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Taking search out of search & rescue

Simrad SA50 SART creates a series of blips on a radar screen for rescuers to follow


Simrad SA50 SART creates a series of blips on a radar screen for rescuers to follow

The day was one that makes snowbirds believe that Miami in February is as close to heaven as they’ll get in this life. A light chop ruffled Biscayne Bay, and the only obstruction to visibility was the blinding glare off the turquoise water. It was enough to keep Capt. Marc Maus from spotting his distant target: two men in a tiny inflatable.

Maus looked down at his radar screen and saw 12 “blips” lined up like ducks in a row, creating a bearing. Maus altered the 38-foot Donzi’s course to follow that bearing to the source of the blips: a Simrad SA50 search and rescue transponder, or SART, aboard the inflatable. Were Maus a rescuer responding at night, or in rain or fog, those blips might have been the only way for him to zero in and find that boat quickly.

“The bearing of that line of blips is the bearing to the stricken vessel,” says Duncan Riddle, Simrad customer support manager.

Maus had set out from Miami’s Sea Isle Marina to demonstrate how the SART works. The Coast Guard views the SART as a homing tool, roughly akin to the 121.5 MHz homing signal contained in a 406 EPIRB.

“The key to success in search and rescue is to take the search out of it,” says Sean Connett, the 7th Coast Guard District’s civilian rescue coordinator. “Anything that’s going to make you more visible to a search-and-rescue unit is definitely an asset, whether it’s SART, flares, smoke or whatever. You want to make yourself as big a target as you can.” Twelve blips on a radar screen draws rescuers’ attention.

The SA50, introduced in mid-2005, is a tubular-shaped unit and the smallest SART on the market at 9.7 inches tall, 3.2 inches wide, and weighing 12 ounces. Large commercial vessels are required to carry at least one SART, and the International Sailing Federation recommends sailors carry one in their life raft grab bag in some offshore races, such as Fastnet.

Stowed on the life raft or in a bracket on the boat, the SART can be activated manually or automatically. Once activated, it waits to be “interrogated” by the signal from an X-band radar, then sends out 12 pulses that appear as 12 blips in a neat line on the rescuer’s radar screen. The target — the distressed boater — is about 50 meters forward of the closest blip. The SART’s range is line-of-sight to the horizon — about 13 miles when the unit is mounted on an optional 6-foot pole. The higher the unit is off the water, the greater its range — up to 25 miles with a 6-kW radar receiver at the other end and 20 miles with a 4-kW receiver, according to Simrad.

One of the two men “rescued” from the inflatable this day was the unit’s designer, Simon Nolan.

“Safety things are important, but people don’t like to pay for them,” Nolan says. The earliest SARTs cost $2,500 to $3,000. The Simrad SA50 SART costs about $975. “This unit has a cost-efficient price,” he says. “It’s accessible to the leisure user. You can afford to put this on your boat.”

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