What type of ships show up on an AIS display, and what doesn ?
Class “A” AIS is mandatory on all ships of 300 gross tonnage and upwards engaged on international voyages, cargo ships of 500 gross tonnage and upwards not engaged on international voyages and passenger ships irrespective of size. See the US Coast Guard web page on AIS for more information. Other smaller commercial ships, such as fishing vessels, will equip themselves with Class B AIS transponders such as the Comar CSB200 voluntarily since there are major safety benefits to using AIS. Naval ships are currently not required to carry AIS, neither do rocks, small ships and pleasure craft (under 300tonnes!) Don’t be misled by descriptions of “AIS Radar”.