By 1999, all vessels covered by the SOLAS Regulations 1 were required to fit radio equipment compatible with the Global Maritime Distress and Safety System.  Under this system distress calls are initially made digitally on Channel 70, automatically alerting all other ships and the Coastguard stations with your identity and (if you have an electronic navigator linked up) your position.  Your oral MAYDAY call is then made on Channel 16, as previously.  Normal calls for specific ship stations or coast stations are made by digital selective calling (DSC), where the call is made to the station’s MMSI number (like dialling a phone number).  This activates only the radio of the called station, which then switches to the selected working channel.

Pleasure craft are not required to fit GMDSS equipment at present (although if you are travelling to foreign ports it will be essential) but there are implications of relevance to inland waterway vessels.  The principal issue is that, while GMDSS equipped ships automatically maintain a listening watch on Channel 70, they have not had to maintain watch on Channel 16 after February 2005, although they are encouraged to do so, and to monitor Channel 13 while at sea.  Similarly, the MCA coastguard stations no longer keep a dedicated ‘headset’ watch on Channel 16, although they have undertaken to maintain a ‘loudspeaker’ watch (which means there will not be a radio officer dedicated to monitoring Channel 16 only).  This is really only important on very maritime inland waterways, as on most UK inland waterways you will be out of range of the coastguard stations anyway and you and other vessels will be working on port operations channels.