A navigational system for submersible vessels that provides warning of impending grounding occurrences. A data base of bottom contours and submerged obstructions is compared to various indicators of the submersible vessel's position and motion to provide alerts and to display bottom hazards ahead of...http://www.google.de/patents/US6734808?utm_source=gb-gplus-sharePatent US6734808 - Method, apparatus and computer program products for alerting submersible vessels to hazardous conditions
