EPIRB plus PLB equals SOS

Allan Tarvid
July 28 at 9:00 am  | Mobile Reader | Pring this storyPrint 

Are you ready for an on-the-water emergency? A floating ditch bag can hold everything you need to call and wait for help.
Are you ready for an on-the-water emergency? A floating ditch bag can hold everything you need to call and wait for help.
Courtesy ACR Electronics

Standing in ankle-deep water on deck while too far from the shore to see it? Congratulations: You are behind a marine-grade 8 ball.

Most people think of a cell phone first when calling for help, but the U.S. Coast Guard suggests using a VHF radio instead. Cell phone networks tend to offer limited coverage in many boating areas, and most of the devices stop working practically on contact with water.

Boaters with marine VHF radios should listen to channel 16 while cruising or fishing and be ready to pass on a distress call if the Coast Guard doesn’t acknowledge it quickly.

Owners of VHF radios with properly registered digital selective calling need only press the red DSC button on the radio to send a distress call automatically. If the radio is connected to an onboard GPS, the distress call will include your coordinates.

But when an emergency happens you might not have time to call for help with a radio or cell phone. VHF radios are not monitored on many inland lakes that might also not have cell coverage.

Here, a life-threatening emergency is more likely to have a happy ending with help from satellites.

The international Cospas-Sarsat system is the gold standard for worldwide search-and-rescue operations. The COSPAS part stands for COSmicheskaya Sistema Poiska Avariynyh Sudov which translates from Russian to English as “space system for the search of vessels in distress” (feel free to bet on that to win the cold beverage of your choice from fellow boaters).

The SARSAT part is short for Search and Rescue Satellite Aided Tracking.

The system now uses satellites in low-earth orbits and in higher, geostationary orbits to detect distress calls from mariners, aviators and recreational enthusiasts, and to quickly locate and rescue them.

A system upgrade is underway that adds SAR receivers to new GPS satellites that operate in medium-altitude Earth orbits.

Since October of 2012 new satellites launched for service with the U.S. Navstar, Russian GLONASS and European Galileo GPS systems have had SARSAT capability built in.

The current geostationary satellites cover the entire Earth except the polar regions and while they can receive distress messages they can’t locate the beacon sending them unless the message includes the beacon’s coordinates.

SARSAT’s four low-earth orbiting satellites can locate a beacon without the help of GPS by using Doppler technology, but each satellite has a view of only a small part of the Earth at any given time, so there might be a delay in receiving a distress signal from one of them.

Once the system upgrade is complete, the GPS satellites in medium-earth orbit will offer the advantages of both current satellite systems without the limitations of either, and will retransmit distress messages and offer independent location-finding of beacons in near real time with worldwide coverage.

The upgrade will also allow a confirmation to be sent to the beacon letting its user know his distress call has been received.

Just as with the DSC function on VHF radios, an emergency SARSAT beacon must be registered. Registration forms include spaces to record a beacon’s unique identification number; the owner’s name, address and contact information; an emergency contact’s name and information; and a remarks section where a boat’s description, owner’s personal medical information or other important data can be included.

The whole idea of registration is to help SARSAT find you faster and be better prepared to help you during the rescue.

Two types of beacons use this international rescue system: EPIRBs (emergency position indicating radio beacons) and PLBs (personal locator beacons).

The larger EPIRBs are designed to ride in a bracket on your boat. All brackets can be released manually, and some are designed to release automatically during sinking when they reach a depth of about 3 feet.

PLBs are smaller and can be tethered to a life jacket on the water or carried in a pocket on land.

My preference is for a PLB, something I can use on land or water.

Both EPIRBs and PLBs come with or without built-in GPS but I wouldn’t waste two seconds looking at a beacon without it. Having GPS built in means the beacon transmits your coordinates with each message string, and that means rescuers can come straight to your emergency “address” on the water.

Beacons are also available with and without a built-in strobe or bright LED light, but I prefer those with lights even if I have a separate emergency strobe light onboard. Redundancy is good, and at night or in a storm the strobe can help rescuers see you.

When you activate a beacon, a signal is sent that includes your unique identification number and, if you were smart enough to buy a GPS-equipped beacon, your latitude and longitude. After a satellite receives your signal it relays it to one or more Earth stations called local user terminals that process it and then retransmit it to a mission control-center.

The mission-control center matches and merges the alert message with any other received messages, geographically sorts everything out and forwards your alert to a rescue coordination center.

There, it is investigated, deemed a real emergency rather than a false alarm and assets are launched to find you.

This all sounds like it should take a week but it’s done in minutes — unless your beacon doesn’t have GPS or for some reason its GPS antenna can’t get a clear enough view of the sky to find your position.†

Your beacon signal is received by both a geostationary satellite that remains in the same position overhead and by the satellites in low-earth, pole-to-pole orbit that move constantly in respect to your position as they circle the Earth every 100 minutes.

The satellites in low-earth orbit use Doppler Effect technology to find your position as they pass over you. Doppler can fix your position to within a mile or less. Then, rescue vehicles, boats or aircraft not equipped to home in on a beacon must get as close as Doppler can get them and then resort to “local” search methods involving radios, flares, strobe lights, signal mirrors or simple eyesight.

You can maximize your odds for a safer time in the water and a faster rescue.

First, make sure everyone onboard knows what to do if your boat gets in trouble; compare this to holding household fire drills.

Everyone should know how to operate the DSC feature on your marine VHF radio, how to release and activate an onboard EPIRB or PLB and understand that its antenna must have a constant, clear view of the sky all the while you are in the water.

If everyone isn’t already wearing a properly adjusted personal flotation device, he or she should be within easy reach of one.

If you have a handheld VHF radio and a strobe light onboard, someone should be assigned to grab them as they leave the boat. If you have flares aboard everyone should know how to launch or ignite them.

Having a floating ditch bag preloaded with these items and stowed where it will float off of a sinking boat if nobody thinks to grab it on the way out can simplify all this.

Stay together in the water near the boat if part of it is still above water, but don’t tie yourself to the boat — it could sink at any time and take you down with it.

Relax and be patient: As of May 23 SARSAT had already resulted in the rescue of 72 people this year just in the United States.†

A PLB is the authorís choice for an emergency beacon because they are small and can be carried.
 





View other articles written Allan Tarvid