Sister ship


A sister ship is a ship of the same class or of virtually identical design to another ship. Such vessels share a nearly identical hull and superstructure layout, similar size, and roughly comparable features and equipment. They often share a common naming theme, either being named after the same type of thing or with some kind of alliteration. Often, sisters become more differentiated during their service as their equipment are separately altered.
For instance, the U.S. warships,,, and are all sister ships, each being 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 American sister ships and, and the German Hindenburg class airship's Hindenburg and Graf Zeppelin II.
The generally accepted commercial distinctions of a sister ship are the following:
The critical overriding criteria are the same hull design. For example, the popular TESS-57 standard design built by Tsunishi Shipbuilding are built in Japan, China, and the Philippines. All the ships of this design are classed as sister ships.
The International Maritime Organization defined sister ship in IMO resolution MSC/Circ.1158 in 2006. Criteria included these: