Like anything, but this is how the CG would like to see it in the perspective of having to come rescue, the more they know the better prepared they can be. Also they were insistent on me knowing that 45 KM off shore and this is totally mute.
There you need to be using high frequency unit or SSB and those should be the same as your main MMSI number, again if in a bailout situation once you leave the vessel way off shore you are on your own and if out of VHF limits it gets harder. Thats where EPIRB comes in, and or PLB. Again these numbers should and are usefull to the CG in tracking and knowing who and what they are dealing with along with sail plan, they would know if your intended desti was bermuda or bahamas or where ever, they will and plan search and rescue based on your filed sail plan, so there is some redundency in this approach.