Essential MOB Gear

In a crew-overboard situation, the latest gear goes a long way toward enabling a successful outcome.
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While safety tethers and ­lifelines are the first line of defense when it comes to keeping crew safe, the hard-boiled reality is that people still end up in the water. Fortunately for mariners, electronic safety technologies have evolved to give those still on board a better chance of ensuring help is on the way. Here, then, is a look at the latest electronic emergency devices for cruisers.

When it comes to electronics and safety at sea, the conversation begins with emergency position-indicating radio beacons. These lifesaving devices are registered to the vessel—not its individual sailors—and in an emergency broadcast alert on the 406 MHz and 121.5 MHz frequencies. Today’s EPIRBs have a 360-degree strobe light and, depending on the model, they can be activated manually or triggered hydrostatically.

Once active, EPIRBs ­transmit a satellite distress message for a minimum of 48 hours. These signals are received globally by satellites operating on the International Cospas-Sarsat Programme’s satellite networks. Information is passed to a ground station, which then relays it to the appropriate rescue-­coordination center. The center then attempts to contact the EPIRB’s registered user (and/or their emergency contacts) while also dispatching a search and rescue team. Once on the scene, rescuers use specialized homing equipment to follow the EPIRB’s 121.5 MHz signal for their “final-mile” search.

Next-generation EPIRBs (and other devices, see below) will allow a return message to be sent, letting those in danger know help is on the way. Sean McCrystal is the senior maritime marketing manager at Orolia Maritime, the manufacturer of the McMurdo, Kannad and Netwave brands. He says: “The signal flashes on the beacon to confirm that the distress alert has been received and that help is being organized. This reassurance signal allows those in distress to make decisions based on a better understanding of their situation.”


While Cospas-Sarsat has been credited with saving more than 46,000 lives since 1982, one obvious shortcoming is that other nearby vessels, which are often significantly closer to the scene than the United States Coast Guard or other responders and therefore able to render help faster, are electronically blind to unfolding emergencies. Because of this, McMurdo introduced its revolutionary Smartfind G8 AIS in fall 2018, which was the first combined automatic information system transmitter and EPIRB. AIS broadcasts are transmitted over specific VHF channels and can alert all nearby boats, much as a mayday broadcast might.

Currently the Smartfind G8 AIS is the only commercially available EPIRB with AIS capability; however, other brands are expected to soon offer similar technologies. While these next-generation EPIRBs are more expensive than standard beacons, they afford a ­considerably wider safety net.

Read Next: Wireless Man Overboard Systems

Getting Personal

While EPIRBs are registered to a particular vessel, sailors can also buy and carry an individually registered personal locator beacon that is essentially a small EPIRB, and which has a strobe light to help make overboard crew more ­visible. ­Next-generation PLBs will also allow “help is on the way” replies. Newer ACR models, for instance, feature a digital screen that displays pre-scripted readouts such as “message received.”

As with EPIRBs, compact and easy-to-carry PLBs leave those still on board electronically blind, however. And PLBs with AIS capability have yet to be approved, though manufacturers are working in that direction.

In the meantime, sailors can consider a personal AIS transmitter. Turned on, they alert all nearby Class A and Class B AIS users—including their own boat—that a crewmember has gone missing, and will broadcast the location of the person continually at a rate of once per minute, for typically 24 or more hours. Reach, of course, is limited to VHF range (up to about 5 nautical miles, depending on conditions).

Tethered Crew

Recent years have seen some marine electronics companies leverage Bluetooth capabilities to create overboard alarms that are aimed at self-rescue rather than broadcasting a satellite or AIS emergency signal. Weems and Plath’s CrewWatcher uses a small, pocket-friendly beacon (hint: it’s also dog-collar-friendly) and a smartphone app. Should someone fall overboard, the Bluetooth link between the beacon and the smartphone is broken when the beacon is submerged or separated by distance, triggering an alarm on the phone. The phone also records its position at the time of the electronic tether snap, and the app can navigate back to the scene of the splash. Likewise, ACR’s new Overboard Location Alert System offers comparable capabilities, starting with the OLAS Crew Tag. The company’s OLAS Float On offers similar capabilities as the Crew Tag but with an LED flashlight, a strobe and a rechargeable battery.

One idea for cruisers who are reluctant to buy a PLB and an AIS MOB is to instead carry a PLB and a Bluetooth device. And for short-handed or singlehanded cruisers who regularly start the motor when the air gets light, some of the next-generation Bluetooth and wireless systems also will offer engine kill switches. For example, Fell Marine offers a line of pendant-style beacons that can stop props, while ACR’s OLAS Guardian offers a ­similar response.


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