{{Unreferenced, date=March 2008 USCGC bertholf 2

Maritime patrol is the task of monitoring areas of water. Generally conducted by

military A military, also known collectively as armed forces, is a heavily armed, highly organized force primarily intended for warfare. It is typically authorized and maintained by a sovereign state, with its members identifiable by their distinct ...

and

law enforcement agencies A law enforcement agency (LEA) is any government agency responsible for the enforcement of the laws. Jurisdiction LEAs which have their ability to apply their powers restricted in some way are said to operate within a jurisdiction. LEA ...

, maritime patrol is usually aimed at identifying human activities. Maritime patrol refers to active patrol of an area, as opposed to passive monitoring systems such as sound-detection fixtures or land-based spotters. A patrol consists of a ship, submarine, aircraft or satellite examining the patrolled area and seeking out activities to be identified and reported. Maritime patrol is critical in wartime situations for navies to locate enemy forces to engage or defend against. Peacetime patrols are important for interdiction of criminal activities and for ensuring legal use of waters. Maritime patrols can be conducted by surface

ship A ship is a large watercraft that travels the world's oceans and other sufficiently deep waterways, carrying cargo or passengers, or in support of specialized missions, such as defense, research, and fishing. Ships are generally distinguished ...

s and

submarine A submarine (or sub) is a watercraft capable of independent operation underwater. It differs from a submersible, which has more limited underwater capability. The term is also sometimes used historically or colloquially to refer to remotely op ...

s, by

aircraft An aircraft is a vehicle that is able to flight, fly by gaining support from the Atmosphere of Earth, air. It counters the force of gravity by using either Buoyancy, static lift or by using the Lift (force), dynamic lift of an airfoil, or in ...

(e.g. MPA) and other aerial vehicles, and even by

satellite A satellite or artificial satellite is an object intentionally placed into orbit in outer space. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioiso ...

s. Human spotting remains an important part of detecting activity, but increasingly electronic systems are used.

Type

* Military: Navies and air forces employ patrols to locate and identify enemy or potential enemy ships and submarines. The patrols report these findings to combat vessels which can then take appropriate action. Characteristics to identify are the numbers and types of vessels, as well as bearing and speed information to assist tracking the units.

Anti-submarine An anti-submarine weapon (ASW) is any one of a number of devices that are intended to act against a submarine and its crew, to destroy (sink) the vessel or reduce its capability as a weapon of war. In its simplest sense, an anti-submarine weapo ...

patrols often deploy

sonobuoy A sonobuoy (a portmanteau of sonar and buoy) is a relatively small buoy – typically diameter and long – expendable sonar system that is dropped/ejected from aircraft or ships conducting anti-submarine warfare or underwater acoustic resea ...

s or other devices to assist with tracking. During peacetime, patrols are maintained by military forces for practice and to prevent surprise deployments by enemies. * Law enforcement: Countries with extensive coastlines are vulnerable to those entering or exiting the country undetected. In particular

smuggling Smuggling is the illegal transportation of objects, substances, information or people, such as out of a house or buildings, into a prison, or across an international border, in violation of applicable laws or other regulations. There are variou ...

is often carried out over water. Law enforcement agencies often employ maritime patrols to assist interception of such activities. * Economic: Water areas, in particular those close to the coast, are areas of economic activity. Not only

shipping Freight transport, also referred as ''Freight Forwarding'', is the physical process of transporting commodities and merchandise goods and cargo. The term shipping originally referred to transport by sea but in American English, it has been ...

but also

fishing Fishing is the activity of trying to catch fish. Fish are often caught as wildlife from the natural environment, but may also be caught from fish stocking, stocked bodies of water such as fish pond, ponds, canals, park wetlands and reservoirs. ...

and even

tourism Tourism is travel for pleasure or business; also the theory and practice of touring (disambiguation), touring, the business of attracting, accommodating, and entertaining tourists, and the business of operating tour (disambiguation), tours. Th ...

are important economic activities to coastal countries. Patrolling these waters falls to maritime patrols. Such patrols may seek fishing vessels which are outside of prescribed fishing grounds (often from neighboring countries' fleets) or which are not adhering to regulations. Additionally, patrols may assist customs agencies by monitoring commercial shipping traffic in controlled waters. * Coast defence: Coast defence identifies and intercepts threats to coastal areas. This may include preventing infiltrations or discouraging enemy surveillance of coastal installations. Law enforcement patrols aim at preventing criminals from reaching the shoreline. * Rescue: Although it is not necessarily a primary mission of maritime patrol assets, they are often used to assist in maritime rescue operations, both for searching and often to extract survivors too. Naval warfare