Teaching CCR Diving

By Jon Wright

As a technical diver, what I enjoy most about teaching is demystifying the more esoteric aspects of physics, physiology, gas management and technique. We do not need to be diving to great depth in order to benefit from this increased knowledge base and in many ways, having a more thorough understanding of the what, why and how of doing things underwater makes diving more enjoyable.

Closed circuit rebreather (CCR) is, for me, by far the best tool we have available for underwater exploration, research and recreation. CCR demands more of the diver, but this effort is more than compensated for by the massive advantages we get over open circuit SCUBA (OC), so its not surprising that my favourite courses to teach always involve rebreathers!

From the get go, in order to dive CCR we need to deepen our understanding (pun intended) of nitrox diving, as we are now diving with a gas blending machine on our back. When we understand the concept of diving with a variable fraction of gas (the percentages of oxygen and inert gases in the nitrox/trimix we are breathing varies according to depth), we can appreciate the power of CCR.

The fun starts in the classroom, for although the theory can seem a bit daunting at first, it really boils down to some fundamental physics, maths and physiology, it’s not rocket science! The degree of classroom work depends on the course, for a recreational rebreather course with 30 meters maximum depth and no required decompression, nitrox diver is a prerequisite, although this can be taught concurrently with the CCR course (as my last student did).

Recreational CCR theory is not particularly heavy and takes about the same amount of time as the theory section of an open water diver course. Obviously it gets a bit more involved when we start undertaking planned decompression dives, diving below recreational limits and using helium in our gas mixtures (trimix), but by this stage the diver has invested in their personal development to a greater degree and is usually soaking up as much information as possible.

The first dive on CCR is comparable to the first dive on OC, it’s all new and exciting, even for seasoned OC divers and it often takes a few dives for the student to get comfortable in the equipment. Once the new skill set is starting to become second nature we can enjoy the benefits of our new diving system and the last dives of any course are the most fun.

The most recent CCR course I taught was no exception, Kevin (our student, diving a KISS Spirit), Gary and I (who on this dive were both on APD Inspiration’s) started on the wreck of the Westsider in a maximum depth of 30 meters, after exploring this lovely old tugboat with its squadron of resident barracuda (some of which are of a very impressive size), we swam, just off the bottom, across to its sister wreck, the Boris, slightly smaller and a few meters shallower but no less impressive. After about 30 minutes on the two wrecks at between 30 and 24 meters, we swam over to Mabouya Garden reef and carried on at around 20 meters for another 45 minutes before rounding the corner towards Whirlpool, were we came up to between 15 and 5 meters for a further 45 minutes, stopping just short of reaching Whirlpool.

A 2 hour dive with substantial time spent below 20 meters, no concerns over remaining gas supplies and no required decompression, coupled with near total silent operation, enabling us to be at one with the marine life, that’s what CCR is all about. As Kevin said after that dive “I don’t think I will dive open circuit again”!

If you are interested in discovering the world of silent diving or are a CCR diver looking for a “rebreather friendly” dive operation, drop us a line. We can tailor make course and diving packages on either KISS Spirit or APD Inspiration CCR’s as well as supporting divers who wish to bring their own units.