Thermal cameras enhance man-overboard safety

When it comes to the subject of man overboard, the best safety measure is to stay on the boat. When the unthinkable does happen, however, voyagers need luck and some good gear to find and recover their lost crewmember. Man-overboard gear ranges from simple throwable buoys to poles to electronic direction finding systems. One particularly useful piece of man-overboard recovery gear that has become available in recent years is the thermal imaging camera. A thermal camera can clearly show the victim in the water even on the darkest night. Now the thermal imaging company FLIR has reduced the price of its low-end, handheld thermal imager, making it a more affordable tool for the average voyager.

The gear available for man-overboard (MOB) situations has evolved from simple visual and audio signals to sophisticated electronic devices unimagined only a few decades ago. The first, and still remarkably effective (if utilized correctly), tool is the simple life ring or horseshoe buoy. Usually colored orange, these flotation aids not only help you see the victim, but assist the person in the water in staying afloat. And if a single ring is good, then more flotation is better. The best thing to do is to throw as much flotation into the water as possible: cockpit cushions, PFDs, anything that the victim can use to keep their head above water.

Getting plenty of flotation to the victim is great, but another big part of MOB recovery is being able to see the person in the water so you can maneuver the boat to rendezvous with the victim. And an early solution to seeing the victim is the MOB pole. A fiberglass pole with a flag on top, attached to a horseshoe buoy with a length of line. This addition to the MOB tool kit immediately makes the victim in the water more visible. The biggest drawback to the MOB pole, however, is quickly and effectively deploying it. One solution to this problem is Switlik’s Man Overboard Module (MOM) that includes an inflatable MOB pole and either an inflatable horseshoe or a small raft that gets the victim out of the water. The MOM can be deployed by pulling a single line.

There is the obvious problem, however, that a pole with flag isn’t terribly effective at night. The next piece to the MOB puzzle was to equip the MOB pole/horsehoe buoy package with a fixed or strobe light, making it useful in the dark.

What about putting a light on the victim? Battery-powered, fixed lights or flashing strobes carried by the victim make them immediately visible at night. Another excellent light solution is the Rescue Laser Flare. This is a felt-tip-marker-sized laser unit with an astigmatizer lens. The lens turns a laser’s dot of light into a line of light, making it easer for the victim to sweep the beam through the field of view of searchers on the water or aboard a search and rescue aircraft.

Yet another solution is to use a radio frequency system like the ACR Vecta3 radio direction finder (RDF) unit. If a crewmember falls overboard and is equipped with a Mini B2 or Mini B300 or an EPIRB transmitting on 121.5 MHz, the Vecta unit can provide a direction to the victim. Another electronic solution is Raymarine’s LifeTag system. Crewmembers wear small LifeTag units and should a crewman fall overboard, the RF link to the LifeTag base station is broken and the unit sounds an audio alarm. It also can send a signal to Raymarine brand multifunction displays, chartplotters and ST290 instrument systems to mark the spot with an MOB symbol and a lat/long.

Perhaps the ultimate electronic solution is for crewmembers to carry personal locator beacons (PLBs). These smaller units transmit on both 406 MHz and 121.5 MHz, just like larger EPIRBs. So for a boat equipped with a 121.5 MHz RDF unit, a PLB will produce a signal for homing.

But what if a crewmember is not carrying a transmitting device or a light or a laser? Or what if the crewmember is injured or cannot activate a rescue unit? A thermal imaging camera works well in these situations because it can show a victim in the water even if the crewmember is unconscious (he or she would need to be wearing a PFD, of course). The thermal camera doesn’t require that a victim do anything, it picks up the crewmember’s body heat regardless, showing the victim’s head as a white splotch against the cooler, darker sea.

FLIR, a major manufacturer of thermal imaging products for the military, fire fighting, security and marine markets, introduced a handheld thermal imaging product called the FLIR i5 in the spring of 2008. That version of the i5 had a price of $2,995. Now, according to FLIR, its production volume is so large, the company is able to lower the cost to $1,595.

The i5 has a 2 percent thermal accuracy and a 2.8-inch display with 80 by 80-pixel resolution. In a man-overboard situation a handheld thermal imager like the i5 could provide a boat’s crew with excellent data for locating the victim in the water — especially if an incident takes place at night.

By Ocean Navigator