Man-overboard devices with AIS gaining in popularity


As the automatic identification system continues to work its way into the recreational boating world, more safety and rescue devices are being equipped with the technology. For offshore sailors, the threat of falling overboard is quite real and if that happens, the best chance of being recovered is if as many vessels as possible in the area know there is a person in the water.

That’s where a man overboard device with AIS comes in. Once an MOB with AIS is activated, it transmits an alert to all AIS receivers and AIS-enabled plotters in a given area. The more vessels there are nearby, the better the chances of a rescue. The AIS is an automatic tracking system used on ships and by vessel traffic services for identifying and locating vessels by exchanging data with nearby ships, AIS base stations and satellites. The biggest difference between a personal locator beacon and an AIS MOB device is the ability of the latter to transmit across the AIS network. Now let’s take a look at some AIS MOB devices.

Ocean Signal MOB1
Ocean Signal recently introduced the compact MOB1. Featuring integrated Digital Selective Calling (DSC), the MOB1 is compatible with compact personal flotation devices. It’s designed to be installed within the PFD and will activate automatically when the life jacket inflates, sending the first alert within 15 seconds. Weighing 92 grams, the MOB1 measures 138 mm by 38 mm by 27 mm.

An integrated strobe light ensures maximum visibility, even in low light, and the MOB1 communicates with the vessel from which the wearer has been separated and with other vessels in the vicinity up to 5 miles, depending on conditions. Once activated, the MOB1 will transmit an alert to all AIS receivers and AIS-enabled plotters in the area for at least 24 hours continuously. The integrated GPS on the MOB1 ensures that the wearer’s precise location is transmitted.

An additional feature of the device is its ability to activate the DSC alarm on the home vessel’s VHF radio, alerting crewmembers to the situation. The MOB1 has a seven-year battery life and it comes with a five-year warranty. Find out more at

Kannad SafeLink R10
One of the first AIS MOBs developed for recreational use, the SafeLink R10 is manually activated and must be mounted on a life jacket using the attachment clips provided. An emergency alert is transmitted to all AIS receivers and AIS-enabled chart plotters within a 4-mile radius and an AIS SAR emergency icon signals the requirement for urgent help in a man-overboard situation. Precise survivor information including GPS position becomes viewable when the chartplotter cursor is positioned over the emergency alert icon. It provides location, range and bearing to locate person(s) in need of assistance.

The SafeLink R10 can be manually activated in two steps. When it’s installed in the life jacket the orange safety tab should be released to make the R10 ready for use. Inflate the life jacket and then pull down the orange tab. This removes the red cap from the R10, which deploys the antenna and switches on the R10. If professionally fitted to a life jacket, the R10 can be semi-automatic — inflating the life jacket triggers activation of the SafeLink R10. The unit has a flashing LED indicator light and transmits target survivor information, including structured alert messages, GPS position information and a serialized identity number back to the onboard plotter. It transmits continuously for a minimum of 24 hours and has a seven-year battery storage life. Learn more at

McMurdo Smartfind S20
McMurdo Marine is the parent company of Kannad and, like the SafeLink R10, the McMurdo Smartfind S20 AIS MOB is designed to be secured to a life jacket using the clips supplied. The Smartfind S20 also has an automatic deployment option if the unit is professionally fitted to a compatible inflatable life jacket. It can also be activated manually. After the life jacket is inflated, pull the orange locking tab downwards to allow the red cap to be released. Pulling off the red cap deploys the antenna and activates the S20 SRS. The Smartfind S20 has similar capabilities as the SafeLink R10. Get more information at

Weatherdock AG easyONE
Made by the German company Weatherdock AG, the easyOne AIS MOB has an automatic trigger. Like the Ocean Signal product, the easyONE attaches to a PFD and is activated when the life jacket inflates. Once activated, it sends an MOB message out over the AIS containing the GPS position and COG and SOG of the victim to vessels within a 7-nautical mile range. Two LED lights also flash, increasing the odds of the wearer being seen.

The easyONE has a battery life of 36 hours once activated the estimated lifespan of the battery is seven years. Find out more at

Sailors who plan to spend a lot of time offshore should consider an AIS MOB device. This is especially true for anyone who sails solo or tandem. The added level of communication that the AIS technology brings could mean the difference between a rescue and a missing crewmember.

Eric Colby is a freelance marine writer who has written for Professional Boatbuilder, Boating and other magazines, and is a test captain for

By Ocean Navigator