All ships to which the 1974 SOLAS Convention, as amended in 1988, applies are required to carry the GMDSS radio equipment, depending on the se areas in which they operate.
One of the basic principles on which the GMDSS carriage requirements is based is a functional requirement to ensure the capability of transmitting ship-to-shore distress alerts by at least two separate and independent means. The capability of performing other communications functions is also required. There are specific carriage requirements for ships according to the sea area(s) in which they operate.
Carriage requirements for GMDSS radio equipment can be summarized as follows:
· Sea area A1 ships will carry VHF equipment and either a satellite EPIRB or a VHF EPIRB;
· Sea area A2 ships will carry VHF and MF equipment and a satellite EPIRB;
· Sea area A3 ships will carry VHF, MF, a satellite EPIRB and either HF or satellite communication equipment;
· Sea area A4 ships will carry VHF, MF and HF equipment and a satellite EPIRB;
· All ships will carry equipment for receiving MSI broadcasts.