GMDSS Sea Area A2

GMDSS Sea Area A2 is defined as the area, excluding Sea Area A1, within range of at least one MF coast radio station providing continuous DSC alerting, typically up to approximately 400 nautical miles from shore. Vessels operating in Area A2 must carry all the equipment required for A1 plus a medium frequency radio installation with DSC capability and an MF radiotelephony watch on 2182 kHz and a DSC watch on 2187.5 kHz. A shipborne satellite EPIRB capable of operating in all sea areas is also required, providing a satellite backup to the primary MF radio alerting path. For vessels on short international voyages or coastal trades that venture beyond reliable VHF range but do not cross ocean basins, an A2 fit is sufficient. The GMDSS Long Range Certificate is required to operate the MF/HF radio installation. Officers must be familiar with the propagation characteristics of MF radio, including the daytime absorption of ground-wave signals that reduces effective range during daylight and the extended range achievable via sky-wave propagation at night. NAVTEX remains the primary means of receiving maritime safety information in A2 waters where NAVTEX coverage extends.