Patrol vessel

Classification

The classification of a patrol boat is often subjective, but they are generally small naval vessels that are used to patrol national waters or a certain jurisdiction. They may be as large as a corvette or even a frigate, though the term may also be used for vessels as small as a yacht or rigid inflatable boat. They can include gunboat, fast attack craft, torpedo boats, and missile boats. They may be broadly classified as inshore patrol vessels (IPVs) or offshore patrol vessels (OPVs). OPVs and medium size cutters are usually the smallest ship in a navy's fleet that are large and seaworthy enough to patrol off-shore in the open ocean, while IPVs are typically too small to do so and are instead kept in lakes or rivers, or close to coasts; IPVs specifically used in rivers can also be called "riverine patrol vessels". Large patrol vessels, offshore patrol vessels and Large cutters are the largest type of patrol ships and are typically more than 100 m (330 ft) in length. Some OPVs may possess significant armament and may approach corvettes in terms of armed capability.