How to avoid collisions and find a person overboard
First GPS told us where we were. Now AIS is telling everyone else where we are.
That's only a bit of an overstatement. The Automatic Identification System isn't universal yet, but A-I-S are the hottest initials in navigation since G-P-S. The number of pleasure boats equipped with AIS is growing by the day, and the positions on the waters of the world at any given instant of the thousands of vessels that have it are now public knowledge.
While mulling this column on a gorgeous fall day, I figured someone had to be smart enough to be enjoying the brisk, bright afternoon on a sailboat instead of, as I was, looking at it through an office window.
I went to one of websites offering real-time AIS tracking of vessels and clicked on an icon on a chart about five miles offshore from my office. Sure enough, it was a Catalina 36, sailing on a course of 21 degrees at 6.9 knots in a 12-knot breeze blowing from 123 degrees. That single click also gave me the name of the boat and showed me a photo of it.
Remember when sailing was a surefire way to get away from it all? Well, not so much anymore, certainly not if you have an AIS transmitter-receiver turned on.
This is all voluntary (for pleasure boats, but not the commercial vessels that are required to have AIS), and it's all good. AIS is whiz-bang technology that translates perfectly to safer seafaring.
It's another progeny of the Information Age, an era in which a lot of the information has to do with where we are on the planet. This is thanks in part to the minuscule GPS receivers embedded in our cell phones. Sometimes our cell phones ask us whether we will allow some entity to know where we are. Sometimes they don't.
In many long-distance yacht races these days, no one asks. Boats are required to carry transponders that transmit their position and other GPS information to a website. This is not AIS, but it acts in much the same way by sending information about the boats to the Internet, where anyone, including sailors on other boats, assuming they can receive data by cell phone or satellite, can access it.
This has changed the game by eliminating the stealth factor. Racers used to be able to take flyers and sometimes, more often by dumb luck than by genius, make spectacular gains in private breezes without their competitors being the wiser. No more. Now everyone with access to the Internet can know not only where every boat is, but also its speed and heading. Some of the tracking systems even use handicap data to compute continuous results.
Race tracking has taken sailboat racing closer to the holy grail of making sailing a spectator sport than anything I've seen. It's created an actual audience for these events. I've talked to folks who claim to have found it fascinating entertainment to follow the movement of tiny sailboat icons on their computer screens.
In a race last summer, we lost the ability to follow race tracking after our boat sailed out of cell phone range and couldn't make a satellite connection. But we were able to keep tabs on a number of boats anyway because they were kind enough to keep their AIS systems transmitting.
AIS sends GPS data and other information on VHF radio frequencies from vessel to vessel, which can be picked up by data communications systems accessible on
AIS is mandated for certain classes of commercial vessels. It's an option for pleasure boats, and is available as a receiving device at low cost or as a transmitter-receiver starting at not much over $500. AIS information can be displayed on standalone instruments or on chartplotter displays.
AIS provides fun for shipping geeks who can follow freighters all over the world and for anyone curious about who's out sailing, but its reason for existence is to prevent collisions.
I've never experienced a dangerously close call crossing the course of a ship, but I've had encounters that were closer than I expected, which is to say a bit scary, and which suggests that old hand-bearing methods are rough guides at best. In the wealth of information AIS instruments can provide are calculations of the distance you will be from an AIS vessel at the closest point.
AIS safety gets even better than that. Now it is taking crew-overboard recovery on a leap forward with compact AIS transmitters that sailors attach to their PFDs or harnesses or carry in some other way. When activated, the devices transmit the GPS position of the person overboard, which appears on AIS-enabled chartplotters on their boats and every other AIS equipped vessel in VHF range.
The Safelink R10 personal AIS transmitters we carry on our boat are about the size and weight of a cell phone and have enough battery power to operate continuously for 24 hours. If deployed properly by the person overboard, the AIS Survivor Recovery System, as it's called by its maker Kannad Marine, can solve one of the most terrifying problems a mariner can face-how to find a person lost overboard.
My enthusiasm for this invention is tempered a bit by the fact it is not all that easy to activate. It takes two hands, and the process would have to be awkward for someone struggling to keep his or her head above the waves. An automatic deployment system would solve the problem, and I imagine that will be coming. In the meantime, a personal AIS transmitter is still a potential life-saver.
I have no idea what the next hot initials to be born of the Information Age will be. But I'm pretty sure they won't be S-P-S. Those have been retired to a warm place in sailing lore. They stand for Seat of the Pants Sailing.