Water police

Water police, also called harbor patrols, port police, marine/maritime police, nautical patrols, bay constables or river police, are police officers, usually a department of a larger police organization, who patrol in water craft. Their patrol areas may be coastal sea waters, rivers, estuaries, harbors, lakes, canals or a combination of these.
Duties and functions.
Water police are usually responsible for ensuring the safety of water users, enforcing laws relating to water traffic, preventing crime on vessels, banks and shores, providing search and rescue services (either as the main provider or as an initial response unit before more specialized units arrive), and allowing the police to reach locations not easily accessible from land. They may also be responsible for coastal security, environmental law enforcement, immigration and smuggling patrols, and diving search operations (although many police organizations have separate units to handle this). Their operations may coordinate with other agencies with similar assets such as in the United States the various Federal, State or Local authorities may work together to promote or achieve similar enforcement or rescue outcomes. In the United States, a number of states have combined the duties of water police with those of conservation officers.
Equipment ranges from personal water craft and inflatable boats to large seagoing craft, but most police vessels are small to medium, fast motorboats. In some areas these vessels incorporate a firefighting capability through a fixed deck nozzle. The operators of these vessels are generally trained in many rescue disciplines including first aid, vessel dewatering, and firefighting. They may also be rescue and scuba divers who are specially trained and also boat operators who may engage in towing operations.