When to Use Mayday
Use Mayday only for grave and imminent danger to a vessel or person, where immediate assistance is required.
- Grave and imminent danger
- Immediate assistance required
Marine Radio revision module 6 of 10
SOS
Distress & Mayday
When to use Mayday, how to structure the voice call, and what to say after sending a DSC distress alert.
Grave and imminent dangerComplete Mayday format and identity
8 guided lessons · 19 practice questions · 19 flashcards
3 outcomes · self-guided revision
- Explain when to use Mayday, how to structure the voice call, and what to say after sending a DSC distress alert.
- Apply Grave and imminent danger to a realistic onboard situation.
- Recall the core check: grave and imminent danger.
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Voice Mayday Structure
A Mayday call needs the distress signal, vessel identity, position, nature of distress, assistance required, persons on board, and any other useful information.
- Mayday x3
- This is vessel x3
After DSC Distress
A DSC distress alert is not the full voice message. After sending the alert, follow up with the voice Mayday on Channel 16 unless instructed otherwise.
- DSC alert first if available
- Voice follow-up on Channel 16
Mayday Threshold
Mayday is for grave and imminent danger to a vessel or person where immediate assistance is required. It is serious traffic and should not be diluted by routine breakdowns or convenience...
- Grave and imminent danger.
- Immediate assistance required.
DSC Alert And Voice Mayday
The DSC distress alert is an alarm and digital identity/position alert, not the full distress message. After the alert, transmit the voice Mayday and message on Channel 16 after acknowled...
- Send DSC distress alert if available.
- Transmit Mayday voice call and message on Channel 16.
Position And Follow-Up
Position is often the difference between a good call and a delayed rescue. Latitude and longitude are preferred when available, but a clear bearing and distance from a known point or a na...
- Give lat/long, bearing and distance, or clear local description.
- Use phonetics for names if needed.
The Complete Current Small-Craft Mayday
After a DSC acknowledgement or about 15 seconds, transmit the voice distress call and message on Channel 16: MAYDAY three times; THIS IS and the vessel name three times; call sign or othe...
- The second MAYDAY marks the start of the distress message.
- Call sign and MMSI are spoken before it and repeated in the full identity after it.
Receiving And Controlling Distress Traffic
On receiving a DSC distress alert, stop any transmission that could interfere and listen on Channel 16. If there is still no DSC acknowledgement after five minutes and you can assist, ack...
- Listen first and protect Channel 16 distress traffic.
- The five-minute rule applies before a capable assisting ship voice-acknowledges an unacknowledged DSC alert.
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