How radios actually keep ships safe — and how misuse creates accidents
Contents
Use the links below to jump to any section:
- What VHF and DSC Really Are
- Why VHF Discipline Matters More Than Equipment
- VHF Channels and Their Practical Use
- Routine Communications – How to Speak Clearly and Correctly
- Safety Communications (SECURITÉ)
- Urgency Communications (PAN-PAN)
- Distress Communications (MAYDAY)
- Digital Selective Calling (DSC) – What It Does and Does Not Do
- Common VHF & DSC Errors Seen in Accidents
- Professional Bridge Radio Mindset
1. What VHF and DSC Really Are
VHF radio is the primary short-range safety communication system at sea.
DSC is not a replacement for voice radio.
It is a digital alerting system designed to:
- attract immediate attention
- prioritise distress and urgency
- reduce missed calls
The radio does not create safety.
Correct use does.
2. Why VHF Discipline Matters More Than Equipment
Most communication failures are not technical.
They are caused by:
- unclear speech
- wrong channel usage
- assumptions instead of confirmation
- excessive or unnecessary chatter
A modern bridge with poor radio discipline is less safe than an older bridge with clear, controlled communications.
Professional radio use is brief, precise, and purposeful.
3. VHF Channels and Their Practical Use
The most important channels every bridge must treat correctly:
Channel 16
- Distress, urgency, safety calling
- Initial calling channel only
- Must be kept clear
Working channels (e.g. 06, 08, 10, 12, 13)
- Ship-to-ship
- Ship-to-port
- Tug and pilot communications
VTS-assigned channels
- Information exchange
- Reporting and traffic coordination
Channel misuse clutters the system and delays real emergencies.
4. Routine Communications – How to Speak Clearly and Correctly
Routine calls should follow a predictable structure:
- Who you are calling
- Who you are
- Your position or context
- Your intention
Example (ship-to-ship):
“Motor vessel Atlantic Star, Atlantic Star, Atlantic Star
This is motor vessel Ocean Trader
On your port bow, distance one mile
Intend to overtake on your starboard side”
Good routine communication prevents collision before COLREGs are tested.
5. Safety Communications (SECURITÉ)
Safety messages warn of hazards to navigation.
Used for:
- navigation dangers
- severe weather
- derelicts
- restricted visibility
Format:
“SECURITÉ, SECURITÉ, SECURITÉ
All stations, all stations, all stations
This is motor vessel …
Safety message follows…”
Safety calls are informational, not dramatic.
Their value lies in clarity, not urgency.
6. Urgency Communications (PAN-PAN)
Urgency messages indicate serious situations not yet life-threatening.
Used for:
- machinery failure affecting safety
- steering problems
- man overboard (initial phase)
- medical emergencies
Format:
“PAN-PAN, PAN-PAN, PAN-PAN
All stations, all stations, all stations
This is motor vessel …
Urgency message follows…”
PAN-PAN exists to buy time before MAYDAY is required.
7. Distress Communications (MAYDAY)
MAYDAY is reserved for grave and imminent danger.
Used for:
- fire
- flooding
- grounding
- collision
- abandonment
Voice format:
“MAYDAY, MAYDAY, MAYDAY
This is motor vessel …
MAYDAY …
Position …
Nature of distress …
Assistance required …
Number of persons on board …”
Clarity saves lives.
Volume and speed do not.
8. Digital Selective Calling (DSC) – What It Does and Does Not Do
DSC sends automatic digital alerts to:
- nearby vessels
- coast stations
- rescue coordination centres
DSC:
- identifies the vessel
- transmits position
- prioritises distress
DSC does not:
- replace voice MAYDAY
- coordinate rescue
- explain the situation
A DSC alert must always be followed by voice communication.
9. Common VHF & DSC Errors Seen in Accidents
Accident investigations frequently show:
- distress alerts sent without voice follow-up
- routine traffic clogging Channel 16
- incorrect channel switching
- unclear position reporting
- failure to acknowledge calls
The radio worked.
The communication failed.
10. Professional Bridge Radio Mindset
Professional bridge teams treat radio use as:
- a safety system
- a shared resource
- a last-resort lifeline
They:
- speak clearly and slowly
- confirm understanding
- keep channels clear
- escalate early, not late
Good radio use sounds calm — even in emergencies.
Closing Perspective
VHF and DSC do not prevent accidents by themselves.
They allow humans to share intent, warn danger, and request help — but only if used correctly.
Most radio failures are not technical.
They are human.
Clear words, correct channels, and disciplined structure save more ships than any piece of hardware ever will.
Tags
VHF radio · DSC · GMDSS · bridge communications · maritime safety · distress procedures