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This page is to add some story's on rebreather blunders and malfunctions. It is here to tell stories of mistakes that can be made by all rebreather divers. I hope it will be helpful to learn how mistakes can be avoided .

updated 26 may 2010


First article is written by Howard Hall and can also be found on his web (published with permission)

Rebreather Blunders and Malfunctions

Howard Hall


Howard and Thurlow with High Def system - ©Michele Hall

   The introduction of the ElectroLung during the late 1960s seemed to herald a revolution within the sport diving industry. But after a few short years and several deaths, this revolution came to a crashing halt. The promise of silent, bubble-free diving was replaced by a consensus that rebreathers promise only death and multi-million dollar lawsuits.

   Despite the grim history and the prospect of certain death guaranteed by many friends and colleagues, I found the dream of silent diving almost overwhelming. Finally, in the late 1980s, opportunity presented itself. I received a contract to make a film about the Sea of Cortez. The film provided the funds and the justification for pursuing rebreather technology. So in the spring of 1989, Bob Cranston and I traveled to Philadelphia to train on a pair of Biomarine 15.5 rebreathers.

   The Biomarine 15.5 was a prototype rebreather designed to replace the US Navy's Mark 15. Fortunately for Bob and I, Biomarine failed to acquire the Navy contract and this failure left a couple dozen of these closed-circuit, mixed-gas rebreathers drifting aimlessly in the civilian community. Biomarine had two of these units at their Philadelphia factory and was willing to loan them to us, assuming we were willing to pay a considerable lease fee and, of course, sign a waiver that detailed the various and likely ways we would almost certainly die using the gear. A few months later, Bob and I donned our leased rebreathers and made our first open water dive in the Sea of Cortez. We were, at once, excited and terrified. We descended to just over fifteen feet and made it back alive.

   After surviving the making of our Sea of Cortez film (Shadows in a Desert Sea, WNET Nature), I acquired and highly modified my own Biomarine 15.5 rebreather. My underwater crew and I have been using rebreathers extensively ever since. And today as I write this, floating on the Undersea Hunter above a beautiful Fijian reef, I celebrated logging my 1,000th closed-circuit hour. That was the only event worth celebrating today, however. During today's dive my trimix computer screen went blank soon after beginning a descent to 270 feet where Bob and I planned to use two underwater IMAX® systems to film Richard Pyle collecting rare fish. Bob's camera jammed after running for only ten seconds. My camera failed to run at all. Our reward for total underwater cinematic failure was to spend three hours decompressing. Our rebreathers, however, worked great! And rebreather reliability is not something to be taken for granted.

   During my 1,000 hours of rebreather diving, the rather high frequency of equipment malfunction has only been exceeded by the much higher frequency of stupid diver mistakes. The editors of Oceans Illustrated believe this magazine's readers may benefit from a chronicle of these dangerous blunders, despite the humiliation such recounting may cause members of my crew and me. My hesitation at humiliating myself by admitting numerous stupid, life-threatening errors while diving closed-circuit is, however, well off-set by the pleasure I take in recounting the stupid mistakes my friends have made.

Always assume your rebreather is going to malfunction at any moment.

   Always assuming that your rebreather is going to malfunction, is a life extending mind-set. The two rebreathers that I leased for my Sea of Cortez film were only 50% reliable. That is to say that the unit Bob used seemed to work just fine most of the time and the one I used almost never worked properly. Since I was paying the lease fees, this seemed completely unfair to me. But Bob never seemed inclined to trade units with me. During our second open water dive (the first having been the intrepid descent to fifteen feet) my rebreather showed an alarm light just after we reached the bottom in sixty feet of water. Seeing the alarm light, I suddenly felt my worst fears had come true. In a moment I was sure to die of oxygen toxicity! I stopped on the top of a rock, grabbed my open circuit bailout regulator (which at the time was attached to a 15 cf tank that hung from my BC harness) and hoped I could get the regulator clear before the inevitable convulsion. The seizure didn't come. After checking my secondary display (which shows the oxygen pressure readings on each of three oxygen sensors), I realized that death was not so imminent.

   Few things actually happen fast when using a rebreather. I had plenty of time to realize that my on-board computer (which controls the rebreather's gas mixtures) had failed and that I would have to add oxygen manually. In fact, I would have had ten minutes or more to sort the problem out even after the rebreather had quite working. Checking my instruments had easily averted a problem.

   The rebreather I used in the Sea of Cortez helped train me to regularly check my instruments. The rebreather encouraged regular instrument checks by failing to function properly on 80% of my dives. An argument can be made for owning a rebreather that almost never works right, since frequent failures encourage good instrument monitoring habits and familiarity with emergency procedures. Personally, however, I wouldn't go so far as purposely seeking out unreliable rebreather designs. However, there is inherent danger in rebreathers that work flawlessly almost all the time. Richard Pyle, an ichthyologist famous for discovering new fish species while diving his Cis-Lunar rebreather to over 400 feet, calls this the "Richard Pyle rebreather paradox." The paradox states that, while everyone desires a rebreather that is reliable, reliability begets complacency.

Check your instruments

   The importance of frequent rebreather instrument checks cannot be over emphasized. Since Bob Cranston's rebreather worked pretty well in the Sea of Cortez, he developed less disciplined instrument checking skills than I did. A flawlessly working rebreather is almost as dangerous as a completely unreliable unit since reliability encourages instrument complacency. Bob discovered the wisdom of this during a dive in Grand Cayman.

   We were filming yellow-head jawfish in fifty feet of water below the boat early one morning. Bob had not had his second cup of coffee. After about fifteen minutes lying quietly on the bottom, Bob was suddenly stricken with dizziness and tunnel vision. Had he failed to act immediately, he would have been unconscious in less than six seconds. Bob's self- training saved him. In the event of dizziness, one should assume low oxygen and inject gas immediately, any gas. In fact, it is wise to inject both diluent and oxygen simultaneously since six seconds is seldom enough time to do more than one thing. If Bob's oxygen tank had not been turned on, attempting to inject oxygen would have failed to solve the problem. Bob injected gas then, for the first time that morning, he checked his primary display. The lights were out. The problem was immediately apparent; he had failed to turn on his rebreather.

   Bob turned on his rebreather and continued to assist me as I filmed the jawfish. Not wanting to admit to suffering from almost fatal stupidity, he didn't tell me he'd had a problem for over two years.

   Almost every closed-circuit diver I know has failed to turn on his rebreather or oxygen tank at least once. In the last two weeks while filming here in Fiji, both Richard Pyle and Mark Thurlow have admitted to this error.

Be aware of the consequences of high oxygen partial pressures. But fear, with all your heart, the consequences of low oxygen levels

   Not wanting to admit such stupidity, Bob told me of his near black-out while in Grand Cayman two years after the incident, and only after he heard me relate my low-oxygen story to a group of aspiring rebreather divers. Unlike Bob, who was too dumb to turn his rig on in the morning, I had turned mine off on purpose. I was using an IMAX® camera to film kelp at an island near San Diego, California. I wanted to do a shot looking up the kelp plant as I swam the camera up to just beneath the kelp canopy. I didn't want any bubbles in the shot. So to minimize bubbles, I exhaled most of the gas out of my counterlung and turned my rebreather off so it wouldn't inject more gas (even if that gas was rather important). I figured there was plenty of oxygen left to keep me alive during that one short shot. I was wrong. And yes, I admit the idea was completely stupid.

   As I swam just beneath the kelp canopy and only about two feet below the surface, with the camera running, I suddenly saw stars, felt dizzy, and then was plunged into a dark visual tunnel that was narrowing at alarming speed. I checked my oxygen level. It read .06 ppO2. Not enough to support life! I barely had time to lift my head above the surface and take a breath.

Howard and Thurlow at 340 feet - ©Bob Cranston

Checking my instruments at the onset of hypoxia was dumb. A hypoxic diver seldom has time to do more than one thing. I should have immediately lifted my head or injected gas.

   Divers unfamiliar with rebreathers often fear them because they may supply too much oxygen and cause oxygen toxicity and convulsions, followed by drowning. While this is certainly possible, oxygen convulsions are not a major danger when diving rebreathers. Most divers use their rebreathers set at 1.3 or 1.4 pp02. Oxygen convulsions become possible at 1.6. However, you would have to be extremely unlucky to get a convulsion while diving a malfunctioning rebreather at 1.6 for a few minutes. In fact, most divers will get lucky and not be struck with oxygen toxicity even at levels as high as 2.0 or even 3.0. Even the most complacent dullard is likely to check his instruments before high 02 causes central nervous system toxicity.

   Several months ago I was descending past 200 feet in the La Jolla submarine canyon with Mark Thurlow. Suddenly I turned and he was gone. I looked up and saw Mark ascending rapidly while blowing gas out through his nose. A moment later he resumed his descent. When I asked Mark about it later, he sheepishly admitted that he had accidentally injected oxygen during his descent, rather than diluent. He noticed he had a problem when he checked his oxygen readings and found the needle pegged off the oxygen pressure scale. High oxygen levels do not necessarily result in dire consequences.

   Low oxygen levels, however, should be feared absolutely. Low oxygen levels can creep up on a diver quickly and are more likely to happen near or at the surface than at depth. Hypoxia is the cause of most rebreather fatalities.

   Once Bob Cranston began relating dumb rebreather mistakes, he seemed unable to stop. He once jumped in and began a dive with all of his electrical cables disconnected (the cables that connect the rebreather computer to the mechanics of the system). But a quick check of his instruments easily identified a problem, and he had no trouble returning to the boat while injecting gases manually.

   Once Bob jumped in with the cover of his rebreather unsecured and, at the same time, the cover of his CO2 scrubber unlatched. He didn't know he had a problem until the end of his dive when, as he ascended with our underwater IMAX® system, his cover popped off followed by the lid to his scrubber. Essentially, his rebreather completely disassembled underwater. Bob might not have mentioned this accident except that most of his buddies were watching him at the time, and he could think of no way to disguise his error.

Never underestimate your capacity for doing something really stupid

   My best advise to an aspiring rebreather diver is to never underestimate your capacity for doing something really stupid. Although Bob's mistakes seem dumb (and certainly were), they are typical experiences for most rebreather divers. I admit to making an equal number of blunders. Actually, I make a few dumb mistakes on every trip. Those that know me can easily understand my predisposition for error. Smarter divers would seem less likely to screw up.

   Richard Pyle is a smart guy, most of the time. But, like Bob, he too has had problems with flooding his counterlung. He once jumped overboard with his breathing hoses disconnected. This mistake immediately resulted in a mouthful of water and flooded rebreather. Richard went to the surface, adjusted his full-face mask, and jumped back in assuming his full-face mask had leaked. Since his hoses were still disconnected, his rebreather flooded again.

   Of course, making that kind of mistake near the surface seems far less frightening than having a complete failure 300 feet below the surface. But Richard has done that too. Richard told me that he once forgot to insert the drain plug in his rebreather prior to a deep dive. When he looked under a rock at 300 feet, turning his rebreather upside down, all the gas flowed out the hole and his counterlung immediately filled with water. Richard's next breath was entirely saline. Fortunately, Richard always carries plenty of bailout gas. He switched to open-circuit, one of his buddies noticed the open orifice and reinserted the plug. Richard then completed his dive.

Carry sufficient open-circuit bailout, and be prepared to use it

   Switching to open-circuit is the last resort when things go wrong on a rebreather. Most problems can be solved by monitoring instruments and adding gases manually. But when everything melts down you need enough open circuit gas to get you to the surface. In over just over 1,000 hours of rebreather diving, I've been forced to switch to open circuit less than a half dozen times. Twice I had oxygen o-rings blow out leaving the rig with no oxygen supply. In both cases, I had plenty of oxygen in the counterlung for ten minutes or more on the bottom before switching to open circuit and ascending. In other instances, I lost the loop.

   Failure of the counterlung to hold breathable gas is called "losing the loop." This has happened to me several times due to perforated breathing hoses or torn mouthpieces. It doesn't take much of a hole before the loop becomes unbreathable.

   While diving at Cocos Island, I developed a tear in my mouthpiece. The hole was small, but the small amount of salt water that entered the loop reacted chemically with the carbon dioxide scrubber materials. The foam rubber water-absorbers inside my counterlung melted, and the gas became very unpleasant to breath. Back on the surface, I fixed the torn mouthpiece by installing a new one. I should have secured the new mouthpiece with a mouthpiece tie. Oops!

   An hour into my next dive I turned my head to get Bob's attention and the mouthpiece popped off. Bob and Mark thought I looked pretty stupid with the mouthpiece sticking out of my mouth and the hoses floating high above my head. Of course, the counterlung immediately flooded. I switched to open-circuit.

Pushing the envelope

   During our current film production, Coral Reef Adventure, my crew and I have logged more than twenty deep trimix dives, many of which were well below 300 feet. Our purpose for making these dives was to film, in the IMAX® format, Richard Pyle capturing undescribed fish species on the deep reef. On some of these dives we descended to below 300 feet with two underwater IMAX® cameras. Planning this film sequence seemed like a good idea at the time.

   One characteristic of closed-circuit mixed-gas rebreathers that make them seductive is their ability to support dives to over 500 feet and theoretically to over 1500 feet. Unfortunately, the normal tendency of divers like myself to lapse into casual stupidity is not so benignly tolerated on deep trimix dives.

   Trimix rebreather dives require multiple gas switches, computer manipulation, huge amounts of bailout gas of various mixtures, and hours of decompression. The degree of complication provides an enormous increase in the number of ways a diver can screw up.

   Of course, I take trimix dives very seriously. Unfortunately, that hasn't prevented me from making serious mistakes. My most serious error was forgetting to make a gas switch on a dive to below 350 feet. The result was a visit to the Fiji Recompression Facility and hours of recompression therapy.

   In the weeks that followed, I decided that forgetting to make the gas switch was understandable, considering the complexity of the dive and the demands on my attention when attempting to film at that depth with a 300-pound camera system. To remember the various gas switches and computer adjustments, I needed a checklist. This is the solution pilots have discovered for minimizing embarrassments such as finding oneself stuck at the end of the runway after skidding to a halt with the landing gear up.

   During the trimix dives that followed my bends incident, my crew and I have found the checklist invaluable. Now, if only I can remember to look at it.

   It now seems inevitable that rebreathers will become increasingly commonplace with sport divers around the world. Certainly there will be accidents as, through trial and error, divers develop the protocols for using these complicated machines. But for those divers who are willing to accept the risks and train themselves accordingly, rebreathers will open a new world of opportunity for underwater exploration.

Story #2 sent by inspiration diver:

During A Normoxic training session,  divers where using there oxygen bottles for Trimix because they did not have special Trimix diluent cylinders. The bottles were marked and provided with good warning signs and stickers. The training went well and no problems occurred. After the training the bottles were stored and refilled for a new dive. This time the bottle was filled with 100% oxygen and put into the Inspiration rebreather. Strange was that calibration would not succeed because the handset kept calling 'Low Oxygen'. It was not understood and a second and third calibration did not solve the case. After analyzing the oxygen bottle it was found to have only 60 % of oxygen. Cause: The bottle was not emptied after being used for normoxic / trimix filling. Lesson: Do not use oxygen cylinders for any other gas!

Story #3 published with permission of Mr. B. Lipman  http://www.barrylipman.com

Troubles with Rebreathers:

A Cautionary Tale of Caustic Cocktails and Other Considerations

Article and photographs ©2001, Barry Lipman, all rights reserved. www.barrylipman.com


I'd been diving a rebreather for about a year and a half and completed ninety-four dives on it before I'd ever experienced a problem. After diving the frigid North Atlantic off the coast of New England, the California kelp forests of Catalina Island, and the wild and unpredictable waters of the Galapagos Islands, a week of diving the warm waters of Curacao looked like it would be a walk in the park.

My first experiences diving with the rebreather in warm-water lived up to all my expectations. It was pure pleasure not to deal with a dry-suit and gloves and all the weight and gear up time entailed in diving cold water. On the seventh of my eight days on Curacao, I planned a leisurely morning dive to photograph the guide rope that led divers to and from the house reef at Habitat Curacao. The rope runs from the end of the dock, across the sand, and down the wall to a depth of about one-hundred and ten feet, while the wall plunges down at least another fifty feet beyond that. After taking a few photographs looking up the wall and showing the rope, I had run up a little bit of a decompression obligation and decided it was time to head for shallower waters. I spent a few minutes in the sixty-foot range, and then spent about seven minutes in the forty foot range. I had just started up to the twenty-to-thirty-foot zone when, without any warning, my rebreather attempted to deliver a lungful of what tasted like Liquid Draino - the dreaded caustic cocktail.

I swallowed a small amount of the caustic liquid, but before I ever had a conscious clue as to what was happening I found myself choking and coughing through my bailout regulator, which I fortunately had been wearing necklace style on a loop of surgical tubing such that it was always no more than a few inches away from my mouth. In the act of bailing out I dropped both my cameras and became positively buoyant, so I quickly kicked down to the nearest coral head and grabbed on so I didn't float to the surface. I dumped some air from my BC, reached up and grabbed the rebreather hose, and shut it off.

I stayed there for a few moments, holding onto the coral head, assessing the situation. My throat felt as though some serious damage had been done - burning and throbbing from the effects of the caustic cocktail. I found myself hyperventilating as a result of the coughing and choking, so I deliberately forced myself to exhale completely and inhale slowly several conscious times in good open-circuit SCUBA style. I regained my composure, reassured by the simple fact that I was still breathing. Things could have been worse! I checked my computers and saw I still had a four minute obligatory decompression stop at ten feet with a ceiling of 5 feet, not much under ordinary circumstances, but given my extreme discomfort from what I assumed was serious throat damage, it seemed a very long time to me. I grabbed my cameras and finned towards shallower waters, paid off the decompression debt, and headed for the dock.

After climbing out of the water, I slipped out of my gear and gargled with fresh water to alleviate the pain in my throat. I soon realized the damage was nowhere near as bad as I had thought, so I cleaned up my cameras with fresh water and headed off to a nearby restaurant for a soothing bowl of soup. Replaying the dive in my head, I realized I had tasted a little bit of saltwater in the mouthpiece a few times and I figured this was the clue that should have led me to abort the dive and avert the problem. Although this proved not entirely true, it would make good practice to abort any dive upon finding even a small amount of seawater in the breathing tubes.

After lunch I took a good look at the rebreather to determine he cause of the problem. Upon inspection, I found a few inches of the gasket that seals the lid on the scrubber canister to be out of place, and I assumed this was where the water had entered the system. I cleaned out the canister and the breathing bags, charged up the canister with fresh scrubber, and reassembled the unit. Soon I was in the water again, diving with no problems. I did two dives that afternoon, both uneventful.

The next morning, I did another uneventful dive. It was during my second dive of the morning and the very last dive of the trip, at a depth of about forty-five feet, that I received another caustic cocktail - this time without any warning. There was not a single taste of saltwater right up until I got a giant mouthful. This time I swallowed none of the caustic liquid, and I once again had my bailout regulator in place almost before I realized it. I quickly regained composure and finished the dive on my bailout regulator, making it back to the boat without any more problems.

Upon returning home, I assembled the rebreather without the housing, submerged it in a bathtub to look for leaks, and found a small tear in the side of the expiration bag. That was the problem all along. The scrubber canister gasket misalignment was a red herring, possibly contributing to the problem, but not by any means the sole, or even the major cause. I reassembled the unit with my brand new backup breathing bags, tested it in the tub, and loaded it into the car for some cold-water New England diving.

It was a typical day on the North Atlantic. We reached the dive site and moored in seas averaging about two to four feet. I geared up and leapt off the stern into water about thirty-eight degrees cold with visibility no more than three or four feet. As I descended, I checked my computers. I saw I was breathing far too rich a mix. I had filled my tanks with EAN36 and was breathing about 36% O2, well above what would be expected running it through the 60% nozzle as I do. I heard more exhaust gas than usual on every exhale. My air-time-remaining gauge showed I was consuming far more gas than normal. Something was wrong.

At about seventy feet down the ascent line, with the above mentioned anomalies giving me the idea that something was wrong, I turned the dive. I had ascended to about thirty-five feet when I breathed in a mouthful of mildly caustic seawater. I immediately spat it out along with the rebreather mouthpiece and slipped my bailout into my mouth. I leaned back to see the rebreather hose floating above my head and out of reach. By leaning back a little farther, I was able to reach up and grab it no problem, pull it down, shut the valve, and continue my ascent. I handed up my camera to the boat's captain and climbed up the ladder.

Upon opening up the rebreather's backpack, I saw that the expiration bag had become disconnected from the scrubber canister. This explained the excess exhaust bubbles as well as the (mildly) caustic cocktail. But why, or how, did the bag become disconnected? I decided the only possible culprit was the round grip on the plug that stopped up the hole in the inspiration bag meant for the Draeger oxygen gauge. I don't use it; I use the Aladdin system that attaches to the bottom of the inspiration hose on the outside of the backpack. I figured my breathing had allowed the plug to somehow depress the release on the exhalation bag.

One might suspect I had not connected the fitting properly in the first place, but that is not likely. I always make sure I hear the "click" of the connector locking into place. If I don't hear it, I take it apart and do it again until I do. Then, to be certain it is tight, I place a finger on either side of the fitting and try to pop it open. If it resists a good push, then it passes the test. Of course, I then perform the positive and negative pressure tests. I do all of the above every time without fail. I take no shortcuts - ever.

The next day I called Draeger and asked if they knew anything about this problem. I was told they suspected it had happened once a couple of years ago to someone diving in a swimming pool. I discussed eliminating the problem by rotating the fitting on the expiration bag so its release faced away from the plug. They felt this would be a good idea. I asked why they would manufacture the bag with the fittings oriented in such a way as to allow such a potentially disastrous problem. I was told that lowly paid workers assembled the parts without regard to the orientation; the final position of the fitting is random.

I had already tried to loosen the fitting and found it too tight to budge. It was suggested I run it under hot water first, which I tried to no avail. I resorted to loosely clamping the outside of the bag's fitting in a vice. The eccentric shape of the fitting stopped it from rotating against the vice jaws. Having removed the overpressure relief valve, I was able to work through the hole and to use a common slip-joint pliers to turn the inside of the fitting by placing the pliers' jaws against the two small nubs on the fitting's inside collar. Without gripping anything with the pliers, I pressed down and turned against the nubs and the fitting loosened to where it was easy to undo it by hand. I rotated it to about one-hundred and eighty degrees away from its original position and tightened it up only as far as I could by hand.


Lessons Learned:

Bailout Training: In bailout training, do not train the students to close the valve on the rebreather mouthpiece before switching to the bailout regulator. Teach the students to secure the bailout first and shut the rebreather valve down only after safely breathing on the bailout. It is far better to risk getting a little water into the rebreather than to delay getting a working gas supply to the diver in distress! Flood the rebreather, or flood one's lungs - you choose!

In my experience, the amount of water that gets in through the mouthpiece is not a significant factor compared to the water that has already got in and made it necessary to switch to the bailout. In none of my three caustic cocktail experiences did enough water get into the breathing tubes to damage my oxygen transmitter, and that was my only real concern regarding water in the system.

During training, to minimize the chances of any water getting into the rebreather, immediately after the student ditches the rebreather mouthpiece and grabs the bailout the instructor can grab the rebreather mouthpiece, shut the valve down for the student, and then release it to float up and out of reach. After the student is stabilized and breathing on the bailout regulator, the rebreather mouthpiece can then be retrieved and the valve can be manipulated as though it were being closed. This way, the student will train to secure the bailout first, then reach for and secure the malfunctioning rebreather mouthpiece. This is simply a matter of priorities. Secure one's breathing gas first, then try to save some malfunctioning equipment from possible further damage. Remember: in an emergency most of us will perform as we have practiced, so practice as though the drill were for real!

Expiration bag fitting: Check the position of the release on the expiration bag to scrubber canister fitting and be sure it does not face the oxygen gauge fitting on the inspiration bag when assembled properly in the backpack. If it does, it can be rotated as described above.

Connecting Fittings: When connecting the fittings, always make sure to hear the "click" of the connector locking into place. If it is not audible, take it apart and do it again until it is. Then, to be certain it is tight, place a finger on either side of the fitting and try to pop it open. If it resists a good push, then it passes the test. Of course, always perform the positive and negative pressure tests after each reassembly. Do all of the above every time without fail. Take no shortcuts, ever.

Bailout Mouthpiece Position: The bailout regulator mouthpiece should be worn on a necklace made of surgical tubing such that it hangs no more than a few inches below the divers chin. This allows it to be popped into the mouth in one quick motion with no need to look for it or detach it in an emergency. If one receives a caustic cocktail at depth, the resulting coughing and choking could easily cause respiration of seawater and subsequent hyperventilation, panic, and even drowning if the bailout regulator is not put into immediate use. Reaching down, finding it, releasing it from its attachment, and bringing it up to the mouth take much more time than necessary or desirable. The necklace solves this allowing one smooth motion to grab and use it should the need arise.

Abort Dive Upon Tasting Seawater: The presence of seawater in the breathing tubes should be taken as an indication that there is a leak of some kind in the system. Ascent should be started immediately and the rebreather should be checked carefully for the source of the leak. Seawater should never be found mingling with the breathing gas supply.

Freshwater, however, may be found circulating in the breathing tubes. It is a normal result of the condensation of the diver's exhaled breath's moisture. One can actually drink this liquid safely while diving, and it can be quite pleasant. At the slightest hint that the water is not sweet - salt or caustic in taste - the dive should be aborted.

Add Another Regulator: In addition to the Dräger mouthpiece and the bailout regulator, an additional open-circuit second stage for use by a distressed diver should be carried, possibly secured by surgical tubing to the side of the rebreather within reach of the rebreather diver and in plain sight of any other diver that may be in need. When assisting another diver, the rebreather diver needs to be able to switch to bailout without resorting to buddy-breathing off a shared reg. The rebreather diver should show this to any divers who will be diving at the same time and could possibly need to use it.

Note: My Draeger Atlantis rebreather has been modified. I have removed the twenty-seven cubic foot tank it comes with and added twin, manifolded, thirty cubic foot tanks with isolation valves. I run the Dräger regulator on one tank and conventional open-circuit SCUBA on the other. I usually dive with a small air bailout bottle in addition. In no way does any of this affect the internal integrity of the breathing bags. I am certain the modification has not increased the likelihood of getting a caustic cocktail or a leak of any kind. I have done more than a hundred dives using this exact configuration and I only had trouble on dives ninety-five, ninety-eight, and ninety-nine. I believe the modification of the breathing gas supply has enhanced the safety and practicality of the unit by increasing the gas supply available to both the rebreather and the bailout system.

This article is published with most appreciated permission of Mr. B. Lipman. I want to thank him for this permission. You can see more of his wonderful pictures and adventures on his homepage http://www.barrylipman.com

Story #4 Great Big Stuff Ups I Have Made 

Published with permission of Mr. Trevor Jackson
By Trevor Jackson - Esperance Star


When I first started using my CCR, a friend of mine handed me a ream of paper. On the front cover it read……..An Introduction to Rebreather Diving by Richard Pyle. It was one of the best things my friend ever did for me, as it outlined many of the near death experiences that Pyle had been through whilst he learnt to use his machine properly. Despite vast amounts of diving experience, even the very finest divers can come unstuck, most get to live through there experiences, some, regrettably, don’t. So at the risk of copping a hiding from some members of the fraternity, I present to you my own version of Pyles invaluable document. By the time you’ve finished reading it, you may think I’m an idiot who should never get in the water again, and if you’re lucky, you may learn something that one day might mean the difference between making the surface, or not. I am actually going to talk about only 2 stuff ups, and in no particular order either, both incidents should have or could have resulted in me floating face up in the water with a ghostly look on my face, but thankfully, by virtue of luck [in one case] and good management [in the other] I’m still here…….so here goes my reputation………

About a year ago I was on a mission. I had a big dive planned and we were going to be using techniques and gear configurations that were well outside the norm. The equipment we would take was complicated and immense, we would be operating in near to total darkness and one slip up would be catastrophic. I had to train myself, I had to go back to basics and learn instinctively where everything was, what it did and how to use it in the dark. I decided to put myself through a self regulated dive course, from start to finish, everything I had ever learnt would be relearnt, again and again. Everything I had ever done would be re-done. Every bad reaction would be recorded and remedied, every time I made a mistake I gave myself an uppercut till there were no more mistakes. Everything that could go wrong I made go wrong and then made myself fix, it was a tough few months, but sometimes we’re our own best teachers [or worst enemies]. Towards the end of this ‘training’ I decided to do a night dive on a wreck that I was quite familiar with. I'd go in and practice swimming around without lights, laying lines, squeezing through gaps, practice gas switches and generally give myself a rough time of it.

It was a fairly calm sort of night, I anchored the Esperance Star above a wreck called the Etmor at Curtin Reef near Brisbane, put my gear on and waddled out to the back deck to jump straight in off the duckboard. I was facing east as I hit the water. Without knowing it, I rotated through 180 degrees during the descent, so when I hit the bottom, instead of facing east I was facing west. I could see the wreck through the dim water and swam over to it, making a right turn as I approached the hull. Because of the rotational descent, I was now actually heading to the northern end of the wreck, towards the stern, whilst the whole time thinking I was heading south towards the bow. I skipped up onto the deck and found the first hole I could, only turning on my lights as I actually entered the hull. Once inside I made a left turn, which I of course assumed would head me north into the familiar rooms of the Etmor. Instead, after swimming about 30 meters into the near black corridors, I came to a dead end where there shouldn’t have been one [or so I thought]. I sat there and pondered what had transpired for a minute or two and slowly figured out what must have gone wrong. No worries I thought. Ill just back track and find the exit, all was cool.

Murphy, my favorite Irishman, was about to come a knocking. Murphy was about to start laying down some of his law. I remember thinking, ‘well Ill be rooted if the light goes out’. Murph must have heard me and intervened, making it so. My primary light failed completely, but like most proficient tech heads, I carried a spare. In fact a brand new spare which had never been in the water, a brand new spare which had never been tested, because if it had been, I would have known that it knew my Irish friend as well, and it liked him better than me. Both lights failed. I was 24 meters down, lost inside a wreck in the middle of the night and with no real idea of the way out. To add insult to embarrassment, the crew of the boat was now so used to my long duration night dives that they probably wouldn’t start to worry for at least 2 hours.

At this point it would probably be stating the obvious that now was not the time to panic! I had a completely full Closed Circuit Rebreather, two full 125cft stage bottles, three reels and about 8 hours to get myself out before I ran out of gas. I sat on the inner decks of the Etmor and tried to nut out a solution. Time was on my side, if I just sat there and waited, I guess someone would have eventually come down, but there was no guarantee that they would find me, and night time penetrations were not normal practice. I had to get out myself. I pulled out my primary reel and attached the line to the nearest strong point, feeling around in the dark. I found a wall and ran along it, spooling off line as I went. A dead-end. I felt along the dead end and kept reeling out line the whole time; I came to another stop. ‘This isn’t going to work’, I thought, ‘All I’m doing here is creating a great big spiders web for myself and I am the Fly’. I had to figure out which wall ran north-south, and which ran east-west. The Etmor lies north-south, but I was so completely disorientated that on more than one occasion I had to feel for the direction of my exhaled bubbles to check if I was upright.

I came to one of the dead ends and pulled off a fin. Using it as a measuring tape, I crawled along the wall, tying a knot in the line every fin length. When I got the next dead end I found the start of the wall and repeated the process. All this took up precious time and gas but the end result was that I now knew that one wall was 34 ‘knots’ long and one was 18’knots’ long. The 34 ‘knot ‘ wall was the north-south wall. I knew that because I had seen plans of the Etmor and remembered it had a long room in its stern, running lengthways. All I had to do now was figure out which end was the end I had come in on, and then concentrate on finding the way out once I had done that. I remembered as I entered that I had swum through some cross bracing, steel girders that had formed an ‘X’ from the floor to the ceiling. I swam to one end of the long wall, swam out a few meters along the short wall, found a tie off point and did 5’ knot ‘ arcs out from that point. Nothing. I went a few meters more along the short wall and tried again, repeating this twice more, finding no cross bracing. I was at the wrong end, but at least I knew that at the other end I would find the way out.
I swam back along the long wall and started to search for a way out once I reached the end. I actually headbutted one of the cross braces while I looked. I remember swearing but I was also quite chuffed at this point because the exit was only minutes away, and the illuminated handsets of my rebreathers computer told me all was well. I stared upward straining to see some light. There was nothing, then faintly off to the left I could see something, not a light source, more like the texture of a rough surface, barnacles, I swam up to them and found an entrance. The bright spotlights on the rear deck of the Esperance Star were my salvation; they ‘just’ penetrated to the bottom, just enough light.

As I stepped onto the duckboard after nearly 2 hours inside the Etmor, the cook came up and said,’ I saved you some dinner’. It was good to be aboard, I looked around and saw that the troops were all happy watching a DVD and eating desert. I, of course, never said a word.

As I lay in my bunk that night I reflected on what had happened. I was fairly happy. I realized that whilst I had done plenty wrong, I had also done plenty right. I had managed a shit situation by thinking my way through it and by not panicking. I gave myself an uppercut, and then thought back to a few months earlier when I hadn’t been thinking too well, on a dive that should have been my last, a dive that made me think seriously about giving the whole thing away.

The President Coolidge, one of my favorite spots. Deep, historic, beautiful. It was my fourth trip to the wreck; we knew her well and had come equipped to do some serious deep shit. Well almost equipped, there was a bit of a hitch there. My buddy Big Max and I had sent some of our gear over on a ship a few weeks prior to our arrival. We were assured that it would be on the wharf when we arrived but those assurances proved unrealistic. Our Helium filled stage bottles and Max’s rebreather bottles were not there, it would take a few more days. One thing that has sent more than a few divers to there peril is diving with unfamiliar gear, another is impatience, I was to be guilty of both, and lucky to get away with it.

Our rebreathers require specific sized bottles, which fit inside the unit to supply oxygen and diluent gas. Max’s were not with us but I had both of mine. We decided to use one of my bottles in Max’s unit as his oxygen bottle, and supply the diluent gas via offboard tanks, which could be supplied by the local diveshop and then jacked in externally to the counterlungs of the rebreathers. This setup was a complete botch job, but it would get us into the water straight away. The only problem would be that the hoses that run from the onboard diluent tank to the BC power inflator would have to be left off, meaning that our BCs would have to be inflated manually. This was OK except we would have to remove our rebreather mouthpieces and breathe off our bailout regs to do it.’ NO drama ‘, I thought. Well actually I didn’t think, and that is why I am writing this.

All went well initially. We descended down to the bow section of the wreck then onto the sand at 35metres just below the first cargo hold. I decided to inflate my BC a touch so I closed my mouthpiece, picked up my bail reg and filled it. I went back onto the rebreather for a second then decided to add a touch more air to the BC. I grabbed the reg again, topped up the BC and replaced the rebreather mouthpiece. A moment later my rebreather went ape. The handset computers, which maintain the partial pressure of oxygen, began to sound their alarms. I looked down to read them, they were telling me that the oxygen PPO2 in the rebreather loop was up at 2.8bar, double the recommended safe limit.

Immediately I assumed that the electronics had failed and had begun to inject O2 at too high a rate, and that to stay on the rebreather would be dangerous. I still had the bailout reg in my hand so I put it back in my mouth and begun to monitor the rebreather to see if I could tell what was wrong. Nothing seemed to change, which was odd. About 2 mins went by and I began to feel that the gas I was breathing was becoming difficult to draw, as if I was actually running low, but I couldn’t be. I looked down to check the contents gauge of the bailout bottle, only to see its reg hanging below it. My foolishness dawned on me in an instant. The rebreather electronics weren’t failing they were reading correctly. At the moment I had picked up the bailout reg the second time, I had actually picked up the open circuit o2 reg attached to my onboard oxygen cylinder. I filled the BC with the O2, then breathed pure O2 back into the rebreather loop, sending the computers haywire. Then Id replaced the O2 reg into my mouth and began breathing straight off it.

It’s only a three-litre cylinder and I had breathed it dry at 35 metres. A PPO2 of 4.5 bar for over 2 mins. I should not have been conscious. I grabbed the bailout reg and did the bolt up the long sandy slope to the surface, wondering if at any point I would conk out and become a statistic. Obviously I made it, but I stood on the beach for an hour afterward kicking myself, again and again. Actually it was longer than an hour, it was more like……………………………EVER SINCE!!!!!!!!!!!!!!!!!!!!!!!!!!

Like anyone I've got an ego. I like to think I am pretty good at what I do. The trouble is when we stop thinking and start taking things for granted we come unstuck. I haven’t had any major self-inflicted fuck-ups since these two, and Ive stopped kicking myself. Life goes on, but from now on, I’ll make bloody-well sure I keep it that way.

Trevor Jackson wrote more : story #5

Learning to Climb Trees
© Trevor Jackson


There's a tree in my mothers back yard that is 1000 feet high. At least that’s how high it used to be. Now its probably only 50 feet high, it shrank considerably as I grew, but to two nine year old boys it would seem a 1000ft. That’s how old we were when my brother and I first climbed it. My mother was never the type of person to inhibit or quash any of our swashbuckling activities as youngsters. Whether it be climbing a 1000ft tree or crossing the 50 mile river, she lived on the theory of ‘feed em, love em, and leave em alone’’.

25 years later after first stepping up onto the lower boughs of that tree, I was sitting on the front deck of the Esperance Star with twenty grand worth of diving gear strapped to me, about to climb another tree, with a minute or two to reflect on the events that had led to me being there.

Climbing a big tree usually starts with a lot of dust kicking around the base, a few nervous looks up, walking up, walking away, some deep breaths…

In mid January this year I was fortunate enough to attend a speech given by Dr. Simon Mitchell about his remarkable life in Diving. He knew I was in the audience and was constantly referring to the fact that I was a pirate and a thieving wreck pillager, occasionally pointing an accusing finger up towards where I was sitting. This amused his captivated audience no end. After the speech Simon invited me round to his apartment for the first session of dust kicking around the base of the Centaur Dive.

Basically we’d both been planning to dive the Centaur, but logistically both plans lacked what the other could bring. We needed lots of divers, lots of gear and lots of practise. What Simon knew about gas physiology I made up for in knowing how to find the wreck. What I knew about putting together a 16 man dive crew Simon made up for in putting together a 4 hour dive plan, a symbiotic relationship at first that would later develop into firm trust and friendship. Neither of us knew if our plans would ever develop into anything more than just a couple of early middle aged bachelors talking shit over too many bottles of red wine. But the more times we got together the higher the dust would fly, and pretty soon others were around us kicking madly, looking up, sneezing and gagging at the idea, maybe we should step up the first rung and see if the base of the tree would hold us all, see if we had the climbing skills, see if our mothers would call us back down.

Our first deep dive together must have filled Simon with doubt about his selection of dive buddy. The weather the night before the dive was atrocious so yours truly had decided that because no sane man would go out and attempt the Jennifer K whilst a 30 knot gale prevailed, I should get heavily and squarely on the piss. At 6 am the next morning the phone was ringing with the Kiwi on the other end saying, “Where the hell are you?.” Even on the way out I doubted the dive was on till his kiwiship kicked me in the guts whilst I was lying on the galley floor of Ocean Cat and asked , “Are you coming softcock?.” I jumped up cleared my head and the dive went uneventfully. “That was 85metres, I thought to myself on the way in, another 100 and we’ll have it cracked.” Our feet were firmly planted at the base of the tree trunk; it was time to look about for some serious dust kickers to give us a hand up.

The one thing I noticed about that first dive off Ocean Cat, and subsequent lead up dives off boats other than my own, was that the dive was a lot easier for me than usual because I didn’t have the added worry of still being responsible for the boat even whilst I was underwater. I know it sounds like a wank thing to say, but part of my mind is always on board when diving from the Esperance Star, and if we were to get anywhere near the Centaur, I’d have to be concentrating 100% whilst down there. When assembling a team to help us, this was the foremost thing on my mind; this has to be sorted properly.
You can count on one hand the number of people in this world that you can trust and rely on absolutely, and you can count on one finger the people with those attributes, plus an inherent knowledge of the boat that was to be our platform on the big day. Dr. Carl Watson was the ONLY person that could do this job. I conned him into it, it must be said he was reluctant, he reckoned he didn’t know enough about tech diving, I told him he knew more than enough about the things he needed to know about. He need to be disciplined, he needed the respect of the other crew and divers, he needed to be able to kick arse and have it stay kicked, he would be in charge, would he do it? Yes he would.
We got together some of the other key players and had a big meeting, fairly loose. Simon brought along his dive plan and some documents which outlined the basic proposal from both diving and philosophical points of view. We talked at length about the role of the support divers, what gases to carry, in what amounts, how long on the bottom, what if we get lost etc. etc. As the weeks went by it became more and more apparent that we were in fact going to attempt to climb this mammoth tree, in some ways the biggest tree that had ever been climbed, by any kid. We’d got up off the ground and were still looking up, no- one was going to call us in for tea, it was time to reach higher, commit further.

Around mid April I started to get the gear together. Each of the support divers would arrange his/her own equipment but there were 12 nitrox/oxygen bottles with regs to source, rig and fill. A 200metre+ shot line would have to be designed and built, plus two spare shot lines to be deployed if the bottom divers got lost and needed to be shadowed by a pickup boat.

The bottles and regs were easy. I rang my old mate Blue Zone Bob and his reply to my request was, “as much gear as you need, no problem”. This was a big call for Bob, every other person we had approached for assistance or sponsorship had kept us at very long arm lengths. Not that I blamed them. There was a very big risk in being involved in a dive like this, but Bob didn’t give a shit, he would help no matter what. The tanks needed to be rigged so that they could be quickly snapped onto the shot line at the required depth once it was set. I went out to the local hardware store and bought a couple of dozen of those clips you would use on the end of your dog lead, I shackled these to the tops of the tanks and this made a very neat little connection point. The first support divers would meet us down at about 40 metres would carry two of these tanks each, they were 88cfts filled with 50/50 nitrox. If we were on open circuit they would clip the tanks to us, if we were ok and still on rebreathers they would take them up and stage them on the line at about 20 metres. We were already carrying enough open circuit gear on our persons to enable us to get up to 20 metres should the rebreathers shit themselves at the worst possible moment, so the guys meeting us at 40 was really just part of the “feel good factor”, which on a dive like this was not something to be taken lightly.

As we were all pretty much first timers on a dive this deep, the shot line took a fair bit of thought. I went out and bought two 120metres coils of 16 mm rope, did a bit of rudimentary mathematics and chopped the length down to 200 metres once they were spliced together. [After we’d finished the dive we realised this was about 30 metres too long, but more on that later]. On the wreck end of the rope we shackled 15 metres of half inch chain and our specially fashioned shot weight/anchor, the “Max Factor.” The ‘Max Factor’ was a modified G-size gas cylinder with 8 steel wings welded to it. It was open at both ends to allow it to fill with water; the wings were to act as grapples when the shot hit the bottom. The whole lot weighed in at about 180 kgs, and took some serious manhandling. The bottom 100 metres of the rope had cyalume sticks attached every 5 metres, because we learned on our 125metre lead up dive that things would be like night time on the bottom, we wanted every chance of seeing it in the dark if we got a little lost. On the surface it was a fairly standard set of floats holding the lot aloft, with loops spliced into the rope for tank attachment every 3 metres from the surface down to about 40 metres. The whole thing took two whole days to put together and sat in 44-gallon drum on the front deck.

May the 1st came. The team had planned to be ready by that date and for all intents and purposes we were. Anxiously we watched the weather. Climbing a giant tree required great weather. We had one or two false alarms, and then on May 12, I rang the team. ’Tommorow night, 8 o’clock’. Simon got there early, about 2, and we sat on the front deck quietly all afternoon drinking coffee and assembling the final items. One by one the guys showed up till at 8 o’clock, with a full compliment, we quietly slipped to sea.

It was our final night of dust kicking, our final walk up to the trunk, this time we would climb and climb to the highest and thinnest branches, they would sway and sway and we knew we’d feel giddy, and we knew the view would be a once only. Next morning I got up at about 6 am and started to steam out past Cape Moreton, setting the GPS up, nine miles to go. Some friends on another boat called, “Predator’ had past us on the way out and had gone to find the site ahead of us so we didn’t have to muck around trying to find it. They did a good job and as we arrived Skipper Tony slotted in ahead of us and led the ES straight to the wreck, it read 177 m on the sounder. Things got real tense for the next half an hour, I remember yelling at some of the crew at one point whilst we were about to drop the shot, something like,’ get the fuck off the front deck’. Everyone was jumpy. With everyone clear I kicked the Max Factor through the side gate and she rocketed down into what was sure to be a darkened seabed. Things got even more tense, there was a fair bit of muffled laughter and a little subdued bravado. It was like goodbye at a train station, we were soldiers going to war, or backpackers flying to London, or somewhere in between. One of the girls started to cry, I made a silly joke, I felt good to have this true and loyal crew around me, it was a moment in time I will never forget. Skipper Billy Marsh took the helm of the ES; we got our gear on very matter of factly and walked out to the back deck. The tanks and cameras were clipped on to us, torches working, computers working. We walked up to the tree, and started our climb.

There was actually a little bit of confusion just prior to the jump. Simon and I had agreed that because my descents were in general slower than his, that I would go first and set the pace on the way down. I positioned myself on the Starboard side of the duckboard to jump in, but the floats had appeared on the Port side of the boat, so Simon jumped first and I would overtake him in the top 10 metres after a short stop on the surface to get settled. At this stage our thoughts were fairly routine, and for a few moments it was just a normal dive. I gathered a left hand full of shot line and started to pull down; my right hand would work the button that controls the gas level in my counterlung and occasionally lift my computers into view so I could check that the PPO2 was being maintained at the required level. Down through 30, 40, 50, 60, 70, 80 and 90 things were fairly simple, we’d been to these branches often enough in our lead up dives. At around 100 things start to take on a different feel, the sun goes down and the moon comes up. Our helium rich bottom gas started to feel a little heavy in the mouthpiece. Through 120 and 130 we were branching out onto thinner and unscaled limbs, clouds came across the moon. The cyalumes on the lower half of the shot line came slowly into view like stars breaking through the cloudbank.

It was fully dark now, the light from our dangling torches made sweeping orbs, probing into the black. The gas got heavier and heavier so I consciously slowed the descent. Around about this point I remember saying, ‘Holy shit this is a long way down’. The cylumes flicked by us slowly, red green, orange, no particular pattern, they were all I could see [at least I didn’t have to look at my butt like the Kiwi did]. The point where I thought we should start seeing the bottom had past 10 metres back, for a second I thought we must have dropped the shot into a deep hole. A quick glance of the depth gauge revealed 157m, surely we must see something soon. The cylumes below took on a different arc, levelling out horizontally across the sand, and then there, peeking through the night, I saw the white sides of the Max Factor resting heavily on the bottom. Touchdown!

To the very tips of the leaves we had climbed, you could touch the sky from there, where the new growth presses upwards into the light, with my depth gauge reading 177metres, a rainforest had been conquered.

Right about now I’d like to waffle on about how mysterious and surreal it all seemed, but that would be fibbing. The truth is, it didn’t seem any different for a little while, it was just like doing a night dive, and as long as we didn’t think about that monolithic column of water pressing down on us, things would be fine. We took a half a minute to get soughted, checked the rebreathers were working ok, no leaks, constant O2 levels, yep shes sweet. I started to look around, the next thought that I recall was,” don’t tell me I’ve come all the way down here for a f***ing sand dive’’! I couldn’t see anything; the lights weren’t penetrating far enough to show any wreck or part thereof. I looked down at my torch and saw that the glass had imploded, yet it still seemed to be working. I turned it off. Man it was black. Simon was behind me and off to the right. For a second, in a way, we were alone in the abyss.

Now if you want to know about gas physiology and the like then my buddy is the one you should talk to, hes the scientist. I knew enough however to know that the strange patterns I was beginning to see in the water above and ahead of me could have been caused by old brain not coping real well with the sudden descent. I checked the PPO2 again, took a quick glance at Einstein and noticed he was looking at this strange phenomenon also, “Great we’re both crazy,” I muttered. Slowly the patterns began to take a more comprehendible form; it looked like black wallpaper with large white flecks. “What the hell IS that?” I asked myself. I remembered where I was, I remembered why I was there, and I remembered the 268 sailors that lay here. This was the Australian Hospital Ship Centaur. The white flecks across the face of this black wall were fish, trillions of them, don’t ask me what species, I wouldn’t have a clue.

We had literally 90 secs of bottom time left. There was no time to unclip a reel and spool over to the ship, and we had planned not to leave the shot line without first attaching a line. I had to make what I thought at the time to be a selfish call. I turned around to Simon and gestured that he should wait for a second with his lights shining. I took off towards the wreck in the hope I could guide him over if I could still see the wreck and the cyalumes at the same time. Arriving beside the hull the seconds had ticked away. As I cast my disbelieving eyes up at this great monolith, and as Simons torch cast a shadow of my considerable girth against the side of the wreck, I knew that visiting hours were up at this Hospital.

A funny thing about climbing giant trees is that you’ve also got to climb down, you can’t just jump. Another funny thing about trees and treeclimbers is that whilst trees take CO2 and turn it into Oxygen, treeclimbers do the opposite, turning O2 into CO2. If a treeclimber produces too much CO2, and is too high up a tree, then things get sticky, branches sway, a climber can get dizzy, a climber can fall.

I made it back to the Max Factor ok. Simon had darted off to check out a fire extinguisher which lay about 5 metres away and I had started my pull up the long line. I shone my lights down on him to help his investigation, and then he left the bottom. The video taken on the boat the night before the dive shows the good doctor explaining the dangers of high CO2 partial pressures to some of the support team. It was irony at its finest. Simon’s rebreather has a giant 4.5 kg scrubber and we knew before the dive that my 2.5 kg Co2 Scrubber was going to be pushed to the limit on the bottom. We did not and do not see this as a fault with the unit. For its rated max depth of 100m this is more than adequate, but we were climbing a bigger tree and had it in mind through out the build up that a Co2 ‘hit’ was a remote possibility. We trained for it, put back up systems in place, if it happened we’d be ready. It happened.
At about 165m I began to feel short of breath, I knew I should not be so I pushed the button on the front of my unit that flushes the counterlungs with fresh gas. I inhaled through the mouthpiece and exhaled through my nose, spilling the counterlung gas out through the edges of my mask. In turn the button I was pushing fed fresh gas into the unit and after a few seconds using that procedure the old counterlung gas was flushed completely out of the unit. Unfortunately, just as the CO2 had taken quite a few minutes to build up to a toxic level, it would take just as long to work its way out of my system, and in the meantime, I was not in a nice place. I had to keep flushing and keep ascending, ever mindful that there was no escape option here; I couldn’t abseil down the tree.

My head was throbbing and I felt sick, I felt like I would lose consciousness for a second, then I went into a plateau where everything seemed ok. I got up to about 120 when it hit me again, harder. Delirious. We learned later that this temporary feeling of wellbeing was the most dangerous point, I almost lost my grip on the branches, and the fall was unthinkable. I tried to concentrate, I thought about my friends on the boat and how I wasn’t going to make them search for a marker float that was never to come. For them I would fight this monster off. I thought about my family, how my brother, the toughest man alive had rung me and told me he felt giddy and sick to the stomach as we steamed out past the Cape. I thought about my mother and how she never stopped me from going that extra step, in anything I ever wanted to do. I would fight this barstard coz I knew he didn’t have my stamina, he would only last another few minutes, I hung onto the line. The light began to come, the cyalumes passed by one by one, the sun began to rise, and with a fresh breeze beginning to blow, I pulled up at 100metres.

Simon had ascended much slower than me. Things in the noggin had settled back to normal except for a throbbing headache which was to last for days in one form or another. The next step was to get back into the fold of the normal dive plan. In my pocket was a tiny plastic booklet which outlined all of the deco schedules we would follow, both in an emergency and if things were going well. I flicked through the book to find the appropriate runtime. Surprisingly things were still perfectly on schedule and I was due to ascend to 80 and stop for a few mins. The only problem was that I still couldn’t see Simon below me. The procedure for separation was that we would both shoot a lift bag to the surface. If we were off the line the pickup boat would deploy with an entirely independent team of support divers with a backup shot line which could be deployed down to the lost diver. I must admit to beginning to feel a little anxious looking down the line of cyalumes and not seeing Simon. The time to ascend to 80 had arrived and I strained to see him, his entire outfit was black, including his unit. I thought about shooting the lift bag to let the surface know we were separated. I reached around and felt for a reel, unclipped it and looked down again. I gave it another minute, then finally, Simon’s torch glared up at me, faintly, but he was there all right. Phew!

Once we’d re-established contact the dive was fairly bog standard. Climbing further and further down the tree was comfortable and easy. Darryl Waters, our first support diver met us bang on schedule at 45 metres, asked few questions like, “Are you alive?”, and then took off to stage his share of the deco bottles on the downline. Shortly after, Dean Wort and Lynn Taylor joined us and from that point on we were accompanied right through to the surface for a final runtime of 3hrs and 44 mins.

Back on board the crew had cleared the loungeroom out and put together what looked like a mobile hospital ward. A massive bed had been made up on the floor and we were quickly into bed and onto the pure O2 for an hour. Darryl took our blood pressures every 15 mins or so and after the hour was up he said something official and doctor like, “Congratulations gentlemen, you’ve just completed one hour of post dive oxygen therapy, BP’s are normal, symptoms of DCS nil”. Everyone in the room applauded. I jumped up and asked for a smoke. I was refused. I looked down at Simon who was still lying there with his O2 reg still in place, “So what are we going to do for kicks now?” I asked. Simon simply shrugged and said, “Don’t know mate, but we’ll think of something

Published with permission on http://www.therebreathersite.nl
Author: Trevor Jackson     - Esperance Star -
Story #6


The anatomy of a serious diving accident.


 Going to sea on a boat and diving down under the water is not the safest thing in the world to do. It is not as safe as say laying in bed at home under the blankets or sitting around watching TV, but in this day and age procedures are in place so that if an accident does occur, help is fairly readily at hand and advise can be sought at a moments notice. Professionally run charter operators and dive shops must have in place an effective procedure to rescue and evacuate a diver who has had an accident. Accidents take many forms, drowning, heart attack, decompression illness, even shark attacks. Emergency procedures must include contingency plans for any occurrence. The following story outlines some of those procedures as they were actually put into practice and some of the aftermath. Private boat owners would be well advised to work out their own procedures. If an accident occurs there will be absolutely no time to start flicking through phone books to get emergency numbers, or wondering what to do. Action must be automatic and decisive as minutes may count in determining the outcome.  The featured accident occurred in May 2003, on the wreck of the St Paul. The victim was using a closed Circuit Rebreather, a device that enables the user to rebreather his/her own gas and maintain a set level of oxygen in that breathing gas. They have many advantages over normal open circuit dive gear in terms of decompression and gas consumption, but they can be deadly if not used in exactly the correct manner. The victim had 100’s of dives to his name and an accident was the last thing on his or anyone else’s mind that calm autumn day. Within minutes of entering the water however, a life-threatening struggle would be taking place. 

Myron Wintonyk is dead. I can see that he is dead, his face is blue. Foam is oozing from his nose and mouth. White foam like from a shaken up beer can. And not just a bit, a lot! His eyes are bulging and they’re open, staring at the sky. The foam seems even to be running from them too. His wetsuit is bloated, his arms are stiff. People are yelling. But its that blue color that tells me he is dead. Its not a natural color, it’s from a movie, or its kids playing with eye shadow.  I’ve not seen one this bad before, only in pictures, only in nightmares. I know that Myron hasn’t breathed for nearly two minutes and I don’t know when the foam will stop, it just keeps coming, how can we get o2 into him if it doesn’t stop. Myron is dead. I point at him and I actually say it, “He’s Dead!” people hear me say it. Then I turn and stop and turn back again. People are looking at me for directions, they want to be ordered, and we have to do something. 

24 hrs after that hellish scene on the duckboard of the Esperance Star, Myron Wyntonyk brought his wife and young son down to the boat to see the crew and pickup some gear. I came up the stairs from the passenger’s accommodation and there he was, large as life. There he was breathing on his own, standing up, not smiling yet, but alive. His wife looked at me with tears in her eyes and simply said, “thanks”. It was a phrase they would be repeating to lots of people, all round town. 

The Players:

Myron Wintonyk, Divemaster, 300+ Dives, the victim

Sean Inglis, rescue diver, 100 Dives, rescuer

Rachel Murphy, Instructor, 500+ dives, rescuer

Robert Cook, 300+ dives, rescuer

Damon Blackwell, Instructor, 500+dives, first aid

David Walton, Instructor, 500+dives, first aid

Lars Van Der Reijden, Divemaster, 100+ dives, first aid

Chris McEwan, Instructor, 300+dives, first aid

Trev Jackson, Skipper, 500+dives, co-ordinator

Simon Mitchell, Physician, 500+dives, phone advisor

Chopper Pilot, name unknown

Paramedic, name unknown

Chopper Winch man, name unknown

Coast Guard Radio Operator, name unknown

Internet Chatroom Poster, critic, not present, name unknown

Matthew McLean, 200+dives, witness


Saturday May 24th 2003 near Cape Moreton Qld.

7.50 am Divers are walking up to the jump point on the port side of the Esperance Star. In buddy pairs they call out there gas levels to the DM and jump in. Its one of the most beautiful days we have had all year, seas are glassy calm and the viz from the surface looks as though its exceeding 20 meters. The wreck of the St Paul lies on the sandy seafloor 40 meters below. Sunk in 1914, she is one of the most popular dives in the area, attracting dozens of divers each week when the weather permits. She is also considered to be in a depth that categorizes her as a dive for experienced divers only. In terms of diving this wreck Myron Wyntonyk, with over 300 dives and the holder of a dive master’s ticket for some years, would be considered an experienced diver. 

8.00 am Myron has appeared on the front deck wearing his Closed Circuit Rebreather. He and the dive master are talking about the dive. The dive master asks Myron if he has completed all his pre-dive checks. Myron replies that he has. He looks happy and I enquire about his intended dive plan. He says he is doing a No- Deco dive of about 9 mins planned bottom time. From outward appearance his unit looks fine and all seems well.

8.05 am   Myron enters the water and begins to descend with his buddy Sean Inglis. Sean reports later that Myron-“ seemed all out of shape with his gear and bubbles were coming out around his mask as if he was on open circuit”

The two divers reach the bottom and can see the wreck just a few meters beyond the anchor. Sean has one eye on Myron the whole time as he felt uneasy about the way Myron seemed to be acting. “ Myron just wasn’t comfortable, he seemed to be falling out of his gear, I asked him if he was ok and he was negative , he wanted to go back up, yet he wanted to swim towards the wreck, there was something seriously wrong. Myron began to swim towards the wreck; I grabbed him and spun him around. He went into a fit and was suddenly unconscious.” 

8.10 am Rachel Murphy was nearby trying to salvage an anchor and some rope she had found. She saw that Sean had grabbed Myron and was trying to drag him back to the anchor. Myron had spat out his mouthpiece and was taking in water, Rachel went to help. She grabbed her own Occy reg and tried to force it into Myron’s mouth- “It wouldn’t go in because his teeth were clenched”.

The pair dragged Myron up the anchor chain passing other divers as they went. At around the 8-meter mark they were met by diver Robert Cook who quickly assessed the situation and grabbed Myron himself. Rachel broke away from the victim and went quickly back down to 12 meters. Robert began to swim Myron to the back of the boat whilst Sean continued to the surface to warn the lookouts that there was trouble. He then dived straight back down to 10 meters to commence some safety stops.

Meanwhile on the boat, Damon Blackwell and myself are on the front deck looking at the bubbles coming up from the wreck. A lift bag had just appeared off the port side of the boat and we were wondering if there might be a diver doing a safety stop under it. I yelled out to Lars to keep an eye on the bag for later retrieval, as it seemed there were no bubbles near it and therefore no diver. There were heaps of bubbles coming up from near the anchor chain. Damon said-“too many bubbles, actually”. Seconds later Sean broke the surface and yelled something. All I remember hearing were the words “Myron” and “Oxygen”.

At first we didn’t know what to think. I thought that Myron was stuck on the bottom or just needed a hand or something. I directed Damon to throw on his gear and get in to find out. Before he had a chance to get halfway along the deck we could hear the commotion at the duckboard at the rear of the vessel.

8.12 am Robert Cook had arrived at the duckboard with Myron. Damon had run down the port side of the vessel and had arrived there also. Lars and Dave were already pulling Myron out of the water and out of his gear. I arrived at the back of the boat seconds later. I look down at Myron and say out loud – “He’s dead”-

people hear me say it. Then I turn and stop and turn back again. People are looking at me for directions, they want to be ordered, we have to do something.

 Myron’s face is covered with foam which just wont stop flowing. I know that we will have to clear his airway if we’ve got any chance of bringing him back. There are people everywhere and divers still in the water. Lars Dave and Damon are on the back deck with Robert and Myron, Christine is in the lounge behind me and I’m standing there in a momentary daze, truly believing that there is nothing we can do to save this mans life. I suddenly get dragged back into reality and someone is yelling, it’s me, but its all one sentence-


8.13 am. The boys drag Myron through the door into the lounge where Christine has already got the O2 ready; he’s as floppy as a rag doll. Dave starts mouth to mouth, checks for a pulse while Damon chops at the wetsuit to expose Myron’s chest. Chris by this stage has handed Dave a pocket mask and he continues EAR. With each breath Myron lungs ooze more foam, then finally he coughs. As soon as it looks like Myron can breathe on his own he is put on the Oxygen while someone else grabs the ventilator bag in case we need to force feed him the O2 at some point in the very near future. This has all happened in seconds. Myron has coughed up more white foam in chunky bits all through the lounge; the place smells like vomit and shit. At this point I’ve turned and raced through to the bridge and flicked through the channels of the marine radio to the station I know the local coast guard will hear me best on.

 8.15am VHF Channel 81

Trev- “Coast Guard Redcliffe, Coast Guard Redcliffe, Coast Guard Redcliffe this is Esperance Star, Esperance Star, Esperance Star”.

CG Operator- “Esperance Star this is Coast Guard Redcliffe go ahead please”.

Trev-“Coast Guard Redcliffe we have a diver in trouble suspected of near drowning and of decompression illness, we require an immediate evacuation to hospital”.

CG Operator-“Affirmative Esperance Star we will dispatch a vessel to your location, could you give me your exact position?”

Trev-“Aaar Redcliffe Coast Guard we are going to require an airlift for this incident, this is a serious situation, I repeat I will require an airlift!”

The coast guard operator soon asked me to go to VHF Channel 63 so I could speak to the Water Police directly. They soon transferred to the Ambulance Service who asked me to describe the patient’s condition, our position and the sea conditions. I had also made a phone call during this time and had Hyperbaric Physician Simon Mitchell on the speakerphone.

8.20am We organized the airlift with the Ambulance then Simon talked me through any secondary aid we might be able to give Myron. This included the ongoing maintenance of his airway, which we were told could present a problem at any stage. Messages from the doctor and Ambulance to and from the first aiders were transferred at a rapid rate, whilst there was still the ongoing issue of divers in the water.

8.40 am It would have been very easy at this point to get a bit slack in our normal dive supervisory duties, so when everyone was back I ordered several headcounts to ensure that the tension of the situation hadn’t made us overlook anything. Lars had been required to go out in the pickup dinghy to gather in a few divers that had lost contact with the boat. With everyone on board I began to winch the anchor as the faint drone of the Chopper could be heard from the west above Cape Moreton. Simon was still on the phone, the guys wanted to give Myron some water but Simon said ‘No Way!!!!!!!!!!!’

8.55am We had established contact with the Helicopter. I knew the protocol for an airlift so we had started to steam with the breeze just on our port bow as fast as the ES could go. I sent several of the crew upstairs to secure anything that could be blown around and to try and lower any radio aerials they could. The chopper would be very close to us and the down force is incredible. We also had the added issue of seagoing traffic. It was after all a perfect day and there were dozens of trailer boats in the vicinity. I looked ahead and could see that there would be problems ahead I told the Chopper that we may have to adjust our course as we weaved through these boats but he didn’t respond, I don’t know if he heard anything.

9.05 am Myron was still with us. As Lars, Damon and Chris had secured the ship for the choppers arrival, Dave had stayed with him the whole time, assisted by Sean. He had begun to speak but it was gibberish. He was actually shouting through the 02 mask, it sounded like he was saying “get me to the border” but we decided later he must have meant either ‘toilet’ or ‘hospital’, or maybe ‘port’, I don’t know.

9.15am With the Paramedics on board the tension was slightly relieved. The Chopper was right above us thundering away as we weaved through a few small boats. It must have been an amazing sight for them. The Paras went over Myron and although he was critical it was determined we could move him onto a stretcher and try to get him into the Chopper. David and Sean picked Myron up and took him onto the back deck where he was strapped into a stainless steel stretcher .We then lowered the dinghy crane and hoisted Myron above and onto the top deck, all the while weaving through a mass of stunned onlookers. The chopper came bearing in and the first Para was snapped off the top deck with Myron strapped beside her in his stretcher.

9.55am Minutes later the second Para was giving the thumbs up and in an instant he was gone and the Chopper sped off to the west. I looked around the top deck at a stunned and silenced boat crew, then wandered down stairs and pulled the revs back. I turned the boat back towards the Cape and wandered if we should just go in to port straight away. We still didn’t know if Myron would live, if he had a major lung expansion injury or anything. I turned to Chris and asked her to make a cup of tea. It had just turned 10.00 o’clock; it had been quite a morning.

1.30pm We had just tied the boat up back at the Marina. It had taken three and a half hours to get in from the Cape. We had decided to call the trip off and head straight in. Rachel was beginning to shows signs of having a mild case of decompression illness. Sean Inglis had all but destroyed the inside of one of his ears in his rapid ascent with Myron in tow. Sean had voluntarily swum from 40 meters to the surface in less than thirty seconds, and then ducked back down to ten meters once he had done what he could. The whole boat was shell shocked, even the Captain. Myron had literally been dragged back from beyond the brink of death. Reports from the hospital were that he was resting and being treated for an Arterial Gas Embolism at the Wesley Hyperbaric Chamber, although the consulting physician was fairly confident that the treatment was purely precautionary.

2.00pm I went out onto the back deck to have a look at Myron’s gear to see if it could be determined what might have caused him to black out at depth. I knew that the workplace inspectors would want to confiscate the gear and find out for themselves, but I also knew that these devices would be new to them and the cause might not be apparent to someone not familiar with the equipment unless there was an obvious fault.

It didn’t however, take long to see what the problem had been.

On page three of the Buddy Inspiration Manual its states:


Attitude keeps you alive: Normally, closed circuit rebreathers are used by experienced open-circuit divers. This can bring a level of overconfidence which can lead to serious problems. You are a novice again, please accept that and build your rebreather experience gradually.

Further into the manual on page 13:

The Work of Breathing of the Inspiration is under 3 joules per litre at 50m. This is the limit specified for open circuit diving regulators. The counterlungs are in the best possible position for overall ease of breathing in each orientation of the diver.

On page 28:

It is essential to keep the breathing bags/counterlungs down on your shoulders.

They are prevented from floating upwards by the Fasted buckle located on the lower edge of each counterlung.

Then on page 31:

Holding the counterlungs down is extremely important and care must be taken to ensure they are not allowed to float above the divers shoulders. If this happens, breathing resistance will increase dramatically…. Increased breathing resistance means increased CO2 retention.

What the manual is basically saying is that inexperience will kill you and that if the counterlungs are not secured firmly down to the shoulders you could experience a CO2 build up, and we know that can kill you. But Myron’s counterlungs weren’t just loose and rising above the shoulder, they weren’t connected to the down straps of the harness AT ALL. This would cause them both to rise almost vertically above his shoulders, causing a massive pressure gradient between his lungs and the counterlungs. He would have to really suck to draw any breath. It would be like trying to breath off a 5-foot snorkel, all sucking with little result. That combined with the effort to get to the bottom at the St Paul, and the influences of partial pressure on the CO2 levels that were no doubt building up in Myron’s system. All of it adds up to a recipe for disaster, and it took only a cursory glance to notice that Myron’s harness was incorrectly fitted and that the counterlungs had not been attached to the harness. It was a mistake that could not have been detected when Myron was standing up in his gear on the front deck, as gravity held the counterlungs close in on Myron’s chest, but in the water there buoyancy lifted them up and high: it was a mistake of the first order. In open circuit terms it would be the equivalent of jumping into the water with your first stage not attached to your tank valve.  Back to that quote on page three of the Inspiration manual.

“Attitude keeps you alive: Normally, closed circuit rebreathers are used by experienced open-circuit divers. This can bring a level of overconfidence which can lead to serious problems. You are a novice again, please accept that and build your rebreather experience gradually”

Myron had succumbed at depth to the insidious effects of CO2 build-up, the curse of the CCR diver. It had taken just minutes to render him unconscious, proceeded by a minute or so of appearing to have lost the plot completely. The reality in Myron’s mind would have been that although he knew something was wrong he didn’t know what and although he knew he had to do something his body wouldn’t do what his mind told it to do.

Sean Inglis had described that Myron did not look right in his gear and he was correct, but not knowing about rebreathers himself, Sean couldn’t determine the exact nature of the problem. He knew enough however to stick close enough to be able to render immediate assistance to the surface when Myron lost consciousness. If a single act should be highlighted as the root cause of Myron’s survival it would be this. Followed in no small way by the first aid administered by Dave Walton at the surface. The outcome of Myron’s accident had been changed by a small degree of luck and some cool heads under extreme pressure.

When Myron brought his family down to the boat the following day I couldn’t help hearing my own words echo through my head “He’s Dead”. Yet there he was. I also couldn’t get the sight of his blue face out of my mind. I asked Sean after they had left what would be the defining moment for him of the whole experience, what image would he keep forever, and it is fitting to complete this story by quoting him directly;

“When I spun Myron around on the bottom and he was gone in the head, he spat his mouthpiece out and began to jerk about, all I could think about was the night before I had watched him saying goodbye to his wife and kid in the car park, I remember noticing that he seemed to spend ages up there with them. I had this picture of him standing there with them, yeh, that’s what I'll remember”


Myron’s report of the incident

“It was the first dive of the weekend.  It was a near perfect day and I was ready to play with my new rebreather.  The first dive was on the St. Paul.  It’s was a familiar site and I’d been here many times before.  What a better way to start the weekend.  But things didn’t start out that well.  During an inspection of my gear just prior to the dive, I realized that my computer has a dead battery.  This doesn’t cause any real concerns though.  Another diver had a spare and it is the same brand as mine so I am familiar with its operation.  After this quick fix, the gear checked out fine.

Because of the last minute gear change, I was nearly the last diver into the water.  This didn’t cause any concern as I didn’t plan a long dive and I’d only be a couple minutes later than the other divers.

Unlike open circuit SCUBA, a rebreather requires you add diluent (in my case air) into the breathing loop as you descend.  As I descended, I did have some difficulty breathing, so, I attributed it to not adding diluent fast enough.  The problem abated somewhat by adding more air, more quickly.  Once on the bottom, I realized that there was another issue.  I had not switched from low set point of 0.7 PPO2 to the high set point of 1.3 PPO2.  This had the effect of making PPN2 higher and I believe I was also suffering from high degree of Nitrogen Narcosis.  I attempted to correct this situation, but I was having difficulty focusing on the task and was unable to locate the handsets to make the switch.  At about that point, I became aware that something else was seriously wrong and that I was getting more anxious by the second.  I signaled my buddy that I had a problem and had to ascend.  Just then, I lost contact with the anchor chain and I was slightly positively buoyant.  I swam back down to the chain and then I started to move along it towards the boat.  My buddy grabbed me and started pulling me the other way I turned to him and signaled again, I have a problem and I have to go up.  He continued to pull me down.  At this point, I remember looking up and thinking I need to go up and my buddy is pulling me down.  I’m not going to make it.  I thought I’m sorry Gisela (my wife), but I’ve failed you.  I fully expected that this would end very badly.  That is the last thing I remember before being revived on board.

I should note that the above paragraph was written from the perspective of a very disoriented person.  I realize now that certain things didn’t make sense.  I kept finding things that weren’t there on the way down.  At the time, I thought that’s odd, where did they come from.  On the surface, the answer is painfully obvious.  My buddy understood exactly what was going on and was pulling me towards safety.  I on the other hand was swimming farther down, thinking I was trying to get out.  It seems that when I lost contact with the anchor chain I tuned myself 180 degrees before I reacquired it.

Some time later, I learned that Rachel herself was in trouble at that point.  She had missed a lot of decompression on the way up due to the rapid ascent.  She returned to do her now mandatory decompression.  Unfortunately, she now did not have enough air to complete the lengthy stop.  Vanessa Dillon arrived on the scene and shared air with Rachel to allow her to complete her Safety stop.  Sean had returned to do his decompression as well.  After bringing me to the surface, he returned to do his decompression was well and burst his eardrum in doing so.

The next thing I remember was waking up in what appeared to be the lounge of the Esperance Star.  I was lying on my side and I recognized the furniture and surroundings.  Not knowing how I could possibly have gotten there, I believed that I was having a dream.  Dave Walton was above me telling me that I’d had an accident.  Bullshit I thought, “I’m having a dream and it’s a weird one at that”.  I looked around some more.  I recognized the people that I could see.  I recognized the furniture.  What the hell was I doing here?  My back was hurting badly.  I tried to lie flat.  Dave would have nothing to do with this and kept me on my side.  My throat was so dry I could hardly speak.  I begged for water.  I was told, “No, the doctor says you can’t have any”.  Bloody hell, what kind of dream is this?

Shortly afterwards, I saw a paramedic.  She introduced herself and spoke briefly with me.  I have no idea what she said.  I remember thinking, “I don’t know this person”.  Perhaps this isn’t a dream after all.  Maybe this situation is serious.  It was about this time that I lost control of my bowels.  Let me tell you, it was a very unpleasant feeling, lying there in my own shit.

I asked the paramedic to repeat her name.  She did.  I could hear the logistics being discussed in the background.  Where should we air lift him from?  Front of back deck?  Back.   I was carried out and placed in a basket on the lower rear deck.  They wrapped me in a blanket and then, I was winched up onto the upper back deck with the boat winch.  The helicopter returned and started to winch me up.  The wind makes me dreadfully cold.  I hit my head on the landing gear of the chopper.  I was too weak to push myself away from it.   They get me into the chopper.  I ask the paramedic what her name was again.  She tells me again.

At this point, I was certain that this is not a dream and it was real life.  OK I thought, I appear to be in good nick.  I’m in a helicopter on my way to the hospital.  I guess I’ll be OK.  A few minutes into the flight, I started having difficulty breathing.  My back hurt so much that it’s very painful to breathe.  The problem grows rapidly worse.  I would estimate I was taking 3 breaths every 2 seconds in an attempt to get air into my lungs.  I am still on oxygen.  I ask the paramedic what her name is, she tells me again.  I ask how far to the hospital.  She shows me her watch.  No, how much longer?  5 minutes she tells me.  I don’t know if I can hold out.  I’ll try.  I hear them radio ahead.  I don’t remember the words, but it sounded like they didn’t expect me to be breathing when I arrived.  Holy shit.  This is serious.

Soon after we landed, they had me in the emergency ward.  I was still not in control of my bowels yet, and there was shit everywhere.  They strapped on a special mask which (as I understood it) forced oxygen into your lungs.  Although I could not take any larger breaths, I was not as starved for air.  I was still in severe pain though.  They asked me if they I wanted them to call my wife.  I told them to wait a couple of minutes.  I was thinking I’d catch my breath and talk to her myself.  That would be better.  Obviously, I still wasn’t thinking straight.  They shot me up with drugs to make my breathing easier.  They didn’t seem to help, but at least I wasn’t in immediate distress.  Things happened rather quickly at this point. There were needles and IVs everywhere.

Now, they’re talking about going to the Wesley for the recompression chamber.  The next thing I know, I’m in another ambulance.  I’m still on nearly 100% O2, but not the forced ventilator now.  Once at the chamber, things slowed down again.

Various tests to see how I was neurologically (stand with your eyes closed, what date is it, and the hardest of all, what time of day is it?  How the hell would I know?  I’ve had other things on my mind …

Into the Hyperbaric chamber at 18 MSW I went for a couple hours on 100% O2 (2.8 PP02).  I looked at the exact schedule, but can’t remember it.  Something like 20 minutes on, 10 off, 20 on, 10 off, 30 on, and then “ascend” to 9 MSW.  30 on, 20 off, 90 on.  Sound pretty boring doesn’t it?  Well, it is during this time that I started to think that I was going to live through this thing.  I began to wonder about the people who rescued me.  I heard that Rachel is on her way to the chamber.  I began to wonder what the hell I was thinking being down there.  Simon Mitchell just happened to be in town and stopped by the chamber after hearing of my problems.  After speaking with him and Trevor through the radio, the exact cause of my problems becomes clear.  When I assembled my gear, I had not strapped the counter lungs down properly.  This caused them to float over my head and increased breathing effort.  Because of this, my body produced more CO2 and could not get rid of it.  A CO2 “hit” is what I experienced.


About the time that I was released from the chamber, Rachel arrives for her treatment.  I was feeling pretty good physically by then, so I spent some time talking with her.  Again I realized the danger that my friends have placed themselves in to save my ass.

I spent the night in the hospital under observation.  Presumably for secondary drowning and salt-water aspiration and any other complications.  I was released from the hospital at about 9:00 the following morning.  I conferred with the hyperbaric chamber and was told that I did not require any follow-up treatments.

Later that day, I returned to the Esperance Star to retrieve my gear and I confirmed that it is assembled incorrectly.  I can’t believe that I made such a stupid mistake.

Although I am physically unscathed, mentally, I am in not in such good shape.  The following few days are very traumatic.  I find myself crying often which is not like me at all.  On the following Tuesday, I contacted a couple of my friends who were there.  After talking to them, I realized that it’s not just me that’s struggling with the aftermath.  They are having difficulty dealing with it as well.  As odd as it seems to me, some were worried that they didn’t do enough.  While I was thinking what else could they possibly have done.  After all, I’m not only alive, but well.

Everyone will need to deal with this in their own way, but it is apparent that it’s not a simple thing.  It’s not just me that has to deal with this, but my family and my friends that were there too.  I can only imagine the picture of me lying on the duckboard, “slate blue grey face, foam oozing from every orifice, his eyes were wide open … unconscious and not breathing or responding to any stimuli”.  My friends have to live with the image, after all, they saw it, “fortunately”, I was elsewhere at the time.

There is no way to thank my saviors.  There is no doubt in my mind that if they had not acted quickly and decisively, I would not be in the condition I am in today.  Perhaps crippled, perhaps brain damaged to some extent, perhaps dead.  The fact that I not only survived, but am at work on Monday is totally amazing.  When I think about it for longer than a few seconds, I start to cry.

I am so sorry to have put people in such danger.  I am so sorry for causing such stress to my friends.  Killing myself I can live with, but …  Thankfully, their injuries were relatively minor in nature.

I am fortunate to be alive, and as Trevor said, there was luck involved, but as I see it, it was the fact that I was on board with the right people.  After that, there was no luck (either good or bad) involved.  I did it to myself.  No excuses.

What have I learned from this incident?  Well, the CCR is a serious piece of kit.  This I knew.  However, what I did not fully comprehend before was the fact that you MUST be able to concentrate and I mean concentrate on 10 things at once.  If you can’t you shouldn’t be using a rebreather.  I think it’s that simple.  I lost concentration and damn near died, probably should have died.  So there are several questions for me to answer over the next 6 weeks while I’m out of the water … will I dive again?  Duh.. yes, for certain.  Will I dive a CCR or OC?  That one is much more difficult.  I certainly want to dive CCR, but to determine that, I must determine if I can concentrate on 10 things at once for an extended period of time.  I have to look at myself, nothing to do with diving.  Can I do this?  I’ve failed once.  If I fail again, the chances of such a good outcome are slim at best.  I have 6 weeks to think about it.  I’ll keep you posted.  If I decide I can’t, perhaps I should have taken that $55 I was offered for the thing at the chamber.  I hear Inspirations don’t sell to well on eBay.


In closing, thanks to all involved.  Trevor has mentioned many of them, but I know in my heart that Trevor himself had a big role too.  If I had to guess, he kept everyone on task and made sure things got done (sound pretty easy).  I owe my life to each and every one of these people.  I downloaded my computer last night.  I see that I was brought from 38M to the surface in less than 30 seconds.  They could have killed themselves.  That’s a selfless act.  I was on board and having CPR administered to me so quickly that there was no brain damage, meaning that CPR began with 4 minutes of me going unconscious.  Damn that’s fast.  A few more seconds here or there and the result would have been somewhat less satisfactory.



From a rescuers viewpoint

We rolled him over and fluid poured from him ( like emptying a container ). When I started EAR fluid would pour out of him with each time his chest contracted. After the first set I looked for a pulse but could not feel it. At that time I looked at Damon who was busy trying to cut away his wetsuit ( with a kitchen knife )so that we could begin CPR. I'm sure that he thought exactly the same as me " that this is useless he's dead". I continued EAR getting more fluid pour out after each breath. I then checked again for a pulse and thought I could feel one. Myron still was not breathing. Christine then handed me a mask which I used for another maybe 6 breaths. It was at this stage that Myron took his first breath and Lars called out to you "He's breathing" I'm certain that you were on the phone
to Simon at this stage. We then got him on the O2 but had to pull the mask away after about every third breath as it filled with fluid. His breathing began to quicken and his pulse became very obvious. ( I suspect that whilst this seemed an improvement was perhaps Myron's most critical time ). His breathing then slowed and he gained consciousness very quickly.

And a passengers
”Today on an early morning dive on the St Paul (42m) a male diver experienced difficulties and soon after reaching the bottom passed out unconscious. The diver’s buddy and a DM on the trip immediately ascended to the surface with the unconscious diver where resuscitation was commenced and breathing re-established by a passenger and staff, while the crew immediately contacted emergency services and called for air evacuation of the patient. Contact was maintained while the helicopter was in transit with a diving physician providing direction on the ongoing treatment of the patient.

The then conscious patient was air lifted off the boat by the rescue helicopter service and transported to Wesley for subsequent treatment.

I would like to say as a witness to a large portion of the above events that the action of several individuals stand out and the whole emergency was handled with exceptional calm, poise and professionalism by the dive staff, involved passengers and crew of the Esperance Star. I cannot strongly impress enough how the quick and decisive actions of the individuals and staff involved prevented an extremely serious incident deteriorating. The successful airlift and transfer of the patient is a credit to all involved.

In light of the accident and the suspected DCS of one rescuer, and blown ear drum of the other, the remainder of the trip was cancelled, and we returned to harbour, so that others could other could seek proper medical assessment.

At this point I can add no other details except that the patient was receiving chamber treatment from last reports and that my thoughts are with the patient and his family and for his speedy recovery.

As usual speculation will be rife in this incident, but I ask that we can all show some restraint and hope that the person involved will be in a position to recount his experience at some point in the future.

To that end I will not be responding on this forum to any inquires regarding the incident.” Matthew MacLean [MHD]



And the predictable critics

“What a great look for the industry, is this Recreational diving Trevor . Why do you need to go so deep and stay so long when to a lot of people you can't do it very well (Look at your History Trevor). How many people is that now on ES, how many more people now have we lost to diving that will never try because of what was reported in the news.
People die and get injured so why do it.
Why praise you, when yes you may of save his life, but how come they always need saving on ES, and with certain dive operators.
Ask some questions on why it happened how it happened and how does the industry stop the people that let it happen.
ES is a boat that the industry need it to stop operating, or Trevor stop doing stupid profiles.
Look at what your actions is doing on the dive industry. Wake or get out or you will get forced out.”Anon


And from the Doctor

“As the "diving physician" referred to in MHD's original post, I would just make the comment that this is yet another example of a critical emergency that was handled in an exemplary manner by the ES crew. My friendship with Trevor Jackson is no secret, but it is an honest friendship and I do not hesitate to tell him when I think he has missed the mark on any issue. Matter such as this are no exception. However, I have been the recipient of patients (previously) and advisor (on this occasion) during emergencies on ES, and in contrast to the vacillation and muddling that I often see, Trevor and his crew never seem to have any difficulty in facing up to what has to be done, and then doing it professionally. My congratulations to all involved. Without any doubt a life saved.” Simon Mitchell


A few months later

 I was at a party recently. The conversation was lively and somehow we got onto the subject of age. All the clichés were there; “I’m 53 but I still feel 17 inside”, “You’re only as young as the woman you feel”. It occurred to me that of all the people in the room, I would be the only one who would say that I felt older than I was. On the way home I sat in the cab staring out as the lights went by, wondering why it was I should feel so drained, so much in need of a yearlong sleep. Id been working a lot that much was true, the boat had never been busier, almost constantly at sea for months, but Id done that forever so it couldn’t just be that. Something else was there.

Nearly four months had gone by since the accident. Since we pulled a blue faced foam gushing diver onto the back deck of Esperance Star. Devoid of life, sightless eyes staring at the sky. We put him in a chopper and he lived.. It was a mixture of luck and good management. The people involved had done a lot right that day and apart from some uninformed criticism, the weeks that followed the accident were a healing time for everyone that had been present, not just the in water victim. Well at least that what I told myself, but looking back I think I see now that the healing process has only just begun, things actually got worse following that day. The system that the government had put in place to protect people in a workplace, can in certain circumstances do more harm than good.

You can put the people involved in that accident into two categories; those that have gotten over it and those that haven’t. One thing separates the two groups quite definitively. The group that haven’t gotten over it were subjected to a witch-hunt by the Dept. of Workplace Health and Safety. The reason they were subjected to a witch-hunt was that they were in the firing line with regard to who would be to blame for this accident. They had to find blame. Now I wont go into details about the woes of the others involved in the investigation, I'll only speak for myself on this one.

We live in a society where individuals are reared on a diet of offloading blame onto the next guy and being responsible for nothing. I can go to a pub get flogged off my head and then win a court case against the pub when I faceplant the pavement up the street, after I probably argued till I was blue in the face when the bar staff told me Id had enough and that I should settle down. I can take up an extreme sport fully aware of the dangers. Make a stupid mistake, get injured, and then get paid out at the cost of some poor soul who was simply providing the service I had asked them to.

One thing I will say about the moment that accident occurred, everyone who could have possibly had the finger pointed at them over the incident, everyone that modern society could have assigned some type of blame to for it, was adversely affected in the way they reacted to the incident because of the thought of that impending blame. If even for a split second we react slowly or stop to ‘consider the consequences”, we are not providing the kind of rapid treatment to a victim that he or she might otherwise receive. Common advice when an accident occurs in a workplace is to document all your actions as you make them on some sought of time scale. In a dive accident for example I might write down

9.34am Diver seen on surface
9.35am Dinghy retrieves diver
9.36 am Diver to ES
etc etc etc.

I mean come on, is this really necessary? Does it help the situation at all? The short answer is no, we do these things to ‘cover our arse’. So when a problem occurs, instead of spending every second tending with the real issue, we waste time bullshitting around with this type of documentation so that when were done saving a person we can later defend ourselves against someone who might say we didn’t do a good enough job when we were saving them. In other words, in the act of actually dealing with an emergency, we are further burdened by the fact that in some way big or small we will have to defend our actions. I remember steaming in after the Myron accident and thinking, “well that was fun, now the shits really gonna hit the fan”.

When accidents like these happen the investigation begins almost before the boat is even tied up. Dive gear must be secured, initial statements taken, thumbscrews applied. When I had my first interview with the department regarding this particular incident the investigator said that in future if we were to have another accident I should phone him before I get to port so he can interview everybody before they leave the ship. I can tell you that if Id have known that before docking there is still no way I would have subjected anyone on board to that type of grilling, given what they had already had to deal with that morning.

The interview he and I had consisted of him basically asking me to dob someone in for what had happened, it lasted for nearly three hours. At the beginning of the interview he asked me not to say anything unless I “knew it had happened”. He then asked a series of questions and when I replied, “I don’t know”, he asked me to reconsider my answer. For example at one point he asked me who had filled tanks that morning, I replied that I didn’t know, he then asked me, “well who could have filled them?”, thereby asking me to speculate when he had earlier clearly asked me not to speculate. At no point did he ask me what I thought had caused the accident and when I offered my professional opinion he said he wasn’t interested, despite him not even knowing what a Closed Circuit Rebreather even looked like and only ever having done 30 odd open circuit dives in his life. In the end I insisted on putting something about the cause of the accident into my statement and he was more or less forced to record it. He then confiscated some of my dive gear for “testing’.

When he finally left I couldn’t believe the line of questioning he had taken. What a meticulous and ruthless hunt this really was going to be. Other interviews were along similar lines, the “so who do you think was to blame” line of questioning seems to be the standard operating procedure. Now I’m not suggesting for a moment that workplace accidents not be investigated. One would imagine that the information gathered may help in the prevention of further accidents, but this didn’t for a split second seem to be the object of the exercise. All the parties involved were given a similar interview; it didn’t take long to realize we were all ‘suspects’ in some sought of surreal crime. Imagine having been through that type of trauma, done your level best, then to be put under the critical microscope for what, as one observer put it was, “a life no doubt saved”. In the end they gave everyone their gear back without so much as a “by your leave”. We felt we had all been hung out to dry.

Until yesterday, the 11th of September 2003, I hadn’t touched my rebreather in nearly four months. It sat still wrapped in plastic, the batteries in a packet beside it, waiting to be picked up and brought to life. Diving using this type of equipment had been a true passion for many years, now it was dead. Whenever I looked at the unit, I had a chill run through me. It had become a lump that had to be shifted from one bunk to another, had clothes piled onto it, been tripped over and cursed. I thought it was because of what we had seen that day. I thought that perhaps subconsciously I had lost my stomach for it, lost my nerve. I justified my lack of diving by claiming that it was because I was too busy, too tired, too sick; too bored. But none of these were the whole truth.

The truth is that I just didn’t want to be there anymore. My beautiful boat had become the bain of my life. My joy in helping people discover the underwater world had dried up and shrivelled. I thought long and hard about giving it up. Not because some ill informed twits had had the odd dig from anonymous internet keyboards, but because despite my best efforts to do a good job, and having done what I considered to in fact be a good job, I was being made feel guilty by a Govt. Dept which is meant to look after my interests as much as the next guy. My mental health, and the mental health of my colleagues, had suffered. Suffered at the hands of the Dept of Health and Safety. In a tangible way we hadn’t been injured, there were no scars or wounds. But its fair to say we were no longer functioning at full capacity either, and some were affected more than others.

I sat on the top deck of the boat yesterday staring at my rebreather, saying, “go on, just pick it up, do the pre-dives and go for a lap, don’t let this shit get to you any longer”.

Most people would consider me a tough guy, big, mean strong, and I haven’t always lived strictly on the right side of the law, but this was a hill I was struggling to climb. To put the unit on and get into the water was somehow a symbolic way of thumbing my nose at the guilt trip the Dept. had laid on me, a way of saying no I’m not taking this shit from you any longer. I flicked on the handsets to start the pre-dive warm-ups, maybe I’d just see if the batteries were still charged. Before long I was standing at the jump gate on the starboard side of the ES and talking to the dive master, telling him I would be taking it easy and doing a ‘no-deco dive’ with 17 minutes on the bottom. The rebreather had booted up perfectly and was urging me on. I jumped in.

The St Paul on a winters’ afternoon is one of the worlds magical places. Giant schools of kingfish swam in a mesmerizing roulette wheel pattern. Estuary Cod darted in and out of the machinery spaces as baitfish were swept down current onto the wreck from the north. I hovered like a spaceman at 38metres, checked the PO2 displays and descended the final few feet to the decks of the antique ship. What a place I thought. The visibility stretched out to about 30 meters and it was easy to forget the problems of the world and become once again hypnotized by the joys of technical diving, not just getting there, but being able to stay there a while too. Sometimes I feel like my progression into technical diving was really about me wanting to become more of a part of the depths, not just an intruder. I felt the weight of the past few months begin to lift. This type of diving was a gift that only a few people had had the chance to discover. Outsiders had been making me feel like the sport I enjoyed was a bad thing, I was beginning to picture them hunting witches in the 18th century, or being on constant lookout for Martians or Communists, history would eventually prove them fools.

I took another glance at my computers, 17 minutes had elapsed, at the 18th minute I knew I had been cleansed, I would regain control from now on. I ascended to 25 meters and turned to take a final glance at the spectacle, “its good to be back”, I thought, and made my way back to my own world.

Authors Note:

1] To my knowledge no charges or infringement notices have ever been issued over this incident

2] A 40 metre, 17 minute no-deco dive is possible using a closed circuit rebreather and careful depth/time monitoring


After nearly four months the whole accident thing was really only just beginning to settle down. It had been a sobering affair and it should serve to all of us as a reminder that we are in a world different from our own out there, outside our comfort zone where our the instincts we have evolved to keep us alive above the water may be tested to the full extent

The caustic cocktail, a personal experience. Story #7

Original text by:

Ron Micjan

The Mobile Install Shop





Many of us have heard the term used in rebreather diving called the “caustic cocktail”.  From stories of just a bad taste in the mouth all the way to a lung full of nastiness. Until yesterday I had just experienced the bad taste in the mouth variety and then only once.  Yesterday I was doing a dive with my friend Kent, off of the Nautilus Explorer, we were poking around the bottom of a wall at about 145 fsw, looking at very large urchin shells that were no longer occupied.  I had about a minute of NDL left and began to move up the wall, Kent was about 20 feet away and 10 feet deeper than me.  Interesting how fast things can change.  With absolutely no warning, one breath of gas changed into a breath of liquid.  I instantly had a mouth and throat full of sodalime dissolved in sea water.  My trachea spasmed (that probably kept me from drowning) and blocked the mixture from my lungs but sent some into my stomach.  Pulling the mouth piece out and closing the DSV took a couple seconds and I was holding my breath and spitting up into the water while the panic was rising in my brain.  Fighting that off I knew I needed to breathe soon and took hold of my Air 2 that was plumbed to my air diluent cylinder and put that into my mouth, cleared it of water and took a tentative breath.  Air is good.  I looked over at Kent and waved my light at him a few times, no response, he was looking the other way.  With only a 13 cf diluent cylinder, that was not full when I started this dive (mistake one)  I knew that I only had a few breaths at the 135 foot depth I was at.  I had neglected to bring along a larger bailout cylinder (mistake two) as I was not expecting to do any deco diving this trip.  I headed for the surface, keeping my airway open and exhaling any time I was not inhaling off my very limited gas supply.  At that point I wasn’t sure if I had the gas to make it to the surface, but I decided that I was going to make it, no ifs, ands or buts about it.  I ascended the 135 feet in about 90 seconds, not the safest ascent rate in the world but the options were, as you might guess, limited.  I hit the surface and waved to the skiff, not the usual diver OK but the two hands crossing above the head distress wave.  Al wasted no time getting the skiff over to me and I climbed aboard all the while coughing, spitting and vomiting my lunch out, and gasping for breath.  I washed my mouth out repeatedly with fresh water and asked for the onboard oxygen bottle, which Al handed down quickly.  I cranked it up to 15lpm and started sucking it down.  I was not feeling any symptoms of DCI but wanted to nip it in the bud if I could.  The length of my bottom time, 17min, the fact I didn’t enter deco, 18 hours since my last dive and the relatively controlled ascent was evidence that I probably wasn’t going to get bent, hard.  I wasn’t taking any chances, I used the whole cylinder.  Then swapped my dil reg over to my O2 cylinder and started using that. By that time most of the divers were up, but some had not heard the recall and were still diving.  I had this horrible burning sensation in my throat and mouth, swallowing was near to impossible and coughing hurt like hell.  This was not fun.  Still no DCI symptoms, Colby, the divemaster was coming by to check on my frequently and when Donny, the other divemaster, returned to the boat from his dive, he took over my looking after.  He holds up three fingers and says, “how many?”  I crossed my eyes and held up one finger back at him.  His reply, “you’re back”.  Donny knows my sense of humor.


A boat ride back to the Nautilus, off with the dry suit, plenty of water, some medical attention from Kim, a nurse who was a guest on the boat and a very sweet lady, (thanks Kim) and things gradually headed back to normal.  My throat was still sore, everything, including water, tasted like crap, but with no signs of DCI, I figured the worst was over.


Its now the next day and my throat is still sore, my voice is mostly gone, similar to a case of laryngitis, and I am sitting out the morning dive and writing this article.


I took the unit apart last night and found that my scrubber lid was leaking.  Either from not being tight enough, or something caught under the seal.  The unit had passed the positive and negative pressure checks, but I'm thinking that when it hit the cold water it may have shrunk the rubber seal enough to allow water to trickle in, slowly filling up the canister until it overflowed into the inhale loop.  I felt no increase in work of breathing, heard no gurgling, and tasted no difference in the loop, until I had a mouthful.


My lessons learned:  Either fill the dil bottle before every dive, or carry a bailout cylinder with enough gas to ascend at a slower rate.  (This is of course only for recreational, no deco, diving, I still carry 2 sling bottles on deco, deep, trimix dives).


In the end, the only thing that saved me was my training and just plain stubborn determination to not die.  I thank my original drager instructor, Alan Studley, for the training that put me on this course of discovery into rebreathers and provided me the tools to stay alive when the shit hit the fan.  Thanks Alan.


My advice to my fellow RB divers, previous performance is no guarantee of continued results.  I told someone the day before this happened that I had never had a flood of my loop.  I should have added the word, yet.  My mistake was not in having a loop flood, but in not being prepared for that eventuality, yes I had some onboard dil accesable from OC, but not near enough. If I had been delayed in my ascent for any reason, I probably would not be here today to tell this story.  The absolute number two thing in RB diving is HAVE A BAILOUT PLAN.  Number one is of course know your PPO2.  Don’t just assume you will never have a flood.  I HAD BECOME COMPLACENT!!!!!  Don’t let this happen to you.  I was lucky, and I had a survival mindset, its what brought me back.  Don’t depend on luck, have a plan that you know will work.  How will you know it will work?  Test it, see how long it takes you to bailout, you can do this shallow and have a buddy time you, then do the math for the same thing at depth, calc your OC bailout gas and then double that number, carry it every dive, even when you are feeling lazy.

It is said that what does not kill you makes you stronger.


Thanks to Mike Lever and the crew of the Nautilus Explorer for their timely help, care and professionalism.


Ron Micjan

4 June 2004

Port Hardy, Canada




With all these messages about the dangers of rebreathers, I thought you

might enjoy hearing about an incident where my using a rebreather probably

prevented a serious injury.

Yesterday I was diving here (in Guam) with my Cis-Lunar in about 65 feet

of water, when I received a strong impact on my rebreather and then a

glancing blow on the back of my head. I was very alarmed, but not injured,

as a large Titan Triggerfish swam in front of me to its nest and prepared

for another attack. A Titan Triggerfish (Balistoides viridescens,

gets over 2 feet long, has big sharp teeth, and is very aggressive in defending its

nest. I am usually very cautious when I see this species, but I had

apparently swam between the triggerfish and its nest without seeing the

triggerfish. Once I saw the triggerfish I fended it off with my hand-nets

(Pyle design, approved for fending off sharks :^) and backed away quickly,

preventing additional attacks. After the dive I saw two deep

scratches on the left tee of my rig, and I figured that if I was wearing a OC rig the

full force of the attack would have hit my head, instead of the rebreather

taking most of the impact. I will definitely keep a sharp lookout for this

species in the future.


Jeffrey Mahon, Ph.D.

General Curator

UnderWater World Guam

1245 Pale San Vitores Rd, Ste 400

Tumon, Guam 96913

(671) 649-9191 x103

Fax (671) 647-1689


'Same Planet, Different World'


And story #9

CO2  Breakthrough

author: Adam Evans
originally posted on the Inspiration news list

I don't know if there is any value in it but I thought I would convey my experiences too. About 6 months ago, I was on a trip when a buddy of mine noted how tight I pack my stack. I use the pat pat method and ensure that the stack is solid (i.e. the granules in the pockets of the scrim at the bottom [the bit where the spring is] do not move). I enquired how he packed his stack and discovered that it was much looser than me. I was concerned that I may over packing and agreed that I would follow his guidelines the following week on a shallow dive. It is also worth noting that he had had a few bad dives as he was feeling "funny" at depth and he felt that he was unfit as he couldn't keep up with me (he is MUCH fitter than me).

The next week, I packed my stack exactly as per his guideline which incidentally is pretty much the "new" method. When I got into the water, we dropped to about 34ish meters and swam along at this depth for a while. After a few minutes, I noticed that I was out of breath and it felt like no matter how deeply I breathed, my unit could not give me enough gas. Also, I didn't feel right, not bad enough to abort the dive, just that this dive was somehow different to "normal" dives but I was having trouble working out what the different was. After a few moments "CO2 build up" jumped into my mind. I stopped and bailed out to OC (I didn't decrease the depth at this point). After about two minutes on OC, I didn't notice much difference. Next, I started to ascend and did start to feel much better. When this initially occurred, I signaled to my buddy that I didn't feel right and he kept an eye on proceedings. When I got to about 28m, I decided to try again with the loop so I switched back, ensuring my buddy was keeping an eye on me. Initially it started to get worse again but as I was still ascending my breathing continued to settle down. At around 22m, I was breathing normally and the dive progressed without further incident.

In the post dive analysis, it became obvious that the stack was under packed and channelling had occurred. This diagnosis became more convincing when the unit was dismantled and the scrubber assembly was inspected.

After that dive, I reverted to my original packing procedure and I have had no problems since. Additionally, the buddy that was having the original problems, now packs his stack tighter and has not experienced further problems. In addition to this, I have never experienced high WOB with my stack. In fact, I found the opposite to be true, when I packed the stack more loosely, it seemed like the WOB was enormous.

The diagnosis of the problem was a process of elimination as there were no signs that the unit was assembled incorrectly. Also, there were no tell tale tracks in the stack to indicate channelling. So in the final analysis, the thing that I had changed was probably the cause of my problems (i.e. packing the stack too loosely).


Safe Diving

adamevans at ntlworld dot com


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