Personal Locator Beacons – This time it’s personal
What good is an emergency locator beacon on the boat if you’re in the water?
A look at the latest in PLB technology.

By Frank Lanier
Chesapeake Bay Magazine February 2004
Offshore Magazine February 2004

Although a good swimmer and careful to boot, I still recall some twenty years later a comment made by the bo’sun during a man overboard drill on the first Coast Guard cutter I was stationed on – “A basketball has a better chance of being spotted in the water than a person.”

The analogy itself is soberingly accurate – your head is likely to be the only thing visible and unless said head is blessed with a shock of red hair like mine, odds favor the basketball even more. The good news is technology now allows even brunets to breathe a collective sigh of relief as relates to falling overboard or being lost at sea because Personal Locator Beacons (PLBs) are here to level the playing field.

Emergency Position Indicating Radio Beacons (EPIRBs) have been around for decades, although their use in the US has by law been limited to vessels, rather than individual crewmembers. That’s all well and good, but what if the boat’s safe and sound and you’re the one who’s in trouble? A snapped lifeline in heavy seas, a misstep caused by tripping over that errant winch during the midnight watch and suddenly you’re in the drink.

Thankfully, recent changes in FCC regulations now allow for the use of smaller “handheld” EPIRBS called Personal Locator Beacons (PLBs) designed to be worn or carried continuously – a decided safety advantage in overboard situations. Traditional EPIRBs have strobe lights (to assist in nighttime rescues), longer transmission times and are typically permanently mounted on the vessel itself. PLBs have shorter transmit times (up to 24 hours), but are also much smaller and have the “wearability” mentioned above.

The basic technology is simple. PLBs (which are simple miniature EPIRBS) are portable transmitters that, when activated, alert the Coast Guard by broadcasting a signal on one of the internationally monitored 406 Mhz or 121.5 Mhz distress frequencies. The first Emergency Locator Transmitting devices (ELTs) were developed for use in the aviation industry during the early 1970s. They transmitted on 121.5 (civilian) and 243 (military) MHz frequencies that were monitored by aircraft and a few specially equipped satellites.

Use of the technology soon crossed over into the maritime realm, however so did some of its major shortcomings - high false-alarm rates (up to 95 percent) and limited satellite detection range, as satellite have to “see” both the activated EPIRP and one of the emergency receiving ground stations at the same time for detection to occur.

Then came 406 class EPIRBs, so named for its transmitting frequency of 406 MHz. Designed to address the shortcomings mentioned above, they utilize an additional network of satellites providing greater accuracy (1-3 miles versus the 5-10 miles of 121.5 MHz versions), reduced response time, worldwide coverage, fewer false alarms, and the ability to relay vessel data to rescuers (once the unit is properly registered).

Although 121.5 MHz EPIRBs are still widely used (most 406 EPIRBs also contain 121.5 MHz transmitters allowing SAR craft to “home in” utilizing a direction finder once in the general vicinity) the benefits of 406 class EPIRBs are overwhelming, so much so that the National Oceanic and Atmospheric Administration (NOAA) has announced satellite processing of 121.5/243 MHz emergency beacons will be terminated on February 1, 2009. As such, the U.S. Coast Guard no longer recommends the purchase of Class A or Class B EPIRBs as a primary distress signal (although units such as the Guardian MOB Wristwatch mentioned below can still prove valuable in local searches).

Class A EPIRBs are 121.5 or 243 MHz units designed to float free from a sinking vessel and turn on automatically, while Class B units (which operate on the same frequencies) have to be manually switched on in an emergency. Categories I and II are used to describe the same functionality in 406 class EPIRBS – CAT I indicating the float free units that turn on automatically, while CAT II denotes those that are manually operated.

A wide variety of PLBs are now available to recreational boaters, ranging in price from around $100 to $700. The ACR Mini B 300 from ACR Electronics ($130) is a miniature, floating personal marker that uses 121.5 MHz. A Class B EPIRB, it has a vertical range of 9.3 nautical miles and a transmission time of around 24 hours.

The Guardian Man Overboard (MOB) Wristwatch by Pains Wessex ($375) is a Class A unit that has all that and the additional benefit of being, well, a wristwatch. Waterproof to 160 feet (50 meters) and with a transmission time of over 6 hours, the PLB can be activated manually or automatically upon immersion in seawater.

Range to an airborne SAR craft is up to 15 nautical miles. Another selling point is the ability to transmit your location back to your own boat (up to a mile away) when used in conjunction with the optional Emergency Surveillance Receiver, a handheld point-and-locate unit ($300) or the Emergency Direction Finder ($3,500), a permanent-mount unit that provides relative bearing and signal strength.

406 Class units include the Pains Wessex Fastfind ($550) and Fastfind Plus ($900) PLBs, both handheld units roughly the size of cell phones that, according to the manufacturer, can transmit a distress signal “from the remotest seas, almost anywhere in the world to the international search and rescue services in just three minutes.”

Billed as the world’s smallest 406 MHz PLBs, they can be carried in a pocket or clipped to lifejackets and foul weather gear. Both units have 121.5 MHz transmitters and the Fastfind Plus also transmits GPS data, reducing fix time and increasing position accuracy. Battery life last up to five years and provide 24 hours of transmit time.

ACR Electronics offers two PLBs ($599 to $700) with characteristics similar to the Fastfinds, although neither have built-in GPS (the GyPSI model ($700) does have an interface allowing you to connect it to an external GPS unit).

Last, but definitely not least, federal law requires that anyone purchasing a new or used 406 MHz EPIRB register it with the National Oceanic and Atmospheric Administration (NOAA). What you’re doing here is providing search and rescue organizations emergency contact information so that if your EPIRP goes off, they’ll know who they’re looking for – it also gives them a someone to call and verify that it’s an actual emergency rather than a false alarm, meaning you’ll need to re-register if any of the information changes.

For more information on PLBs and EPIRBs in general, visit the company websites below or give them a call. Purchasing a PLB could be the best safety move you’ve ever made – and you don’t even have to dye your hair red.

(954) 981-3333,

McMurdo Pains Wessex
(800) 576-2605,