Ron wrote: You can always check vessels in radar range. In decent weather, we've got binoculars. John used his eyes to correct the AIS data.> And yes we do. However the point is you have AIS, which is mandated for all boats over 300 tons and passenger carrying vessels. Then they are being short changed if the data is bogus. For them...is it better to not have it and use more traditional methods or have it and need to question the correctness of every target? It would seem, if I were on the bridge, I'd take the former stance...however that stance means now I'm not using what has been mandated so I'm automatically in the wrong. The load of BS paperwork is already distracting the watch officer's job on most ships. Do we need another layer of this. Ships owners seem to think that a person just standing watch should really be doing something useful vs. just standing there looking around making little check marks on a chart or log....my what a waste of manpower and money!! This will soon all scale down to trawlers and the like very soon. VTS areas are already asking for better identification of all traffic....what better way than AIS...if it works smoothly. The Homeland Security boys want to know who is approaching and what they're in, where they are coming from, where they are headed. What better way than AIS? We all have to report up to our arrivals in Ports now, in some case up to 96 hours, wow wouldn't the authorities like to have AIS to make sure we don't get there and anchor out waiting for the clock to tick...what better way than AIS? Sooooo we'd all better get used to AIS and learn what we can and how we might be able to get it improved so at least we can rely on the data we receive and transmit. As always YMMV.... Cheers Dave & Nancy Swan Song Roughwater 58 Caribbean Cruise '07