Maritime VHF radio operation
What this domain tests
The Maritime VHF radio operation domain tests correct, calm radio procedure: which channel to use, how to make a distress, urgency or safety call, and how to keep Channel 16 clear for its real purpose.
Core rules
- Channel 16 is the international distress, urgency, safety and calling channel. Make initial contact there, then move promptly to a working channel. Do not use it for routine chat or radio checks.
- Channel 6 is for ship-to-ship working communications. Channel 70 is the DSC channel and must not be used for voice.
- MAYDAY means grave and imminent danger and requires immediate assistance. PAN PAN means urgency - serious but not immediate danger to life. SECURITE is a safety message, such as a navigation warning.
- Speak slowly and clearly. Give the vessel name and call sign, position, nature of problem, assistance required and number of people on board. Use the phonetic alphabet for names and call signs.
Worked example
Your engine fails and you are drifting towards rocks with three people on board. This is grave and imminent danger: use MAYDAY. Message: “Mayday, Mayday, Mayday. This is Sea Hawk, Sea Hawk, Sea Hawk, call sign ZM1234. Position: one nautical mile east of Bean Rock. Engine failure, drifting towards rocks. Require immediate tow. Three persons on board. Over.” If you were simply delayed but safe, PAN PAN would be more appropriate.
Exam traps
- Using MAYDAY for a non-urgent breakdown.
- Staying on Channel 16 after contact instead of moving to a working channel.
- Omitting position or number of people on board.
- Using Channel 70 for voice.
- Speaking too fast or failing to use the vessel name.