Sometimes when I've called ships to ask if they could see my Class B transponder, it's taken a few minutes for someone on the bridge team to look it up. In other words, don't presume that a transponder-equipped ship will necessarily see your transponder-equipped boat, not because they've turned you off, as the legend purports, but because they don't yet have A.I.S. overlay on their primary plotter and radar screens. But this, too, shall pass.
The I.M.O. is working on mandates for such A.I.S. integration along with guidelines on how to do it well. And some of those good ideas are already being borrowed by the recreational marine-electronics developers. A Garmin update last summer, for instance, started treating targets as either Active-a bold icon with name, heading line, and speed-or Inactive-a small, simple, nondistracting icon. A user can activate a target manually or let it happen automatically when its C.P.A. comes within a user-set threshold, which also turns the icon red and graphically marks the C.P.A. spot. This plotting scheme works quite well, minimizes clutter, and will, one hopes, become common, but Garmin still needs to add several parameters so users can avoid unnecessary and irritating A.I.S. audible alarms. You don't need to be buzzed, for instance, just because you putter close to a docked vessel with its transponder on.