Line of battle

The line of battle or the battle line is a tactic in naval warfare in which a fleet of ships (known as ships of the line) forms a line end to end. The first example of its use as a tactic is disputed—it has been variously claimed for dates ranging from 1502 to 1652. Line-of-battle tactics were in widespread use by 1675.

Compared with prior naval tactics, in which two opposing ships closed on one another for individual combat, the line of battle has the advantage that each ship in the line can fire its broadside without fear of hitting a friendly ship. This means that in a given period, the fleet can fire more shots. Another advantage is that a relative movement of the line in relation to some part of the enemy fleet allows for a systematic concentration of fire on that part. The other fleet can avoid this by manoeuvring in a line itself, with a result typical for sea battles since 1675: two fleets sail alongside one another (or on the opposite tack).

The first recorded mention of the use of a line of battle tactic is to be found in the Instructions, provided in 1500 by Manuel I, king of Portugal, to the commander of a fleet dispatched to the Indian Ocean. The precision in the Instructions suggests that the tactic was in place before this date. Portuguese fleets overseas deployed in line ahead, firing one broadside and then putting about in order to return and discharge the other, resolving battles by gunnery alone. In a treatise of 1555, The Art of War at Sea, Portuguese theorist on naval warfare and shipbuilding, Fernão de Oliveira, recognized that at sea, the Portuguese "fight at a distance, as if from walls and fortresses...". He recommended the single line ahead as the ideal combat formation.

Line-of-battle tactics had been used by the Fourth Portuguese India Armada at the Battle of Calicut (1503), under Vasco da Gama, near Malabar against a Muslim fleet. One of the earliest recorded deliberate uses is documented in the First Battle of Cannanore between the Third Portuguese India Armada under João da Nova and the naval forces of Calicut, earlier in the same year. Another early, but different form of this strategy, was used in 1507 by Afonso de Albuquerque at the entrance to the Persian Gulf, in the first conquest of Ormuz. Albuquerque commanded a fleet of six carracks manned by 460 men, and entered Ormuz Bay, being surrounded by 250 warships and a 20,000 men army on land. Albuquerque made his small fleet (but powerful in its artillery) circle like a carrousel, but in a line end-to-end, and destroyed most of the ships that surrounded his squadron. He then captured Ormuz.^{[citation needed]}

From the mid-16th century, the cannon gradually became the most important weapon in naval warfare, replacing boarding actions as the decisive factor in combat. At the same time, the natural tendency in the design of galleons was for longer ships with lower forecastles and aftercastles, which meant faster, more stable vessels. These newer warships could mount more cannons along the sides of their decks, concentrating their firepower along their broadside, while presenting a lower target to their enemy.^{[citation needed]}

Until the mid-17th century, the tactics of a fleet were often to "charge" the enemy, firing bow chaser cannon, which did not deploy the broadside to its best effect. These new vessels required new tactics, and "since ... almost all the artillery is found upon the sides of a ship of war, hence it is the beam that must necessarily and always be turned toward the enemy. On the other hand, it is necessary that the sight of the latter must never be interrupted by a friendly ship. Only one formation allows the ships of the same fleet to satisfy fully these conditions. That formation is the line ahead [column]. This line, therefore, is imposed as the only order of battle, and consequently as the basis of all fleet tactics." The Dutch admiral Maarten Tromp first used the line of battle tactic in the Fight in the Channel, although some have disputed this.

Captains on both sides of the First Anglo-Dutch War appear to have experimented with the technique in 1652, possibly including Robert Blake at the Battle of Dover (19 May 1652). Tromp faced Blake as he approached from Rye with 12 ships. After Tromp refused to strike sail in salute, a battle took place, but the Dutch, despite their superior numbers, failed to capture any English ships. The engagement was, according to the historian Ben Wilson, "a good old-fashioned melee lacking any sophisticated tactics".

The Battle of the Kentish Knock (28 September 1652) revealed the weakness of the Dutch fleet, largely consisting of smaller ships, against the English. The Dutch consequently began a large shipbuilding programme. The Battle of Dungeness (30 November 1652) was a victory for the Dutch, and led to the revitalisation of the Commonwealth Navy. One innovation introduced by George Monck (the first English professional soldier to become a senior naval officer) and Deane was the Articles of War, which introduced the concept of Red, White, and Blue squadrons, each with an admiral, a vice admiral, and a rear admiral, The Articles of War established the line of battle as a tactic for naval warfare.