A warship or combatant ship is a naval ship that is used for naval warfare. Usually they belong to the navy branch of the armed forces of a nation, though they have also been operated by individuals, cooperatives and corporations. As well as being armed, warships are designed to withstand damage and are typically faster and more maneuverable than merchant ships. Unlike a merchant ship, which carries cargo, a warship typically carries only weapons, ammunition and supplies for its crew.
In wartime, the distinction between warships and merchant ships is often blurred. Until the 17th century it was common for merchant ships to be pressed into naval service, and not unusual for more than half of a fleet to be composed of merchant ships—there was not a large difference in construction, unlike the difference between a heavily armoured battleship and an ocean liner. Until the threat of piracy subsided in the 19th century, it was normal practice to arm larger merchant ships such as galleons. Warships have also often been used as troop carriers or supply ships, such as by the French Navy in the 18th century or the Imperial Japanese Navy during the Second World War. In war since the early 20th century, merchant ships were often armed and used as auxiliary warships, such as the Q-ships of the First World War and the armed merchant cruisers of the Second World War.
Types and classes The main types of warships today are, in order of decreasing size: aircraft carriers – amphibious assault ships – cruisers – destroyers – frigates – corvettes – fast attack boats. A more extensive list follows:
Submarine, are ships capable of staying submerged for days. Modern submarines can stay underwater for months, with food supplies as the only limiting factor. Fleet submarine is a type of submarine with the speed, range, and endurance to operate as part of a navy's battle fleet. Ballistic missile submarine is a submarine capable of deploying submarine-launched ballistic missiles (SLBMs) with nuclear warheads. Cruise missile submarine are submarines equipped with cruise missiles. Attack submarine is a submarine with the purpose of attacking other submarines. Coastal submarine or littoral submarine is a small, maneuverable type of submarine with shallow draft well suited to navigation of coastal channels and harbors. Midget submarine is any submarine under 150 tons, typically operated by a crew of one or two but sometimes up to six or nine. Submarine aircraft carrier is a submarine equipped with aircraft for observation or attack missions. These submarines saw their most extensive use during World War II, although their operational significance remained small. Cruiser submarine were a type of a very large submarine designed to remain at sea for extended periods in areas distant from base facilities. Amphibious warfare ships are warships employed to land and support ground forces, such as marines, on enemy territory during an amphibious assault. Amphibious assault ship is a type of amphibious warfare ship employed to land and support ground forces with ship-deployed helicopters and V/STOL aircraft on enemy territory by an amphibious assault. Landing helicopter dock is a multipurpose amphibious assault ship that is capable of operating as a helicopter carrier and also has a well deck for supporting landing crafts. Amphibious transport dock is an amphibious warfare ship, that embarks, transports, and lands elements of a landing force for expeditionary warfare missions. Dock landing ship is an amphibious warfare ship with a well dock to transport and launch landing craft and amphibious vehicles. Landing craft are small and medium seagoing watercraft, such as boats and barges, used to convey a landing force (infantry and vehicles) from the sea to the shore during an amphibious assault. Landing craft utility is a type of landing craft used by amphibious forces to transport equipment and troops to the shore. They are capable of transporting tracked or wheeled vehicles and marines from amphibious assault ships to beachheads. Landing craft mechanized is a landing craft designed for carrying vehicles during amphibious assaults. Landing ship, tank is the naval designation for ships first developed during World War II to support amphibious operations by carrying tanks, armoured fighting vehicles, transport vehicles, cargo, and landing troops directly onto shore with no docks or piers. Landing craft support were two distinct classes of amphibious warfare vessels used by the United States Navy during World War II to support landing crafts. Capital ship, the largest and most important ships in a nation's fleet. These were previously battlecruisers, battleships, and aircraft carriers, but the first two warship types are now no longer used. Aircraft carrier, a warship primarily armed with carrier-based aircraft. Fleet carrier is an aircraft carrier designed to operate with the main fleet of a nation's navy. Light aircraft carrier is an aircraft carrier that is smaller than the standard carriers of a navy. Escort carrier, also called a "jeep carrier" or "baby flattop" is a slow type of aircraft carrier used during WWII. Anti-submarine warfare carrier is a type of small aircraft carrier whose primary role is as the nucleus of an anti-submarine warfare hunter-killer group. Aircraft cruiser (also known as aviation cruiser or cruiser-carrier) is a type of warship that combines the features of the aircraft carrier and a surface warship, such as a cruiser or battleship. Helicopter cruiser. Helicopter carrier, an aircraft carrier especially suited to carry helicopters and V/STOL aircraft. Seaplane tender, a boat or ship that supports the operation of seaplanes. Some of these vessels, also known as seaplane carriers, could not only carry seaplanes but also provided all the facilities needed for their operation; these ships are regarded by some as the first aircraft carriers and became obsolete at the end of the Second World War. Battleship, a large, heavily armored warship equipped with many powerful guns. A term which generally post-dates sailing warships. Ironclad battleship, battleships built before the pre-dreadnought in the late 1850s to the early 1890s. Pre-dreadnought battleship, sea-going battleships built to a common design before the launch of dreadnoughts, between the mid-1880s to the early 1900s. Pre-dreadnoughts commonly featured a mixed main battery composed of several different caliber guns. Dreadnought, an early 20th-century battleship, which set the pattern for all subsequent battleship construction. Dreadnoughts differ from pre-dreadnoughts in that they feature an all-big-gun main battery. The advantage lies in that if all the big guns have the same characteristics, only one firing solution will be needed to aim them all. Fast battleships were battleships which emphasized speed without – in concept – undue compromise of either armor or armament. Battlecruiser, a ship with battleship-level armament and cruiser-level armour; typically faster than a battleship because the reduction in armour allowed mounting of more powerful propulsion machinery, or the use of a more slender hull shape with a lower drag coefficient. Cruiser, a fast, independent warship. Traditionally, cruisers were the smallest warships capable of independent action. As of 2024, only two countries operated active duty vessels formally classed as cruisers: the United States and Russia. Guided missile cruisers are cruisers armed with anti-ship missiles. Torpedo cruiser is a type of cruiser that is armed primarily with torpedoes. Armored cruiser was a type of warship of the late 19th and early 20th centuries. It was designed like other types of cruisers to operate as a long-range, independent warship, capable of defeating any ship apart from a battleship and fast enough to outrun any battleship it encountered. Large cruiser is the class of the battlecruiser-sized Alaska-class cruisers of the United States Navy during World War II. Heavy cruiser was a type of cruiser, a naval warship designed for long range and high speed, armed generally with naval guns of roughly 203 mm (8 in) caliber; its parameters were dictated by the Washington Naval Treaty of 1922 and the London Naval Treaty of 1930. Pocket battleship, nickname for the Deutschland-class heavy cruisers. Light cruiser is a type of small or medium-sized warship. The term is a shortening of the phrase "light armored cruiser", describing a small ship that carried armor in the same way as an armored cruiser: a protective belt and deck. Scout cruiser was a type of warship of the early 20th century, which were smaller, faster, more lightly armed and armoured than protected cruisers or light cruisers, but larger than contemporary destroyers. They were used for scouting. Protected cruiser is a type of naval cruiser of the late-19th century, gained their description because an armored deck offered protection for vital machine-spaces from fragments caused by shells exploding above them. Unprotected cruiser was a type of naval cruiser in use during the early 1870s Victorian or pre-dreadnought era. Coastal defence ship were a type of cruiser-sized warship built for the purpose of coastal defense. Destroyer, a fast and highly maneuverable warship, traditionally incapable of independent action. Originally developed to counter the threat of torpedo boats, they are now the largest independent warship generally seen on the ocean. Guided missile destroyer are destroyers armed with anti-ship missiles. Escort destroyer was a small warship built to full naval standards which was optimised for air-defence and anti-submarine duties in wartime, but which retained many of the capabilities of a traditional fleet destroyer, enabling it to conduct operations in conjunction with main fleet units as well as carrying out convoy escort and ASW patrols. Destroyer escort was the United States Navy mid-20th-century classification for a 20-knot (37 km/h; 23 mph), warship designed with the endurance necessary to escort mid-ocean convoys of merchant marine ships similar to frigates. Frigate, originally a medium-sized sailing ship. Although they date back to the 17th century, frigates in modern navies are typically used to protect merchant ships and other warships. Armoured frigate are frigates with armour which was added to ships based on existing frigate and ship of the line designs. The additional weight of the armour on these first ironclad warships meant that they could have only one gun deck, and they were technically frigates, even though they were more powerful than existing ships-of-the-line and occupied the same strategic role. Guided missile frigates are frigates armed with anti-ship missiles. Corvettes were small ships during the Age of Sail. The concept was revived again in WWII as a merchant convoy escort and anti-submarine ship. Today they are used for anti-submarine warfare and patrolling. Littoral Combat Ship is a United States Navy classification of warships with the size and role of corvettes. Fast attack crafts are a small, fast, agile, offensive, often affordable type of warships armed with anti-ship missiles, guns or torpedoes. Missile boats are small, fast warship armed with anti-ship missiles. Torpedo boat, are small, fast surface vessels designed for launching torpedoes. Torpedo ram is a type of torpedo boat combining a ram with torpedo tubes. Motor torpedo boat is a type of fast torpedo boat, especially of the mid-20th century. Patrol vessels are relatively small naval vessels generally designed for coastal defence, border protection, immigration law-enforcement, search and rescue duties. They may be broadly classified as inshore patrol vessels or offshore patrol vessels. Mine warfare vessels: Minesweeper are small warships designed to remove or detonate naval mines. Minehunter are naval vessels that seek, detect, and destroys individual naval mines.