In the 1980s, agencies including the International Telecommunications Union and the International Maritime Organization collaborated on the development of a global search and rescue plan based on a combination of satellite and terrestrial radio services. Called the Global Maritime Distress and Safety System, it changed international distress communications from being primarily a system of ship-to-ship communications, to a ship-to-shore communications system. It spelled the end of Morse Code communications for all but a few users, primarily amateur radio operators.
GMDSS relies upon the establishment of specific sea areas and redundant distress communications systems. It required the installation of upgraded suites of communications equipment on board vessels and at shore based telecommunications centers. The GMDSS provides for the automatic identification of the caller and the location of a vessel in distress. It went into effect aboard commercial ships in 1999.
For these vessels the GMDSS system is compulsory. Recreational boats are termed voluntary vessels because they can choose whether or not to carry GMDSS-compliant equipment. Rescue authorities strongly encourage them to do so. This program offers an overview of modern distress and safety communications.
Global Maritime Distress & Safety System
EPIRBS & SARTS
Produced in conjunction with the National GMDSS Task Force. DVD Video, 22 minutes