I have a BoatUS MMSI number I’m told I need an international MMSI number for my AIS in order to go to the Bahamas I applied for a FCC number and was told is $220 could that be true or am I using the wrong form please help. What would happen if I used my boat US MMSI number with my AIS and did go to the Bahamas?
Technically, it's illegal to not have a Ship's Station license, and a Radio Operator's license when visiting other countries. Can you get away without it? Maybe? Probably? You call, but that's what the $220 is buying you, and you get an international MMSI along with it.
The advantage of an international MMSI is that your boat info is in an international search and rescue data based, so if your DSC alarm goes off, they can look it up and see your boat details, contact info, etc. That can help head off a false alarm, and/or aid in finding you since they know what sort of a boat they are looking for.
If you have a BoatUS MMSI, your info goes into a domestic database only, used for the same purpose.
That said, if you trigger your domestic MMSI somewhere else in the world, it will be heard and won't be ignored. SAR will just be at a disadvantage not knowing what they are looking for.
Also keep in mind that if you get a different MMSI, your VHF(s) and AIS will have to be reprogrammed, and that typically involves returning them to the manufacturer or a repair center, and often a service fee.