Panbo

Capn Voyager, playing AIS chicken over IP

... written for Panbo by Ben Ellison and posted on Feb 13, 2006

CapnAIS crop

That yellow vessel with the bold range rings is Capt. me off Boston a couple of days ago, or at least a simulated Capt. me. But the AIS targets were real! That’s because at least this beta version of The Capn lets you get AIS targets off the Internet, in fact comes set up (see below) to get all the receivers being streamed by SeaLinks (which includes Penobscot Bay, my home waters). The feature is not something you’d use at sea, but it sure is useful for seeing how an ECS handles AIS targets. For instance, I really like the way the Capn plots the actual CPA; for the target ahead it’s that little (167 yard) dotted under the the 2nd range ring. It helped me understand better what the pass was going to look like, and being prudent, I decided to turn another 20° right.

Notice, by the way, how The Capn lets you turn off anchored and docked targets. It makes sense but watch out. When I checked out Penobscot Bay this afternoon, the towboat Penn #4 was doing 8 knots off Monhegan but broadcasting “At anchor”, while Penobscot, doing .01 knots at a pier in Rockland, was labeled “Underway under power”. Garbage in, garbage out!

Capn AIS dialog

Comments

I'd say at least 70% of the vessels using AIS over in this part of Asia forget to change their Navigational Status when they start (or end) their voyages. So, sounds like a very dangerous thing to turn off these vessels. At a minimum the software should allow you to turn off vessels with a stationary Navigation Status AND speed of 0 or slightly higher to allow for swinging on the anchor.

Posted by: Dave at February 14, 2006 1:09 AM | Reply

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