Cardinal Buoy : A seamark, i.e. a buoy, indicating the North, East, South or West, i.e. the cardinal points from a fixed point. such as a wreck, shallow water, banks, etc.NAV 46/WP.3
International Maritime Organization (IMO) Sub-Committee on Safety of Navigation & Rijeka College of Maritime Studies, IMO Standard Marine Communication Phrases (SMCP), London, UK 2000. http://www.segeln.co.at/media/pdf/smcp.pdf, (Mrn Commun Phrases - Brit) {563}