Troop ship

A troopship (also troop ship or troop transport or trooper) is a ship used to carry soldiers, either in peacetime or wartime. Operationally, standard troopships – often drafted from commercial shipping fleets – cannot land troops directly on shore, typically loading and unloading at a seaport or onto smaller vessels, either tenders or barges.

Attack transports, a variant of ocean-going troopship adapted to transporting invasion forces ashore, carry their own fleet of landing craft. Landing ships beach themselves and bring their troops directly ashore.

Ships to transport troops were already used in Antiquity. Ancient Rome used the navis lusoria, a small vessel powered by rowers and sail, to move soldiers on the Rhine and Danube.

The modern troopship has as long a history as passenger ships do, as most maritime nations enlisted their support in military operations (either by leasing the vessels or by impressing them into service) when their normal naval forces were deemed insufficient for the task. In the 19th century, navies frequently chartered civilian ocean liners, and from the start of the 20th century painted them gray and added a degree of armament; their speed, originally intended to minimize passage time for civilian user, proved valuable for outrunning submarines and enemy surface cruisers in war. HMT Olympic even rammed and sank a U-boat during one of its wartime crossings. Individual liners capable of exceptionally high speed transited without escorts; smaller or older liners with poorer performance were protected by operating in convoys.

Most major naval powers in the late 19th and early 20th centuries provided their domestic passenger lines with subsidies to ensure ships capable of transporting troops would be available during wartime. The British government aided both Cunard and the White Star Line to construct the liners RMS Mauretania, RMS Aquitania, RMS Olympic, RMS Britannic. When the vulnerability of these ships to return fire was realized most were used instead as troopship or hospital ships.

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