Avoiding an AIS traffic jam

Sometimes a new technology can become a victim of its own success. The automobile was a great invention — but think of how often you find yourself in a traffic jam because there are so many cars on the road. A marine invention like the automatic identification system (AIS) is a fantastic way to avoid collisions at sea. But will this safety tool’s fast acceptance by mariners create an electronic traffic jam on users’ displays?

AIS is mandated for commercial vessels larger than 300 tons. AIS units are also being installed on countless smaller commercial, fishing vessels and recreational craft. According to some reports, the U.S. Coast Guard will soon require as many as 17,000 more vessels to carry AIS. This is good news, of course. Widespread use of AIS makes collisions far less likely. The only downside to this situation, however, might be AIS’s very omnipresence. What happens in a busy harbor when you have a fleet of AIS transponders squawking their name, position and speed? How does a vessel operator make sense of all those triangles on an AIS display screen, representing all types of vessels from supertankers to 20-foot runabouts?

One solution uses the electronic brains of the AIS unit to filter the data and only display the most important contacts. After all, the unit may be able to display a 900-foot tanker six miles away that will have a closest point of approach (CPA) of five miles, but do you really need to see that? Or is it a better solution to a cluttered display to only show those few contacts that represent the biggest threat? That’s the approach taken by Vesper Marine in its new AIS WatchMate 850 Transponder.

In a busy stretch of shipping lane, for example, the WatchMate 850 calculates the CPA and time to CPA (TCPA) of all the myriad vessels in view. However, the WatchMate simply doesn’t display the vessels that are not a threat. The WatchMate is still in contact with all vessels and should one of these non-displayed vessels change course or speed to create a potential problem, it will pop up on the screen.

This feature has been tested by Vesper Marine founder, Jeff Robbins. He once found himself 60 to 70 miles off Panama with more than 100 ships surrounding him. “The device said, look at these four,” Robbins said. The other 96 contacts were either too far away, or on non-threatening courses and so there was no need to display their information on the screen. That’s a great way to make a boat operator’s job easier by using the unit’s built-in brain power. The WatchMate assigns a priority to each vessel based on CPA, TCPA and range. It will show highest risk first.

To ease installation issues, the WatchMate is equipped with a built-in GPS and GPS patch antenna. And the WatchMate has a USB port that allows you to attach it to a computer. The USB cable can supply enough power to run the WatchMate unit in receive-only mode.

Like many AIS units, the WatchMate 850 can pick up AIS signals from non-vessel sources. It also can receive search and rescue transponder (SART) signals, popping a special symbol on the display should one be in range. A growing trend is the use of AIS transmitters on aids to navigation like buoys or light towers. AIS units can get an AIS message from a buoy. And if the buoy is equipped with its own GPS unit, the buoy can know exactly where it is and even warn AIS users that it is off-station. The Vesper Marine WatchMate 850 will be available in October and will carry a suggested price of $1,100.

Maybe with clever use of filtering and prioritization, AIS units will avoid electronic traffic jams after all.

By Ocean Navigator