The fascination with depth among newer rebreather divers has  always given me pause to ponder the thought processes accompanying that fascination.  From a pragmatic viewpoint one could say you go down, swim around and come back up.  Certainly with todays’ technology it is it is not an unreasonable assumption for one to embrace.  Or is it?

Rationalizing that you can successfully manage the challenges presented by deeper dives creates an attractive proposition,  especially for the newly certified, less experienced diver.  It becomes very tempting for them to emulate others who appear to have successfully negotiated the path they are contemplating; one which exceeds their current level of training and experience.
Nothing can be further from the truth.  While on any given day anyone can successfully complete a deep (100 meters plus) dive, when things go awry it is only experience that will save you.

Excursions below 100 meters require more than just meticulous planning.  They require that plus a highly developed skill set which which is created by spending a vast amount of time under the water so you develop the muscle memory necessary to survive.  Skills learned and perfected in a class need to be securely cemented into memory by repetition over time.   Instinct and the ability to spontaneously make the correct decisions under duress are what will permit you to successfully solve problems below 100 meters.  If you have to think about what to do you are probably already doomed.

There was a time when 100 + meter dives were the domain of a small number of divers who had the requisite open circuit skills and were committed to perfecting them.  You needed to manage large numbers of bottles, multiple gasses and often times had to cut your own tables.  Rebreather and computer technology was not yet developed and mainstreamed.  There were no Shearwater Computers nor were there any of the rebreather options available today.

Fast forward to 2020 and almost anyone with the money can buy a rebreather, purchase some training and be doing 400 and 500 foot  (130 – 160 meter) dives in a relatively short period of time.  In most instances s/he will be successful in the endeavor because the technology is so evolved it becomes very easy to become lulled into a false sense of security.    If nothing goes wrong even a chimp can be trained to dive 500 foot depths in a few weeks.  What can’t be done is to train him to react appropriately when things go seriously wrong.  Only time and experience can train that.

So about now you might be wondering what my motivation to write this piece is.  It’s actually quite simple and straight forward.  Over the past few years I have been seeing people on rebreathers routinely diving beyond the level of their training and knowledge base and far more importantly, beyond their experience levels.  Because you have a certification does not mean you have the experience or the knowledge to recognize a bad dive plan, especially when it is proposed by someone you perceive to be an expert.  Certification only gives you the opportunity to learn and expand your skill set so you may evolve and get the experience.  It also gives you the opportunity to make bad choices and does not always prepare you to recognize poor planning.

For instance I have been hearing tales of divers running outrageously high ppO2’s on below 100 meter dives as part of an effort to reduce the decompression obligation.  This is a divers form of Russian Roulette.  Because you won yesterday does not mean you will win today.

All of us participating in this type of advanced technical rebreather diving have at the very least, a bit of Type A personality.  We all like to push the envelope.  It is part of our persona and that is fine as long as we never let it morph into recklessness.  There is a huge difference between managed risk and normalization of deviance.  All too often risk is dismissed because we succeeded in the past so the appropriate precautionary steps are overridden by unrealistic expectations of a successful outcome.  Goal oriented enthusiasm  should never override critical evaluation of what we are about to participate in.   The goal will often be accompanied by tunnel vision that cloaks any risk mitigation analysis you may have done.

So, in summation there are questions one should ponder before engaging in any serious deep rebreather dive.

  • Is the risk worth the reward?
  • Am I willing to gamble my life for it?
  • Is the plan viable?
  • Are there appropriate safety measures in place?
  •  Were I to experience a total equipment failure could I survive it?
  • Is my skill set such that I am confident in my abilities to manage any problem that might come my way?
  • Am I confident in my abilities to efficiently render assistance to a distressed team member?
  • Am I confident in the abilities of my team members?
  • Am I able to competently deal with any DCS issues and is the necessary equipment available to do so?

There is no set of correct answers to the above questions.  These are only thoughts divers should ponder before undertaking any extreme depth dives.  I truly believe in freedom of choice and if the risks are acceptable to you I say go for it.  My only caveat is to know exactly what you are getting into before you commit.