Gunboat
A small, heavily armed naval vessel designed for coastal defense, patrol, or operations in shallow waters.
Shallow draft: A vessel's limited underwater depth, allowing it to navigate shallow water. A shallow draft let gunboats approach coasts and enter rivers inaccessible to larger warships.
Gunboat diplomacy: The use or threat of naval force to influence another state's actions. The vessel's visible firepower made it an instrument of coercive diplomacy.
Yangtze Patrol: A United States Navy force that operated on China's Yangtze River from 1854 to 1949. Its armed vessels illustrate the long use of gunboats to protect foreign interests on a major river.
Torpedo boat: A small, fast warship designed primarily to attack larger vessels with torpedoes. Torpedo boats relied on speed and torpedoes, unlike gunboats built around gunfire and patrol.
Naval artillery: Artillery designed for use aboard naval vessels or against maritime targets. Gunboats concentrated their firepower in guns suited to shore bombardment and close engagements.
Steam-powered gunboat: A gunboat propelled by a steam engine rather than sails or oars. Steam propulsion let gunboats maneuver against currents and remain effective in confined waterways.
Brown-water navy: A naval force operating in rivers, estuaries, and other inland or shallow waters. Gunboats are characteristic vessels of forces built for inland waterways.
Corvette: A small warship, generally larger and more ocean-going than a patrol craft. Corvettes could operate farther offshore, while gunboats were especially suited to coastal and shallow waters.
Riverine warfare: Military operations conducted on rivers and other inland waterways. Gunboats used navigable rivers as routes for patrol, support, and attacks on inland targets.
Opium Wars: Two wars between Qing China and Britain, with France joining the second, over trade and political control. Western gunboats supported river and coastal operations during conflicts that expanded foreign power in China.