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Electronics

Radio Lifelines

Electronics — April 2001
By Tim Clark

Radio Lifelines
Onboard direction finders might help you beat the Coast Guard to the rescue.
   
 


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With the proper equipment, training, and preparedness, boating is as safe as it is satisfying. And PMY readers are safer than most. For example, of the most serious boating accidents in 1998, 85 percent occurred on boats less than 26 feet in length. And of those, more than half involved boats of 16 feet or less. Although such statistics are reassuring, responsible boaters never view matters of safety complacently. Moreover, knowing that you are prepared for any misadventure only adds to the pleasure of boating.

Usually, the only time someone leaves your boat for the water they do so willingly (often gleefully), via the swim platform. However, the risk of someone going over accidentally is inherent in boating, even if the chances are slim. A handful of electronic systems designed for man-overboard situations are now on the market. They are worth the consideration of all boaters, but especially those who regularly fish and cruise and those who often have children onboard. The most dramatic advantage to all these systems is--so to speak--elimination of the middleman. In a man-overboard situation, every moment counts. The response time between a call to the Coast Guard and the arrival of search-and-rescue teams can sometimes simply be too long. Having effective tools and skills at hand to mount an immediate search can make all the difference.

Based on radio homing technology, these systems use one or more individual signaling devices tuned to the same frequency as an onboard receiver. The Sea Marshall Rescue System, manufactured by the company of the same name founded in the UK but now based in New York City, uses an SMRS-8L Personal Rescue Beacon (PRB) that sends out a signal on the 121.5-MHz frequency used internationally for search and rescue. (Essentially it's what is also known as an Emergency Locator Transmitter [ELT].) Sea Marshall's PRB (see photo, top of page) measures just 27/8"L x 2"W x 11/8"H and is designed to be worn around the user's neck on a plastic cord that houses both a transmitting antenna and an electro-luminescent fiber that glows once the device is turned on. It can be activated manually, or it will automatically go to work following 20 seconds of immersion in water.

Sea Marshall sells two receivers for the PRB: the CrewGuard CRWG-1 and the CrewFinder MDF-202 (pictured below). The CrewGuard's signal-strength indicator can be used to estimate the direction and distance to the person overboard. It will sound an alarm as soon as it recognizes the PRB's 121.5-MHz signal, and it can be interfaced with a GPS, which can instantly record an estimate of the signal's origin. You can also integrate it with an engine kill switch or with an autopilot that has been programmed to, for instance, turn the boat hard over in response to the CrewGuard's alarm.

Next page > Electronics continued > Page 1, 2

This article originally appeared in the May 2003 issue of Power & Motoryacht magazine.

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