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, physical countable object (or class thereof), or physical noncountable ...

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

La Niña La Niña (; ) is an oceanic and atmospheric phenomenon that is the colder counterpart of as part of the broader El Niño–Southern Oscillation (ENSO) climate pattern. The name ''La Niña'' originates from Spanish for "the girl", by an ...

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

serial code A serial number is a unique identifier assigned incrementally or sequentially to an item, to ''uniquely'' identify it. Serial numbers need not be strictly numerical. They may contain letters and other typographical symbols, or may consist enti ...

; 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 will 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 and today also. Later, with the i ...

– 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 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 HIN is used to trace the boat's history. The precise usage varies by country and type. United S ...

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 An ENI number (European Number of Identification or European Vessel Identification Number) is a registration for ships capable of navigating on inland European waters. It is a unique, eight-digit identifier that is attached to a hull for its enti ...

(''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 A Naval Registry Identification Number is a unique identifier that the U.S. Navy used for privately owned and naval vessels in the first half of the 20th century. Overview During World War I, in 1916, the U.S. Navy began a registry of privately own ...

– United States until 1920s, replaced by hull classification symbol system *

IMO number The IMO number of the International Maritime Organization is a generic term covering two distinct meanings. The IMO ship identification number, is a type of hull number used as a unique ship identifier, and the IMO company and registered owner ...

– a unique identifier issued by the

International Maritime Organization The International Maritime Organization (IMO, French: ''Organisation maritime internationale'') is a specialised agency of the United Nations responsible for regulating shipping. The IMO was established following agreement at a UN conference ...

(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 author ...

– an identifier used during radio transmissions, used mainly during verbal transmissions and sometimes incorporating a vessel's MMSI *

Maritime Mobile Service Identity A Maritime Mobile Service Identity (MMSI) is effectively a maritime object's international ''maritime telephone number'', a temporarily assigned UID, issued by that object's current flag state, (unlike an IMO, which is a global forever UID). ...

(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 ...

– 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/n ...

– 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) The Royal Canadian Navy uses hull classification symbols to identify the types of its ships, which are similar to the United States Navy's hull classification symbol system. The Royal Navy and some European and Commonwealth navies (19 in total) us ...

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 (WS) is the world governing body for the sport of sailing recognized by the International Olympic Committee and the International Paralympic Committee (IPC). History The creation of the International Yacht Racing Union (IYRU) beg ...

. 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