Hull classification symbol explained

The United States Navy, United States Coast Guard, and United States National Oceanic and Atmospheric Administration (NOAA) use a hull classification symbol (sometimes called hull code or hull number) to identify their ships by type and by individual ship within a type. The system is analogous to the pennant number system that the Royal Navy and other European and Commonwealth navies use.

History

United States Navy

The U.S. Navy began to assign unique Naval Registry Identification Numbers to its ships in the 1890s. The system was a simple one in which each ship received a number which was appended to its ship type, fully spelled out, and added parenthetically after the ship's name when deemed necessary to avoid confusion between ships. Under this system, for example, the battleship Indiana was USS Indiana (Battleship No. 1), the cruiser Olympia was USS Olympia (Cruiser No. 6), and so on. Beginning in 1907, some ships also were referred to alternatively by single-letter or three-letter codes—for example, USS Indiana (Battleship No. 1) could be referred to as USS Indiana (B-1) and USS Olympia (Cruiser No. 6) could also be referred to as USS Olympia (C-6), while USS Pennsylvania (Armored Cruiser No. 4) could be referred to as USS Pennsylvania (ACR-4). However, rather than replacing it, these codes coexisted and were used interchangeably with the older system until the modern system was instituted on 17 July 1920.

During World War I, the U.S. Navy acquired large numbers of privately owned and commercial ships and craft for use as patrol vessels, mine warfare vessels, and various types of naval auxiliary ships, some of them with identical names. To keep track of them all, the Navy assigned unique identifying numbers to them. Those deemed appropriate for patrol work received section patrol numbers (SP), while those intended for other purposes received "identification numbers", generally abbreviated "Id. No." or "ID;" some ships and craft changed from an SP to an ID number or vice versa during their careers, without their unique numbers themselves changing, and some ships and craft assigned numbers in anticipation of naval service were never acquired by the Navy. The SP/ID numbering sequence was unified and continuous, with no SP number repeated in the ID series or vice versa so that there could not be, for example, both an "SP-435" and an "Id. No. 435". The SP and ID numbers were used parenthetically after each boat's or ship's name to identify it; although this system pre-dated the modern hull classification system and its numbers were not referred to at the time as "hull codes" or "hull numbers," it was used in a similar manner to today's system and can be considered its precursor.[1]

United States Revenue Cutter Service and United States Coast Guard

The United States Revenue Cutter Service, which merged with the United States Lifesaving Service in January 1915 to form the modern United States Coast Guard, began following the Navy's lead in the 1890s, with its cutters having parenthetical numbers called Naval Registry Identification Numbers following their names, such as (Cutter No. 1), etc. This persisted until the Navy's modern hull classification system's introduction in 1920, which included Coast Guard ships and craft.

United States Coast and Geodetic Survey

Like the U.S. Navy, the United States Coast and Geodetic Survey – a uniformed seagoing service of the United States Government and a predecessor of the National Oceanic and Atmospheric Administration (NOAA) – adopted a hull number system for its fleet in the 20th century. Its largest vessels, "Category I" oceanographic survey ships, were classified as "ocean survey ships" and given the designation "OSS". Intermediate-sized "Category II" oceanographic survey ships received the designation "MSS" for "medium survey ship," and smaller "Category III" oceanographic survey ships were given the classification "CSS" for "coastal survey ship." A fourth designation, "ASV" for "auxiliary survey vessel," included even smaller vessels. In each case, a particular ship received a unique designation based on its classification and a unique hull number separated by a space rather than a hyphen; for example, the third Coast and Geodetic Survey ship named Pioneer was an ocean survey ship officially known as USC&GS Pioneer (OSS 31).[2] [3] The Coast and Geodetic Surveys system persisted after the creation of NOAA in 1970, when NOAA took control of the Surveys fleet, but NOAA later changed to its modern hull classification system.

United States Fish and Wildlife Service

The Fish and Wildlife Service, created in 1940 and reorganized as the United States Fish and Wildlife Service (USFWS) in 1956, adopted a hull number system for its fisheries research ships and patrol vessels. It consisted of "FWS" followed by a unique identifying number. In 1970, NOAA took control of the seagoing ships of the USFWS's Bureau of Commercial Fisheries, and as part of the NOAA fleet they were assigned new hull numbers beginning with "FRV," for Fisheries Research Vessel, followed by a unique identifying number. They eventually were renumbered under the modern NOAA hull number system.

The modern hull classification system

United States Navy

The U.S. Navy instituted its modern hull classification system on 17 July 1920, doing away with section patrol numbers, "identification numbers", and the other numbering systems described above. In the new system, all hull classification symbols are at least two letters; for basic types the symbol is the first letter of the type name, doubled, except for aircraft carriers.

The combination of symbol and hull number identifies a modern Navy ship uniquely. A heavily modified or re-purposed ship may receive a new symbol, and either retain the hull number or receive a new one. For example, the heavy gun cruiser was converted to a gun/missile cruiser, changing the hull number to CAG-1. Also, the system of symbols has changed a number of times both since it was introduced in 1907 and since the modern system was instituted in 1920, so ships' symbols sometimes change without anything being done to the physical ship.[4]

Hull numbers are assigned by classification. Duplication between, but not within, classifications is permitted. Hence, CV-1 was the aircraft carrier and BB-1 was the battleship .

Ship types and classifications have come and gone over the years, and many of the symbols listed below are not presently in use. The Naval Vessel Register maintains an online database of U.S. Navy ships showing which symbols are presently in use.

After World War II until 1975, the U.S. Navy defined a "frigate" as a type of surface warship larger than a destroyer and smaller than a cruiser. In other navies, such a ship generally was referred to as a "flotilla leader", or "destroyer leader". Hence the U.S. Navy's use of "DL" for "frigate" prior to 1975, while "frigates" in other navies were smaller than destroyers and more like what the U.S. Navy termed a "destroyer escort", "ocean escort", or "DE". The United States Navy 1975 ship reclassification of cruisers, frigates, and ocean escorts brought U.S. Navy classifications into line with other nations' classifications, at least cosmetically in terms of terminology, and eliminated the perceived "cruiser gap" with the Soviet Navy by redesignating the former "frigates" as "cruisers".

Military Sealift Command

If a U.S. Navy ship's hull classification symbol begins with "T-", it is part of the Military Sealift Command, has a primarily civilian crew, and is a United States Naval Ship (USNS) in non-commissioned service – as opposed to a commissioned United States Ship (USS) with an all-military crew.

United States Coast Guard

If a ship's hull classification symbol begins with "W", it is a commissioned cutter of the United States Coast Guard. Until 1965, the Coast Guard used U.S. Navy hull classification codes, prepending a "W" to their beginning. In 1965, it retired some of the less mission-appropriate Navy-based classifications and developed new ones of its own, most notably WHEC for "high endurance cutter" and WMEC for "medium endurance cutter".

National Oceanic and Atmospheric Administration

The National Oceanic and Atmospheric Administration (NOAA), a component of the United States Department of Commerce, includes the National Oceanic and Atmospheric Administration Commissioned Officer Corps (or "NOAA Corps"), one of the eight uniformed services of the United States, and operates a fleet of seagoing research and survey ships. The NOAA fleet also uses a hull classification symbol system, which it also calls "hull numbers," for its ships.

After NOAA took over the former fleets of the U.S. Coast and Geodetic Survey and the U.S. Fish and Wildlife Service Bureau of Commercial Fisheries in 1970, it initially retained the Coast and Geodetic Survey's hull-number designations for its survey ships and adopted hull numbers beginning with "FRV", for "Fisheries Research Vessel", for its fisheries research ships. It later adopted a new system of ship classification, which it still uses today. In its modern system, the NOAA fleet is divided into two broad categories, research ships and survey ships. The research ships, which include oceanographic and fisheries research vessels, are given hull numbers beginning with "R", while the survey ships, generally hydrographic survey vessels, receive hull numbers beginning with "S". The letter is followed by a three-digit number; the first digit indicates the NOAA "class" (i.e., size) of the vessel, which NOAA assigns based on the ship's gross tonnage and horsepower, while the next two digits combine with the first digit to create a unique three-digit identifying number for the ship.

Generally, each NOAA hull number is written with a space between the letter and the three-digit number, as in, for example, or .[5]

Unlike in the U.S. Navy system, once an older NOAA ship leaves service, a newer one can be given the same hull number; for example, "S 222" was assigned to, then assigned to NOAAS Thomas Jefferson (S 222), which entered NOAA service after Mount Mitchell was stricken.

United States Navy hull classification codes

The U.S. Navy's system of alpha-numeric ship designators, and its associated hull numbers, have been for several decades a unique method of categorizing ships of all types: combatants, auxiliaries and district craft. Although considerably changed in detail and expanded over the years, this system remains essentially the same as when formally implemented in 1920. It is a very useful tool for organizing and keeping track of naval vessels, and also provides the basis for the identification numbers painted on the bows (and frequently the sterns) of most U.S. Navy ships.

The ship designator and hull number system's roots extend back to the late 1880s when ship type serial numbers were assigned to most of the new-construction warships of the emerging "Steel Navy". During the course of the next thirty years, these same numbers were combined with filing codes used by the Navy's clerks to create an informal version of the system that was put in place in 1920. Limited usage of ship numbers goes back even earlier, most notably to the "Jeffersonian Gunboats" of the early 1800s and the "Tinclad" river gunboats of the Civil War Mississippi Squadron.

It is important to understand that hull number-letter prefixes are not acronyms, and should not be carelessly treated as abbreviations of ship type classifications. Thus, "DD" does not stand for anything more than "Destroyer". "SS" simply means "Submarine". And "FF" is the post-1975 type code for "Frigate."[6]

The hull classification codes for ships in active duty in the United States Navy are governed under Secretary of the Navy Instruction 5030.8D.[7]

Warships

Warships are designed to participate in combat operations.

The origin of the two-letter code derives from the need to distinguish various cruiser subtypes.[8]

BattleshipHeavy gun-armed vessel (–1962)BB
Cruiserarmored (1921–1931)
heavy (1931–1975)		CA
large (–1947)CB
battle
command
(–1961)		CC
light (–1950)CL
aviation or volerCV
DestroyershipDD
escortDE

Aircraft carrier type

Aircraft carriers are ships designed primarily for the purpose of conducting combat operations by aircraft which engage in attacks against airborne, surface, sub-surface and shore targets. Contrary to popular belief, the "CV" hull classification symbol does not stand for "carrier vessel". "CV" derives from the cruiser designation, with one popular theory that the V comes from French voler, "to fly", but this has never been definitively proven.[9] [10] The V has long been used by the U.S. Navy for heavier-than-air craft and possibly comes from the French volplane.[11] [12] Aircraft carriers are designated in two sequences: the first sequence runs from CV-1 USS Langley to the very latest ships, and the second sequence, "CVE" for escort carriers, ran from CVE-1 Long Island to CVE-127 Okinawa before being discontinued.

Surface combatant type

Surface combatants are ships which are designed primarily to engage enemy forces on the high seas. The primary surface combatants are battleships, cruisers and destroyers. Battleships are very heavily armed and armored; cruisers moderately so; destroyers and smaller warships, less so. Before 1920, ships were called " no. X", with the type fully pronounced. The types were commonly abbreviated in ship lists to "B-X", "C-X", "D-X" et cetera—for example, before 1920, would have been called "USS Minnesota, Battleship number 22" orally and "USS Minnesota, B-22" in writing. After 1920, the ship's name would have been both written and pronounced "USS Minnesota (BB-22)". In generally decreasing size, the types are:

Submarine type

Submarines are all self-propelled submersible types (usually started with SS) regardless of whether employed as combatant, auxiliary, or research and development vehicles which have at least a residual combat capability. While some classes, including all diesel-electric submarines, are retired from USN service, non-U.S. navies continue to employ SS, SSA, SSAN, SSB, SSC, SSG, SSM, and SST types.[28] With the advent of new Air Independent Propulsion/Power (AIP) systems, both SSI and SSP are used to distinguish the types within the USN, but SSP has been declared the preferred term. SSK, retired by the USN, continues to be used colloquially and interchangeably with SS for diesel-electric attack/patrol submarines within the USN, and, more formally, by the Royal Navy and British firms such as Jane's Information Group.

  • AGSS: Auxiliary Submarine
  • AOSS: Submarine Oiler (retired)
  • ASSP: Transport Submarine (retired)
  • APSS: Transport Submarine (retired)
  • LPSS: Amphibious Transport Submarine (retired)
  • SSLP: Transport Submarine (retired)
SSP, ASSP, APSS, and LPSS were all the same type, redesignated over the years.

Patrol combatant type

Patrol combatants are ships whose mission may extend beyond coastal duties and whose characteristics include adequate endurance and seakeeping, providing a capability for operations exceeding 48 hours on the high seas without support. This notably included Brown Water Navy/Riverine Forces during the Vietnam War. Few of these ships are in service today.

Amphibious warfare type

Amphibious warfare vessels include all ships having an organic capability for amphibious warfare and which have characteristics enabling long duration operations on the high seas. There are two classifications of craft: amphibious warfare ships, which are built to cross oceans, and landing craft, which are designed to take troops from ship to shore in an invasion.

The U.S. Navy hull classification symbol for a ship with a well deck depends on its facilities for aircraft:

Ships

Landing Craft

Expeditionary support

Operated by Military Sealift Command, have ship prefix "USNS", hull code begins with "T-".

Mine warfare type

Mine warfare ships are those ships whose primary function is mine warfare on the high seas.

In 1955 all mine warfare vessels except for degaussing vessels had their hull codes changed to begin with "M".

Coastal defense type

Coastal defense ships are those whose primary function is coastal patrol and interdiction.

Auxiliaries

An auxiliary ship is designed to operate in any number of roles supporting combatant ships and other naval operations.

Combat logistics type

Ships which have the capability to provide underway replenishment (UNREP) to fleet units.

Mobile logistics type

Mobile logistics ships have the capability to provide direct material support to other deployed units operating far from home ports.

Support ships

Support ships are not designed to participate in combat and are generally not armed. For ships with civilian crews (owned by and/or operated for Military Sealift Command and the Maritime Administration), the prefix T- is placed at the front of the hull classification.

Support ships are designed to operate in the open ocean in a variety of sea states to provide general support to either combatant forces or shore-based establishments. They include smaller auxiliaries which, by the nature of their duties, leave inshore waters.

Service type craft

Service craft are navy-subordinated craft (including non-self-propelled) designed to provide general support to either combatant forces or shore-based establishments. The suffix "N" refers to non-self-propelled variants.

Submersibles

Yard and district craft

Miscellaneous ships and craft

Airships

Although aircraft, pre-World War II rigid airships were commissioned (no different from surface warships and submarines), flew the U.S. ensign from their stern and carried a United States Ship (USS) designation.

Rigid airships:

Lighter-than-air aircraft (e.g., blimps) continued to fly the U.S. ensign from their stern but were registered as aircraft:

Temporary designations

United States Navy Designations (Temporary) are a form of U.S. Navy ship designation, intended for temporary identification use. Such designations usually occur during periods of sudden mobilization, such as that which occurred prior to, and during, World War II or the Korean War, when it was determined that a sudden temporary need arose for a ship for which there was no official Navy designation.

During World War II, for example, a number of commercial vessels were requisitioned, or acquired, by the U.S. Navy to meet the sudden requirements of war. A yacht acquired by the U.S. Navy during the start of World War II might seem desirable to the Navy whose use for the vessel might not be fully developed or explored at the time of acquisition.

On the other hand, a U.S. Navy vessel, such as the yacht in the example above, already in commission or service, might be desired, or found useful, for another need or purpose for which there is no official designation.

Numerous other U.S. Navy vessels were launched with a temporary, or nominal, designation, such as YMS or PC, since it could not be determined, at the time of construction, what they should be used for. Many of these were vessels in the 150 to 200 feet length class with powerful engines, whose function could be that of a minesweeper, patrol craft, submarine chaser, seaplane tender, tugboat, or other. Once their destiny, or capability, was found or determined, such vessels were reclassified with their actual designation.

United States Coast Guard vessels

Prior to 1965, U.S. Coast Guard cutters used the same designation as naval ships but preceded by a "W" to indicate Coast Guard commission. The U.S. Coast Guard considers any ship over 65 feet in length with a permanently assigned crew, a cutter.[54]

USCG classification symbols definitions

USCG classification symbols for small craft and boats

National Oceanic and Atmospheric Administration hull codes

The letter is paired with a three-digit number. The first digit of the number is determined by the ships "power tonnage," defined as the sum of its shaft horsepower and gross international tonnage, as follows:

The second and third digits are assigned to create a unique three-digit hull number.

See also

Notes

Citations

General and cited references

Further reading

External links

Notes and References

  1. Naval History and heritage Command Online Library of Selected Images (archived from the original at https://web.archive.org/web/20100329212007/http://www.history.navy.mil/photos/shusn-no/spid-no.htm).
  2. https://books.google.com/books?id=uYSPAAAAMAAJ&dq=Ocean+Survey+Ship+%28OSS%29+MSS+CSS&pg=PA3612 United States Department of State, United States Treaties and Other International Obligations, Volume 23, Part Four, Washington, D.C.:U.S. Government Printing Office, 1972, p. 3612.
  3. Web site: United States Department of Commerce, Annual Report of the Director of the Coast and Geodetic Survey for the Fiscal Year Ending June 30, 1964, U.S. Government Printing Office, Washington, D.C.: 1964, pp. 3–5. . 6 May 2014 . https://web.archive.org/web/20130219015620/http://docs.lib.noaa.gov/rescue/cgs/011_pdf/CSC-0205.pdf . 19 February 2013 . dead .
  4. Derdall and DiGiulian, (section: Nomenclature history)
  5. Wertheim, The Naval Institute Guide to Combat Fleets of the World, 15th Edition: Their Ships, Aircraft, and Systems, p. 1005.
  6. Web site: U.S. Navy Ships – Listed by Hull Number. Naval History and Heritage Command.
  7. https://www.nvr.navy.mil/5030.8D.pdf SECNAVINST 5030.8D
  8. Derdall and DiGiulian, (section: Cruisers)
  9. Book: Grossnick, Roy. United States Naval Aviation 1910-1995. Naval Historical Center. 1997. 0-945274-34-3. Naval History and Heritage Command, Washington, D.C.. 625.
  10. Web site: English Translation of "voler" Collins French-English Dictionary. www.collinsdictionary.com. en. 2019-02-07.
  11. United States Naval Aviation 1910–1995. Appendix 16: US Navy and Marine Corps Squadron Designations and Abbreviations.
  12. https://www.dailypress.com/news/dp-xpm-20050417-2005-04-17-0504170205-story.html Military naming conventions: The ABCs of US ships
  13. Web site: 2021-06-12. Flush-deck destroyers converted as seaplane tenders (AVD). 2021-10-11. https://web.archive.org/web/20210612121543/https://destroyerhistory.org/flushdeck/avd/. 12 June 2021.
  14. See .
  15. https://www.history.navy.mil/content/dam/nhhc/research/histories/naval-aviation/Naval%20Aviation%20News/1940/pdf/1aug43.pdf Bureau of Aeronautics, Navy Department."New Carrier Designations". BuAER News (title later changed to Naval Aviation News). Washington, D.C. No. 198 (1 Aug 1943) p. 9.
  16. http://babel.hathitrust.org/cgi/pt?id=mdp.39015031962056;view=1up;seq=3 United States. Office of Naval History. Glossary of U.S. Naval Abbreviations. 3d ed. Washington: U.S. Govt. Print. Off., 1947. p. 20.
  17. United States. Office of Naval Records and History. Glossary of US Naval Abbreviations. 5th ed. Washington: U.S. Govt. Print. Off., 1949. Naval History and Heritage Command. accessed 6 May 2017.
  18. Web site: The Vari-Purpose Carrier . 4 August 2011 . https://web.archive.org/web/20160304053703/http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=AD0757047 . 4 March 2016 . dead .
  19. See .
  20. See .
  21. See .
  22. See .
  23. See .
  24. see .
  25. Book: Friedman, Norman . U.S. Destroyers: An Illustrated Design History . Revised . Norman Friedman . 2003 . U.S. Naval Institute Press . Annapolis, MD . 978-1-55750-442-5 . 266–267 . ...a gutted . This "corvette" (DDC) "can be readily obtained...".
  26. Derdall and DiGiulian, (section: Torpedo Boats, Destroyers, Escorts and Frigates)
  27. http://www.military.com/daily-news/2015/03/04/navy-plans-to-expand-speed-up-lcs-modifications.html?ESRC=todayinmil.sm Navy Plans to Expand, Speed-Up LCS Modifications
  28. Russia still employs several SSA and SSAN class submarines like the Delta Stretch as well as one SST, China has older SSB and SSG types such as the Golf and Mod Romeo classes, and North Korea has built many SSCs and SSMs. See 2007–2008 Janes Fighting Ships.
  29. http://www.nvr.navy.mil/CLASS.HTM U.S. Navy Ship And Service Craft Classifications
  30. See .
  31. Buff . Joe . Joe Buff . June 2007 . Subs in the Littoral: Diesels Just Blowing Smoke? . Proceedings of the Naval Institute . 133 . 6 . 40–43 . 0041-798X . 2007-06-13 . Diesel AIP boats are known as SSIs, differentiating them from purely diesel-electric-powered hunter-killer subs, or SSKs. .
  32. http://www.nvr.navy.mil/oldclass.htm Inactive Classification Symbols
  33. This odd entry is not recognized by the U.S. Naval Vessel Register, and appears only in MIL-STD-2525A: Common Warfighting Symbology (15 December 1996) and later editions (MIL-STD-2525B: Common Warfighting Symbology (30 January 1999) and MIL-STD-2525C: Common Warfighting Symbology (17 November 2008)). It seems to refer to some kind of nuclear-powered submarine used by Special Operations Forces.
  34. See .
  35. http://www.dia.mil/publicaffairs/Foia/abbrev_acron.pdf 28034_cov.fh
  36. See .
  37. See X-1 submarine.
  38. Web site: World Wide Landing Ship Dock/Landing Platform Dock. 2012-05-17.
  39. Book: Friedman, Norman . U.S. Amphibious Ships and Craft: An Illustrated Design History . Naval Institute Press . 2002 . Illustrated Design Histories . 656 . 1-55750-250-1 .
  40. News: SECNAV Del Toro Names New Class of Medical Ships After Bethesda Medical Center . May 2023 . Heather . Mongilio . USNI News . United States Naval Institute .
  41. Web site: Hull Classification Symbol. militarypower.wikidot.com. 17 January 2018.
  42. In 2020 the US Navy began to develop this new type of ship, construction of the first is planned for 2026
  43. News: Report to Congress on Navy Light Replenishment Oiler . April 2023 . USNI News . United States Naval Institute .
  44. See .
  45. See USS Crane Ship No. 1
  46. See
  47. See
  48. See
  49. See
  50. See
  51. Web site: PCER-848. navsource. 21 December 2017.
  52. See Deep Submergence Vessel NR-1.
  53. See Akron-class airship.
  54. Web site: United States Coast Guard . 27 April 2020 . https://web.archive.org/web/20060101111600/http://www.uscg.mil/datasheet/index.shtm . 1 January 2006 . en . 1 January 2006 . dead.
  55. Web site: National Oceanic and Atmospheric Administration (NOAA) Home Page. US Department of Commerce, NOAA Office of the Chief Administrative Officer (OCAO). Elias. Abunassar. www.corporateservices.noaa.gov.

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