Hi John- Yes, normally we would see that, but with a slow speed on a small-scale chart, the predictor is very short; thus it was missed. In thinking about this, our eyes tend to give precedence to the triangle unless the predictor is sufficiently long. My point is that complacency with only a cursory look (pun intended), and then seeing what you expect to see, can be dangerous. Some forty years ago while working as engineer on a ferryboat, I had the pleasure of serving under a captain whose landings were so consistent I never had to look at the telegraph, although I usually did, as he always rang the same exact sequence of orders. One day, he rang up something different, and I gave him "the usual" instead. Fortunately, my oiler was on the ball and noticed the difference in time to avoid an accident. An aside - this captain had served 35 years on a CG buoy tender and possessed pilotage from Calais, ME to Boston - over 1500 miles of coastline. Regards, John > I'm used to seeing a projected course track that extends outward from the target, the distance proportional to the ship's speed. At least that's how Furuno displays show it when using the Furuno AIS. Very handy, as you can graphically see where the target is going to cross your course line. Not sure if all units work that way or if that would also have been confused by the tug. John Marshall N5520-Serendipity On Jun 3, 2007, at 5:39 PM, Truelove39@aol.com wrote: > As we proceeded up the Hudson River today, a tow hove into view > ahead. > Penny, at the helm, noted that he was upbound, too. After a few > minutes, I looked > up and observed that the tug was not only closer but behind the > barge; he was > in fact, downbound. A glance at the AIS display (on CE) showed the > triangle > symbol facing the wrong way! Further investigation showed that all > the data > was correct, including course, but his heading was fixed at 17 > degrees! So we > learned something today, fortunately not the hard way: a simple > glance at > that elongated triangle may not always tell the truth! > > Regards, > > John > "Seahorse" > ************************************** See what's free at http://www.aol.com.