How to use marine VHF
Channel 16 is the international distress, safety and calling channel. Keep a loudspeaker watch on 16 when the radio is on, unless the ship is in a port that requires another watch. After calling on 16, move to a working channel. Channel 70 is for DSC only and must not be used for voice. Port and pilot channels change by country, so always check the ALRS or the local port guide before arrival.
About this list
The table below is a short memory aid for common channels. It is not the full ITU Appendix 18 list and it is not a substitute for the ship’s GMDSS procedures. Some channels are duplex and some are simplex. National authorities can allocate extra uses, so confirm locally.
Who should use it
Useful for cadets and officers refreshing channel numbers before a pilotage or a drill. For a distress alert, follow the posted GMDSS card at the radio.