With the advent of digital selective calling (DSC) in marine radiotelephones, and with the advent of automatic identification system (AIS) transceivers of lower cost and Class-B mode, the recreational boater has been introduced to a new concept for identification of his vessel, the marine mobile service identity or MMSI.
In DSC radios, the MMSI is like a telephone number, and it allows selective calling to one particular radio by another radio. This removes the need for continual monitoring of the calling channel, 156.800-MHz or Channel 16, listening for calls directed to your ship, and instead your ship (actually its radio) can be individually called by another ship (by its ship radio).
In AIS, the MMSI is a ship identifier that can be quickly transmitted, to uniquely distinguish one vessel from another, as the ship broadcasts information about its movements, such as course, speed, and heading, which can be sent as frequently as every two seconds.
The initialization of a DSC radio or an AIS transceiver with the ship's MMSI, by design, is limited to a single opportunity. Once a DSC or AIS device has been configured with a ship's MMSI, that encoded identity cannot be changed by the user without assistance from the manufacturer of the device. The motivation for this limitation is not particularly explicitly expressed in any regulation or recommendation, but the rationale can be inferred: making changing of the MMSI by the end user impossible without out assistance from the manufacturer prevents accidental and unintentional modification of the the MMSI or identity of the vessel while in general use. A further reason is that the intentional alteration of the MMSI in order to disguise the vessel or to impersonate other vessels is also made more difficult.
A further feature of the MMSI as an identifier is that the person who registers the vessel initially (the registrant) to obtain an MMSI from an issuing agency becomes closely associated with that ship as a point of contact, should a situation arise in which marine authorities want to contact the ship owner. Such an instance could arise in the case of a broadcast of an emergency condition from the ship. Authorities may want to reach the registrant of the MMSI to inquire about the location or status of the ship as a means to verify there is an actual emergency taking place.
As a result of the intentional permanent nature of the MMSI in ship radios and AIS transceivers once entered, the general concept of the MMSI is that the MMSI is associated with the ship, and not associated with an individual person who registered the ship when the MMSI was obtained.
This concept works well in the case of ships that do not change owners frequently, particularly if the change in ownership does not mean a change in the country flag the ship will be sailing under. But for recreational boats, there is a much higher chance that a particular boat that has been identified with an MMSI might be sold to a new owner. When this occurs, the new owner will need to modify the original registration details to indicate this change in ownership, particularly to identify himself as the registrant and point of contact for the boat.
When buying a used recreational boat that has DSC and AIS gear aboard, as part of the purchase process the buyer should coordinate with the seller to get information from the seller about what agency was used to for MMSI registration, and to work with the seller to notify that agency that there needs to be a modification to the registration to reflect the new ownership of the boat. Typically the previous owner will need to notify the MMSI-issuing authority that he is no longer the owner, and to then coordinate the process of transferring the registration to the new owner.
If required coordination with the previous owner was not part of the purchase agreement--for example, by holding back an amount of the purchase price to be contingent of getting that coordination, then changing the registration without coordination can be difficult.
I will explain several options that can be useful to remedy the problem of newly purchased used boat already having been configured with a marine mobile service identity (MMSI) that is not associated with the new buyer as the registrant.
FIRST OPTION
The first option to remedy the problem is to contact the MMSI issuing authority that created and registered the MMSI. From there you will workout the mechanism to change the registration to be in your name and contact information, without involvement of the former owner. In the USA this process is a bit awkward unless the MMSI was issued by the FCC. A general indicator of the MMSI being issued by the FCC is the number ends in a zero.
If the current MMSI ends in a zero, you can look up the registrant in two ways: you can use the FCC ULS search to find the name of the licensee, as typically if the trouble was undertaken to get an MMSI from the FCC then a SHIP STATION LICENSE was also issued; or, you can look up the ship name or other identifying elements using the ITU Ship Station search feature.
If the MMSI does NOT end in a zero and the boat was registered in the USA, that is a general indicator that the issuing agency was a private MMSI issuing agency. For excellent advice about how to contact an issuing agency in the USA or how to search for an MMSI, please visit the FCC website at
FCC MMSI Information
https://www.fcc.gov/wireless/bureau-divisions/mobility-division/maritime-mobile/ship-radio-stations/maritime-mobile
and read the advice given there. The cited page contains links to various resources you can use.
SECOND OPTION
If the original registrant of the MMSI is not known or cannot be contacted or is completely unresponsive, and you cannot find the registering agency, or the registering agency won't modify the registration without consent of the original registrant, then you can move to the next option, which is to obtain an new MMSI, abandon the current one, and try to reprogram the existing radio to have the new MMSI.
But before going further, the type of MMSI you should obtain needs to be determined, as it depends on the nature of your use of the boat. If the boat will go NOT to foreign ports, will NOT contact foreign shore stations, and is NOT required by any USA regulations to be mandatory-equipped with a radio, then your ship station is licensed by rule, and you can get a new MMSI from a private-issuing authority. You can find such an agency using the links to the FCC page given above.
For more details of what type of licensing you need for a ship radio, refer to this article:
FCC Licensing for the Maritime Radio Service for Recreational Boaters
https://continuouswave.com/forum/viewto ... 938#p45819
If the nature of your boating does not meet the three exemptions needed, you will have to get a SHIP STATION LICENSE from the FCC and at the same time you can get an MMSI from the FCC for no additional charge. This will cost about $220 for a ten year license authorization, and require you to complete a lot of rather confusing paperwork from the FCC. If you do this you should also get an OPERATOR'S LICENSE or a RESTRICTED OPERATOR'S PERMIT at the same time. The permit option is usually issued for the lifetime of the operator. The fees are relatively modest, about $65.
Once you have a new MMSI you can attempt to change the MMSI already in the radio. The general recommendation regarding changing the embedded MMSI in a DSC radio is that such that a change cannot be done without "advice from the manufacturer." This suggests you should contact the manufacturer for advice.
In terms of changing the MMSI in a radio that has already been programmed with an MMSI, the best outcome will be the manufacturer will provide you with advice that allows you to change the MMSI yourself. This service is often provided at no charge or for a modest fee and may be available, but it depends entirely on the particular manufacturer of the radio and the particular model of the radio. Recent DSC radios from Standard-Horizon support allowing field modification of the MMSI by use of a special password or key provided by the manufacturer that is unique to a particular radio and its current MMSI.
A worse outcome will be the manufacturer tells you must physically take the radio to an authorized service provider to get it changed for a fee.
The worst outcome will be the manufacturer tells you to ship the radio at your expense to their factory, and prepay a hefty fee to have the manufacturer erase the existing MMSI and reset the radio to an initialization state where you can enter a new MMSI, and the charges and shipping costs will approach or exceed the cost of a new radio—which is another option.
Another possible outcome is you can find some information from non-manufacturer sources that reveals an otherwise hidden process for changing the MMSI in a DSC radio of a particular brand and particular model by use of a generally obscure procedure of holding down buttons during power-on and entering secret codes.
As for changing the MMSI in an AIS transceiver, advice from the manufacturer will again be necessary. At this writing I am not aware if there are any manufacturers and models of AIS transceiver that provide the ability to have the MMSI changed in the field by the user. Generally a change in the MMSI in an AIS transceiver will require returning the device to the manufacturer. For this reason, staying with the original MMSI and just modifying the registration is a much preferred approach.
THIRD OPTION
If you decide to abandon the existing DSC radio or AIS and get a new DSC radio or AIS, you can then enter into the new DSC radio or new AIS your new MMSI. When you perform this procedure be very careful; typically you can only enter the MMSI once, so be sure to get it correct.
MMSI Registrant Changes
Re: MMSI Registrant Changes
Good advice, JimH. I recently purchased a Standard Horizon handheld on a whim and every time I power it up it asks me for a MMSI. I bypass it. I have one for the fixed base radio on the boat but it is going to be replaced soon with an AIS capable radio. It will also require an MMSI. I guess my question for you is: does the MMSI pertain to the boat or the individual radio. Can a boat with multiple radios use the one MMSI? Thanks for bringing this up by the way..