Safe at Sea: What is AIS and why is it valuable?
A few years ago (certainly “pre-Covid”), we were on an Asian cruise that took us in and out of Singapore on a series of eastern and western “loops” throughout southeast Asia. A pure stroke of luck put us in a cabin whose balcony overlooked the rear of the ship, offering a 180-degree view throughout the trip. An unexpected highlight was entering and exiting the port of Singapore, one of the busiest global ports of call.
One very foggy dusk, we sat on the balcony mesmerized by both the volume and the proximity of marine traffic. We could see easily 30-plus ships of all sizes surrounding us, moving into and out from port. Our ship, clearly the largest fast ship, passed all manner of boats/ships, one as little as a 30-foot sampan to lengthy tankers/cargo ships to all sizes between. I’d never seen anything like it, and I couldn’t help but wonder how this was being managed.
I learned exactly how this was done. First, we were traveling in a “traffic separation scheme” (TSS), which is a highly structured multi-lane route in and out of a specific destination. In reality, it reminded me of Route 10 outside Los Angeles — a 10-lane (actually 20) interstate in California. Except in the TSS, there were side-by-side reverse routes. Make sense?
All of this is a long introduction to a critical marine system that makes traveling in very busy waters safer: Automatic Identification System, or AIS.
AIS transmits a ship’s position so that other ships are aware of its position. The International Maritime Organization and other management bodies require large ships, including many commercial fishing vessels, to broadcast their position with AIS in order to avoid collisions.
AIS is intended, primarily, to allow ships to view marine traffic in their area and to be seen by that traffic, as well. This requires a dedicated VHF AIS transceiver that allows local traffic to be viewed on an AIS-enabled chartplotter or computer monitor while transmitting information about the ship itself to other AIS receivers.
All AIS transceiver-equipped traffic can be viewed this way very reliably but is limited to the VHF range, about 10-20 nautical miles. However, when traveling in a heavily traveled route and/or especially when traveling at night, AIS is invaluable.
How else is AIS valuable?
– Collision avoidance (obviously)
– Fishing fleet monitoring/control
– Maritime security
– Search and rescue
– Accident investigation, et cetera
Visit MarineTraffic’s Global Ship Tracking Intelligence at https://www.marinetraffic.com/. What will appear on your screen is the capacity to view — worldwide — all AIS-equipped vessels. By hovering over any vessel’s icon (seen as an arrow indicating the direction traveling), information will appear as to the ship’s purpose (tanker, pleasure cruise or cargo), the ship’s name and other identifiers.
When I did so, I couldn’t resist moving the map to Singapore and — once again — marveling at the TSS and sheer volume of marine traffic. And AIS made the entire system work safely and efficiently.
Pat Schmidt is a member of America’s Boating Club of Sanibel-Captiva. For more about the chapter and its courses, visit www.sancapboating.club or contact education@sanibelcaptivasps.org or 612-987-2125.