A Ship of the Line was any ship that was expected to play a direct part in a fleet battle. From the middle of the seventeenth century, the ‘line of battle’ had been the main feature of major naval battles. Both fleets would form a single line of ships, and the two lines would fire into each other until one or the other cracked. The line of battle was designed to get the best use out of the broadside, but it tended to lead to indecisive battles, as both sides suffered similar levels of damage.
By the outbreak of war in 1793, the ship of the line was always at least a two decker. The 64-gun ship was the smallest ship expected to perform this duty, although many thought that even this was too small, and that the 74-gun ship was the real minimum. Warships were divided into six ‘rates’, of which the first three were ships of line, fourth rates were in a grey area, and fifth and sixth rates were frigates. Command of a ship of the line was the aim of most captains at this period, although there were some that preferred to remain in the smaller frigates. The Ship of the Line of Battle eventually evolved into the Battleship, and some remnants of the line of battle can be seen as late as the battle of Jutland.