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The Who’s Who of Sidemount



Christophe Le Maillot

Chris is a cave explorer, a cave and sidemount instructor and instructor evaluator, a DPV and RB80 rebreather instructor and co-owner of Zero Gravity dive center in Puerto Aventuras, Mexico. He has over 30 years of diving experience and has conducted more than 7000 cave dives in Mexico, Belize, Honduras, France, Bosnia & Herzegovina, Italy, Brazil, China, Australia and USA. He was the founding member of Grupo de Exploracion Ox Bel Ha (GEO) (1998-2001), a founding member of the Mexico Cave Exploration Project (MCEP), and a member and research diver for the Centro Investigador del Sistema Acuifero de Quintana Roo (CINDAQ), a Mexico NGO. Chris was instrumental in developing the Global Underwater Explorers (GUE) Sidemount Diver program.

Interview by Michael Menduno

What is sidemount to you?

Sidemount is just another gear configuration that helps me to achieve specific objectives on some dives. I would extend this point to the use of DPVs, rebreathers, back-mounted configuration, stages and sidemount rebreathers on certain dives. You pick and choose the right tool, type thing. It is just a mean to be polyvalent underwater, and adding more strings to your diving bow so to speak, nothing more.

Was there an epiphany moment for you?

To be honest, no. Historically, people have been sidemounting here since the 1980s. I believe that it had something to do with the configuration and the type of caves that we have here. It was and still is quite practical, as some of the caves are quite intricate and need to be dived in sidemount rather than backmount- sometimes just to travel beyond that one restriction. 

When Fred [Fred Devos, co-owner of Zero Gravity] and I first arrived here in 1996, we did our cave training through CEDÁM Dive Center with Chuck Stevens. Chuck and Mike Madden were in the middle of exploring Nohoch Nah Chich. All their exploration was in sidemount, so we quickly got the idea that this was perhaps a good thing to do. We were trained in backmount, but, sidemount was definitely the must-have equipment configuration if you wanted to do some exploration. That’s how we really got introduced to sidemount.

It has enabled you to go to places you couldn’t reach otherwise.

Yes, no question about it. Also, keep in mind that at the time, some caves were difficult to access due to limited roads. So, a lot of time was spent hiking equipment in the jungle or packing mules and horses with gear. Single tanks were a lot easier to deal with. So overall, it was the most appropriate configuration for what we wanted to do at the time, which was exploration!

What were your considerations in creating the GUE sidemount program?

The main idea with this was adding a formal teaching structure to something that we have been doing for a long time. There was a great amount of interest from GUE divers too. Some were already diving in small caves, or remote locations in different parts of the world. This led to a collaborative work effort between a few of us GUE people. I don’t really want to be taking too much credit here. Andrea Marassich, Osama Gobara and Fred had a lot to do with this too. On the gear developing side of things, we were happy with all the help from Halcyon Mfg especially Ken Charlesworth. Ken is a keen sidemount diver in Florida. We wanted something that was more appropriate with diving aluminum or smaller steel cylinders (like the Faber 85s). A wing with sufficient lift of course, an easy to adjust harness, streamlined and practical, something that allowed us to swim through the most intricate part of the cave without too much complications.

But I understand that the course is not specific to the Halcyon sidemount system, it can be done in a suitable system. Right?

Yes. It just requires a system appropriate for the type of diving we’re going to be doing. Of course, there are specificities needed with equipment like with any other training program. But, it does not relate to a particular gear manufacturer.

So with regards to the GUE sidemount program, are there any, I don’t know, special or unique aspects of the program? I’m assuming it’s got the GUE flavor, of course. It is a GUE course.

We have always looked at cave sidemount along with Cave DPV and Survey as more of advanced cave diving techniques/programs. We know for a fact that it takes time to hone skills, and to understand the cave environment. We still believe that there is nothing wrong starting with the well-rounded, easy to adjust, versatile, and proven back-mount configuration for cave diving. 

In this sense, a diver entering the GUE sidemount cave program has already gone through substantial GUE cave training—Cave 1, Cave 2, sometimes Cave Survey and Cave DPV- in addition to personal experience dives—a well known GUE requirement between training levels. 

So, when we teach the sidemount class, students are already diving in caves that are technically more challenging and quite naturally this eventually leads them to caves where the use of sidemount is the most appropriate configuration. 

I think that this is the basic idea behind continuing education. A slow and progressive approach to learning with plenty of time in-between levels to gain proficiency through different personal diving experiences.

Do you see GUE Sidemount eventually being offered at lower level, kind of like what GUE did with their CCR program, making it available to anyone with Tech 1?

Yeah, I don’t know. 

Maybe, but again we don’t really know what the future holds. And, things change, you know that, Michael. But as long as it makes sense and that it is consistent with the rest of GUE’s philosophy—and just not following a trend—then many of us would be willing to consider new training opportunities, for sure.

Things are definitely evolving.

Things are always evolving, and not just with diving. GUE has come a long way in 25 years. Plenty of interesting technologies emerging. It is all quite engaging, really. 

In the future, what will we need to know to keep up with studying and exploring underwater? GUE has always been quite dynamic this way, in giving divers the training and knowledge necessary to pursue their different diving activities.

I hadn’t been to Mexico for a while. But when I visited last year for diving I was surprised. We pulled up to Ponderosa. In the past, It seems like there would be 10 twinsets to 1-2 sidemount rigs. This time, there were 10 sidemounters to every couple of backmounters. I mean wow, it was really noticeable.

That’s a fair observation. I mean it’s funny to see that because we’ve been sidemounting for so long but it’s just the way it is now. Sidemount has become very popular. But a more recent trend has also seen some of these long-time sidemount divers only now discovering benefits of backmount cave diving.

Keep in mind that 99.5% of all the caves here—and we’ve got well over 1,200 kilometers of it—are all backmountable. So, the caves did not suddenly start shrinking.

Yeah, there’s plenty of running room.

Many of the caves here could accommodate a 747 airliner (or two for Ox Bel Ha). But at the end, whatever people feel comfortable with and enjoy doing.

If people are passionate about their sidemount system/wing /rebreather/sidemount rebreather etc. great. It’s good to be passionate about something in life. But we are really passionate about caves, and we are fortunate here to visit them every day of the year.

Thank you Chris! Please say hi to them for me. I’ll be down there before long.

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GUE 25 Anniversary Conference Round Up




Global Underwater Explorers held a conference to commemorate the organization’s 25th anniversary. Held at GUE headquarters in High Springs, Florida, where it was founded by a group of cave divers founded in 1998, the organization convened instructors and divers from all over the world to recall the people and diving technologies that shaped GUE, how they’ve changed over time, and how they’ll evolve in the future.

In addition to celebrating the occasion, GUE convened speakers to present on topics related to its three biggest priorities: Exploration, Education, Conservation.

Shipwreck explorer Mario Arena, for example, gave a presentation on the “Battle of Convoys in the Mediterranean,” his 16-year project discovering and documenting dozens of shipwrecks left behind by the three-year-long battle during World War II and how his team is bringing the wrecks back to life using new technologies.

Cave explorers Fred Devos, Julien Fortin, and Sam Meacham gave a presentation on their efforts to document Ox Bel Ha, the largest underwater cave system in Mexico, a project which is concurrently celebrating its 25th anniversary. The project started out with, as Meacham called it, “two chainsaws, a compressor, and a horse,” and has begun to resurvey 144 square miles of caves with advances in diving equipment. Advances as simple as upgrades to lightbulbs and batteries, for example, enable the explorers to see through new passages.

Bill Stone, a cave explorer and head of Stone Aerospace, discussed “Recent Advances in Machine Exploration,” chronically how he’s used machines to explore underwater caves farther than any human. Stone’s autonomous drone, called Sunfish, uses sonar mapping to produce 3D maps and models deeper than photogrammetry divers can dive.

Ulrik Juul Christensen, a founder and chairman of Bonaire’s Area9 Mastery Diving Research Center, is developing an adaptive learning education platform for GUE and has spent about as much time as the organization has been in existence building education technologies. Christensen’s talk, “Learning That Matters,” focused on how to create new systems to help educate learners at their own pace so that knowledge, and not speed, is the priority.

In a complementary presentation, Sean Talamas, a managing partner and executive coach at leadership development consulting firm, discussed “The Depth of Character: Cultivating Grit, and a Growth Mindset.” The presentation focused on research by Angela Duckworth suggesting success is not achieved through talent, but a combination of passion and persistence she called “grit.” 

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GUE Instructor Trainer Andrea Marassich gave a presentation on “Building Capacity for Extreme Explorations” about the Sa Conca e Locoli Cave Project in Sardinia, Italy. Learning, he suggested, happens when you go out of your comfort zone, but not all the way to what he called the “panic zone,” where you are overwhelmed to the point that you don’t learn but instead shut down and it becomes extremely dangerous.” “You need a mentor,” Marassich said. “Someone who knows you enough to push you when you need to be pushed and pull back when you need to pull back.” 

These were just a few of the education- and exploration-focused presentations. Speakers also included Blue Green Expeditions Managing Partner Faith Ortins on how divers can support environmentally conscious destinations, Peter Gaertner on citizen science conducted in the Caves of Gulf of Orosei project, Daniel Ortego on the Marine Genome Project, and Neal W. Pollock on the physiological limitations of technology in diving. 

Max Deco & Bubble Trouble entertained conference attendees at the Friday night social with a pre-dive playlist of classic rock. Band members: John Kendall vocals, Gary Franklin vocals, Bill Stone lead guitar, Andrew Dow guitar, Francesco Cameli bass, Michael Menduno bass, Jason Cook drums.


You can find the full conference photo album here

InDEPTH: GUE’s 25th Anniversary Timeline-Picturing 25 years of Global Underwater Explorers.

InDEPTH: Twenty-five Years in the Pursuit of Excellence – The Evolution and Future of GUE

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