That is because no one is in Somalia receiving the information and sharing it on this network.
The parent has a valid point. If AIS (Automtic Identification System) is being broadcasted by ships that traverse the area around Somalia, pirates could indeed decode these transmissions using a simple VHF radio and free associated software, and literally have a map of detailed locations of all broadcasting ships within about 25-50 miles of the receiver (VHF is typically line of sight)
This is just AIS Live. AIS (Automtic Identification System), or UAIS (Universal AIS) is now required by law on all vessels over 5000 tonnes. The original idea was to help prevent collision at sea under the SOLAS (Safety of Life at Sea) convention. It uses self-organised time-domain multiplexing to broadcast GPS Lat/Long (usually WGS84) and current SOG (Speed over Ground) and COG (Course over Ground), augmented by heading, cargo, port of departure, next port of call, and waypoint information.
It also broadcasts the ship name, registration number, physical size, tonnage, loading and other information.
Interestingly, although it's required by law that it be carried, it is not required by law that it be turned on.
Note, the above is all from memory, and some may be a little out-of-date or inaccurate. It's close enough to give you the idea, and if you want more accuracy it's easy to look up.
The captain of the marine salvage ship Odyssey complained about this system on one of the Treasure Quest TV episodes because it allows competitors and amateurs to know the location of his ship. He has to employ countermeasures, such as not staying over the location of a promising site for too long. That suggests it cannot legally be turned off.
"Ships fitted with AIS shall maintain AIS in operation at all times except where international agreements, rules or standards provide for the protection of navigational information."
Yes, but in international waters there are no real sanctions, and no patrols to check. When closer to shore it sometimes gets checked, but in my experience very few vessels are caught, and even fewer are fined, if their AIS is simply off.
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[ 4.7 ms ] story [ 30.0 ms ] threadThe parent has a valid point. If AIS (Automtic Identification System) is being broadcasted by ships that traverse the area around Somalia, pirates could indeed decode these transmissions using a simple VHF radio and free associated software, and literally have a map of detailed locations of all broadcasting ships within about 25-50 miles of the receiver (VHF is typically line of sight)
It also broadcasts the ship name, registration number, physical size, tonnage, loading and other information.
Interestingly, although it's required by law that it be carried, it is not required by law that it be turned on.
Note, the above is all from memory, and some may be a little out-of-date or inaccurate. It's close enough to give you the idea, and if you want more accuracy it's easy to look up.
http://dsc.discovery.com/tv/treasure-quest/ome.html
From "The December 2002 amendments" http://www.imo.org/Conventions/contents.asp?topic_id=257&... (about 2/3 of the way down)
However, the amendment is news to me - thank you.