This is the first book to cover the Global Marine Distress and Safety System (GDMSS) in a comprehensive and readable way. GDMSS is now being developed to provide a new global communications and locating network to alert search and rescue services, and all students of navigation or maritime technology, and practising navigation officers, will need to be trained in its use. This accessible reference textbook provides students and new radio operators with all the knowledge necessary for a complete understanding of GMDSS and its related systems.