I guess since the sub was only 40GT (gross tonnage) it didn't have an Automatic Identification System (AIS) on it only ships over 300GT require an AIS. Even if

I guess since the sub was only 40GT (gross tonnage) it didn't have an Automatic Identification System (AIS) on it only ships over 300GT require an AIS. Even if it did I wonder if an AIS operates separate from the ship's radio system. You can track ships by their AIS and some website sell historical data to show where a ship has been. https://www.marinetraffic.com/en/ais/home/centerx:10.2/centery:56.1/zoom:6 https://www.marinetraffic.com/en/ais/home/centerx:10.2/cente...