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By Andy Pilley
Header photo by Marcus Rose.
At the beginning of March 2020, I completed Global Underwater Explorers’ (GUE) Closed Circuit Rebreather Diver Level 1 (CCR1) course with Rich Walker. Taking this course had been a long term goal since I began diving under the GUE framework. By way of an introduction, even though I had been curious about GUE for a couple of years, my focus had been on training to use a CCR so that I could extend my diving and undertake more challenging dives. At this point, taking a ‘step back’ to participate in a Fundamentals course, the first step in the GUE education system, was not high on my agenda, and I pushed ahead with a 60 m/196 ft normoxic trimix and Cave CCR.
In May 2018, I had joined a trip to Molnar Janos in Budapest, where we did some relatively deep dives to the 60m/196 ft section of the cave. During one of the dives I realized that if something were to happen at this point (deepest phase and farthest point from the entrance), the likelihood that any of the divers I was with would be able to effectively assist me in an emergency, was slim to none. After returning from this trip, I completed my “Fundies” with Marcus Rose, and made the decision to pack away my JJ-CCR and dive with the growing GUE community we now have in Scotland. My end objective was to get back on to my CCR, but only when I was ready and could be an effective and vigilant teammate.
Since completing Fundies, I have built up experience, worked on my core skills to develop my capacity as a teammate, and undertaken more serious dives. Following up on this, I completed GUE’s DPV1 and Tech 1 courses in order to develop my abilities with mixed gas diving.
We’re very fortunate in Scotland that there is such a wealth of maritime history around our coastlines, and divers can find wrecks to suit any level of depth and ability. The east coast of the town of Eyemouth provides access to a huge range of wrecks, which include HMS Pathfinder, U-12, the British submarines HMS K4 and HMS K17, as well as the NJ Fjord passenger liner. Many of these wrecks were on my list to dive; but, I wanted to do them with a team that I trusted, so it made sense to proceed with my training in the appropriate manner.
A huge problem in Scotland is that helium prices are astronomically expensive, and a fill of Trimix 21/35 can cost in the region of £180/US $219 if filled from empty cylinders. This of course restricted the frequency of when we could carry out these dives. In addition to this, there are a number of very remote sites that we have dived in the recent past, and gas logistics became the biggest problem in being able to carry out these trips. We would often load up with two twinsets and two stage cylinders each for a weekend, and the cost of these fills soon adds up. As I’m sure you can imagine, the ease of logistics that is made available by using a CCR became appealing very quickly.
Diving Into The Course
What struck me about the course with Rich Walker was the level of detail that went into every aspect of using these machines. In my previous CCR courses, we had carried out checklists for pre-dive assembly and breathing checks. But, these were done as a group of individuals rather than as a team. Prior to this there had never been a sense of accountability toward my teammates, as it was very much a solo diving mindset.
For example, with the GUE class, the pre-build checklist sticker, recording individual measurements of cell linearity, and cell manufacture dates contained a new level of detail that I hadn’t experienced before. That is not to say they weren’t discussed in my previous training, but cell linearity went only as far as, “If the cells sit between 46-54mv (millivolts) they’ll be ok,” and, “remember to change your cells every 12 months.” It was left to us as individual divers to maintain our own equipment without any real accountability to those we were diving with. Needless to say, looking back on this from a GUE view point, I was shocked that I had once been prepared to accept that level of risk.
From the start of the GUE CCR1 course, the point was made that rebreathers are meant to facilitate dives that are infeasible on open circuit due to gas logistics. When you are venturing into these remote and hostile places, why would you be willing to expose yourself to an intolerable level of risk? Especially when something as simple as a checklist could identify faults and prevent a potential failure that could result in an aborted dive for you and your teammates. Teamwork requires that each member be accountable to the others. Something as simple as a completed checklist confirms that you are thinking with the end in mind, and providing reassurance that you have physically checked each element of your unit.
My previous CCR training had no prerequisites in terms of skill level prior to enrolling in the course; the only requirement was a minimum number of dives. I managed to complete Module 1 without too much difficulty; however, Module 2 was a different story.
In my previous CCR training, when I started Module 2, I felt as if I was ready to start undertaking deeper dives. However, my lack of fundamental skills, stability, and buoyancy control became apparent when we started diving with two bailout cylinders and trying to manage these effectively. My buoyancy fluctuated massively, and problems I encountered became progressively worse as new skills and increasing depth were introduced and I became task-loaded.
As with Module 1, I managed to pass the course; however, looking back on my performance at that time, I should never have passed. I should have been sent home to work on my foundational skills since what I was missing was the appropriate skill level.
After completing GUE’s Fundamentals, that solid base became apparent.
Capacity and Configuration
As we moved on to learn new rebreather skills in my CCR1 class, the necessity for solid fundamental skills was clear, as we now had to manage our loop volume in addition to our wing and drysuit buoyancy. As I mentioned previously, prior to undertaking Fundamentals I had perceived this as a ‘step back’ from the point where I thought I was in terms of my own diving. However, I cannot emphasize enough the importance of having a solid skill base from which to build your capacity, and progress in your diving.
The capacity that GUE training instills in divers provides a common baseline for the team. It provides the reassurance that each diver is trained to the same standard, and will respond in the same manner to particular scenarios. In contrast, the skills taught in my original CCR courses varied depending on which instructor taught them. This could lead to a significant variance in an individual’s response in any given scenario without guarantee that the response will be correct, and more importantly safe. The difference led me to consider GUE’s rebreather configuration in particular, and the benefits it offered in comparison to a standard CCR configuration.
The rig, configured GUE style, looked very different from what I had seen previously, but after it was explained to me, and how it fits into the GUE framework, it all made sense. I first saw the setup about four years ago in a video demonstrating how a long hose deployment would work, and my first impression was that it looked very complicated and time consuming. ‘Why would you not just hand over a bailout cylinder and be done with it?’ was my thinking back then. In hindsight, I believe that deploying a long hose is much less risky than giving/receiving a bailout cylinder that may or may not have been analysed by that particular diver. Some of the CCR divers I had dived with prior to coming across GUE, don’t analyze their bailout gas before each dive. [Ed. note: GUE standards mandate analyzing and labeling gas the day of the dive.]
Incorporating a twinset of diluent into the rig reduces the number of external cylinders that must be carried on any given dive. As I alluded to earlier, I was carrying two Ali80’s (11 liter cylinders)—one bailout, one for deco—during my Mod2 course and was overweighted to the point that my wing was fully inflated and impeding my ability to manipulate the valve on my oxygen cylinder during a high PO2 drill.
Maintaining muscle memory from using a twinset allows for a smooth and familiar manipulation of the valves when required, and mounting the O2 bottle farther back removes any risk of the valve being caught by the wing if it’s overinflated. Overall, the rig feels safer to me, particularly when bailing out to open circuit. As mentioned previously, my prior training had been to use an external bailout cylinder and deploy that if the breathing loop was compromised.
I was not taught a set drill for verifying and deploying the bailout reg in my original CCR classes, and in a state of panic, I could very well have switched to a cylinder containing 50%, rather than a deep mix. In the case of the GUE configuration, it’s a case of either switching to a backup reg or using a bailout valve (BOV). Personally, I would prefer to do this, rather than running through a full gas switch procedure, especially if I was hypercapnic for example.
With this piece, I thought I would provide an overview of the particular elements of the course rather than a day-by-day account. I hope you’ve found this an interesting account of my experience and reflection on how the course sits in comparison to some other CCR training courses. If your objective is to move to CCR diving in the future, I would thoroughly recommend this course. I look forward to diving more with the GUE community and seeing you all on projects in the future.
Andy Pilley is a Chartered Surveyor, team member of GUE Scotland, passionate wreck & cave diver and Ghost Fishing UK team diver. Andy started diving with the Scottish Sub-Aqua club in 2011 and began diving with GUE in 2018. Andy dives on the east and west coasts of Scotland where there is a rich maritime history and an abundance of wrecks to be explored. He has a passion for project diving and is developing objectives for a number of sites with the GUE Scotland team. He hopes to assist on the Mars Project and with the WKPP in the future.
Our Most Read Stories of 2020
Dive into our most read stories of 2020. Can cameras kill? What about those peculiar GUE rebreathers? Gradient factors anyone? Was it a world record dive? Find out.
Header photo by Sean Romanowski
This December marks the second full year of publishing InDepth, and what a crazy year it’s been. With the pandemic still raging throughout most of the world, it has been a most challenging year for the diving industry, as I’m sure you’re aware. I would like to take this opportunity to thank you, our readers for your continuing interest and support, and also thank our thoughtful contributors who make the blog possible.
Over the last year, we published nearly 100 InDepth stories covering the latest developments in exploration, technology, training, conservation, diving science & medicine, image making and technical diving culture. We also added select translations into Chinese, Italian, and Spanish . In doing so, I believe that we have grown our coverage in terms of breadth, depth and sophistication. Call it, a geeky labor of love!
In addition, we’ve added some depth-full sponsors to the mix, that have made it possible to grow and sustain InDepth. Our special thanks to DAN Europe, Dive Rite, Divesoft, Fourth Element, Halcyon, The Human Diver, and Shearwater Research. May your brands continue to flourish!
Similar to 2019, we celebrate the coming new year with our Most Read Stories from 2020/2019. If you like what you read, please SUBSCRIBE, it’s free! That will ensure you’ll get our latest stories and content delivered to your inbox. Here’s to a hopefully wet and most excellent 2021!
1. Cameras Kill Cavers Again
Cave explorer, photographer and instructor Natalie L Gibb wants to make “taking pictures” the sixth rule accident analysis. How can toting a camera underground get you into trouble? Take a breath, clip off your camera, and say cheese, Gibb will explain.
2. The Thinking Behind GUEs Closed Circuit Rebreather Configuration
GUE is known for taking its own holistic approach to gear configuration. Here GUE board member and Instructor Trainer Richard Lundgren explains the reasoning behind its unique closed-circuit rebreather configuration. It’s all about the gas!
3. Gradient Factors in a Post Deep Stop World
World-recognized decompression physiologist and cave explorer David Doolette explains the new evidence-based findings on “deep stops,” and shares how and why he sets his own gradient factors. His recommendations may give you pause to stop (shallower).
4. Fact or Fiction: Revisiting the Guinness World Record Dive
Newly released information calls into question the validity of former Egyptian Army Colonel and instructor trainer Ahmed Gabr’s 2014 world record scuba dive to 332 m/1,090 ft in the Red Sea. InDepth editor-in-chief Michael Menduno reports on what we’ve learned, why this information is coming out now, and what it all may mean.
5. Can We Save Our Planet? What About Ourselves? Interview With Sea Shepherd founder Paul Watson.
Managing editor Amanda White poses the BIG questions to environmental activist Captain Paul Watson, founder of Sea Shepherd Conservation Society and the architect behind its strategy of aggressive non-violence. His answers may surprise you—and even bring you to tears. What motivates the 70-year Environmental Hero of the 20th Century to keep up the fight despite widespread ignorance, apathy and greed? Find out.
6. Isobaric Counter Diffusion in the Real World
Isobaric counterdiffusion is one of those geeky, esoteric subjects that some tech programs deem of minor relevance, while others regard it as a distinct operational concern. Divers Alert Network’s Reilly Fogarty examines the physiological underpinnings of ICD, some of the key research behind it, and discusses its application to tech diving.
7. Deepest Freshwater Flooded Abyss in the World
The efforts to explore and map Hranice Abyss, located in Hranice (Přerov District) in the Czech Republic span more a century. Currently, the monstrous chasm is known to reach 384 m/1260 ft deep. Explorer and member of the Czech Speleological Society Michal Guba has the deets.
8. Urination Management Considerations for Women Technical Divers
Tech diver and doctoral student, Payal Razdan, offers an in-depth review of the options available to women tech divers for handling the call of nature.
9. Situational Awareness and Decision Making In Diving
Situational awareness is critical to diving safety, right? But how much of your mental capacity should be devoted to situational monitoring, e.g., How deep am I? How much gas do I have? Where is my buddy? Where is my boat? More importantly, how does one develop that capacity? Here GUE Instructor Trainer Guy Shockey, who is also a human factors or non-technical skills instructor, explores the nature and importance of situational awareness, and what you can do to up your game.
10. Examining Early Technical Diving Deaths
The early days of technical diving were marred by an alarming number of fatalities that threatened the viability of this emerging form of diving. Here InDepth editor-in-chief Michael Menduno presents the original accident analyses of 44 incidents that resulted in 39 fatalities and 12 injuries, as reported in aquaCORPS Journal and technicalDIVER in the early to mid 1990s.
11. A Voice In The Wilderness
Just when you thought you’ve seen it all, along comes underground picture-maker SJ Alice Bennett, who is shedding new light on the dark, moody, twisting karst passageways that form what explorer Jill Heinerth calls “the veins of Mother Earth.” If you’re ready for a new perspective on the ‘doing of cave diving,’ switch on your primary and dive right in.
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