Electronic Beacons Can Save Your Life
2/6/2005 6:33:45 PM by MARSHALL BRODIE
Two divers in the Gulf of Mexico, off the coast of Bradenton, found themselves in a frightening situation one day last April when they discovered they had drifted too far from their boat. They struggled to swim back to the boat against the current, and then became separated from each other, as well.
Eventually, a passing boat picked up one of the divers; the other could not be found in the falling darkness. The Good Samaritan returned the rescued diver to his boat where, luckily, there was the ultimate panic button: a Personal Locating Beacon (PLB), purchased just two months earlier at the Miami International Boat Show.
The PLB was activated, and an hour later a Coast Guard cutter arrived and rescued the missing diver. Fortunately, she had used the flash from her underwater camera to signal the cutter.
Another rescue took place recently in the Everglades: An airboater was found after he became stranded high and dry on an island. He, too, had activated his PLB.
You'd think it would be hard to find a boater who doesn't think a PLB is a great lifesaving device to have onboard, yet few boaters do. That seems to be changing, though, as sales are steadily climbing since they were introduced several years ago.
Besides the PLB, there is also the more familiar and larger EPIRB (Emergency Position Indication Radio Beacon). How do they compare, and who needs one?
The original EPIRB (commonly pronounced E-purb) system was based on an analog signal and worked on a frequency of 121.5 MHz. Despite saving more than 5,000 people since its inception in the early '80s, the EPIRBs had several notable faults. Among them, they were only able to narrow the user's position to within about 1,260 square kilometers and were plagued by frequent false alarms.
Additionally, EPIRBs could not include important user identification information in their signal, which made it harder for rescuers to identify the boat in distress. As a result, the 121.5 MHz EPIRB is being phased out and will be no longer be monitored as of Feb. 1, 2009.
The 406 MHz EPIRBs are the current standard. These beacons produce a digitally encoded signal that includes important user data (but only if the device is properly registered) that can aid rescuers and help reduce false alarms.
This data includes information about the owner. The size and description of the boat and emergency contact persons can then be linked to the signal received via satellite at ground monitoring stations.
The 406 MHz EPIRBs also drastically reduce the search area to just 13 square kilometers -- that allows a rescue to be made in as little as one hour.
For more precision, 406 MHz EPIRBs are available with an integrated GPS. The EPIRB will send the GPS location in the encoded signal, and that can significantly reduce the search area to the size of a football field, some manufacturers say.
PLBs have been authorized by the FCC for use since July 2003. Unlike the EPIRB, Personal Locating Beacons are designed to be carried instead of keeping it on the boat. This means that a PLB can also be used on land for activities such as hiking or mountain climbing.
At about six inches long and nineto- 12 ounces, they are smaller and slightly cheaper than the EPIRB. PLBs transmit on the same 406 MHz frequency and work similarly. They also must be registered and are available with and without a built-in GPS.
There are, however, some important differences between EPIRBs and PLBs. PLBs must be activated manually, while EPIRBs will activate automatically when they are immersed in water (they can be manually activated, too). APLB is designed to operate for a minimum of 24 hours while an
EPIRB operates for at least 48 hours. EPIRBs also include a strobe light while PLBs do not. EPIRBs are designed strictly for marine use and must be floated with the antenna upright.
Chris Edmonston, director of boating safety for Boat/US, a boating advocacy group, feels that for most boaters an EPIRB is the better choice because of its automatic activation, strobe light and longer operation time. However, if you are on a budget, he says the basic PLB is satisfactory.
Boat/US also offers rental EPIRBs for boaters who rarely need one.
Who needs a PLB or EPIRB? Obviously, anyone who crosses the ocean should have one. This includes boaters who even venture over to the nearby Bahamas. The Gulf Stream can quickly carry a disabled boat northward from its original track by the time a search is initiated for an overdue arrival.
How about the local boater who stays only in coastal waters? Edmonston says that a PLB or EPIRB is probably unnecessary if you stay within VHF radio range of the U.S. Coast Guard.
ACR Electronics and McMurdo Pains Wessex are the two largest manufacturers of EPIRB and PLB devices, though there are others. Prices for a basic PLB range from about $500 to around $1,500 for a fullfeatured EPIRB.
The NOAA (National Oceanic and Atmospheric Administration) website includes plenty of useful information about the COPAS/SARSAT satellite monitoring system for EPIRBs and PLBs. Also, visit Fort Lauderdale-based ACR Electronics website at acrelectronics. com or McMurdo Pains Wessex's website at www.mcmurdo. co.uk for more information.