Module 6 - Distress & Mayday
Voice Mayday Structure
What you will learn
Distinguish the distress alert, voice distress call and distress message, then use the identity sequence without dropping the second MAYDAY or the registered identifiers.
The VHF distress workflow has a digital alert and a voice transmission. Within the voice transmission, the opening distress call gains attention and the following distress message provides the information needed to respond.
The digital DSC alert is not the complete voice message. It can carry the vessel's programmed MMSI, position and selected nature of distress, but the Channel 16 voice transmission still gives the human-readable identity, position, problem, assistance and persons information needed by the Coastguard and nearby listeners.
The MCA voice format starts MAYDAY three times, THIS IS and the vessel name three times, followed by call sign or other identification and the vessel MMSI. A further MAYDAY then introduces the distress message, whose identity line contains vessel name, call sign and MMSI again.
That repetition has a purpose: a listener may join after the alarm or miss the first identity block. It is different from padding the message. Once the second identity is complete, give position, nature of distress, assistance required, persons on board, other useful information and OVER.
| Part | Core content | Decision it supports |
|---|---|---|
| DSC distress alert | Programmed identity and position, plus a nature code where selected | Raises the digital distress alarm and points listeners to the follow-up |
| Voice distress call | MAYDAY ×3; THIS IS; vessel ×3; call sign; MMSI | Establishes distress priority and identifies the caller |
| Voice distress message | MAYDAY; full identity; position; nature; assistance; people; useful information; OVER | Lets responders locate, understand and resource the incident |
Use three blocks instead of one memorised blur
A crew member must read a cockpit card while another person manages flooding. Stress makes it easy to jump from the first vessel name straight to the position.
1. Name the blocks
Point to alert, voice call and voice message before pressing PTT.
2. Complete the identity
Give the call-sign and MMSI fields in the opening, then use the second MAYDAY and repeat the complete identity before the position.
3. Move to response facts
Position, nature, assistance, persons and useful information should answer what rescuers need next.
Sense check: A transcript should contain four spoken MAYDAY signals in the MCA format: three in the opening call and one before the full distress message.
Common mistake or limitation
- Treating the DSC alert as a substitute for the Channel 16 voice message.
- Omitting call sign and MMSI from the opening identity block.
- Jumping straight from the first vessel-name repetition to position and losing the second MAYDAY and full identity.
Recap
- The digital alert, voice distress call and distress message do different jobs.
- The current MCA voice format includes a second MAYDAY before the full message identity.
- The message ends OVER because a response is expected.
Optional quick check
Section 2 of 10
What does the second spoken MAYDAY introduce?
Sources and factual review
Reviewed 1 September 2026 - Compass Revision editorial review.
Continue studying Distress & Mayday
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