Real world AIS B #3, jumping bean plots

AISB_Spirit_Bermuda_cPanbo crop

So somehow when I was actually plotting Spirit of Bermuda’s Class B AIS output in Hamilton Harbor my screen shots failed to save. But I still have the marks I made every time its plot updated and you can sort of see the jumping bean effect that results from Class B’s 30 second update rate. I connected them with route lines so you can get a better sense of scale, bigger here. As discussed earlier, a 30 knot boat is going to plot every .25 nautical miles; Spirit at 9 knots plotted at about .07 mile increments. It was a little disconcerting, especially when she made large course changes rounding up to a pier. (And, by the way, would have been twice as bad if I had been using a single-channel-at-a-time receiver). But, again, I still think Class B is valuable regardless, plus I figure some smart developer(s) is going to figure out a way to dead reckon these targets in a way that’s not confusing.
   Finally, small world department, Spirit was built only a few miles from Panbo HQ at Rockport Marine, and we watched her launch from the bridge of Shanghai Baby last August, as noted in an article just published in PMY.

Ben Ellison

Ben Ellison

Panbo editor, publisher & chief bottlewasher from 4/2005 until 8/2018, and now pleased to have Ben Stein as a very able publisher, webmaster, and editing colleague. Please don't regard him as an "expert"; he's getting quite old and thinks that "fadiddling fumble-putz" is a more accurate description.

1 Response

  1. Ben,
    I’ve automated the screen capture process using the Snagit program, available at
    Since using it I’ve never lost a capture!

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