before you become a rebreather diver, you’d better read this
Conventional open-circuit scuba is sold as “not being rocket science.” PADI and its like have made it available to almost everyone. Scuba is fun. It’s for all the family. Once you’ve grasped Boyle’s Law and the repercussions of breathing compressed gas underwater, it’s only a matter of gaining the confidence to do things underwater. Well, that’s true if you confine yourself to open-water scuba depths in benign water conditions. Of course, mistakes can be made.
Scuba diving out in the ocean can introduce complications, and an understanding of seamanship might be required. It’s also all about your managing your air supply because if it stops, you can’t breathe.
Decompression requirements or the limits of no-stop diving can easily be taken care of by observing your diving computer.
Even when you want to go deeper than conventional diving depths using different mixed gases, some of which might be anoxic in the shallows, it’s not hard to understand scuba diving. In-water confidence plus the ability to put the right regulator in your mouth at the appropriate depth is all that’s required. Of course, mistakes can be made. The wrong regulator with the wrong gas mix can be selected, but it takes a conscious (if wrong) decision to do that.
Scuba diving without a visible surface above adds the proviso that you must be confident and not panic when unexpected circumstances arise. Cave systems and enclosed wrecks without direct access to the surface and fresh air are no place for beginners. That’s another thing that doesn’t take much to understand.
And that is why we have a culture of having fun and enjoying ourselves when learning to scuba dive. This is imparted by instructors who make sure to make it fun. They really want you to have a good time (something very clearly missing if you’ve ever seen Israeli army recruits learning to scuba). Generally speaking, training in open-circuit scuba is delivered in a light-hearted, even casual, manner.
But then there’s closed-circuit or CCR diving.
I met Buzz Aldrin briefly at a DEMA show. He was the guest on the booth of Silent Diving, one of the leading suppliers of closed-circuit rebreathers. It didn’t surprise me that the ex-astronaut was a competent CCR diver. There’s a lot in common with breathing from a system in the inhospitable vacuum of space and breathing from a closed-circuit system in the inhospitable environment that is water.
CCR diving is different from OC scuba in that you can always breathe, but you need to be confident in what you are actually breathing. Closed-circuit rebreathers recirculate the gas (either nitrox or mixed gas with added helium) in the system and your lungs so that the only gas you use is the oxygen you metabolize, which is surprisingly little. The gas is moved around in a loop between the user’s lungs and the CCR unit.
In the process, oxygen is added, either automatically or manually, to make up the difference in what is used, and the waste product of metabolism, carbon dioxide, is removed by a chemical scrubber that is packed by the user.
Hypoxia, caused by a shortfall in oxygen, has one symptom underwater — death. Hypercapnia, the poisoning caused by an excess of carbon dioxide in the breathing loop, results in breathlessness, confusion, and errors of judgment, very soon followed by death underwater.
How often were you told you might die during open-circuit scuba training? I doubt the subject ever came up. Statistically, the chances of dying on scuba are very remote indeed. Not so with CCR.
With few exceptions, divers gravitate to CCR after first learning conventional scuba techniques. The problem arises when scuba instructors gravitate to CCR instruction from conventional scuba instruction. Conventional scuba is not rocket science, but CCR diving is. There is no place for the cavalier attitudes of some scuba instructors in CCR training. Which brings us to the tragic story of Brian Bugge.
Brian Bugge, 35, a U.S. Pacific Fleet Integrated Undersea Surveillance Systems officer, was off-duty, on a closed-circuit rebreather training dive in Honolulu, when he died.
Brian obviously had good in-water confidence. He was quick to pick up the techniques of conventional scuba, but within two years, he had moved on to CCR training and training to use CCR with helium in the gas mix. That’s about as advanced as it can get.
His diving career is a litany of training mistakes. For example, he and his wife Ashley were allowed to dive in cenotes without a clear route to the surface, while still only open-water divers. They got away with all these risks without ill-effect. Brian’s confidence in his scuba abilities blossomed. However, he became the victim of casual CCR instruction allied to peer pressure. In my opinion, he moved on to mixed gas CCR too quickly, and the quality of the instruction he was given was too casual.
The outcome was for him to step off a dive boat and enter the water without his oxygen cylinder turned on. Unlike OC scuba, where, if your tank is not turned on, you soon know when you try to breathe because you get no air; a CCR can allow you to breathe a hypoxic mix. Within seconds Brian had used what little oxygen there was in the system. The effect is the same as a bullet in the brain.
Now many CCR divers will insist that cannot happen to them. There are warnings, both visual and aural, that trigger in a CCR unit if the partial pressure of oxygen in the breathing loop is either too high or too low. Brian obviously did not become aware of them. A new mixed-gas CCR diver, he was too distracted. Who was monitoring what he was doing? Where was his instructor at this time?
As what some would call a pioneer CCR diver (I started in 1993), I was always aware that my CCR unit could kill me. This led to a culture of checklists and double-checking, and doing the same for my dive buddy. I learned quickly how important it was to always know the partial pressure of oxygen in the gas I was breathing from the CCR unit.
Technical diving guru Rob Palmer advised me, “Get it wrong and you’re dead.” Good advice that I never forgot. However, it didn’t stop me writing numerous magazine articles extolling the advantages of CCR diving. CCRs have since become common on dives.
We do not go diving because we are fighting a war. We are only doing it for fun. The tragedy of Brian Bugge is that his death should never have happened. I suspect that many other CCR diving deaths should not have happened either.
You can see the whole tragic story of Brian Bugge unravel by watching the documentary If Only, bravely contributed to by his wife, Ashley.
In it, producer Gareth Lock, a high risk and human error expert (www.thehumandiver.com), contends that you can get away with errors 95 percent of the time. He says, “Brian Bugge made a number of mistakes on 20 May 2018, and a couple of them were critical. But there were also many other factors in place, including distractions and incomplete/inadequate training. This is no different from many other divers too. However, to focus on the fact that he didn’t turn on his oxygen valve misses a huge amount of learning that is available.”
I take some issue with this: Failing to open your oxygen tank valve on a CCR and becoming hypoxic is an error you can never, ever get away with. “Get it wrong and you’re dead.” You can watch the documentary made by Gareth Lock and Ashley Bugge here: https://vimeo.com/414325547
— John Bantin
Sr. Editor, Undercurrent