Emergency signaling choices


From the time radio communications arrived it was understood that getting a message out in an emergency was of prime importance. Now that type of fast distress signaling is possible, but for these systems to work their best you need good batteries and fully filled out registration forms.

In the early days of radio, most equipment was simply too large and bulky to be easily transported, making emergency use limited. Then came WWII; with aircraft often flying over large expanses of open water and ships at sea that could fall victim to prowling submarines, it became imperative to have a way for survivors to send messages for help.

One of the first truly portable emergency transmitters was developed by the German military. Allied forces captured some of these radios and copied them. These units had an hourglass shape and were hand-cranked to supply power. The operator would strap the unit between his legs to hold it firmly and crank the handle. They were puckishly nicknamed “Gibson Girls.” The units required an antenna to be flown from a kite or balloon and would automatically send out an SOS signal. Although imperfect, these emergency radios remained in use until the late 1950s and can still be found in some military surplus stores.

An Ocean Signal 406 EPIRB1, reportedly the most compact EPIRB available.

Courtesy Ocean Signal

Fast-forward to today and we have emergency transmitters, or emergency position indicating radio beacons (EPIRBs) and personal locator beacons (PLBs) that are vastly superior to the old Gibson Girls. Today’s units are small lightweight devices that transmit to satellites and land stations, making it possible to be found virtually anywhere on the planet in a relatively short period of time. Most of today’s units will also transmit a GPS position to further aid in location and rescue. New battery technology has also enabled reliable, lightweight, small transmitters that are easy to maintain, carry and store. Modern batteries can remain stored for more than five years and still perform as needed when needed.

In 1982, Cospas-Sarsat was formed between Russia, the U.S., Canada and France. SARSAT stands for search and rescue satellite-aided tracking. COSPAS is an acronym for the Russian words “cosmicheskaya sistyema poiska avariynich sudov,” which translates to “space system for the search of vessels in distress.” Since then, 29 other countries have joined this consortium. This organization monitors and relays distress signals from Earth-based emergency beacons to satellites. With this network, it is possible to have most of the globe monitored for emergency signals, resulting in rapid response and rescue. 

An ACR EPIRB in a mounting with the front cover removed. The black cylindrical unit at the top is a hydrostatic release.

Wayne Canning

Three basic types
Modern emergency locator beacons come in three basic types and it is important to understand the differences to know just which unit is best for your own use. EPIRBs are beacons that are registered to the vessel on which they will be used. Next are PLBs, smaller units that are usually carried by a person and are useful both on land and at sea. A PLB can send a distress signal for 24 hours or more whereas an EPIRB will operate for more than 48 hours. Finally, there are AIS locators or beacons; these are used for man-overboard situations and only transmit a VHF signal to be picked up by a vessel equipped with AIS receivers. AIS beacons do not transmit to satellites.

EPIRBs are the granddaddy of the locator beacons. They have been around for some time now and were first used on commercial vessels. As technology improved, these units got smaller and — more importantly — more affordable. Early units only transmitted an emergency signal without position data, but almost all modern units now have a built-in GPS that will transmit the beacon’s position. These units are registered to the vessel and transmit vessel information along with position. This aids the rescue personnel in determining the type of emergency. These units come in two types, Category I and Category II. Category I units are self-activating when in the water. Many in this class will also have a hydrostatic release that will allow the beacon to float free of the vessel. Category II units must be manually activated and, because of this, are usually in a manual release bracket as well. EPIRBs have a longer battery life than PLBs, with a required battery life of 48 hours or more. EPIRBS will also float in an upright position, allowing for clear transmission to the satellites. Most also have a built-in strobe light as well to further aid in location. While these units are not required on pleasure vessels, any offshore vessel should have a Category I EPIRB with a Category II or PLB in the ditch bag.

A PLB is an personal-sized EPIRB you can carry with you.

Courtesy McMurdo

PLBs are the next type of locator beacon often used on boats. Unlike EPIRBs, PLBs are registered to an individual rather than a vessel. PLBs are smaller and easier to carry in your pocket or in a backpack. They are primarily designed to be used on land but can be useful on a boat as well. When used on a boat, there are a few things to keep in mind. Most do not float, so if they are dropped in the water they will sink. Some do have floats as an option and most can be tied to a float. That said, when operating they must be held in an upright position to allow the antenna to transmit well. This may be possible in a life raft but would be hard to do for a swimmer. The battery life is shorter as well, only being good for 24 hours; also, most do not have a built-in strobe light. They are less expensive and can be used on both land and at sea, making them a bit more useful for those who hike as well as sail. Their low cost makes them an attractive alternative for those doing coastal cruising. Like EPIRBs, new PLBs have a built-in GPS as well.

Another type of PLB is the personal position locator and messenger, such as the SPOT and DeLorme InReach. These units will transmit your position in regular intervals and most have a built-in SOS or emergency button. The SPOT unit, which uses the Globalstar low-Earth-orbit (LEO) satellite network, can send tracking information and short text messages back to your friends and family. The InReach unit, which makes use of the Iridium LEO satellite network, can also send text messages and emergency position alerts.

Although products like SPOT and InReach can be used as an emergency beacon and have been responsible for hundreds of rescues around the world, keep in mind that they do not use the Cospas-Sarsat system and instead rely on private companies to relay any distress signals. Although they do have a good record of rescues, their coverage is not the same. They may not cover open ocean or some areas outside U.S. territories. Most use replaceable batteries that will not have a USCG-required operational life or one as long as the PLBs or EPIRBs. Also unlike EPIRBS and PLBs, these units require a monthly subscription fee. They are, however, very useful for keeping family and friends updated with their text-based messaging, and some voyagers have opted to rely on them and have been pleased with the results. 

AIS emergency beacons
Relatively new to the beacon market — having been around for only five years or so — are the AIS emergency beacons. These are designed primarily as a man-overboard locator and do not transmit to satellites. Instead they use the VHF/AIS system to transmit and have a range of about four miles. Unlike the MOB devices of old, which required both transmitters and a receiver, these units use existing AIS equipment on the vessel to help locate an MOB. These smaller units can be worn by crew and are manually activated should the crewmember fall overboard. An AIS alarm can be activated on the vessel’s chartplotter, indicating activation of the transmitter. As most of these units have built-in GPS, the transmitter’s position is shown on the chartplotter just as another vessel would be, helping to guide the helmsman back to the MOB. Most have a battery life of 24 hours and have a built-in strobe light as well. These beacons cost around $250 to $300, making them a cost-effective MOB device.

A closer look at the McMurdo Smartfind personal AIS.

Courtesy McMurdo

Like most things on a boat, you cannot simply purchase an EPIRB or PLB and forget about it. They do require proper installation and maintenance. When installing a self-deploying Category I EPIRB, care should be used when selecting a location for the mount. I am often surprised when conducting a survey at how many of these units I find installed inside the boat or in a cockpit enclosed with canvas. These units would clearly be trapped inside the vessel should it sink, making self-deployment useless. If installing one of these units, make sure it will be in a location to float free of the vessel — remember, boats do not sink level. For Category II EPIRBs, you want to make sure they can easily and rapidly be located and released in an emergency. Close to the companionway or helm station are good locations. Make sure all crewmembers are aware that you have such a device and where it is as well. PLBs should be attached to a life jacket and/or in a ditch bag. Remember most of these units do not float, so securely attaching them to something that floats makes sense.

All types of beacons will need periodic battery replacement. It is mandatory that beacons used in commercial service are inspected and have the battery replaced every five years. Because of this, manufacturers date their batteries for five years, even when used for yachts. For devices other than the personal messengers, the beacons will have to be sent to a factory-authorized service center for battery replacement and service. I often hear complaints of the high cost of battery replacement, and many beacons will only allow two or three battery replacements in their lifetime. It’s true that battery replacement is not cheap and, in some cases, almost equals the cost of a new unit, but there are reasons for this. When you send a unit in for battery replacement, not only are the batteries replaced along with the housing seals, but the beacon is put through a series of tests to ensure it will be good for another five years of service. Any damaged parts or switches will also be replaced. Keep in mind that these are lifesaving devices and not something you want to cut corners on by trying to replace the batteries yourself. 

A GPS receiver-equipped EPIRB.

Courtesy McMurdo

Registration is key
A critical part of owning an EPIRB and/or PLB is having it properly registered with NOAA. This is a free and relatively painless process but still a critical one. With a properly registered beacon, rescue could be a matter of hours away, versus a day or more for an unregistered beacon. When search and rescue personnel receive a distress signal, they first have to verify if it is real or a false alarm. Sending out boats and planes is expensive and sometimes dangerous; agencies do not want to deploy assets and personnel unless they know for sure there is an emergency. With a beacon that is properly registered with all the required contact information on record, a few quick phone calls can verify if the signal is a true emergency or simply a beacon that has gone off by accident. This can save precious time when it is needed most.

Some new innovations coming to EPIRBS and PLBs include better accuracy through the use of medium-orbit satellites and built-in AIS that will allow signals to local vessels and allow SAR personnel to locate persons in distress once on scene.

This close-up shows that this EPIRB’s battery needs replacing by November 2017.

Wayne Canning

Since EPIRBs first came out in 1982, more than 40,000 rescues have taken place with untold lives saved. Florida now offers a discount on registration fees for vessels equipped with an EPIRB or PLB, and other states are considering similar discounts. A well-maintained and registered beacon is a critical part of your vessel’s safety gear. Any vessel traveling outside of cellphone or VHF range should have at minimum one working PLB aboard. Additionally, an AIS transponder can be a matter of life and death for a crew overboard and should be carried by every crewmember when on deck.

For any vessels with older Class B emergency transmitters, it should be noted that in February 2009, the Federal Communications Commission phased out the use of this type of EPIRB that transmitted on the 243 MHz frequency.

Contributing editor Wayne Canning is a marine surveyor, writer and photographer. Visit his website at www.4ABetterBoat.com.

By Ocean Navigator