|
|
 |
| Used Boat Classifieds>>
Useful Boating Articles
|
| |
Emergency Position Indicating Radio Beacons
|
|
What They Do
EPIRBs (Emergency Position Indicating Radio Beacons) are small transmitters that send out an emergency signal to rescue services. If you are out of VHF range and experience serious difficulties, an EPIRB is a highly effective, internationally recognized way to summon help. Their use is limited to situations of grave and imminent danger, e.g. when your vessel is in danger of sinking or you have a medical emergency and all other measures of rescue have been exhausted. So don't activate an EPIRB if you run out of beer or you decide your cruising companions are Neanderthals. The deliberate misuse of emergency beacons may result in substantial fines and/or incarceration.
Note that the quantity of information that an EPIRB transmits is very limited compared to even a 60 second voice communication or a 50 word text message. If you can reach rescue agencies with a SSB or Inmarsat C message or via Iridium or Globalstar phone, you can relay much more detailed information about the nature of your distress. The records show that EPIRB is critical for saving lives in emergencies when other forms of communication are compromised or unavailable.
How they work
EPIRBs transmit on internationally recognized distress frequencies, monitored by aircraft, satellites, land stations and rescue vessels. Over the last decade, COSPAS/SARSAT global weather and mapping satellites have become available for EPIRB monitoring. The satellites can compute a fix on the position from where the signal is being transmitted, so ships or aircraft can be diverted to attempt a rescue. Satellites relay detected EPIRB signals to ground stations, which are called Local User Terminals (LUTs). LUTs are located all over the world, and provide the link between the satellites and Mission Control Centers (MCCs). The MCC (in the U.S. it's a NOAA office near DC) tracks the signal, and attempts to identify the transmitting vessel using the database of registered EPIRBs. Then the MCC informs the Rescue Control Center, (RCC) that is monitoring the area of the incident, e.g. the Coast Guard, civil air patrol or a foreign country's military, so the RCC can launch the Search and Rescue effort. International rescue operations necessitate effective communication across borders, language barriers and agency limits and may take a little longer to launch depending on available resources.
What to look for
Class A & B EPIRBs: Class A EPIRBS deploy and activate automatically while Class B units have to be deployed and activated manually by the crew. Class A and B EPIRBS transmit on two recognized emergency frequencies in the VHF band: 121.5 MHz (civilian) and 243.0 MHz (military). They have saved many lives over the course of the years, but they also lack accuracy and can trigger false alarms that waste crucial time and resources. Therefore, Class A and B units are being replaced by new and improved technology, the so-called 406 MHz EPIRBs. As an aside: NOAA will stop monitoring 121.5 MHz signals as of Feb. 1, 2009.
406 MHz EPIRBs: These more sophisticated EPIRBs, transmit on 406.025 and 406.028 MHz (therefore, commonly called "406 EPIRBs"). If you have an older style Class A or B unit, we recommend replacing it with a 406 MHz model for the following reasons:
SARSAT satellites listen for a 406 MHz EPIRB's emergency message and store it until they are within range of a listening station on the ground, making worldwide coverage a reality.
The 406 signal has an embedded code which contains a unique identification number, thus allowing rescue agencies to look up your emergency information (including name, phone number, vessel type, emergency contact etc), in a database. So before they unleash vessels, helicopters and planes to look for you, they can verify your itinerary with someone who knows your plans.
A 406 MHz signal allows the satellite to calculate the position of the sender to less than a 2-nm radius (instead of 12 nm with the older Class A and B EPIRBs), resulting in a faster and less costly rescue response.
The average time to notification of RCCs via 406 MHz EPIRBs is approx. 1 hour worldwide.
GPS/EPIRB Combinations: For the sake of efficient rescue efforts it made perfect sense to combine Global Positioning System (GPS) receivers with 406 MHz EPIRBs. This technology uses geo-stationary satellites (GEOSAR), which are capable of detecting 406 MHz signals (between 70šN and 70šS) and relaying them to the ground, but they cannot pinpoint the position of the transmitter since they don't move relative to the beacon. But since GPS/EPIRB units can transmit your GPS position in addition to the normal identification information, geo-stationary satellites can immediately relay your signal and position to Mission Control Centers around the world. Thus, you don't have to wait for a orbiting weather satellite to pass overhead to pick up your distress signal. This can reduce the time to notification to as little as 4 minutes, and increase the accuracy of a transmitter's position to within 0.05 NM. Today's WAASenabled12- channel GPS are providing position fixes that are accurate to within a few feet, but the COSPAS-SARSAT message protocol only allows precision to four seconds of accuracy. This is good enough to determine who is the closest rescue asset. The drawback of EPIRBs with built-in GPS is that the acquisition of an accurate position depends on good visibility of orbiting GPS satellites and data has to be acquired from a cold start, which can take a while.
ACR RapidFix: Without having to wait for a cold start acquisition from a built-in GPS, the ACR RapidFix uses an optical interface connection to the ship's GPS to update and store the vessel's current position. When activated the RapidFix can immediately relay the vessel's last known position. Based on practical tests, ACR says RapidFix has proven to be more reliable and faster than position fixes from EPIRBs with built-in GPS receivers.
Category I and II: By rule, all EPIRBs have to activate and transmit when they are placed in the water. Category I brackets will automatically deploy the beacon when being submersed to a depth of 14 ft, while Category II brackets need to have the beacon released manually.
Personal Locator Beacons: As of July 1, 2003 the FCC has approved the sale of Personal Locator Beacons (PLB). They are similar to Category II EPRIBs in the message they transmit. However they have no strobe, operate for only 24 hours and are not required to transmit in an upright floating position. PLBs are smaller and less expensive so they can be carried as part of your personal gear. PLBs are intended for land, sea or air use: their encoded signals identify them as being a personal beacon, and they may or may not float. Personal 406 MHz EPIRBs: FCC approval for so-called Personal 406MHz EPIRBs is still pending. They are very similar to PLBs, but they float and their signals identify them as marine units. They are also programmed with a different location transmission protocol that would send the distress signal to the appropriate rescue agencies.
Register your 406 EPIRB!
It is mandatory that you register your 406 EPIRB/PLB with NOAA/SARSAT. This is important because they are the agencies who will coordinate the rescue should your beacon begin transmitting a distress signal. The Coast Guard says that 94% of EPIRBs alerts are false and that registration data has enabled them to resolve 65% of the alerts prior to launching SAR operations. There is no fee for registration; you simply complete the NOAA form packaged with your EPIRB and mail or fax it in. Online Registration has just become available under http://www.beaconregistration.noaa.gov. This will make it even easier to keep your contact information up to date. When filling out the registration form, carefully select the person(s) the NOAA or the Coast Guard should contact in the case your beacon goes off. These should be individuals who are familiar with your plans, and who will be likely to be available. Contact NOAA toll-free at 888-212-SAVE or visit NOAA's search & rescue web site http://www.sarsat.noaa.gov for more information.
However, you no longer have to license your 406 EPIRB with the Federal Communications Commission (FCC) on Form 506 if you are a "Voluntary Ship." That is the FCC's name for a vessel not required by law to carry a radio, using no transmitting equipment other than marine VHF, radar and EPIRB and not visiting any foreign countries other than Mexico and Canada.
Can I lend my 406 MHz EPIRB to another boater?
The problem, of course, is that if you lend your 406 to a boater with a different boat description or different land contacts, you are likely to send the Coast Guard on a wild goose chase. The key to this is alerting NOAA of the change of information, even if only for a week or two. Fax another registration form documenting the new information, and the approximate time that this will be in effect, to the MCC at 1-301-568-8649. You can download a new registration form off the web at www.sarsat.noaa.gov under the heading Register Your Beacon, or you can use the online
registration to maintain your contact info.
Conclusion
An emergency transmitter should provide timely, accurate information to rescue
agencies about an emergency situation in a timely fashion to reduce the
time of response and increase your chances of being saved. If you own
an older Class A or B EPIRB, think about upgrading to a Category I or
II 406MHz EPIRB because the new technology offers dramatic improvements
in accuracy and speed of notification to Rescue Control Centers, which
in turn drastically improves your chances of getting rescued quickly.
New technologies such as GPS enabled beacons are more powerful, accurate
and portable, so we expect to see an increase of their use in marine,
aviation and land-based applications. One thing is for sure, however:
You must do your part in registering your EPIRB/PLB and keeping the emergency
contact information up to date, so rescuers can validate the authenticity
of the distress signal.
|
| |
Class
A/B |
PLB |
Cat
I/II no GPS |
Cat
I/II w/GPS |
| Coverage |
30%
worldwide |
Worldwide |
Worldwide |
Worldwide |
| Approx.time
to Notification |
6 hrs. |
40 min. |
40 min. |
40 min. |
| Accuracy |
12nm |
2nm |
2nm |
0.05nm |
| Search
Area |
452nm2 |
12.5
nm2 |
12.5
nm2 |
0.014
nm2 |
| Cost |
$145 |
$599 |
$709 |
$1049 |
| |
|
|
Useful Boating Articles
|
|
|
