The Imperator-class was a series of three large ocean liners designed and built for the Hamburg America Line (HAPAG). Envisaged by HAPAG chairman, Albert Ballin, the three ships - SS Imperator, launched in 1912; SS Vaterland (1913), launched in 1913; and SS Bismarck, launched in 1914 - each displaced over 50,000 tons, with each successively holding the title of the world's largest passenger ship. Vaterland was seized by the United States during the First World War, while Imperator and Bismarck were turned over to the Allies as reparations following the war's end.
Background
The Hamburg America Line was one of two German shipping companies which operated transatlantic crossings, the other being North German Lloyd. The latter had had much success with the advent of their so-called Kaiser-class ocean liners, the first of which was the SS Kaiser Wilhelm der Grosse. Lloyd soon had a fleet of four liners with weekly transatlantic crossings on offer. By the turn of the century, HAPAG had only one flagship the SS Deutschland (1900). Though successful, the Deutschland could not rival the "Four Flyers" owned by Lloyd. HAPAG soon added the Kaiserin Auguste Viktoria