Virtual AIS set to grow


Organizers of the recent America’s Cup races in San Francisco Bay had an important task: keeping spectator boats away from the race course. This need was heightened by the high speeds of the foiling multihulls in the race; the potential for a nasty high-speed collision was real. One tool used to address this problem was virtual AIS: a local AIS beacon station broadcasts race boundary lines that appear on spectators’ electronic charts.

It is a technology that can do much more than show boundary lines. Virtual AIS can be used to show “area special messages,” shapes and zones that mark temporary hazard areas, anchorage areas, security zones or a variety of other information.

The company leading the charge in virtual AIS is Vesper Marine from Auckland, New Zealand. It was a Vesper Virtual AIS Beacon that provided the virtual race course boundaries in San Francisco Bay for both the America’s Cup challengers series and for the final cup races between Oracle Team USA and Emirates Team New Zealand.     

The control center where virtual AIS lines were generated for the America’s Cup boundary marks.

Race course boundaries are just one of the latest uses for virtual AIS. This technique has been deployed in New Zealand for the Port of Auckland, for bar entrances that change frequently and for remote coastal areas. Vesper Marine CEO Jeff Robbins wrote in an e-mail that, “virtual AIS is being used in Africa and Australia in industrial operations for mooring, barge and underwater asset identification and offshore asset deployments.”

One of the original applications for virtual AIS was for aids to navigation. In places where it was difficult or expensive to place a buoy, AIS broadcasts could be used to put a virtual buoy or other aid to navigation on an electronic chart. An early application of this approach was at the wonderfully-named Doubtful Sound, a remote location on New Zealand’s South Island. The Doubtful Sound beacon displays a virtual buoy to warn mariners away from the dangerous Tarapunga Rock. Attempts to place a physical buoy at this location have been thwarted by big seas, which can grow to 20 feet. A virtual buoy, however, is always on station and doesn’t suffer wave damage.

Another intriguing use of AIS is for towing applications. Seismic vessels used in oil exploration stream towlines behind them with arrays of sensors. These towlines can be miles long. The exploration company wants to prevent other vessels from running into the expensive equipment in their towline. A virtual AIS beacon on the tow ship helps avert this type of accident by broadcasting the location of the tow elements. Other vessels can see the length of the tow and avoid crossing the towline.     

After demonstrating the capability for doing individual buoys, the next step was to draw lines and area shapes on the chart. According to Vesper’s Robbins, the IMO has set out procedures for how various shapes should be drawn using positions and angles. These shapes range from circles to rectangles to polygons. They can designate a wide variety of special maritime zones.
During the recent America’s Cup races in San Francisco Bay, Vesper Marine invited representatives from the Coast Guard, the San Francisco Police Department, the Port of Oakland, the Alameda County Sheriff’s Office, and the Port of San Francisco for an on-the-water demonstration of what virtual AIS can do not only for designating bridges, piers, rocks, reefs and other fixed underwater hazards, but also for displaying zones on a chart. The Coast Guard calls these Area Special Messages (ASMs). “The Coast Guard is quite interested in this,” said Robbins. “They want to use this for a variety of things, from safety zones at events to a lot more.” Watch for a wider implementation of ASMs in the future.

Virtual AIS has big advantages in terms of added functionality for mariners using electronic charts. The technique also has advantages in lowering costs for maritime authorities since virtual buoys, markers and zones made of pixels cost much less than aids to navigation made of steel and plastic. Given the reduced expenses of the virtual approach, will we see a gradual replacement of physical aids to navigation with virtual ones? Robbins doesn’t think that will happen any time soon, “I’m not leaning that way,” Robbins said. “They [virtual AIS] won’t eliminate buoys but will augment aids to navigation around the world.”    

By Ocean Navigator