I think most rebreather divers and certainly all rebreather instructors have been asked that question at one time or another; and in many cases, more than just one time. Unfortunately, it is an impossible question to answer with anything approaching accuracy or truth, because the question is so ill-defined it is meaningless. One might just as easily ask: “How long is a piece of string?”
If there is a secret to getting a definitive answer, it lies in framing the question within a few well defined parameters.
Rebreather diving is dangerously close to taking on a sort of silver bullet status as the right solution for every type of diving. However, common sense, and a quick summary glance at accident statistics, tells us that it clearly is not.
Running a Closed-Circuit Rebreather is an order of magnitude more complex than throwing a regulator on a scuba cylinder and going for a dive. Dive for dive, operating a CCR safely requires divers to pay attention and develop a skillset way beyond anything required on all but the most complex open circuit dive.
For example, a sure sign that something is wrong with open-circuit life-support is that it stops delivering gas to the diver. This is a graphic indication that some immediate action is called for. A CCR system will continue to deliver gas to the diver but that gas may be totally unsuitable for his current situation and if he is not paying attention, he will continue to breathe until he passes out and dies.
Consequently, the risk-benefit analysis for CCR diving has a very different complexion to a similar analysis for open-circuit diving, tech or otherwise. Short version, there has to be a good reason to choose CCR over OC for any dive; better yet, there should be several good reasons to choose CCR over OC for every dive.
And with this, we arrive at an important waypoint on the way to answering the “is it right for me?” question.
Anyone asking this question needs first to define for themselves what they believe are the advantages of a CCR; what sort of conditions they expect to dive in; and how often they expect to dive. I think as well, they need to look seriously at their dive budget.
Operating cost is one so-called advantage of CCR that gets mentioned time and time again. Specifically that helium costs for deep excursions on CCR are insignificant compared to doing a similar dive on open circuit. For a new CCR diver, this cost benefit can be ignored.
If cost is a person’s main reason for switching from OC to CCR, they are in for a shock and cost should not be a final tipping point in the argument to go with a CCR. Consider first that there is a compelling body of evidence pointing out that for many tens of hours following certification on their unit, regardless of model or type, a diver should revert to tyro-level dives and forego “technical” profiles altogether.
For someone diving as a weekend warrior, this will probably translate into a year or two without seeing a hint of helium in their diluent bottle. (And anyone thinking of taking up CCR diving, especially experienced “technical” divers, should ask themselves if they are honestly willing to accept that “limitation” to their diving? If their answer is no, there is a statistically compelling reason for them to either adjust their thinking or drop CCR diving from their wish list.)
Without doubt, there are dives for which the best tool is a rebreather, but often the pros and cons sort of wash each other out and the final arbiter is personal or team comfort with regards to one or two ‘gray’ issues. I dive a rebreather as a default in but am far from committing 100 percent to it because there are occasions when CCR simply does not make sense.
I guess you could say that my answer to the ubiquitous “is CCR right for me?” question is that it depends.
Douglas Adams, the English writer responsible for The Hitchhiker’s Guide to the Galaxy, wrote: “There is an art to flying. The knack lies in learning how to throw yourself at the ground and miss.” I believe similar logic can be applied to rebreather diving. Sometimes flying is best but occasionally, the bus is a safer option.