AIS tracking websites
Various websites offer AIS (Automatic Identification System) ship data, on which current and historical data of ship positions and movements can be consulted. Popular sites include MarineTraffic, FleetMon, VesselFinder, and Vesseltracker.
Such websites base their information on the data that AIS transponders of ships transmit via a radio signal. Ships can thus see additional information about each other on an electronic map or a radar screen. Two channels in the marine radio band are reserved for this purpose. Satellites and receiving stations on shore send this data via the internet to the websites.
For large seagoing vessels, such an AIS transponder is mandatory, other vessels can choose to have one on board.
AIS transponders transmit a number of fixed and variable data of the ship, which are important for safe navigation (for example: identification code, ship name, dimensions, course and speed). The identification code that is used is the MMSI number. This number is assigned for Bonaire, Sint Eustatius and Saba by the RDI in the Ship Station Licence.
The MMSI number consists of 9 digits, of which the first three form the country code. In the case of the Bonaire, Sint Eustatius and Saba islands, the country code is 306. This country code is the original code that was assigned to the Netherlands Antilles (without Aruba). Because the number of available numbers is scarce, the International Telecommunication Union did not want to assign new country codes and the series 306 has been divided among Curacao, Sint Maarten and the Caribbean Netherlands (the BES islands)
Country code CW
RDI sometimes receives questions about ships of Bonaire, Sint Eustatius and Saba that are shown on AIS tracking websites as originating from Curacao (CW) as flag state. RDI has sent several emails to various websites in recent years requesting that this be changed and that the flag state be based on the combination of MMSI number and call sign, but without success. The official list of country codes can be found here.
Other AIS identifications
There are also other AIS stations, which can be recognized by the different format of the MMSI numbers (MID is the country code, X is a number between 0 and 9):
- 00MIDXXXX: Shore stations, such as coast guard radar stations;
- 99MIDXXXX: Aids to Navigation (AtoN), obstacles at sea, such as windmills, buoys and wrecks;
- 111MIDXXX: Search and Rescue aircraft.