Distress Communications
DSC (Digital Selective Calling) is the modern method for raising a distress alert. Press the red distress button on the VHF radio (usually under a cover). This transmits your vessel's MMSI number, position (from GPS), and the nature of distress to all vessels and coastguard stations in range.
A voice MAYDAY is broadcast on VHF Channel 16. The format is: MAYDAY MAYDAY MAYDAY — This is [vessel name ×3] — MAYDAY [vessel name] — My position is [lat/long or bearing and distance from known point] — I have [nature of distress] — I require [assistance needed] — [number of persons on board] — Over.
An EPIRB (Emergency Position Indicating Radio Beacon) transmits a distress signal via satellite when activated. A SART (Search and Rescue Transponder) shows up on other vessels' radar screens to guide rescuers to your position.
Key Points
- DSC distress alert — red button on VHF; sends MMSI, position, and nature of distress
- MAYDAY — voice distress call on VHF Ch 16 for grave and imminent danger
- PAN PAN — urgency call (serious but not immediate danger to life)
- SECURITÉ — safety message (navigational or weather warning)
- EPIRB — satellite distress beacon
- SART — radar transponder for search and rescue