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/nationality. In the modern environment, prefixes are cited inconsistently in civilian service, whereas in government service a vessel's prefix is seldom omitted due to government regulations dictating that a certain prefix be used. Today the common practice is to use a single prefix for all warships of a nation's navy, and other prefixes for auxiliaries and ships of allied services, such as coast guards. For example, the modern navy of Japan adopts the prefix "JS" – Japanese Ship, or the US navy has adopted the USS prefix. However, not all navies use prefixes. Among the blue-water navies, those of France, Brazil, China, Russia, Germany, Ukraine, and Spain do not use ship prefixes. NATO designations such as FS (French Ship), FGS (Federal German Ship), and SPS (Spanish Ship) can be used if needed.
Usage Historically, prefixes for civilian vessels often identified the vessel's mode of propulsion, such as "MV" (motor vessel), "SS" (screw steamer; often cited as "steam ship"), or "PS" (paddle steamer).
Today, general civilian prefixes are used inconsistently, and frequently not at all. In terms of abbreviations that may reflect a vessel's purpose or function, technology has introduced a broad variety of differently named vessels onto the world's oceans, such as "LPGC" (liquified petroleum gas carrier), or "TB" (tug-boat), or "DB" (derrick barge). In many cases though, these abbreviations are used for purely formal, legal identification and are not used colloquially or in the daily working environment. Prefixes indicating a vessel's purpose (e.g., "RMS" for a Royal Mail ship or "RV" for research vessel) are also used.
Prefixes used for naval ships primarily reflect ownership, but may also indicate a vessel's type or purpose as a sub-set. Historically, the most significant navy was Britain's Royal Navy, which has usually used the prefix "HMS", standing for "His/Her Majesty's Ship". The Royal Navy also adopted nomenclature that reflected a vessel's type or purpose, e.g. HM Sloop. Commonwealth navies adopted a variation, with, for example, HMAS, HMCS, and HMNZS pertaining to Australia, Canada, and New Zealand, respectively.
In the early days of the United States Navy, abbreviations often included the type of vessel, for instance "USF" (United States Frigate), but this method was abandoned by President Theodore Roosevelt's Executive Order No. 549 of 1907, which made "United States Ship" (USS) the standard signifier for USN ships on active commissioned service. United States Navy prefixes officially only apply while a ship is in active commission, with only the name used before or after a period of commission and for all vessels "in service" rather than commissioned status.
However, not all navies used prefixes; this includes the significant navies of China, France and Russia.
From the 20th century onwards, most navies identify ships by letters or hull numbers (pennant numbers) or a combination of such. These identification codes were, and still are, painted on the side of the ship. Each navy has its own system: the United States Navy uses hull classification symbols, and the Royal Navy (e.g. "D35" is destroyer 35 – HMS Dragon) and other navies of Europe and the Commonwealth use pennant numbers.
These tables list both current and historical prefixes known to have been used.
Generic (merchant navy) prefixes
These prefixes are generally used for merchant vessels of any nationality unless specified.
Prefix MeaningAEAmmunition shipAFS Combat stores shipAHTAnchor handling tugAHTSAnchor handling tug supplyAOOilerAOGGasoline tankerAORReplenishment oilerAOTTransport oilerASDSAutonomous Spaceport Drone ShipATBArticulated Tug BargeCRVCoastal Research VesselC/FCar ferryCSContainer ship or Cable shipDBDerrick bargeDEPVDiesel Electric Paddle VesselDLBDerrick Lay BargeDCVDeepwater Construction VesselDSVDiving support vessel or deep-submergence vehicleDVDead vesselERRVEmergency Response Rescue VesselEVExploration VesselFPSOFloating production storage and offloading vesselFPVFree Piston Vessel orFishery Protection VesselFTFactory Stern TrawlerFVFishing VesselGTSGas Turbine ShipHLVHeavy lift vesselHMTHired military transport (not currently in use)HMHSHis(/Her) Majesty's Hospital ShipHSCHigh Speed CraftHSFHigh Speed FerryHTVHeavy transport vesselIRVInternational Research VesselITBIntegrated Tug bargeLBLiftboatLNG/CLiquefied natural gas carrierLPG/CLiquefied petroleum gas carrierMFMotor ferryMFVMotor fishing vessel (mainly UK Royal Naval Reserve)MS (M/S)Motor ship (interchangeable with MV)MSVMultipurpose support/supply vesselMSYMotor Sailing YachtMTMotor TankerMTSMarine Towage and Salvage / Tugboat / Motor Turbine ShipMV (M/V)Motor Vessel (interchangeable with MS)MY (M/Y)Motor YachtNBNarrowboatNRVNATO Research VesselNSNuclear shipOSVOffshore supply vesselPSPaddle steamerPSVPlatform supply vesselQSMVQuadruple screw motor vesselQTEVQuadruple turbo electric vesselRMPRoyal Mail PacketRMSRoyal Mail Ship or Royal Mail SteamerRMVRoyal Mail VesselRMMVRoyal Mail Motor VesselRNLBRoyal National LifeboatRNMBRoyal Navy Motor BoatRRSRoyal Research ShipRV / RSVResearch vessel/Research Survey VesselRSV Aurora Australis 1989–2020 Australian Antarctic Division, 25 January 2017. Retrieved 26 February 2021.SBSailing BargeSLSteam LaunchSS (S/S)Single-screw steamship(also used as generic term for any steam-powered ship)SSCVSemi-submersible crane vesselSSSSea Scout ShipSSVSailing School Vessel, or Submarine and Special Warfare Support VesselSTSteam tug or Steam trawlerSTSSail training shipSTVSail Training Vessel or Steam Turbine VesselSV (S/V)Sailing VesselSY (S/Y)sailing yacht or steam yachtTBTug boat TIVTurbine Installation VesselTEVTurbine electric vesselTrSSTriple-screw steamship or steamerTSTraining Ship or turbine steamship or turbine steam shipTr.SMVTriple-Screw Motor VesselTSMVTwin-Screw Motor VesselTSMSTwin-Screw Motor ShipTSSTwin-screw steamship or steamerTSTTwin-screw tugTT (T/T)"Tender to" ..., the prefix is placed on the tender followed by the name of the mother ship; or Turbine TankerTVTraining vesselULCCUltra Large Crude CarrierUSMSUnited States Mail ShipVLCCVery Large Crude CarrierYDYard derrick/Floating craneYTYard tug/Harbor tugYTBBig yard tug/Large harbor tugYTLLittle yard tug/Small harbor tugYTMMedium yard tug/Medium harbor tugYW Water barge, self-propelledYWN Water barge, non-self-propelled
National or military prefixes