EPIRB Search and Rescue Patterns: Part 2

Above: the that-morning patterns run by Coast Guard and Navy aircraft in their search for survivors of a Massachusetts commercial fishing boat whose EPIRB activated offshore in the dead of a New England winter. Note that the Coast Guard's dirft model sent them on a pattern that extends far southeast and east/northeast of where the EPIRB was initially spotted by an overflying Coast Guard jet.

If Coast Guard or other search-and-rescue air and seacraft are in search of us after receiving word, via personal locater beacon, SPOT, VHF radio maday or friend [link forthcoming], that we are lost or in trouble, they'll make many assumptions about where we'll drift as time wears on.

Their predictions come from drift models (formerly JAWS, now SAROPS) that take into account surface current, tide and wind.

Created by tides and winds, surface currents tug us, along with our gear and kayaks, in reasonable-to-assume directions, which gives search-and-rescue personnel a leg-up on where in a vast ocean or bay to concentrate their resources. But we drift differently than a sailboat, which drifts differently from a person in the water, which drifts differently than a sinking fishing vessel, etc.

The Coast Guard takes into account all those differences - which drives home the point of identifying in a mayday what kind of boat we're in.

The Coast Guard factors all of those differences into how they calculate their search model for us or whoever has gone missing.

In the image above , you'll notice that the Coast Guard in New England (US, Boston area) made easterly assumptions about where the crew of Lady Luck, a 55-foot Newburyport, Ma. commercial fishing boat, had drifted in the several hours after the sunken vessel's EPIRB emitted its distress signal.

Were the search for one of us, equipped with a personal locater beacon [link forthcoming] or not, the Coast Guard would assume something similar about our drift.

Since time is of the essence in all rescues, and especially in this case, given that the Lady Luck sank during the winter, the Coast Guard concentrated their densest search patterns where they assumed the crew, in either survival suits or a life raft, would have drifted.

The image below shows the later, that-afternoon search. Note how the drift model has begun making different predictions now that time has worn on and conditions have changed: the densest searches now took place far northeast, and southeast, of where the EPIRB was initially located.

By now a Coast Guard cutter and Canadian helicopter have joined the search. The search patterns take on an even more easterly aspect, as well as north and northeast, of the of the initial sighting of the EPIRB:


Later in the day the search shifited further east, with the densest patterns running north and east, but trending southeast, of the original sighting:

The search would grow ever wider in the coming 36 hours. Neither survivors nor the Lady Luck -- aside from assorted pieces of commercial fishing gear that floated off the sinking boat -- were recovered.

The search pattern evolved further, as you'll note in the third post.

To read more about the personal locater beacons which act as stand-ins for EPIRBs for kayakers in remote waters, and about the newest addition to emergency electronics, the SPOT beacon, which sends text or email messages and Google Maps showing your exact location, to friends or emergency personnel, wait a few days while I post up photos and video I shot of one of the former, available from plbrentals.com

copyright 2007Just Another Guy Named Dave
images courtesy USCG
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EPIRB Rescue Search Patterns: Part 1

Above: Coastal New England (US). The first in a series of images illustrating the efforts Coast Guard units expend on search-and-rescue operations activated by EPIRBs, or emergency position indicating radio beacons.

In order to develop a search plan, we take the crew's last known position, wind, wave and current sea states, and develop a simulated scenario, known as a drift model, in a computer. We fast-forward the model from the time of their last known position to our current time in order to find a most likely position the victims could be at.
--- Coast Guard petty officer describing Coast Guard search and rescue

An EPIRB is a serious piece of emergency equipment you'll see lashed to the cabin housing of most every commercial fishing boat in the US, from the smallest lobster boat to the largest trawler.

They're expensive, bulky, not form-factored to the tastes of consumers, and are cousin to the myriad $500 personal locater beacons, or plbs (read more about plbs in earlier posts) sold by outdoors outfitters like REI and marine suppliers like West Marine.

Above: a 406 EPIRB fastened to the cabin top of a day-boat seiner in Gloucester, Massachusetts. EPIRBs activate automatically during a boat's sinking, or when submerged in nine feet of water. Size is that of about two large grapefruits.

A couple of winters ago New England Coast Guard units responded to an EPIRB transmission (EPIRBs do not transmit voice data) from the 52-foot commerical fishing vessel Lady Luck, a recently upgraded boat skippered and crewed out of Newburyport, Ma. by two men in their 20's.

The EPIRB activated when the Lady Luck sank while enroute to Gloucester, Massachusetts, my hometown.

The EPIRB gave the Coast Guard a fix of 43.20.4 north , 69.54.8 west, or about 30 miles east of Cape Elizabeth, Maine, just past where New Hampshire's token coastline gives way to the sprawling east-sliding unravellings of Maine.

After zeroing in on the EPIRB's electronic signal, a Coast Guard jet visually sighted the EPIRB's flashing strobe but not the Lady Luck.

The jet circled and dropped a life raft in the hopes that the EPIRB and the raft would follow the drift pattern of the survivors.

A Coast Guard helicopter ran at first light that day the search pattern shown below: wide pie slices radiating out from where the EPIRB was first located:
After the helicopter's initial search , a helicopter and Navy plane ran a series of tightly-spaced and overlapping parallel tracks:

As you can see, the tightest grids were flown south and southeast of the EPIRB's initial location.

The drift model shows that the Coast Guard, tracking the drifting EPIRB and running a drift model, assumed that survivors would float southeast: New England's prevailing winter winds are northwesterlies.

The search patterns began to vary greatly over time, varying with the Coast Guard's ever changing dirft models of the survivors over time.

Above: Sean Cone, owner of Lady Luck, unloads fresh cod at the Pigeon Cove/Whole Foods market in Gloucester. Whole Foods' fish buyers and processing plant are dockside in town. They buy much of the local fleet's groundfish (cod, haddock, flounder, etc.) Peter Prybot photo/AP/Gloucester Daily Times

As an aside, know in advance that, sadly, neither the Lady Luck nor its crew were found. The Lady Luck sank in 500 feet of water and was later videographed by an underwater probe as part of the Coast Guard's investigation into why the vessel sank.

It's unlikely Sean Cone, 24, the ship's captain and owner, and his crewman, Dan Miller, 21, had time to don survival suits.

Above: a 406 EPIRB fastened to the cabin door of a lobsterboat docked at the State Fish Pier at Gloucester, Massachusetts. Note the unit's strobe light and bulky whip antenna.

images and text copyright 2007Just Another Guy Named Dave
map images courtesy USCG
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EPIRB Rescue Search Patterns: Intro

Above: Lady Luck steams into port at Gloucester, Massachusetts. Peter Prybot photo

To run rescue searches, the Coast Guard does its best to corral chaos: directed by an onland command center, air and water crews run search patterns based on drift models that assume where wreckage and survivors will drift over time, according to the effects of winds, surface currents and sea state. Below, one recent story bout the Coast Guard's futile search for the fishing vessel Lady Luck.

Just Another Guy Named Dave
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Personal Locater Beacons (PLBs)

Above: the bottom face plate of the ACR Microfix personal locater beacon and the unit's lanyard. Personal locater beacons are an excellent alternative to bulkier and more expensive EPIRBs. The advantage of the Microfix is that the unit includes your gps coordinates with the registered distress signal it sends to satellites which in turn relay your distress to a large battery of search and rescue resources.

I recently received in the mail a demonstrator model of the ACR Microfix, a pricey but invaluable piece of safety gear anyone planning a remote offshore expedition might want to consider.

Here's how the Microfix, a personal locater beacon, works. You buy or rent the unit (purchase is about $500, rental about $50/week), register it with NOAA, test the battery, test the internal gps, then strap the beacon to your pfd and off you go.

If during your expedition (the death of Andrew McCauley comes to mind), you find yourself in grave and immediate danger, you unfold the unit's bent antenna, push the transmit button, and watch as the 406 and 406/gps buttons confirm their transmission.

Depending on the temperature and other factors, the device transmits your registered distress signal and low-frequency position signal for 24 hours or more.

It's a passive method, and not one that gives you license to give up on trying to save yourself.

Local search and rescue personnel can't communicate with you via the device, for example. You'll need to remain on alert for their arrival, and keep in mind that should the gps signal be obscured by weather, submersion, or tree cover, SAR won't have access to your coordinates. In short you'll need handheld if not rocket flares to guide search and rescue personnel as they approach and zero in on your triangulated position.

Above: the Mircrofix personal locater beacon with its bent antenna opened for transmission the day before a violent New England nor'easter. Note the large red transmit button which is covered by the antenna tab when the antenna is wrapped, preventing accidental activation.

Personal locater beacons are a different animal than the EPIRBs found on commercial vessels such as lobster and fishing boats.

Personal locater beacons have to be deployed manually: open the antenna, push the transmit button, keep the unit from getting submerged. Most don't float and thus need to be securely fastened to your pfd (or backpack, if the case might be).

Perhaps most important, personal locator beacons are half the cost and an eighth the price of EPIRBs, are not restricted to marine applications, and are free to register in the US.

Below: the warning plate that covers the MicroFix's internal gps unit and antenna:
If you want to best assist search-and-rescue personnel enroute to help you, make sure the unit's gps can receive your latitude and longitude. If you're on land, move out from beneath tree cover. If you're in the water, do your best to keep the unit above water.

Note that the unit's 406 distress signal, distinct and separate from the gps signal, is more robust and not as vulnerable to obstructions.
Above:the unit's all-important lanyard. This PLB unit won't float. Drop it overboard and it's gone.
Be sure the unit is attached to your pfd or person. You want search-and-rescue personnel to look for you and not the random piece of gear the unit is attached to and that has floated off.

Finally, avoid the all-too-common VHF radio user's error: don't store the unit in a hatch. Should you need to activate the unit, last mistake you want to make is to open a hatch during violent weather. You run the risk of swamping and will be off-balance as you twist to open your day hatch.

Below:the unit's clip-on harness. The harness provides two sturdy molded loop points through which to run pfd straps or backpack webbing:
For more on units of this type, including the SPOT beacon, a distress beacon which is less expensive, and smaller, and which utilizes both different technology and different methods to signal your distress, see the previous pair of posts.

Below: what techies call the anatomy of a plb/EPIRB-based rescue. Note that EPIRB and gps/EPIRB signals are captured by different sets of satellites. In either case, your distress signal has to be processed by three authorities before it's relayed to search-and-rescue personnel local to your area. That might be a local Coast Guard Station, harbormaster, volunteer moutaineering unit, park ranger unit, etc:

text and photos copyright 2007Just Another Guy Named Dave
demo unit courtesy plbrentals.com
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EPIRB Search Patterns: Part 3

Above: the Coast Guard's airborne search patterns as their soon-to-be 40-hour search for the fishing vessel Lady Luck spread out along the southern Maine coast of New England (US, near Boston). Note the tighter grid the Coast Guard ran northeast of the EPIRB's initial location, the looser grid they ran further to northeast. The Coast Guard left the Lady Luck's EPIRB in the water the hope that its drift would mimic that of the small fishing vessel's two-man crew lifeboat or their crews in their survival suits, also known as immersion abandonment suits.

Below: the Coast Guard soon had two aircraft and the cutter Seneca involved in the search. The search grids laid down by the searchers was by now broad, widely-spaced, loose. Note how the aircraft, following drift models, focused their flyovers far southeast of where the EPIRB was initially pinpointed by an overflying Coast Guard jet:
Below: the search continues to evolve, and now includes a second Coast Guard cutter, the Flying Fish, and two aircraft. The search patterns dip far southeast of the EPIRB's initial location, to waters northeast east of Boston, Ma., and includes cursory runs along the Portland, Maine shipping lanes and east of intricate coast of downeast Maine (links to Maine Island Trail Association).
Below: the saddest image. When the Coast Guard finally called off what was a 40-hour search for the two young crewmen of the EPIRB-equipped fishing vessel Lady Luck, the search had covered 8,000 square miles. Note how dense and thorough the search pattern appears in areas adjacnet to Lady Luck's EPIRB transmission, and how loose, yet specific, the outlying search patterns are to east, far northeast, and far southeast:

Read parts 1 and 2 and 5 of this 5-part series. Part 4 isn't written yet:
Part 1
Part 2
Part 5
copyright 2007Just Another Guy Named Dave
images USCG
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