Napoleonic Era Naval Tactics (2/5): The Weather Gage

Contrary to the movies, most prizes were not seized by grappling to and boarding after firing broadside for broadside. Seizing a prize was largely a question of sailing skill — the supreme importance of maneuver. In every encounter of sail, wind and position were of supreme importance. In addition to fighting the enemy, the captain must harness the powers of the wind and sea to make them work for him.

The weather gage (less commonly weather gauge) is the favorable position of a sailing vessel relative to the wind. This is generally any direction upwind; vessels holding the weather gage are able to turn and move quickly downwind to their choice of new positions.

In Nelson’s era the French sought to disable an enemy ship by destroying his means of manoeuver, concentrating their fire on the masts and rigging. This was accomplished by firing a broadside on the upward roll of the ships. The British took the opposite approach, firing on the down roll into the enemy’s hull, producing a storm of splinters that killed and maimed the enemy crew. The British tended to chose the weather gauge and the French the lee, so the French guns were pointing high, and the British low, as their ships heeled in the wind.

The first phase of the battle would be a race between to gain the wind. For a ship to “have the weather gage” is to say that one ship or a line of ships are windward of another ship or line of ships. To be windward means that side from which the wind comes. If one ship is windward of another one,  it is “upwind” of it. Holding the weather gage means being upwind from the enemy. The outcome of many battles during the age of sail was decided by the ability of one captain to hold the weather gage.

A ship sought weather gage of its enemy, so that it had freedom of maneuver, and could close if it wished. Approaching a ship from windward, which is tacking up into the wind, has the advantage of speed and maneuverability. He will probably reverse course and run. The leeward enemy, if unwilling to fight, could sail downwind away from the pending fight. Thus, the weather gage did not give unilateral control over the time of the battle.

The French fleet lay in Lynn Haven Bay, just within the Chesapeake, near Cape Henry, on the morning of 05 September 1781. At sunrise the British fleet was seen off Cape Charles. At first Count De Grasse supposed it to be the squadron of De Barras, but being soon undeceived, he prepared for battle. The wind was fair, and the British fleet sailed directly within the Capes for the purpose of attacking the French. De Grasse slipped his cables, and put to sea, desiring more room for conflict than the waters of the Chesapeake afforded. Admiral Graves bore down upon De Grasse, and both fleets, in attempting to gain the weather gage, slowly moved eastward, clear of the Capes, upon the broad Atlantic. At four o’clock in the afternoon, a partial action commenced between the van and part of the center of the two fleets, and continued until sunset. Several ships were considerably damaged, but neither commander could claim a victory. Admiral Graves preserved the weather gage during the night, and intended to have renewed the battle on the following morning; but, having ascertained that several ships of the van division, under Admiral Drake, could not safely be brought into action again without being repaired, he deferred an attack. For five successive days the hostile fleets were in sight of each other, sometimes approaching quite near, but neither party seemed desirous of renewing the contest.

Sailors defined four basic points of sail: running, reaching, beating (also known as “close hauled“) and “in irons“. When the wind is coming from astern, the ship is said to be “Running before the wind.” Running is not the optimum point of sail — it is fast, but can be tricky. When the wind is along the sides, the ship is “Reaching”. When the ship is moving downwind, but also across it, the ship is on a broad reach. When the the wind is coming directly across the beam, the ship is on a beam reach. When the ship is heading upwind, it is on a close reach. The reaches are the fastest points of sail, and the close reach is the fastest of the three. A ship is beating when it is as close to the wind as it can get, beating their ways against it. This point of sail is also known as close hauled, due to the sails being hauled in tightly to perform this maneuver. Sailors commonly refer to beating as being “on the wind, while reaching and running are “off the wind”.

The fourth point of sail is “in irons” [or “in stays“]. To be “in stays” is to lie with the head to the wind, and the sails so arranged as to check her progress. The risk in sailing too close to the wind was that the vessel would get too close into the wind and be “taken aback” stopped “dead in the water.”

The ship having the weather gage is able to approach the enemy more directly. The other ship must maneuver more often, each maneuver putting her in irons — having no wind support for her sails, which slows the ship considerably. When a ship sails into the wind and stops forward motion (usually not on purpose), it is said to be “in irons”. The sails are flapping and so is the rudder — nothing is working. If the boat doesn’t have enough forward momentum at the time, it can be stopped by a wave and loses “steerageway.” When the boat is “dead in the water,” the rudder is useless because there is no water flow past it to be deflected. Since the ship is headed directly into the wind, the sails are shaking, (luffing). It is necessary to fill the sails with wind in order to gain forward motion and steerageway. The crew will quickly push out a sail into the flow of wind to develop some pressure to turn the stalled ship. Once the ship is turned, the sails can be properly trimmed and the ship will regain speed through the water – and the rudder will again function.

To “take the wind out of his sails” was a maneuver by which one vessel would pass close to windward of another, thereby blanketing the breeze from the other’s canvas and making him lose way. A ship with the weather gage would steal their wind, as the sails are not only capturing the wind to propel the ship, but blocking the wind from the enemy’s sails.

Another advantage of having the weather gage involves heeling. The wind causes a vessel to heel — to lean away from the wind. A ship with the weather gage will lean away from the wind and toward the enemy. Conversely, the enemy, if attempting a parallel tack to engage his broadside, will be leaning away. This means the guns of the ship with the weather gage are depressed in relation to the enemy. This gives a much easier time bringing them to bear, using the elevation quoins — wedges at the rear of the cannon designed to elevate the gun. The enemy’s guns will be elevated even without the quoins and he will have to struggle to bring them to bear.

A major factor in battles at sea was the improvement in sailing made possible by using a full ship rig. The improved handling ability of these vessels made it easier for a ship to avoid a boarding action. Square riggers were very maneuverable ships capable of intricate sailing. Their only disadvantage was an inability to sail very close to the wind.

Courtesy of John Pike and Global Security.

Image: The Great Chase (the USS Constitution fleeing a Royal Navy squadron), artist unknown.

Dr. Maturin suggests further reading

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