A ship identifier refers to one of several types of

identifier An identifier is a name that identifies (that is, labels the identity of) either a unique object or a unique ''class'' of objects, where the "object" or class may be an idea, person, physical countable object (or class thereof), or physical mass ...

s used for maritime vessels. An identifier may be a proper noun (''

La Niña LA most frequently refers to Los Angeles, the second most populous city in the United States of America. La, LA, or L.A. may also refer to: Arts and entertainment Music *La (musical note), or A, the sixth note *"L.A.", a song by Elliott Smit ...

''); a proper noun combined with a standardized prefix based on the type of ship (e.g. ); a

serial code A serial number (SN) is a unique identifier used to ''uniquely'' identify an item, and is usually assigned incrementally or sequentially. Despite being called serial "numbers", they do not need to be strictly numerical and may contain letters ...

; a unique, alphanumeric ID (e.g. A123B456C7); or an alphanumeric ID displayed in international signal flags (e.g. , representing U6CH). Some identifiers are permanent for a ship while others may be changed at the owners' discretion although regulatory agencies will need to approve the change. Modern ships usually have several identifiers. In addition to proper nouns, types of ship identifiers include: *

Code letters Code letters or ship's call sign (or callsign) Mtide Taurus - IMO 7626853"> SHIPSPOTTING.COM >> Mtide Taurus - IMO 7626853/ref> were a method of identifying ships before the introduction of modern navigation aids. Later, with the introduction of ...

– an identifier for a ship that is displayed on vessels by ICS flags representing the letters of the alphabet and numbers 0–9, e.g. the flags (from top to bottom) represented the identifier "USMW" *

Hull number A hull number is a serial identification number given to a boat or ship. For the military, a lower number implies an older vessel. For civilian use, the Hull Identification Number (HIN) is used to trace the boat's history. The precise usage varie ...

or Hull Identification Number (HIN) – a number used as an identifier for civilian and naval vessels, national/regional subtypes include: ** Craft Identification Number – a permanent unique fourteen-digit alphanumeric identifier issued to all marine vessels in Europe **

ENI number Eni is an Italian oil and gas corporation. Eni or ENI may refer to: Businesses and organisations * Escuela Nacional de Inteligencia, the Argentine intelligence academy * Groupe des écoles nationales d’ingénieurs (Groupe ENI), a French engine ...

(''European Number of Identification'' or ''European Vessel Identification Number'') – a unique, eight-digit identifier for ships capable of navigating on inland European waters that is attached to a hull for its entire lifetime, independent of the vessel's current name or flag ** Naval Registry Identification Number – United States until 1920s, replaced by hull classification symbol system *

IMO number The IMO number of the International Maritime Organization is a generic term with two distinct applications: * the IMO ship identification number is a unique ship identifier; or, * the IMO company and registered owner identification number is u ...

– a unique identifier issued by the

International Maritime Organization The International Maritime Organization (IMO; ; ) is a List of specialized agencies of the United Nations, specialized agency of the United Nations responsible for regulating maritime transport. The IMO was established following agreement at a ...

(IMO) for ships *

Maritime call sign Maritime call signs are call signs assigned as unique identifiers to ships and boats. All radio transmissions must be individually identified by the call sign. Merchant and naval vessels are assigned call signs by their national licensing autho ...

– an identifier used during radio transmissions, used mainly during verbal transmissions and sometimes incorporating a vessel's MMSI * Maritime Mobile Service Identity (MMSI) – a unique, nine-digit identifier used over radio frequencies to identify a vessel, used mainly for automated, non-verbal transmissions *

Official number Official numbers are ship identifier numbers assigned to merchant ships by their flag state, country of registration. Each country developed its own official numbering system, some on a national and some on a port-by-port basis, and the formats hav ...

– a ship identifier number assigned to merchant ships by their country of registration, this system has been superseded by the IMO number system *Ship name – a proper noun chosen at the shipowner's discretion; may change several times during the vessel's lifetime **

Ship class A ship class is a group of ships of a similar design. This is distinct from a ship type, which might reflect a similarity of tonnage or intended use. For example, is a nuclear aircraft carrier (ship type) of the (ship class). In the course o ...

– a common name for a group of ships with similar design, usually named for the first vessel of the class, e.g. "''Nimitz''-class aircraft carrier" *

Ship prefix A ship prefix is a combination of letters, usually abbreviations, used in front of the name of a civilian or naval ship that has historically served numerous purposes, such as identifying the vessel's mode of propulsion, purpose, or ownership/na ...

– a combination of letters, usually abbreviations, used in front of the name or hull number of a civilian or naval ship, e.g. "HMS", "MV", "RV", "SS", or "USS"; naval prefix systems include: **

Hull classification symbol 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 ind ...

( List of U.S. hull classifications) – United States since 1920s, replaced the Naval Registry Identification Number system ** Hull classification symbol (Canada) **

Pennant number In the Royal Navy and other navies of Europe and the Commonwealth of Nations, ships are identified by pennant number (an internationalisation of ''pendant number'', which it was called before 1948). Historically, naval ships flew a flag that iden ...

– United Kingdom and Commonwealth countries **Tactical number - a number painted on the hull of a military ship, for identification either during combat or peacetime. *Sail number - unique identifiers used especially for racing yachts but also windsurfers, and displayed on the sail to assist with

search and rescue Search and rescue (SAR) is the search for and provision of aid to people who are in distress or imminent danger. The general field of search and rescue includes many specialty sub-fields, typically determined by the type of terrain the search ...

operations. The sail code prefixes are mandated by

World Sailing World Sailing is the international sports governing body for sailing (sport), sailing; it is recognized by the International Olympic Committee (IOC) and the International Paralympic Committee (IPC). History The creation of the International Yac ...

. In some countries, out of sequence numbers akin to

vanity plate A vanity plate or personalized plate (United States and Canada); prestige plate, private number plate, cherished plate or personalised registration (United Kingdom); personalised plate (Australia, New Zealand, and United Kingdom) or custom pla ...

s can be purchased, although the registered number remains with the vessel on sale.

References

{{Reflist Ship names Ship identification numbers Identifiers