Fireships served in the Royal Navy over a period of several centuries. The earliest fireships – ships filled with combustible and flammable materials and explosives and sent into lines of enemy ships to attempt to set them on fire – were small merchant vessels deployed in large fleet actions, such as by Sir Francis Drake against the Spanish Armada at the Battle of Gravelines in 1588. Fire was a major hazard on the wooden warships of the time, which carried large quantities of flammable and explosive materials into battle. Both sides used fireships in a number of engagements during the Anglo–Spanish War, with varying levels of effectiveness. Fireships reappeared in unconventional forms during the English Civil War, and were used in earnest during the Anglo-Dutch Wars, particularly to great effect in 1666 during Holmes's Bonfire. Successes such as the burning of the at the Battle of Solebay in 1672 caused considerable interest in the application of such vessels, eventually resulting in the construction of purpose-built ships. Interest in the fireship declined during the eighteenth century. Though new vessels continued to be taken into service, they did not play a significant role in either the Seven Years' War or the American War of Independence. There was a resurgence in the use of fireships during the 1790s during the wars with France, and they were deployed with some success by Thomas Cochrane at the Battle of the Basque Roads in 1809, but they were steadily supplanted by new methods of war, such as heated shot, torpedoes and mines. The vessels employed by the navy in the fireship role were very varied. They were initially often converted warships or merchant vessels between 60 and 90 feet in length. Despite their rating, most served as sloops or frigates, only being fitted with combustible materials when there was the intention to expend them. The ships used were generally purchased and converted vessels, as it was not considered cost-effective to build new ships with the intention of burning them when a cheaper option existed. Purpose-built fireships were therefore a rarity, though some classes were built during the eighteenth and early nineteenth centuries. Ship's boats were used for a similar purpose, carrying parties of men with combustible materials over to enemy ships, often while they were at anchor. New methods of attack were being pioneered by the early nineteenth century. The Raid on Boulogne in 1804 used