For international operational purposes the GMDSS system sub divides the World into 4 main geographical Sea Areas, that are GMDSS Sea Areas A1, A2, A3 and A4. The communication range of the different types of radio communication systems necessarily carried on board of SOLAS vessels at sea, substantially defines the geographical boundaries of these Sea Areas.

The following table includes the information regarding sattelite and radio communication coverage and SOLAS vessel radio equipment carriage requirements for all GMDSS Sea Areas.

GMDSS Sea Area

Geographical satellite and radio communication coverage

Radio and Satellite communication equipment

Automatic and portable radio equipment

A1

Within continuous VHF (Very High Frequency) DSC (Digital Selective Calling) coverage from a CRS with follow on VHF RT (Radio Telephony)

(about 20 - 30 NM from the coast)

VHF radioDSC and RT

NAVTEX receiver - Automatic reception of MSI (Maritime Safety Information)

406 MHz EPIRB (Emergency Position Indicating Radio Beacon)

SART (Search And Rescue Radar Transponder)

VHF handheld radio

A2

Outside Sea Area A1

Within continuous MF (Medium Frequency) DSC coverage from a CRS with follow on MF RT

Up to 150Nm offshore, yet adequate coverage is often possible as far as 400Nm or more from the shore

MF radio – DSC, RT and Telex

Plus

The equipment included for Sea Area A1

406 MHz EPIRB

SART

VHF handheld radio

A3

Outside Sea Areas A1 & A2

Within INMARSAT (International Maritime Satellite Organisation) coverage, that is between 700 North and 700 South

HF (High Frequency) radio – DSC, RT and Telex

Or

INMARSAT systems B,C or Fleet – Satellite Communication


Plus

System for reception of MSI in Sea Area A3 (EGC or Radio Telex)

Plus

The equipment included for Sea Areas A1 & A2

406 MHz EPIRB

SART

VHF handheld radio

A4

Outside Sea Areas A1, A2 & A3

Above 700 N and below 700 S

HF radio – DSC, RT and Telex

Plus

The equipment included for Sea Areas A1 & A2

406 MHz EPIRB

SART

VHF handheld radio

Radio communication coverage and SOLAS vessel radio equipment carriage requirements for all GMDSS Sea Areas

Details of SOLAS vessel radio equipment carriage requirements may be found in ALRS Volume 5.

R18-A-crop

Map of Norwegian, Greenland and Barents sea with GMDSS Sea Areas colour coded A1 (red), A2 (green), A3 (blue) and A4 (grey).

On the above map It can be seen that along the coast of Iceland there is no GMDSS Sea Area A1 indicated. This is because Iceland has not supplied operational VHF MRCC. However, Norway has a GMDSS Sea Area A1 bordering its coast, having established operational VHF MRCCs on its coastlines. At least Iceland has MF MRCC and so its coastline is in GMDSS Sea Area A2. Between Iceland and Norway and northward is an area not covered by MF MRCC, but with HF MRCC. If the area is at the same time covered with Inmarsat Satellites (between 70o N and 70o S), then it is considered area A3; otherwise it is area A4.

The radio equipment that increases safety at sea mentioned above does not include mobile phones or satellite non-GMDSS compliant equipment, which a lot of people still rely on at sea. It is absolutely crucial to consider that commercial services are not designed to provide distress communications at sea.
Last modified: Saturday, 25 April 2020, 7:50 PM