Sister ship

For the term sister ship, there are two meanings. Colloquially, it refers to the extreme similarity of two or more ships, as if they come from a family. In the technical language refers only to such ships as sister vessels actually comes from a series by largely the same plans and thus are identical in the essential characteristics. As far as characteristic variations within a production run made ​​, it is also called half-sister ships.

As in shipbuilding large cost shares in both the design and planning phase and emerge later in the shipyard, you can for the construction of ships with the reuse of design plans and the experience gained during the construction cost savings ( synergies ). At the same time standardization simplifies deployment. The spare parts for repairs are cheaper by such small series.

The first unit of such a series is called type ship. The then resulting sister ships same initially often very strong. Later upgrades, rebuilds and repairs are often requiring that after some time characteristic differences arise, the individual sister ships ( or certain assemblies as so-called subclasses) characterize (ship genealogy). For large classes of ships can be so whole " family trees " of a type development show. Consequence classes are often based on similar designs of their predecessors, so that only small changes sometimes remains disputable whether it is a new subgroup of a class or a new class.

As a rule, sister ships are characterized at least by an identical hull, superstructure may vary or lead to different ship types (example: in the class of Japanese battleships Yamato and Musashi were caused by change of plans during the completion of a half-sister as aircraft carriers, the Shinano ).

As the practice shows only how well a design meets all the requirements placed on it, it may, after the construction of the ship type are changes made to certain construction details, which then differentiate the sister ships of their type ship. Examples are other driving areas with or without ice strengthening, open bridge plate for tropical areas, closed for cold areas, other machinery, other structures or in warships different armament.

Civilian example

Sister ships of the civilian shipping were for example the Olympic ( here as the basic design ), Titanic and Britannic White Star Line, the Olympic, the type of ship, the Titanic was the bigger sister ship. Other famous sister ships from the era of the ocean liner Mauretania and the Lusitania were the Cunard Line or the Bremen and the Europe of the North German Lloyd.

Military example

In the military seafaring there regularly called for units of all sizes classes, which are usually named after their lead ship. One of countless examples is the last battleship class of the U.S. Navy, the Iowa - class. The Iowa is the type of ship, and her sister ships are New Jersey, Wisconsin and Missouri. Even at completion 1943/44, all ships were to be distinguished by minor differences, for example in the bridge, the electronics and the light antiaircraft armament, but were generally in practically identical.

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