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. However, not all navies use prefixes. Among the blue-water navies, those of France, Brazil, China, Russia, Germany, 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"...