RMS Alcantara was an ocean liner

Ocean liner

An ocean liner is a ship designed to transport people from one seaport to another along regular long-distance maritime routes according to a schedule. Liners may also carry cargo or mail, and may sometimes be used for other purposes .Cargo vessels running to a schedule are sometimes referred to as...

 of the Royal Mail Lines, a successor to the that had been sunk in World War I

World War I

World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...

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Alcantara was built by Harland & Wolff in Belfast

Belfast

Belfast is the capital of and largest city in Northern Ireland. By population, it is the 14th biggest city in the United Kingdom and second biggest on the island of Ireland . It is the seat of the devolved government and legislative Northern Ireland Assembly...

, and launched in 1927. She ran the route from Southampton

Southampton

Southampton is the largest city in the county of Hampshire on the south coast of England, and is situated south-west of London and north-west of Portsmouth. Southampton is a major port and the closest city to the New Forest...

 to the east coast of South America

South America

South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

. In 1934 the ship was rebuilt with more powerful engines, increasing her top speed to 18 knots.

She was converted to an armed merchant cruiser

Armed merchantmen

Armed merchantman is a term that has come to mean 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...

 in 1939, and refitted with a single funnel

Funnel

A funnel is a pipe with a wide, often conical mouth and a narrow stem. It is used to channel liquid or fine-grained substances into containers with a small opening. Without a funnel, spillage would occur....

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