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 sattelite and radio communication coverage

Radio and Sattelite 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

(about 100 NM from the coast)

MF radio – DSC and RT

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

Or

INMARSAT – 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

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.

It can be seen that along a part of the North coast of Africa and a part of the West coast of Portugal there is no GMDSS Sea Area A1 indicated. This is because the following countries have not supplied operational VHF MRCCs on their coastlines, they are- Egypt, Libya, Morocco, Portugal and Tunisia. However, it can be seen that all other countries on the following map have a GMDSS Sea Area A1 bordering their coast, by having established operational VHF MRCCs on their coastlines.

R4-A-crop

Map of the Mediterranean - West with GMDSS Sea Areas colour coded A1 (red), A2 (green) and A3 (blue).

The radio equipment that increases safety at sea mentioned above does not include mobile phones, on which still a lot of people rely at sea. Mobile phones shouldn't be used at sea as a sole means of raising the alarm because of the following (compared to the VHF radio):

  • Mobile services are not designed to provide distress communication at sea.
  • Rescuers cannot pinpoint the position of a casualty using a mobile. Radio equipment not only provides the best way of contacting the shore based stations or other vessels in an emergency, but also can enable SAR services to locate the vessel through the radio signal (flares should also be carried to help rescuers locate the craft in case of emergency).
  • Mobile phones have very limited battery life.
  • Other nearby vessels are unable to pick up the signal and assist if needed, because it is a closed communication system. You are only connected to the number you called. VHF radio communication is an open system, all vessels in the vicinity equipped with a VHF radio will be able to monitor or take part in the communication.
  • Mobile network signal strength is unreliable.
  • The range of a VHF radio signal is normaly much wider.
  • Depending on injuries, a small mobile may prove difficult to use.
  • A mobile phone relies on a mobile network (this could be congested or malfunctioning) while a VHF radio is an independent unit.
  • A VHF radio is easy to use, also in bad circumstances. Also,it will give a good audio signal and this will allow several people to listen at the same time to received messages.
Ostatnia modyfikacja: sobota, 25 kwiecień 2020, 19:50