In any month, half the tanker fleet has gaps in AIS data transmission. This does not mean all these tankers are operating in the dark, explains maritime analytics company Windward
In an analysis of tanker AIS transmissions in October 2019, maritime analytics company Windward found that half the tanker fleet had gaps in their AIS transmissions. On average they had seven separate instances of AIS transmission gaps with a typical duration of eight hours.
Windward reports that these gaps are often not deliberate and are caused by:
As AIS is a one-way radio signal, it is not possible to ping the transmitter to inspect the status remotely. Furthermore, there is nothing illegal in switching off AIS. Fitting an AIS transmitter is required but using it is voluntary.
The problem with AIS gaps is that they are an indicator of possible nefarious activity, and prompt compliance professionals to investigate if the AIS gaps are a potential risk. For each gap they identify they need to escalate the case, to manually investigate the likelihood of the vessel making a port call in a sanctioned country, or meeting with a sanctioned entity during that time. This is a time- and labour-intensive process when dealing with a large number of tankers.
Deliberately switching off AIS may also be done for safety, such as when tankers transverse pirate-infested waters (Horn of Africa) or to avoid detection by Iran or its proxies when making a passage through the Straits of Hormuz. The problem for compliance teams is weeding out the gaps and spotting the dark activity which could be:
Hear more about using big data in shipping operations at the Optimised Ship Forum, London, 10 December 2019