Armed merchantmanAn armed merchantman is a merchant ship equipped with guns, usually for defensive purposes, either by design or after the fact. In the days of sail, piracy and privateers, many merchantmen would be routinely armed, especially those engaging in long distance and high value trade. In more modern times, auxiliary cruisers were used offensively as merchant raiders to disrupt trade chiefly during both World War I and World War II, particularly by Germany.
WarshipA warship or combatant ship is a naval ship that is built and primarily intended for naval warfare. Usually they belong to the armed forces of a state. 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. Warships usually belong to a navy, though they have also been operated by individuals, cooperatives and corporations.
Q-shipQ-ships, also known as Q-boats, decoy vessels, special service ships, or mystery ships, were heavily armed merchant ships with concealed weaponry, designed to lure submarines into making surface attacks. This gave Q-ships the chance to open fire and sink them. The use of Q-ships contributed to the abandonment of cruiser rules restricting attacks on unarmed merchant ships and to the shift to unrestricted submarine warfare in the 20th century.
PiracyPiracy is an act of robbery or criminal violence by ship or boat-borne attackers upon another ship or a coastal area, typically with the goal of stealing cargo and other valuable goods. Those who conduct acts of piracy are called pirates, vessels used for piracy are pirate ships. The earliest documented instances of piracy were in the 14th century BC, when the Sea Peoples, a group of ocean raiders, attacked the ships of the Aegean and Mediterranean civilisations.
Battle of the AtlanticThe Battle of the Atlantic, the longest continuous military campaign in World War II, ran from 1939 to the defeat of Nazi Germany in 1945, covering a major part of the naval history of World War II. At its core was the Allied naval blockade of Germany, announced the day after the declaration of war, and Germany's subsequent counter-blockade. The campaign peaked from mid-1940 through to the end of 1943.
PrivateerA privateer is a private person or vessel that engages in maritime warfare under a commission of war. Since robbery under arms was a common aspect of seaborne trade, until the early 19th century all merchant ships carried arms. A sovereign or delegated authority issued commissions, also referred to as letters of marque, during wartime. The commission empowered the holder to carry on all forms of hostility permissible at sea by the usages of war. This included attacking foreign vessels and taking them as prizes and taking crews prisoner for exchange.