Saw a tug with tow going inter island. The AIS gave nothing but the GPS data. To me, tugs with tows are the most dangerous vessels because it's real easy to miss the not so bright lights on the barge and sail between the vessels with interesting results. A real mariner would know what the vertical white lights mean. Unfortunately, there are a ton of boats out there with crew that know little more than how to start the engines land be entertained by the pretty pictures on their instruments. There should be some enforcement by the CG that commercial vessels properly program there AIS.