Why ships fought in a line
The ship of the line takes its name from a tactic. Once heavy guns were carried along the sides of ships, the best way to use them was to bring as many broadsides as possible to bear on the enemy while exposing as few ships as possible to his fire. By the middle of the seventeenth century, particularly in the Anglo-Dutch wars, fleets began to be arranged in a single column, ship behind ship, with each vessel following the one ahead. The fleet commander gave orders by signal, and ships were expected to keep station.
This formation made the line only as strong as its weakest member. As a result, navies concentrated on building ships that could survive in the line and deliver heavy fire, and kept smaller ships out of it. The word “battleship” is a later contraction of “line-of-battle ship”. Lighter vessels, such as the sailing frigates, took on scouting and other jobs.
Rates and guns
British ships were organised into “rates” by size and number of guns. The system changed over time and differed between navies, so the numbers below are general. A first rate was a large three-decker with more than 100 guns. A third rate was usually a two-decker of about 64 to 80 guns. The 74-gun two-decker became the standard workhorse of many fleets in the eighteenth century, valued as a good balance of strength, cost and handling, and the French pioneered much of its design. Ships of less than about 50 guns were generally not considered fit for the line in later periods.
The heaviest guns were on the lowest deck. A ship such as HMS Victory, launched in 1765 and still preserved, had 32-pounder guns on her lower deck, lighter guns on the decks above, and carronades on the upper works. The number of guns is a poor guide to broadside weight, since only about half could fire to one side at once, and the weight of shot varied by deck. Victory’s story is told further under HMS Victory.
Design and construction
A ship of the line was a very large wooden machine. Its hull was built of oak frames covered with thick planking, with the sides sloping inward at the top to reduce weight above the waterline. The sides of the largest ships were very thick, often described in feet rather than inches at the waterline. Constructing one required thousands of oak trees, as well as iron, hemp, canvas and pitch, and the supply of suitable timber was a continuing concern for navies. Royal dockyards, such as those in Britain, existed to build, repair and fit out these ships.
Three masts were carried, each with several square sails stacked one above another, and a very large crew was needed. A big ship might carry several hundred men, many of them manning the guns. Conditions below decks were crowded, and life at sea was hard, as described in shipboard daily life. Many ships were also manned by compulsion, as with press gangs in Britain.
In battle
A fleet action began with ships forming line and approaching the enemy, usually on parallel or converging courses. Ships fired as their guns bore, aiming at the hull to disable guns and kill the crew, or aiming high at the rigging to reduce the enemy’s mobility, a choice that depended on the navy and the commander. Fighting at close range, it could take hours, and it was often indecisive. Many battles of the period ended with both sides still afloat and few ships actually sunk. Ships were more commonly captured, dismasted, or disabled than destroyed.
Commanders sought ways to break this pattern. At Trafalgar in 1805 Nelson attacked the Franco-Spanish line in two columns rather than in parallel, aiming to cut it and fight at close quarters. The result was a crushing British victory, though it is sometimes overstated as a break with all earlier practice. The same idea, concentrating force at points in the enemy’s line, features in discussions of Trafalgar tactics. Earlier, the Spanish Armada campaign of 1588 had used large sailing warships, but without the formal line that later became standard.
The end of the type
The ship of the line was costly to build and maintain, and navies could only afford a limited number. A few survived into the steam era. Steam auxiliary engines were fitted to some ships in the 1840s and 1850s, and a few were built as steam battleships with wooden hulls. The introduction of shell guns and then armour, covered in the story of ironclad warships, ended the usefulness of a wooden hull.
The line of battle itself survived as a formation. The successors of the old ships kept the same logic: heavy, protected ships in a column, supported by lighter vessels. Seen this way, the dreadnoughts of the early twentieth century were the direct descendants of the great wooden ships, even if the materials and the weapons had changed beyond recognition.