In early 1805, the Armee de l'Angleterre was concentrated at Boulogne,
preparing for the invasion that would crush Perfidious Albion once and for all. The recently-crowned Emperor of the French ordered a grand naval review, in which his thousands of soldiers would practice embarkation and
maneuvers at sea. But when the Emperor arrived at his place, he saw that
the review had been cancelled.
He turned to Admiral Bruix and demanded an explanation. Bruix told him that there seemed to be a storm brewing, and it would be foolish to risk the lives of so many brave soldiers for the sake of pageantry. Bonaparte flew into a rage, dismissed Bruix his post, and ordered the newly-appointed Admiral Magon to carry out the review.
The spectacle went forward, and the promised storm appeared. Several of the shallow-draft barges capsized, and the Emperor, ever mindful for his personal safety, dashed into a lifeboat and abandoned his own vessel. The next day, 200 bodies washed onto the shoreline at Boulogne.
Bonaparte was understandably in a bad temper. From that day on, he was much less inclined to trust the vagaries of the sea in order to put forward his designs. He discovered, rudely, that although his men could march and countermarch to his instructions on land, that once on the sea his men were beating to a different drummer. The winds and tide were unimpressed by the force of His Imperial Majesty's will. This disillusionment may have been confirmed by the disaster at Trafalgar that followed some months later. Though he built a new French fleet after Trafalgar, he never made room for it in his strategic designs. Britain was to be allowed to rule the waves without significant opposition from the Emperor of the French.
Bonaparte simply didn't understand the nature of warfare at sea; and he was apparently unwilling to take the effort to learn. Principles of warfare in the age of fighting sail were vastly different from principles employed on land, and the differences had much to do with the art and science of sailing under square rig.
In order to examine these differences, and how they were put into practice by the different naval powers and their admirals, the historian must learn the things that Bonaparte never realized he lacked, a basic and fundamental knowledge of the workings of the sailing warship.
BASICS: A NAUTICAL VOCABULARY
The square sail is the simplest sail in conception: the mast can be a simple T-shape, from the crossbar of which (the yard) hangs a square piece of cloth, the sail. The wind, coming from behind the sail, pushes on it and provides momentum, and the boat to which the mast is attached sails on downwind. The sail, on other words, acts like a kite. Ships with the wind behind them could clip along at great speed.
All of which is fine, assuming that you want your ship to move in the same direction as the wind. But what if you don't? Throughout the age of sail, entire fleets were generally limited by the fact that they couldn't sail into the wind, that there was a giant arc in and about the wind into which they could not point their ships. Napoleon's invasion fleet came to grief because they couldn't sail away from the rocks, into the direction of the wind.
In the age of sail, the men who dealt with these realities on a day-to-day basis developed a specialized vocabulary which they used with one another.
First, they divided the compass into 32 "points", each of 11.25 degrees. This was done simply, by taking the four cardinal points (N, E, S, W) and halving them (producing NE,SE,SW, NW), halving them again (NNE, ENE, etc.), and then halving them yet another time (E by N, SE by E, etc.).
This gave them an easy reference for both the direction of the wind and their vessel. If the vessel was sailing SE with the wind at N, the vessel was sailing 12 points off the wind.
Compass points were also used to express just how close to the wind a given ship could sail. A ship that could sail six points into the wind was more "weatherly" than a ship that could only sail seven. It could "point nearer the wind".
Throughout the age of fighting sail, indeed until the 20th Century, it was assumed that all sails act like kites and derive their effect from the wind pushing on them. But early in the 20th Century the principles of aerodynamics began to be understood, and quite suddenly it was realized that sails behave in an entirely different way.
A sail is not simply a piece of cloth hanging straight down from its yard -- when filled with air it is a curved surface. And when the wind passes over a curved surface it creates lift, just as lift is created when wind passes over the curved surface of an airplane wing. The final vector of the lift is partly in the direction of the wind -- in other words, an aerodynamic sail can sail nearer the wind. it was also discovered that aerodynamic effect is at its greatest when the vessel is sailing nearer the wind -- in other words, when a kite-sail is at its most inefficient. Aerodynamic effect is at its weakest in a situation in which a kite-sail is most efficient - with the wind directly behind the craft.
A sail is not a flat piece of cloth; it is cut so as to form a curved surface. The sailmakers of old were using aerodynamic effect without understanding it, having discovered its effects without understanding its causes.
The most aerodynamic sails are a variety known as fore-and-aft sails, from the fact that they normally do not lie athwart the ship (as a square sail), but lie more or less parallel to the ship's keel. This maximizes aerodynamic effect, although efficiency is lessened when sailing downwind. The principle of the fore-and-aft sails were introduced to Europe during the middle ages by the Arabs, who had presumably developed them.
European ship designers saw the advantages of this, but they didn't want to give up the square sail altogether. The square sail was very well suited to long-distance downwind sailing, and a square-rigged ship also made a stable platform for gunnery. Plus, square sails could be "backed" (see below) so as to keep a number of ships together, such as a fleet in line-of-battle. So they began, in their usual trial-and-error fashion, to combine fore-and-aft sails with their traditional square sails, and discovered they could develop ships that could point nearer the wind.
This development was going on throughout the age of fighting sail. We shall see how it affected tactics. But first, a few more basics.
The action of wind on the sails was not the only important factor in calculating a ship's motion. Another significant factor is leeway. Leeway is the effect of the wind pushing the hull and rigging of the ship downwind. This effect is resisted by the ship's keel, and results in the ship heeling over to leeward (downwind).
Leeway increases or decreases depending on the details of the ship's design, but it is always a factor. Ships with high sides (which present a higher silhouette to the wind) tend to have more leeway than those without, and leeway will always increase as the wind velocity increases.
This is particularly significant in a storm or gale. With a strong wind blowing, a ship capable of making six points into the wind might find its gain to windward turned to a negative number, a particularly dangerous situation if there is land -- a "lee shore" -- just downwind. This is just the situation in which Napoleon's barges found themselves.
Sailors found several ways for coping with the enormous wedge-shaped area of the compass into which they could not sail. They could wait for friendly winds. Or they could simply zig-zag in the direction they wished to go, keeping as near to the wind as was possible.
If they were zigzagging, they had to cross that wedge-shaped area somehow at each change of course. There were two main ways of doing this.
The first is called tacking, otherwise known as "coming about" or "going
about". In order to tack, the ship builds as much momentum as possible,
then steers directly into the wind, hoping that, with the ship crossing the eye of the wind the wind will push them off on their new course (Fig. 1).
With clumsy square-rigged ships, this was not always possible. Quite frequently the ships would simply hang there in the wind, in irons, having missed stays. They would then sail slowly backwards, rudder-first through the water, until such time as fortune or the helmsman's skill succeeded in rescuing them from the situation.
The advantages to tacking was that the ship would not lose ground to leeward. The disadvantage was that it didn't always work -- which was a reason why it was rarely resorted to in combat situations.
The other major tactic was to wear out of the wind, by steering out of the wind in a big circle until such time as the ship has come to its new course (Fig. 2). The crew could be drilled to perform this maneuver with efficiency, but no matter how well it was performed the ship would always end up some distance downwind of where it started. The disadvantage of wearing was this loss of ground, which made it dangerous to use if there were land or an enemy under the fleet's lee, but its advantage was that the maneuver was (unlike tacking) sure to work.
A significant advantage of the square rig over its competition was the fact that it could be used to back sail. If (and only if) the ship was close to the wind, such that aerodynamic effect was maximized, some of the sails could be turned to that they became aerodynamically inefficient, thus slowing the ship to a very precise degree. This was used for the purposes of station keeping -- fast ships could back sail in order to keep station with slower ships. Ships could even stop dead in the water by throwing some of their sails "aback", meaning that the wind was pushing on their forward surfaces, acting not as a kite but as a brake. Ships stopping by using this method were said to be hove to.
The fact that the ships had to be near to the wind in order to utilize this tactic must be emphasized. It is of major importance in understanding 18th-Century fleet tactics.
A few more terms have to be absorbed before we can get down to a solid description of how this all worked in practice. Starboard is the right side of the ship, facing forward. Port or larboard is the left side of the ship, also facing forward. To be on the starboard tack means that the wind is blowing towards the ship from its starboard side, relative to the ship. Leeward means downwind, weather means upwind.
Heim orders are always given by rule of contrary. To put the helm to starboard means the ship is turning to port. To put the helm "up" (meaning to weather, i.e., upwind) means the ship will turn downwind. To put the helm "down" (meaning to leeward) means the ship will be turning upwind. Though initially confusing, this can be understood by visualizing a ship's tiller, which is always pointing toward the opposite side of the ship from the rudder to which it is attached.
All of this may seem elementary, even old hat, until one remembers that Napoleon, the foremost military mind of his day, understood none of it -- and that Napoleon's military empire ended up on the rocks.
A History of Sailing Tactics in the Age of Fighting Sail Part I
A History of Sailing Tactics in the Age of Fighting Sail Part II
- Battle of Toulon and Minorca
Additional Instructions, Anson, and Hawke
Morogues, Villehuet, and Ushant
Signal Reform
DeGrasse and Suffern
A History of Sailing Tactics in the Age of Fighting Sail Part III
Back to Table of Contents -- Courier Vol. VI No. 1
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© Copyright 1985 by The Courier Publishing Company.
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