Division of sea areas

A1 sea area

Refers to the area covered by at least one VHF coast radiotelephone with continuous DSC alarm capability.

A2 sea area

Refers to the area covered by at least one MF coast radiotelephone with continuous DSC alarm capability, except A1 sea area②

A3 sea area

Refers to the area covered by INMARSAT geostationary satellite with continuous alarm capability, except A1 and A2 sea areas.

A4 sea area

Refers to the area outside A1, A2 and A3 sea areas.