GUNBOAT, a term originally applied to small craft mounting usually a single gun and employed exclusively in the defense of coasts and rivers. Experiences in the Crimean War suggested the extension of the use of gunboats to offensive warfare.
In the United States the gunboat figured to a very considerable extent in coast and lake warfare in our first two wars. They were first used on the Delaware River, in 1775-76 and drove the British frigate Reliance out of the roads. In December 1807 there were 69 of them in United States service, and the Congress ordered 188 more built, as an auxiliary to the embargo declared a few days later, making 257 in all. Improved ordnance has made them valueless, and they had a bad effect on the service, but there was strong opinion in their favor at the time, and they did good service in the War of 1812. The theory was that these movable batteries could act in water where large vessels could not, could be concentrated against the latter so as to afford as large an armament, yet present only a number of small targets, while their antagonist presented only one large one; that shots aimed too high would do no harm to gunboats, but would injure masts and rigging of frigates; that loss of rudder and sail ing gear, the most crippling of accidents to a ship, could not happen to the gunboats, propelled and steered by sweeps; that nearness to the water level gave the guns more accurate aim; and that 75 gunboats could he built for the cost of one 36-gun frigate. On the other hand the
instability and unseaworthiness of the gunboat greatly limited its sphere of usefulness. In most countries the gunboat has been superseded by modern torpedo-boats and destroyers except for use in rivers.
Old gunboats have been converted into mother ships for submarines, airplanes and other small craft.