White Star Line "Olympic" class were to be the biggest and most luxurious ships in the world. The "Olympic" was the only ship of this class that was profitable for White Star. "Titanic" sank on her maiden voyage, while "Britannic" was requisitioned by the British government before she was fully fitted, and used as a hospital ship during World War I. "Britannic" hit an underwater mine, in the Kea Channel off the Greek island of Kea, and sank on the morning of 21 November 1916. Like many other shipping lines, the White Star Line suffered heavy losses during the First World War which
Sister ship an . The most famous sister ships were the White Star Line's , and . As with some other liners, the sisters worked as running mates. Other sister ships include the Royal Caribbean International's and . "Half-sister" refers to a ship of the same class but with some significant differences. One example of half-sisters are the First World War-era British s where the first two ships had four guns, but the last ship, , had two guns instead. Another example is the American s of the Second World War that came in "long-hull" and "short-hull" versions. Notable airships include the