Blind Sectors : Areas which cannot be scanned by the radar of the vessel because they are shielded by parts of its superstructure, masts, etc, or shore obstructions.
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}