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Infrared and a man-overboard scenario

Each year at the Miami International Boat Show, FLIR Systems takes media representatives on a cruise, typically using the opportunity to demonstrate how well its infrared cameras show a human being in the water.

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The demonstration, using a real person treading water, makes a convincing argument for a thermal-imaging camera as a man-overboard recovery aid. The swimmer can't be seen by the naked eye, but is easily visible on the camera display - a human shape aglow in a color that contrasts with the cooler water.

Let's imagine a real-life scenario a couple of years from now. A crewmember has fallen off the boat and, after several minutes of unconsciousness, revives and activates the man-

overboard beacon attached to his inflatable life vest. One more thing: It's a dark and stormy night.

Once the beacon is activated, the helmsman knows someone has been lost. But that's not all. The lost crewmember's beacon has a built-in GPS and may use either DSC-VHF or AIS technology to transmit GPS coordinates back to the boat.

As soon as the first burst of information is received, the vessel's integrated electronics system goes into man-overboard mode. A marker on the chart plotter shows the location of the casualty with an MOB icon, the chart immediately goes to the best possible scale for approach and recovery, and the radar display sets itself to the appropriate range. With the press of a button, the autopilot takes over the helm and drives the boat toward the coordinates of the MOB.

MOB mode includes the FLIR camera, which immediately slews to cue, the cue being the GPS coordinates for the lost crewmember. Focusing on that distant point, the camera looks for a human thermal pattern. When the person is in its view, a window opens on the display, showing the distant crewmember in real time. Automating the process of finding a casualty allows the skipper and crew to concentrate on the best final approach and method for getting their buddy back on board.

A scenario such as this, speculative though it may be, may help to explain why FLIR was so eager to acquire a full-suite marine electronics manufacturer such as Raymarine.

See related stories:

- Night vision - What's out there?

- Should rescue beacons be mandatory?

- A small phone with wide-ranging reach

This article originally appeared in the February 2011 issue.