Question:

When we bought our second-hand cruiser, the previous owner had helpfully stuck the vessel’s MMSI number above the VHF radio and written the radio call sign onto the Mayday script stuck to the bulkhead.

I logged a passage with the Coastguard recently over VHF and they asked for my call sign.

I gave them this number, but I have no idea if this is the correct and current number.

Exactly what do the MMSI number and call sign do, why do I need them, and do I need to register my details anywhere to make them valid and up to date?

If so, how and with whom do I do this?

Paul Colley

Answer:

Maritime Mobile Service Identity (MMSI) numbers are a series of nine digits, used to uniquely identify a radio station or group of radio stations.

Ian Lockyer is marketing manager at ICOM (UK) Ltd and is a leading expert in marine radios and communications

When sending a DSC message the MMSI is automatically included, and you can address messages to specific vessels or groups using their MMSIs.

In the UK MMSIs are assigned as a part of the ship’s radio licensing.

All marine VHF, MF and HF radios require the user and vessel to hold a relevant licence.

The vessel’s licence is like a car tax disc, but it is also the key to obtaining an MMSI number.

You can obtain an application form for a ship’s radio by applying via: ofcom.org.uk

Ian Lockyear is marketing manager at ICOM (UK) Ltd and is a leading expert in marine radios and communications

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