We know that information about antenna placement is part of static data on AIS even on our Class “B” sets. However, we cannot access this data at all. I assume that CPA calculations on all type of AIS sets are done as if both vessels were mathematical points located at their GNSS antennae – is this correct? And do you have access to antenna location data on your AIS sets?
I guess it’s not of practical importance so long as you are always crossing with everyone at a sufficient safe distance that the exact location of the antenna is not significant, but it’s still an interesting question.
It was hammered home to me last summer when I was sailing through an anchorage in the German Bight (waiting area for Weser/Bremerhaven) last summer. Weather was fine and calm, and I thought a cable would be enough from a very stationary anchored ship. Well, a cable from his antenna is NOT indeed a cable from the bow of a big tanker! Fortunately this became quite apparent in good time