Module 6 - Distress & Mayday
After DSC Distress
What you will learn
Complete the immediate sequence after a DSC distress alert instead of waiting silently for the digital alert to solve the emergency.
Once the alert has been sent, the next radio action is the voice Mayday on Channel 16—after a DSC acknowledgement or after about fifteen seconds—followed by a listening watch and responsive updates.
The MCA procedure says that on receipt of a DSC acknowledgement, or after about fifteen seconds, transmit the distress call and message on Channel 16. The short interval is not a five-minute wait. The separate five-minute interval belongs to a receiving vessel considering a voice acknowledgement of someone else's unacknowledged alert.
Confirm Channel 16 and use distress power rather than the routine low-power-first habit. Deliver the complete voice message, say OVER, release PTT and listen. A pressed PTT prevents the acknowledgement from reaching you, and rapid automatic repetition can cover a Coastguard or nearby-vessel reply.
Continue the instructed watch. Answer questions, read back critical instructions and report material changes such as a new position, rate of flooding, fire spread, abandonment, recovery of a person or a change in persons accounted for. Keep casualty management and other alerting or locating equipment coordinated rather than treating the radio call as the end of the emergency response.
Turn the digital alert into a two-way rescue conversation
The set shows that a DSC distress alert has transmitted. No acknowledgement appears during the first fifteen seconds and the vessel is still taking water.
1. Move to voice
Select Channel 16 and make the complete Mayday voice call and message; do not wait five minutes for this step.
2. Create the reply interval
End OVER, release PTT and listen for the Coastguard or another station.
3. Maintain the information loop
Respond to instructions and transmit concise updates when the position, danger, assistance or people information changes.
Sense check: The alert should be followed by an intelligible voice message and a real opportunity for responders to answer.
Common mistake or limitation
- Waiting five minutes before making your own voice Mayday after sending DSC.
- Leaving the set on Channel 70 for speech; Channel 70 is DSC-only.
- Holding PTT or repeating continuously so that no acknowledgement can be heard.
Recap
- After acknowledgement or about fifteen seconds, make the voice Mayday on Channel 16.
- OVER must be followed by releasing PTT and listening.
- Update material changes and follow the coordinating station's instructions.
Optional quick check
Section 3 of 10
Your DSC alert has transmitted and no acknowledgement has appeared after about fifteen seconds. What is the next radio action?
Sources and factual review
Reviewed 1 September 2026 - Compass Revision editorial review.
Continue studying Distress & Mayday
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