AIS near miss, Malacca Straits, part 2

Valhalla screen shot

It’s great that Terry Sargent has joined our discussion about the AIS-documented near miss he had in the Malacca Straits. I really admire his desire to thoroughly debrief his experience, and his willingness to share it with the rest of us. Terry has also expanded his web page about the AIS hardware and software he’s using. Above is a clip from a screen shot he took while transiting the Singapore Straits, with the red circle added to highlight Valhalla and the nearby passenger ship Megastar. He notes that his SOB freeware is calling the collision potential “VERY HIGH” even though he and the ship are almost beam-to-beam during a standard port-to-port pass. That just means that the logic behind SOB’s warning is imperfect. Note also that SOB’s AIS data window is unusual in that it lists CPA as a position with a separate DCPA to give the distance between vessels during the CPA and also DTG for the distance to go (until you arrive at the CPA). Calculating just CPA (as distance) and TCPA is the norm. SOB is trying to give as much information as possible, which is admirable, and I’m sure a user would get used to its style. By the way, here are some more AIS screenshots—this time using Nobeltec on the North Sea—posted by a Kees Verruijt on his Scanner 391 site.

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.

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