Recently, two merchant vessels collided in the Bay of Biscay about 250 miles from Land’s End. One of the vessels began taking on water and its crew of seven took to two life rafts before the vessel sank.
When we investigated, exactAIS® had picked up the track for the one of the vessels without any problem, however, the other vessel was strangely lacking in data. In fact, the last time we had picked it up was on November 30th and then again on December 9th, after the incident had already taken place. Is it possible the AIS transmitter was turned off and then turned back on after the collision?
I believe the condition of the AIS unit should be checked, in particular the output power. It is also of note that a Tanker is required to go to 1W while in port, it could be that this unit was put in low power operation and never reset back to high power.
Sometimes the lack of data can be just as interesting and puzzling as having a wealth of data.