Prophet and (no) loss – despite the AIS report

n My AIS unit apparently reported my boat Prophet leaving its home berth in Buckler’s Hard Marina on the Solent without me on board. (I have a MarineTraffic account and email alert setup to report instances of Prophet leaving or returning to any port.)

I was immediately concerned that the boat had either been stolen or had broken away from the pontoon and somehow activated its AIS system. Neither of these seemed likely, but because I live about 90 minutes’ drive away, and Buckler’s Hard is unmanned after 8pm (so I couldn’t get them to check), I wanted to confirm whether this AIS reading was correct or if something was wrong.

About two hours later I received a further AIS signal from Prophet arriving in Berthon Boat Company Marina in Lymington, which was plausible: it was about a two-hour motor away, so now I was really worried. It looked pretty conclusive that my boat had indeed been stolen, so I contacted Solent Coastguard to see if they could verify the AIS signals. They confirmed the location of the boat and contacted Berthon Marina to see if their nightwatchman could find the boat, given the precise nature of the AIS contact location. However, it was a stormy night, and he couldn’t locate it.

The Solent coastguard’s advice was to file a missing boat report to the local police in Hampshire, which I did. They were very helpful, but said the most likely explanation was ‘phantom AIS data’, which I very much hoped was true. I managed to get hold of Kate, the harbour master at Buckler’s Hard, at 8am the next morning and she checked on the boat: it was there in its berth, and probably hadn’t moved all night. This was a big relief, so I contacted the police, cancelled the missing boat report and informed the Solent coastguard that the boat appeared not to have moved.

All this time I was unable to get hold of anybody at Marine Traffic to check the nature of these signals. I filed a bug report with them the next day to see if there is any way to confirm, or rule out, the accuracy of AIS data.

MarineTraffic are clear that the AIS data could have errors in it, but with AIS being such an important information system we really should have a mechanism to verify data that we suspect may be incorrect, surely?