Maritime Communications (GMDSS)
The GMDSS paper tests sea-area equipment carriage, distress procedures, and the correct use of DSC, EPIRB, SART, and NAVTEX. It is procedural, so exact channel and frequency knowledge earns marks.
Sea areas and carriage
Sea Area A1 is VHF coast-station coverage; A2 is MF; A3 is Inmarsat coverage; A4 is outside A1–A3 and relies on HF. Equipment includes VHF DSC on Channel 70, MF/HF DSC, Inmarsat terminal, 406 MHz EPIRB, 9 GHz SART, NAVTEX on 518 kHz, and two-way VHF on 121.5/123.1 MHz. A distress alert is sent by DSC, then followed by Mayday on Channel 16 or 2182 kHz.
Worked example
A fire forces abandonment. Lift the EPIRB clear, activate it, and take the SART to the lifeboat. Switch on the SART and tune the rescue radar to 9 GHz. Send a DSC distress alert on Channel 70 with the nature 'fire, abandoning ship', then transmit Mayday on Channel 16 with position, persons on board, and assistance required. If no acknowledgement arrives within about 3.5 minutes, repeat or use another system.
Traps
Speaking on Channel 70; using 490 kHz instead of the international 518 kHz NAVTEX frequency; expecting a SART to show on S-band radar; forgetting EPIRB registration and battery expiry; and failing to cancel a false alert through the correct coast station.