Ian Waugh - A Mariner\'s Guide to Marine Communications

Appendix V

V Vessel identification (radiO and satellite services)

WHENEVER YOU USE MARINE RADIO (VHF, MF or HF) to communicate

with other vessels, or with coast stations, you must use a form of

identification specific to your vessel. The forms of identification available

to you are:

Vessel name

May be used in voice communications and written messages.

Radio callsign
May be used in voice communications and written messages -
particularly useful when there is more than one vessel with the same
name (radio callsigns are unique to the individual vessel).

Maritime Mobile Service Identity (MMSI)
All DSC equipment, afloat and ashore, is programmed with a
unique identity - the individual MMSI. Every GMDSS-fitted vessel will
have a unique, individual MMSI, as will every DSC Coast Station.
If your vessel is one of a fleet, or group of ships, your DSC
equipment can be programmed to respond to a 'group' identity (in
addition to your individual ID and 'all ships' calls).

Maritime Mobile Service Identity (MMSI)

There are three different types of MMSI - those for Ship Stations,

Groups (for a fleet of ships - national or commercial) and Coast

Stations. All MMSIs consist of nine digits. They include a three digit

Maritime Identification Digit (MID) - indicating the country licensing

the 'station' For example - 232 is a MID allocated to the UK.

Ship Station MMSIs always start with the three digit national MID,

followed by six digits depicting the specific vessel. Group MMSIs

always have one leading zero; and Coast Stations have two leading

zeros, for example:

232878000 would represent a (UK registered) ship's MMSI

023288998 would represent a (UK) Group (Fleet) MMSI

002320014 is allocated to MRCC Falmouth - an MF DSC Station

Whenever you send a DSC Alert, your MMSI is automatically
included in the transmitted information.

230 THE NAUTICAL INSTITUTE