Merchant ship in the context of "East Indiaman"

The Barbary corsairs, Barbary pirates, Ottoman corsairs, or naval mujahideen (in Muslim sources) were mainly Muslim corsairs and privateers who operated from the North African coast, known in Europe as the Barbary Coast, in reference to the Berbers. Slaves in Barbary could be of many ethnicities, and of many different religions, such as Christian, Jewish, or Muslim. Their predation extended throughout the Mediterranean, south along West Africa's Atlantic seaboard and into the North Atlantic as far north as Iceland, but they primarily operated in the western Mediterranean. In addition to seizing merchant ships, they engaged in razzias, raids on European coastal towns and villages, mainly in Italy, France, Spain, and Portugal, but also in Britain and Ireland, and Iceland (commemorated as the Turkish Abductions).

While such raids began after the Muslim conquest of the Iberian Peninsula in the 710s, the terms "Barbary pirates" and "Barbary corsairs" are normally applied to the raiders active from the 16th century onwards, when the frequency and range of the slavers' attacks increased. In that period, Algiers, Tunis and Tripoli came under the sovereignty of the Ottoman Empire, either as directly administered provinces or as autonomous dependencies known as the Barbary states. Similar raids were undertaken from Salé (see Salé Rovers) and other ports in Morocco.

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.

A merchant navy or merchant marine is the fleet of merchant vessels that are registered in a specific country. On merchant vessels, seafarers of various ranks and sometimes members of maritime trade unions are required by the International Convention on Standards of Training, Certification and Watchkeeping for Seafarers (STCW) to carry Merchant Mariner's Documents.

King George V bestowed the title of the "Merchant Navy" on the British merchant shipping fleets following their service in World War I; since then a number of other nations have also adopted use of that title or the similar "Merchant Marine".In most jurisdictions, they are seen on the same level as Road or Air Transportation. However, in some countries, such as the UK, due to their uniformed identity and previous war and peace time contributions they are seen as a uniformed 'service'. This is demonstrated in the UK by the Red Ensign and Blue Ensign being on the sides of the Cenotaph in London.

A clipper was a type of mid-19th-century merchant sailing vessel, designed for speed. The term was also retrospectively applied to the Baltimore clipper, which originated in the late 18th century.

Clippers were generally narrow for their length, small by later 19th-century standards, could carry limited bulk freight, and had a large total sail area. "Clipper" does not refer to a specific sailplan; clippers may be schooners, brigs, brigantines, etc., as well as full-rigged ships. Clippers were mostly constructed in British and American shipyards, although France, Brazil, the Netherlands, and other nations also produced some. Clippers sailed all over the world, primarily on the trade routes between the United Kingdom and China, in transatlantic trade, and on the New York-to-San Francisco route around Cape Horn during the California gold rush. Dutch clippers were built beginning in the 1850s for the tea trade and passenger service to Java.

Unrestricted submarine warfare is a type of naval warfare in which submarines sink merchant ships such as freighters and tankers without warning. The use of unrestricted submarine warfare has had significant impacts on international relations in regard to both the First World War and the Second World War. Its history has been dominated by German decision making.

There have been attempts to limit the use of unrestricted naval warfare, with some dating back to before the turn of the 20th century as an extension of rules for surface raiders. While initially submarines operated successfully by attacking on the surface using deck guns, attacking without warning while submerged reduces the opportunity for the target to escape or defend itself if armed.

A passenger ship is a merchant ship whose primary function is to carry passengers on the sea. The category does not include cargo vessels which have accommodations for limited numbers of passengers, such as the ubiquitous twelve-passenger freighters once common on the seas in which the transport of passengers is secondary to the carriage of freight. The type does however include many classes of ships designed to transport substantial numbers of passengers as well as freight. Indeed, until recently virtually all ocean liners were able to transport mail, package freight and express, and other cargo in addition to passenger luggage, and were equipped with cargo holds and derricks, kingposts, or other cargo-handling gear for that purpose. Only in more recent ocean liners and in virtually all cruise ships has this cargo capacity been eliminated.

While typically passenger ships are part of the merchant marine, passenger ships have also been used as troopships and are often commissioned as naval ships when used, for that purpose.