 Complete the following phrase:  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 AngloSpanish 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 Holmess 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 