Ah, but that doesn't apply in the UK where we need no registration at
all for the sea and if I gave out my local lake registration when on the
sea, it would mean nothing to anyone else. Sure I could just make up a
name, but I wondered if there was any proper procedure...
--
Nick

Could easily be that much of what I included in that article does not apply in
the UK.

Another way to identify your boat would be
"This is 17-foot motor vessel off your starboard bow" if hailing a boat that is
in sight.

If calling for assistance ona Mayday, you might say, "This is an unnamed
vessel. We are 21 feet, LOA, white with green canvas, located at
................"