Greetings Fishies!
being issued.
Recalling the tragedy of the F/V Big Valley you may remember that no distress call was made. Had it not been for the EPIRB activation, no one would have known her location.
While some of the following is a bit dated, Wikipedia has some information about them:
Emergency Position-Indicating Radio Beacons (EPIRBs), Emergency Locator Transmitters (ELTs) and Personal Locator Beacons (PLBs) are tracking transmitters that operate as part of the Cospas-Sarsat satellite system. When activated, the beacons send out a distress signal that allows the beacon to be located by the satellite system and search and rescue aircraft to locate the people, boats and aircraft needing rescue.
EPIRBs are used for maritime emergencies, where ELTs are used in aircraft applications and PLBs are used for personal use.
The basic purpose of the emergency beacons is to get people rescued within the "golden day" when the majority of survivors can still be saved.
Between 1982 and 2002, these systems enabled the rescue of 14,700 people. As of 2002, there are roughly 82,000 registered beacons, and over 500,000 of the older unregistered type.
Most beacons are brightly-colored, waterproof, fit in a cube about 30 cm on a side, and weigh 2-5 kg. They can be purchased from marine suppliers, aircraft refitters, and (in
There are two types: manually activated, and automatically activated.
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In the
Current types
Current EPIRBs are generally divided into three classes; Category I, Category II, and Class B (or Category B).
Category I EPIRBs are considered the best but are also the most costly. Category I EPIRBs can be either deployed manually or set to deploy automatically in the event of a disaster at sea. These EPIRBs are generally housed in a specially designed bracket on deck and the buoyant beacon is designed to rise to the surface and emit two signals, an emergency homing signal on 121.5 MHz and a digital identification code on 406 MHz that can be used to identify the stricken vessel. Category I EPIRBs used in American waters must be registered with NOAA.
Category II EPIRBs are similar to Category I EPIRBs but are generally manual deployment only. Also like Category I EPIRBs, Category II units must be registered. Category II EPIRBs are also generally less costly averaging less than US$1,000.
Class B EPIRBs, also called Category B or "Mini B", operate a 121.5 MHz homing signal only and are usually manual deployment only units. They are the cheapest units but also the least capable. Since the signal has no identification component, Class B EPIRBs are not registered. Due to their limitations, Class B EPIRBs are slowly being phased out. The International Cospas-Sarsat program will no longer monitor Category B EPIRB signals as of
What is meant by Manual and Automatic Deployment and Activation?: For an EPIRB to begin transmitting a signal (or "activate") it first needs to come out of its bracket (or "deploy"). EPIRBs can be activated manually - when a button on the unit is pushed, or automatically - when water comes into contact with the unit's "sea-switch". Deployment can happen either manually - where someone has to physically take it out of its bracket - or automatically - where water pressure will cause a Hydrostatic Release Unit to release the EPIRB from its bracket. If it does not come out of the bracket it will not activate. There is a magnet in the bracket which operates a reed safety switch in the EPIRB. This is to prevent accidental activation when the unit gets wet from rain or shipped seas. The Category I - type is recommended by
Registration
Modern emergency beacons transmit a serial number. When the beacon is purchased this number should be registered with the relevant national authority. Registration provides the national authority with phone numbers to call, and a description of the signaling vessel, including its home port. The registration can give much of the information needed for starting the rescue. Also, they provide an easy way for the notification services to check and eliminate false alarms quickly.
All the systems work something like this: A beacon is activated by a crash, a sinking, or manually by survivors. The beacon's transmission is picked up by one or more satellites. The satellite transmits the beacon's signal to its ground control station. The satellite's ground station processes the signals and forwards the data, including approximate location, to a national authority. The national authority forwards the data to a rescuing authority. The rescuing authority uses its own receiving equipment to locate the beacon and makes the rescue or recovery. Once the satellite data is in, it takes less than a minute to forward the data to any signatory nation.
The most modern 406 MHz beacons with
An intermediate technology 406 MHz beacon (US$ 500-900) has world-wide coverage, locates within 2 km. (12.5 km² search area), notifies kin and rescuers in 2 hours maximum (46 min avg.), and has a serial number to look up phone numbers, etc. This can take up to two hours because it has to use moving weather satellites to locate the beacon. To help locate the beacon, the beacon's frequency is controlled to 2 parts per billion, and its power is a hefty five watts.
Both of the above types of beacons usually include an auxiliary 25 milliwatt beacon at 121.5 MHz to guide rescue aircraft.
There have been instances where the EPIRB was accidently acitvated leading the Coast Guard on a frustrated chase. This usually happens when the EPIRB is knocked off of its bracket. However, some people forget to deactive the EPIRB when it is retired. The satellites have tracked them in the back of garbage trucks, floating in fish ponds, in the mooring basin etc.
Stay tuned!
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