'', one of the earliest warships with a broadside armament; illustration from the
Anthony Roll, c. 1546 Since ancient times, war at sea had been fought much like on land: with melee weapons and bows and arrows, but on floating wooden platforms rather than battlefields. Though the introduction of firearms was a significant change, it only slowly changed the dynamics of ship-to-ship combat. The first guns on ships were small wrought-iron pieces mounted on the open decks and in the
fighting tops, often requiring only one or two men to handle them. They were designed to injure, kill or simply stun, shock and frighten the enemy prior to boarding. As guns were made more durable to withstand stronger gunpowder charges, they increased their potential to inflict critical damage to the vessel rather than just its crew. Since these guns were much heavier than the earlier anti-personnel weapons, they had to be placed lower in the ships, and fire from
gunports, to avoid ships becoming
unstable. In Northern Europe the technique of building ships with
clinker planking made it difficult to cut ports in the hull; clinker-built (or clench-built) ships had much of their structural strength in the outer hull. The solution was the gradual adoption of
carvel-built ships that relied on an internal skeleton structure to bear the weight of the ship. The development of propulsion during the 15th century from single-masted,
square-rigged cogs to three-masted
carracks with a mix of square and
lateen sails made ships nimbler and easier to maneuver. Gunports cut in the hull of ships were introduced, according to tradition, in 1501 by Breton shipwright called Descharges, but it is just as likely to have been a gradual adaptation of loading ports in the stern of merchant vessels that had already been in use for centuries. Initially, the gunports were used to mount heavy
stern chasers pointing aft, but soon gun ports migrated to the sides of ships. This made possible coordinated volleys from all the guns on one side of a ship for the first time in history, at least in theory. Guns in the 16th century were considered to be in fixed positions and were intended to be fired independently rather than in concerted volleys. It was not until the 1590s that the word "broadside" in English was commonly used to refer to gunfire from the side of a ship rather than the ship's side itself. The main batteries in 20th century
battleships tended to be powered
gun turrets which could swivel 180 degrees or more to establish wider firing arcs around the entire vessel. Although this could allow at least some of the main guns to be focused directly forward or aft, battleships still relied on broadsides for maximum firepower, as structures such as the bridge tower in the middle of a battleship would prevent guns in the aft portion of the ship from firing forward, and vice versa. Additionally, directing the guns to the port or starboard side projected the massive muzzle blast out over the ocean, while firing the guns too close to the deck could cause damage to the ship. ==Measurement of firepower capacity==