Marine VHF Channel 16

Marine VHF channel 16 is the international distress, urgency, safety, and calling frequency, 156.800 MHz, set by ITU Radio Regulations Appendix 18. Ships use it to broadcast a Mayday, to make an urgency (Pan-Pan) or safety (Securite) call, and to call another station before shifting to a working channel. SOLAS GMDSS ships keep a listening watch on channel 16 while at sea, alongside the continuous DSC watch on channel 70. A distress call on 16 is voice, made after or instead of a DSC alert, and coast radio stations and many coast guards guard it around the clock. Routine chatter on 16 is prohibited because the channel must stay clear for distress.