Module 4 - Safety
Distress Communications
What you will learn
Select MAYDAY, PAN PAN or a safety message and carry out the DSC-to-voice distress sequence without assuming one device guarantees rescue.
The priority signal describes the situation: MAYDAY is for grave and imminent danger requiring assistance, while PAN PAN covers urgent safety concerns that have not reached that threshold.
For grave and imminent danger when assistance is required, send the VHF DSC distress alert on Channel 70 by pressing and holding the covered control until the set confirms it has sent. The alert identifies the vessel by MMSI and can include position and time when valid navigation data reaches the radio. It carries the selected nature of distress, or an undesignated distress if none was selected.
On receiving a DSC acknowledgement, or after about 15 seconds, transmit the voice distress call and message on Channel 16 when circumstances permit. Give MAYDAY three times, vessel name three times, call sign or other identity and MMSI, then repeat MAYDAY and give vessel identity, position, nature of distress, assistance required, number of people on board and other useful information before OVER.
PAN PAN is for an urgent concern about the safety of a person or vessel that does not meet the MAYDAY threshold. Current MCA small-boat guidance uses a DSC All Ships Urgency call with a nominated working channel, an announcement on Channel 16 and the full message on that working channel. Safety information follows the radio's supported safety-call procedure or a voice call on Channel 16 before moving as directed.
An EPIRB transmits a 406 MHz distress alert by satellite; GNSS-equipped units can include position. An EPIRB or 406 MHz PLB carried on a UK-registered ship or watercraft must be registered with the UK Beacon Registry and kept up to date. A radar SART is a close-range locating aid. VHF range depends strongly on antenna height, so use the appropriate available alerting and locating methods rather than assuming one device guarantees contact or immediate rescue.
Worked example
The yacht is taking water faster than the pumps can control it and the crew may have to abandon. A fixed VHF with valid position data and DSC is available.
- 1Press and hold the covered DSC distress control until the set confirms that the alert has been sent.
- 2On acknowledgement or after about 15 seconds, transmit the MAYDAY call and message on Channel 16.
- 3State the vessel identity, position, uncontrollable flooding, assistance needed, people on board and preparations being made.
- 4Maintain the listening watch, follow Coastguard directions and prepare other appropriate locating or survival equipment without delaying immediate life-saving action.
Sense check: If the spoken message does not tell rescuers who, where, what is wrong, what help is needed and how many people are involved, it is not yet a useful MAYDAY message.
| Signal | Use it when | Initial voice route |
|---|---|---|
| MAYDAY | Grave and imminent danger; assistance required | DSC distress alert, then Channel 16 voice message |
| PAN PAN | Urgent safety concern below the MAYDAY threshold | DSC urgency announcement, Channel 16 call, then nominated working channel |
| Safety message | Navigational, weather or other safety information | Supported DSC safety procedure or Channel 16 voice call, then the directed channel |
Match the priority to the developing situation
A stable yacht has a crew member with a suspected fracture. The vessel remains under control, but medical advice or assistance is needed and the situation could deteriorate.
1. Assess
Decide whether there is grave and imminent danger now or an urgent safety concern that has not reached that point.
2. Alert
Use the radio's appropriate DSC priority and the current voice sequence; do not use Channel 70 for speech.
3. Update
Escalate to MAYDAY if the situation becomes grave and imminent, and tell the responding station about material changes.
Sense check: The priority describes the real risk, not how dramatic the event feels. A PAN PAN can become a MAYDAY if the danger changes.
Common mistake or limitation
- A DSC alert does not contain every detail rescuers need; follow it with the Channel 16 voice message when possible.
- Position is included only when valid data reaches the radio, so the skipper must know how to obtain and speak a reliable position.
- PAN PAN is not simply a quieter MAYDAY: the current DSC announcement and working-channel sequence is different.
Recap
- MAYDAY requires grave and imminent danger and a need for assistance; PAN PAN is an urgent safety concern below that threshold.
- Send the DSC distress alert, then speak the complete MAYDAY message on Channel 16 on acknowledgement or after about 15 seconds.
- Register and maintain 406 MHz beacons, and use complementary communications and locating methods because range and coverage vary.
Optional quick check
Section 2 of 6
A stable yacht has an injured crew member and needs urgent medical advice, but there is no immediate danger to life. Which priority fits the information given?
Continue studying Safety
This public lesson is part of Revision Module 4. Full revision access adds the guided Learn, Practise and Test flow, flashcards and revision progress.