11.2.3 Use of Handheld VHF Radios

11.2 Types of radio distress calls

All information will be displayed on any receiving sets’ display panel. Transmitting and receiving sets will switch to Channel 16 to allow further information to be transmitted, e.g. spoken MAYDAY message, nature of emergency, etc.

The advent of the Global Maritime Distress and Safety System (GMDSS) has brought about a number of changes in the manner and procedure in which distress calls from craft are initiated.

11.2.2 Non-Automated Calling

VHF sets without DSC must rely on the traditional format of broadcast on Channel 16 for making a MAYDAY call. Ensure the set is selected to Channel 16 and that it is transmitting at its full power.

Modern VHF radios are fitted with a Digital Selective Calling (DSC) facility whereby a distress call is activated by pressing a dedicated switch on the radio. This system transmits an all station call on Channel 70.

The MAYDAY broadcast format as described on page 158 should be used.

For non-DSC radios, Channel 16 remains the listening channel for distress calls.

11.2.3 Use of Handheld VHF Radios

Therefore there are two possible scenarios:

Portable VHF radio equipment can be used on small boats particularly where it is impracticable to install a fixed VHF radio. This equipment should be licensed and issued with a radio call sign.

11.2.1 Automated Calling

This only works on DSC radio sets. The operator initiates an all station call by simply uncovering and pushing the red SOS switch on the radio’s panel. This will transmit the Maritime Mobile Service Identity (MMSI) code - a series of 9 digits without any further action required by the crew.

The portable VHF will only be licensed for use on a boat for communications with coast stations, harbour authorities, marinas and other boats - it should not be used on land.

In addition to the MMSI code, if interfaced with a GPS, it can also give a boat’s position and possibly the type of emergency (depending on settings).