to decline to engage in a decisive battle. For the French, the ocean was a flank to be held while the decision was fought out on land. Whenever they believed their war aim would be determined on land, they adopted one of two naval strategies: they either would maintain a substantial fleet to divert the British navy (not always successfully) and look for opportunities to do so, or they would conduct a guerre de course, raiding commerce in hopes of achieving a moderate gain at little cost.
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When the Royal Navy learned how to close and fight a decisive battle, the French, who wished to avoid fighting, were devastated tactically and therefore were severely hampered strategically.