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September 2008    Download the Entire Issue (PDF) Available to the Public Vol. 34, No. 9   RSS Feed for Undercurrent Issues
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Rescue Devices For Saving Your Bacon

the role that flags, flashlights, etc. play if you’re lost at sea

from the September, 2008 issue of Undercurrent   Subscribe Now

By now you have heard recent stories of divers accidentally separated from their boats and being left to drift helplessly at sea. I’m aware of nine such incidents involving 28 divers in the first half of 2008 alone. Many years ago, six Japanese divers were lost in the waters near Palau and their bodies were found too late, but not before one of them had written on her slate, “We can see you searching for us but you can’t see us.” That encapsulates the problem. You may surface to easily see your boat, but can the people in the boat see you?

I had my own uncomfortable experience as a dive guide in Sudanese waters back in 1992, when technical problems wit the boat meant that my group had to be abandoned for a few hours after surfacing from a dive. It certainly gives one time to think out a better strategy. Many sport divers dive without any form of surface signaling device. Some liveaboard operations hand out simple safety sausages that can be inflated at the surface. Provided the diver keeps the open end closed and under the water, one will stand upright, but how easily can it be seen?

Some Devices Are Dependent on the Time of Day

After a boatload of British divers were lost and left to drift until dark, when their dive lights could be spotted by searchers, it became a rule within Egypt’s marine parks in the Red Sea that all divers must carry a surface marker and a dive light for such eventuality. Another group of day-boat divers that got separated on the surface from their boat at the Elphinstone Reef (not part of the marine parks) were less lucky and only one survived after he made the long swim to the shore.

A reliable light held in reserve with fully charged batteries can be a life-saver once darkness falls. An emergency strobe beacon of the type that is rated to as much depth as you are ever likely to take it will give a piercing flash of light in all directions regularly and for many hours. But wouldn’t it be nicer to be found before nightfall?

In May this year, an American and British diver on the Great Barrier Reef were rescued after 19 hours at sea. Soon after that, another group of five divers made the news when they were ‘swept away on a strong current’ at Komodo Island in Indonesia. Strong currents are often a feature of the world’s most notable dive sites.

Surface marker buoys come in all shapes and sizes and vary in their ability to be seen. Standard ones are only good over a distance of, say, half a mile. Some divers carry an old CD with them that can be used to flash a reflection of the sun - - if there is sunlight. You don’t just flash at will. You must create a visible and consistent reflection of light toward the direction of your potential rescuer. Years ago it was possible to buy a heliograph mirror for divers. It was simple to aim it by means of a sighting device so at least you knew that it was doing its best to tell people you were there. It didn’t prove popular in the marketplace.

Very loud whistles like the Dive Alert siren (approximately $40; can be attached to the direct-feed inflator of your BCD or on a stand-alone hose and make use of compressed air from your tank. They emit an ear-piercing screech that can attract the attention of your pick-up boat driver if he is inattentive when you surface. Don’t expect anyone to hear that screech over the sound of a boat engine at full throttle, though. And if a boat crew does hear an unexpected whistle, it still leaves the problem of identifying where it comes from. Visual indicators are always important.

What About Flares and Beacons?

Flares come in numerous shapes and sizes. Some produce a colored smoke that will make a diver into a larger subject for a searching aircrew while an emergency plastic streamer does the same thing but for longer. A parachute flare gives boat crew an idea of the general direction they should be looking in for a lost diver but they represent a one-hit-wonder. It is not worth sending up a flare, unless you know that someone relevant can see it. That seems to be the crux of all attention-grabbing surface devices. Someone must know that you will need rescuing.

Personal Locator Beacons (PLBs) were originally missold as Emergency Position Indicating Radio Beacons (EPIRBs) until the Coast Guard rightly pointed out that they are not sufficiently powerful, nor do they use the now-current 404-Mhz frequency, so no Thunderbirds get launched. Neither are EPIRBs really suitable for the quick response needed by divers, because it can take up to 90 minutes for rescue services to be alerted this way. However, using a different radio wavelength (121.5-Mhz), PLB devices can be very effective over surface distances of three miles if the search vessel is equipped with a suitable tracking device, and longer when the beacon is sought from the air.

In the UK, lifeboats are also so equipped but there is little point in buying a lone transmitter for use anywhere else if there is no tracking device available. And you’re still left with the possible unreliability of batteries and electronics that have been taken underwater. Some PLBs now use both frequencies but usually need a waterproof case for diving. The Undersea Hunter boats at remote Cocos Island in the Pacific equip every diver with an emergency-only PLB transmitter, and crews are welltrained in the use of the tracking device. A good way to ensure a strong outgoing signal is to combine the unit’s flexible aerial with an inflated SMB. McMurdo makes PLBs with and without GPS (prices start at $300;

My Favorite Rescue Device

I prefer a low-tech answer because I always know if it is going to function properly. Since that fateful day in the Sudan, I have always carried a big fluorescent yellow flag on a long extending pole. I attach it to my tank by means of two elastic straps. The biggest problem seems to be getting your signal marker high above cresting waves. The flag can be raised on its extending pole above the swell and forms a horizontal shape with an attention grabbing flutter on a sea breeze.

On one occasion when I was using mine to signal my arrival at the surface to my cover boat after a dive with a closed-circuit rebreather, divers on another cover boat returning to the Sea Hunter noticed my flag from a distance of several miles. I have used my surface flag in earnest in the waters of the Mergui Islands, in the Maldives, in the Galapagos, after the quick drift dives of Aldabra, and almost every time after a high-voltage dive at Cocos or Malpelo.

Research done by Heriot-Watt University on behalf of the British government some years ago determined that a yellow flag was the most visible marker when it came to search by sea or from the air. It stated, “The folding flags were by far the most reliable and cost-effective location device we tested, particularly the day-glo yellow pennant, which was consistently spotted at more than one mile and up to two miles. Yellow was the most conspicuous color in all sea states, even with breaking wave crests, and could be located in deteriorating light when it was impossible to locate pennants of any other color.”

I recommend every diver gets so equipped.

(Note: The only place we could find yellow diver flags easily for sale online was at Bowstone Diving in the United Kingdom at; $33, plus $27 shipping. But check with your local dive shop for options closer by.)

John Bantin is the technical editor of DIVER magazine in the United Kingdom. For 20 years, he has used and received virtually every piece of equipment available in the UK (and the U.S.) and makes about 300 dives for that purpose, and he is also a professional underwater photographer.

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