The Automatic Identification System (AIS) was originally conceived as a means of inter-ship identification, so that one vessel, perhaps on a collision course with another could ascertain its identity and communicate positively, as it provided its name, course and speed. But it quickly was seen as a far more versatile tool, which would be enormously useful to Vessel Traffic Services, in port approaches or narrow channels, with an operator being able to positively identify an echo on his screen.
Then it was realised that AIS would also be very useful in identifying and tracking ships in the waters of a coastal state, particularly ships which needed special attention as they represented a safety or pollution risk. Rather than having a busy officer of the watch trying to raise a coastal radio station and report his position, this would be automatically ascertained and the OOW could concentrate on his navigation.
It was also realised that the ability to identify passing ships could be enormously useful for traffic planning by coastal states and navigational authorities who needed to have a better idea of the traffic that was passing. And while the numbers of ships could be discovered from radar monitoring, until AIS came along there would be no indication of the identity of the various radar echoes. Once the identity is established, the characteristics of the ships can be easily determined, and a better idea obtained of their navigational needs. For instance, if AIS revealed that a large number of deep draughted ships were concentrating in a specific place, it might be possible to enhance the aids to navigation to keep these huge ships safer.
It might, after AIS information had been studied, put the case for a traffic separation zone, or an existing one to be changed to make it more user-friendly. And AIS can also be installed on buoys, beacons and other navigational marks, making their identity obvious when seen on a ship’s radar. It has been suggested that the advent of electronic charts might make it possible to have AIS signals representing a “virtual” navigational mark, something that is of interest in places like the Arctic, where ice makes it difficult or even impossible to station conventional aids to navigation.
The identity of a ship and its position can also be of great interest to a range of shipping professionals. It could provide a useful proof to Customs that a ship has not moved outside a particular region, and thus can dispense with some of the arrival paperwork. Agents and port authorities can more accurately plan for a vessel’s arrival, if they know where it is precisely, without harassing the Master for Estimated Time of Arrival information.
