A
patrol boat is a relatively small
naval vessel generally designed for coastal defense duties. There have been many designs for patrol boats. They may be operated by a nation's
navy,
coast guard, or
police force, and may be intended for marine (
blue water) and/or
estuarine or river ("
brown water") environments. They are commonly found engaged in various border protection roles, including anti-
smuggling, anti-
piracy,
fisheries patrols, and
immigration law enforcement. They are also often called upon to participate in
rescue operations. Vessels of this type include the original
yacht (from Dutch/Low German
jacht meaning hunting or hunt), a light, fast-sailing vessel used by the
Dutch navy to pursue pirates and other transgressors around and into shallow waters.