Sister ship

Sister ships RMS Olympic and RMS Titanic at Belfast, circa 1912

A sister ship is a ship of the same class as, or of virtually identical design to, another ship. Such vessels share a near-identical hull and superstructure layout, similar displacement, and roughly comparable features and equipment. Often, sisters become more differentiated during their service as their equipment (in the case of military ships, their armament) are separately altered.

For instance, the U.S. warships USS Iowa, USS New Jersey, USS Missouri, and USS Wisconsin, are all sister ships, each being an Iowa-class battleship.

The most famous sister ships were the White Star Line's RMS Olympic, RMS Titanic and HMHS Britannic. As with some other liners, these sisters worked as running mates.[1] Other sister ships include the Royal Caribbean International's Explorer of the Seas and Adventure of the Seas.

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 Courageous-class battlecruisers where the first two ships had four 15-inch (381 mm) guns, but the last ship, HMS Furious, had two 18-inch (457 mm) guns instead. Another example are the American Essex-class aircraft carriers of the Second World War that came in "long-hull" and "short-hull" versions.

The generally accepted commercial distinction of a sister ship are Type: Identical main type (Bulk, Tank, RoRo, etc.)

  • DWT: +/- 10% on the DWT (So if the ship is 100,000 DWT, then 90,000 to 110,000 DWT)
  • Built: +/- 5 years (So if the ship is built in 2000, then built 1995-2005)
  • Builder: Identical shipbuilding company name (NOT the ship yard location or the Country of build)

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:

  • A sister ship is a ship built by the same yard from the same plans
  • The acceptable deviation of lightship displacement should be between 1 and 2% of the lightship displacement of the lead ship, depending on the length of the ship.[2]


See also

References

  1. ^ Olyympic Class Encyclopedia Titanica
  2. ^ "DEVELOPMENT OF EXPLANATORY NOTES FOR HARMONIZED SOLAS CHAPTER II-1" (PDF). SUB-COMMITTEE ON STABILITY AND LOAD LINES AND ON FISHING VESSELS SAFETY. International Maritime Organization. 2 June 2006. p. 3. Retrieved 21 May 2015. 


This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.