Distress signals by radio

The most common way of sending a distress signal is by radio.
Modern radios conform to the GMDSS (Global Maritime Distress and Safety System).
GMDSS is an international system that uses terrestrial and satellite technology and ship board radio systems to allow rapid response in an emergency situation.
Nowadays distress messages can be initiated digitally by pressing the call button on the radio set.
Radio sets which are not according to the GMDSS standard transmit a distress message by voice on channel 16 on a VHF transmitter, or on 2182 kHz on an MF transmitter.
The reception range of a VHF transmitter to a coastal station averages 35 nautical miles and between an MF transmitter and a coastal station 150 nautical miles.
If you or your vessel are in grave and immediate danger use the MAYDAY call.
MAYDAY is the internationally recognized radiotelephony distress signal for a person or a vessel in grave and imminent danger.