Module 18 - Signals & Communications
DSC Distress Alerts
Digital Selective Calling (DSC) sends an electronic distress alert from the VHF set. A DSC distress alert normally includes the vessel MMSI, position if the radio is connected to GNSS, time, and the selected nature of distress. It alerts coastguard stations and DSC-equipped vessels in range.
The red distress button is not a replacement for the voice call. After sending a DSC distress alert, transmit the spoken MAYDAY on VHF Channel 16 unless the crew are unable to do so. The spoken call gives the human detail that rescuers need: position, problem, assistance required, and people on board.
Key points
- DSC sends an electronic distress alert
- MMSI identifies the vessel
- Position is included if GNSS is connected
- Follow DSC distress alert with a voice MAYDAY on Channel 16
- Cancel accidental alerts immediately and inform the coastguard
Tip: Check during pre-passage setup that the VHF has a valid MMSI and live position input. A DSC set with no position data is much less useful in an emergency.
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