It's good to get some solid hand's on time with the Vesper WatchMate AIS plotter, which I admired when it first appeared, then as it got a built-in receiver option, and finally as seen live in Miami. And, yes, that is the 750 foot deep water drill ship Stena Forth now anchored in Penobscot Bay for an amazing warranty repair, mentioned in comments this week and to be explored further. But for a really vivid example of why Vesper's sophisticated AIS alarming is valuable, consider the Bermuda Race fleet crossing the shipping lanes last night...You may recall that the Siitech Pro AIS Web viewer shows Class A's as classic triangles and B's as boat shaped targets, and that a year ago we pondered about how they're seeing 2 watt B's over 40 miles from any possible shore station. At any rate, I watched a Buzzard's Bay bound ship run right through the fleet last night and I'm guessing a lot of navigators learned how many controls you need to make AIS alarms effective rather than annoying.
Which is what the WatchMate is so talented at. Its many alarm parameters, and also the profiles you can customize for different situations are discussed in those earlier entries, and of course at the Vesper Marine web site. I can tell you that they are all pretty easy to manage on the little screen, which is also notably power efficient. I also cabled (NMEA 0183) the WatchMate to a PC running the latest version of Kagstrom's AIS Simulator, and while it didn't seem to understand SAR aircraft, it did pop up a special alarm for an AIS SART, which will become much more common once SRT's new little module rolls out.