Buoy

A buoy is a navigational aid which marks marine traffic routes for boats and ships. It consists of a floating object that is usually anchored to a specific location on the bottom of the sea or to a submerged object. Buoys are used to locate channels, dangerous rocks or shoals, mooring positions, submerged shipwrecks, and for a variety of other purposes. Various countries have devised systems of shapes and colours to be used on buoys for specific purposes. Buoys sometimes carry bells, lights, or other such beacons.

Submarines sometimes carry buoys to be released in case of emergencies or for communication.