By Ashley Stewart. Images courtesy of Simon Mitchell unless noted.
On March 11, a little more than three weeks after completing what is believed to be the first-ever rebreather dive with hydrogen as a diluent gas, Dr. Richard “Harry” Harris convened the group of scientists and researchers who had spent years helping to plan the attempt.
He started with an apology. “All of you had the sense that you were party to this crime, either knowingly or suspecting that you were complicit in this criminal activity,” Harris, an Australian anesthesiologist and diver known for his role in the Tham Luang Cave rescue, told the group.
The apology came because the dive was dangerous—not just to Harris who was risking his life, but for the people who supported him were risking a hit to their reputations and worried their friend may not return home. Harris and his team put it all on the line to develop a new technology to enable exploration at greater depths.
A significant challenge to deep diving is an increased work of breathing and CO2 buildup as breathing gas becomes more dense at greater depths. This can not only culminate in fatal respiratory failure but also increases the risk of practically everything else divers want to avoid, like inert gas narcosis and oxygen toxicity. For this reason, helium is favored by divers for its low density and non-narcotic effect. However, at such great depths, helium increases the risk of tremors and seizures from High Pressure Nervous Syndrome (HPNS). This can be ameliorated by keeping a small amount of narcotic nitrogen in the mix. The problem is that even small amounts of nitrogen makes the mix too dense past 250 meters.
Harris’s experiment would determine if divers can turn to an even lighter gas: Hydrogen, the lightest in the universe. Hydrogen is about half the density of helium. It’s also slightly narcotic and hence thought to ameliorate HPNS, thus allowing elimination of nitrogen from the mix.
The addition of hydrogen into a breathing gas, however, comes with one small technical uncertainty—the extremely explosive nature of hydrogen. History confirmed this reality with the 1937 Hindenburg disaster in which the hydrogen-filled dirigible airship burst into flames. As Harris tells it, he set out to dive hydrogen in his diluent gas while avoiding the nickname “Hindenburg Harry.”
Hydrogen in the Mix
Why would anyone attempt to breathe hydrogen? Harris and his colleagues have spent more than a decade and a half exploring the Pearse Resurgence cave system in New Zealand. This extremely challenging, cold water cave system (water temperature is 6ºC/43ºF) has been explored by Harris and his team, who call themselves the Wetmules, to a maximum depth of 245 meters/803 feet in 2020. Their gas density at depth was 7.2 g/l, significantly above the recommended hard ceiling of less than 6.2 g/l.
Diving past this point introduces increased risks, not only of CO2 buildup, but narcosis, decompression sickness, HPNS, cold breathing gas, having adequate gas supply or bailout, and isobaric counter diffusion (ICD) in which different gasses diffuse into and out of tissues after a gas switch causing bubble formation and related symptoms, cold breathing gas, and having adequate gas supply or bailout.
Divers have been examining hydrogen as a breathing gas for decades. The Swedish Navy was the first to experiment with hydrogen as a possible deep diving gas during World War II. The U.S. Navy in a 1965 paper proposed replacing helium with hydrogen due to projected helium scarcity. Later, beginning in 1991, researchers at the Naval Medical Research Institute (NMRI) in Bethesda, Maryland spent a decade studying hydrogen’s potential physiological impacts and biochemical decompression. French commercial diving contractor Comex (Compagnie maritime d’expertises) launched its hydrogen program in 1982, and the Undersea Hyperbaric Medical Society (UHMS) held a workshop “Hydrogen as a Diving Gas,” in 1987.
Even technical divers considered hydrogen. Legendary cave explorer Sheck Exley considered hydrogen in the early 1990s to mitigate HPNS symptoms, which are ultimately believed to have contributed to Exley’s death at Zacatón in 1994. Nearly all of the experimental hydrogen work up until this point used surface-supplied systems and saturation diving versus self-contained diving, and none of it, as far as we know, has been done with a rebreather.
The primary objective of Harris’ hydrogen experiment was to address the issue of increased work of breathing. Harris’s team had previously encountered CO2 incidents at the Pearse Resurgence. In one incident, while at 194 meters/636 feet, explorer Craig Challen—Harris’s primary dive buddy since 2006—lost buoyancy but was unable to find his buoyancy compensating button quickly. He kicked up a couple of times to stop his descent and immediately got a CO2 hit. Challen was able to grab the wall, calm down, slow his breathing, and survive. Based on such incidents, it’s clear to the team that they have reached the limits of the gas. “I feel we are on the knife edge all the time,” Harris said, in terms of physiology and equipment.
While hydrogen in the diluent breathing mix was expected to address increased work of breathing, the rest of the issues associated with deep diving were “major unknowns,” and some (such as respiratory heat loss) were potentially even made worse by hydrogen.
“At what depth do the risks of introducing this new technology outweigh the risks of carrying on with trimix?” Harris said. “That’s a very difficult question to answer. At some point we are going to have to consider different technologies and, at this point, hydrogen is perhaps the only one available to us.”
H2 Working Group
In 2021, the year after Harris completed his deepest dive at the Pearse Resurgence, InDepth editor-in-chief Michael Menduno was taking a technical diving class and reading about the government looking at hydrogen as a diving gas again. “Technical divers should be at the table,” Menduno said he thought to himself at the time, “our divers are as good as anybody’s.” He called John Clarke, who had spent 27 years as scientific director of the U.S. Navy Experimental Diving Unit (NEDU), and discussed setting up a working group. Menduno’s next call was to Harris, who had shared his troubles with gas density at the Pearse Resurgence. Harris had also, separately, been thinking about hydrogen.
The so-called H2 working group met for the first time in May 2021 and included many of the top minds in diving medicine and research, including Clarke, NEDU’s David Doolette and Greg Murphy, research physiologist Susan Kayar who headed up the US Navy’s hydrogen research at the Naval Medical Research Institute (NAMRI), along with her former graduate student Andreas Fahlman. There was diving engineer Åke Larsson who had hydrogen diving experience, deep-diving legend Nuno Gomes, decompression engineer JP Imbert who had been involved in COMEX’s Hydrogen diving program, and anesthesiologist and diving physician Simon Mitchell. The group was later joined by Vince Ferris, a diving hardware specialist from the U.S. Navy, and explorer and engineer Dr. Bill Stone, founder of Stone Aerospace.
The working group met regularly with the goal of figuring out how one might possibly operationalize hydrogen for a deep technical dive using the Resurgence as an example. During one of their meetings, Clark used a breathing system simulator built for the Navy to predict how hydrogen would affect gas density in a closed circuit rebreather at depths to 300 meters/984 feet.
To Doolette, who has known Harris for decades and supervised his Diploma of Diving Medicine project in 2001, it was immediately clear this was not a hypothetical discussion. “Unlike some of the scientists, I was under no illusion that the question before the working group was fiction, I knew that Harry was likely to try a H2 technical dive in the Pearse Resurgence,” said Doolette, a cave explorer in his own right, who has laid line in the Resurgence.
By fall of 2022, it was clear to many in the group that Harris was going to attempt the dive. The group had mixed feelings ranging from cautious optimism to comments like, “My friend is going to die.”
Doolette was concerned Harris and Challen would not survive the dive due to either ignition of hydrogen—in the worst case, inside the rebreather at depth—or a serious adverse response to respiratory heat loss (the latter was especially if Harris attempted diving beyond 245 meters/803 feet as he had originally planned) he said. “I have known Harry for longer than most in the group. I encouraged him to take up cave diving, so I felt a personal responsibility toward him,” Doolette said. “I have a lot of experience in operationalizing new diving technology. My goal was, if unable to discourage him, to force him to focus on the important issues.”
Leading up to the dive, Menduno scheduled Harris to give the banquet talk about the expedition at the Rebreather Forum 4 industry meeting in April. The outcome of the dive, of course, was uncertain, and the two had to make an alternate plan in the event that Harris did not return. “We had to say we were going to talk about your dive one way or another,” Menduno said. “If you don’t make it back, Simon Mitchell is going to have to give a presentation about what went wrong. Harry made some typical Harry joke like, ‘Well, as long as you don’t stop talking about me.’” Harris’s lighthearted tone betrays how seriously he took the dive and its preparation, people close to him said.
While no one involved was taking as big a risk as Harris and Challen, they were risking a hit to their professional reputations by being associated with a controversial dive, especially in the event of a tragic outcome.
“At heart, I’m an explorer, and that was pure exploration,” Mitchell, who was the diving supervisor on Harry’s dive, said when asked why he would take such a risk. “Exploration in the sense that we were pioneering a technique that hadn’t been used for quite some time and never in technical diving, not deep technical diving.” He also emphatically added, “I was more worried about my mate dying than about my professional reputation.”
Later, in planning Harris’s trip to the RF4 event, Menduno had occasion to speak to Harris’s wife, Fiona who brought up the dive.
“She said to me ‘I hope Harry is going to be OK’,” Menduno said. “I had no idea how much Harry told her, what she knew and didn’t know. All I could say was he’s got the best people in the world on his team, and if anybody can do it, he can.”
“We all held our breath and waited,” Menduno said.
‘Hydrogen Trials’ at Harry’s House
Ahead of the dive, Harris was preparing at home. The first thing Harris said he had to get his head around was—no surprise—the risk of explosion, and how to manage the gas to mitigate that risk. The potential source of explosion that Harry was most concerned with was static ignition within the CCR itself, plus other potential ignition sources like electronics, the solenoid, and adiabatic heating. Industrial literature—or “sober reading” as Harris calls it—suggested that the tiny amount of static necessary to initiate a spark to ignite hydrogen is .017 mJ, 400 times less than the smallest static spark you can feel with your fingertips and several hundred times less than required to ignite gasoline. “It ain’t much, in other words,” Harris said, noting that counterlung fabric rubbing against itself could generate just such a spark.
Ultimately, Harris came across research that suggested that static decreases with humidity. “I started to feel like there was no source of ignition inside a rebreather, but then again I said to myself, ‘Harry you only need to be wrong once’.”
The other concern was whether he could actually fill hydrogen safely while decanting, or filling one tank from another at the same pressure, and boosting the gas to reach higher pressures.
“I decided there is only one way to actually resolve this and that is to retire to the shed, order a sneaky bottle of hydrogen, and without telling my wife what was going on down the back of the house, start to actually have a bit of a play with this,” Harris said.
First Harris had to make his own DIN fitting (though not out of the ordinary for the anesthesiologist who built and tested his own rebreather before buying a commercial one in 2002) to decant the gas. Next he took his dual Megalodon rebreather with 100% hydrogen in one diluent cylinder and 100% oxygen in the other to the “test bed” in his backyard—his pool—and started to introduce hydrogen into his rebreather.
“Putting an explosive device into water was perhaps not the most logical approach because it becomes more like a depth charge than a bomb, but I thought, ‘Well, at least it might contain the blast somehow into the pool.’ I knew if I broke the back windows in the house or worse, my life wouldn’t be at risk just from the hydrogen. There would be bigger trouble afoot,” Harris said. “I left the lid of the rebreather unclipped in the vain hope it would spare me and the pool and the dog, who was helping with this experiment.”
He pressed the button of the Automatic Diluent Valve (ADV) on his rebreather, introducing hydrogen to the loop, and finally activated the solenoid before he started breathing from it. The first breaths were pleasant, he said. “It did feel very light and very slippery, and the hydrogen voice is even sillier than the helium voice, as you would expect,” he said. “I don’t want people to rush away thinking this is a safe and sensible thing to do. I’m under no illusions I’ve produced any evidence for you to see, but this is an honest account of the hydrogen trials at my house.”
The unit had not exploded with a fill of oxygen from zero to 70%, and very low humidity. “Harry, dog, and CCR survive,” as Harry wrote in his report of the trials. “Nothing bad had happened, so it was reasonable to move to the next step,” he said.
Harris, Challen, and other members of the Wetmules, arrived at the site of the Pearse Resurgence on New Zealand’s south island in February 2023. The cave system is so remote they needed around 10 helicopter trips to transport the team and all of its equipment. Mitchell, the diving physician, ran surface operations with “mixed feelings,” as Harris put it.
The group stayed for two weeks at a campsite, complete with a gas-mixing station, an electronics shelter for charging gear, and a “big green army tent where we meet and drink a lot of coffee and try and put off going back into the water each day,” Harris said.
The expedition was plagued with an unheard of number of problems, Harris said, “Every time we got in the water, something popped or blew up or failed.” The campsite is where Harris boosted hydrogen for the first time, from 100 to 150 bar. He flushed the booster and all the whips with hydrogen prior to boosting to make sure no oxygen was left in the system, but it was an anxious moment.
On dive day, Harris and Challen set out on what would be a 13 hour dive to 230 meters/754 feet—a “comfortable depth,” as Harris put it. Due to some problems during the expedition, it was decided that Harry would dive hydrogen, while Craig would dive trimix. At 200 meters/656 feet depth, Harris pivoted the switch block to introduce hydrogen into the loop. “The first cautious sip of hydrogen just to activate the ADV was satisfying,” he said. Gas density was not subjectively improved, but Harris noticed an obvious benefit—the HPNS-induced hand tremors he typically experienced after 180 meters/590 feet disappeared. Harris kept his setpoint at .7 during the descent and working portion of the dive, careful not to reach a fraction of oxygen above 4% which would make the mix explosive, and proceeded to the 230-meter test depth.
After completing their time at 230 meters, the team began their ascent. Harry shut off the hydrogen feed to the active loop of his dual Megalodon rebreather back at 200 meters, and then conducted a diluent flush every 10 meters/33 feet to remove the hydrogen from the loop until reaching 150 meters/492 feet. At that point, Harris boosted his PO2 to 1.3 from his set point of 0.7 (Challen remained at 1.3 throughout the dive), and they continued their ascent decompressing on a trimix (O2, He, N2) schedule, treating hydrogen as if it were helium. The complete technical details of the dive will be published in a forthcoming paper in the Diving and Hyperbaric Medicine Journal.
As soon as the team were helicoptered back to civilization, Harry called Michael from the road. “Michael, we did it!,” Harris said.
“Harry, you’re alive!,” Menduno responded.
At that March meeting with the H2 working group, Harris presented his findings from the dive. “I’m not sure what to conclude to a highly scientific, analytical, and evidence-based audience like yourselves,” he told the group. “Conclusions: N=1,” meaning it had been successful one time.
Doolette, who had been the most vocal in the group about his concerns, suggested Harris could add to his conclusions “the probability of survival is greater than zero.” Doolette, whom Mitchell contacted as soon as they reached civilization, said he “was relieved to hear that Harry survived this test dive” but remains disappointed with some aspects of the experiment, and concerned about possible future attempts. “For instance, I imagine among the engineers he consulted would have been someone with the ability and resources to do a computational fluid dynamic analysis of the Megalodon rebreather to establish the ignition risk, but instead Harry filled his rebreather up with hydrogen in his backyard.”
Overall, Harris said his findings are that hydrogen can be handled and boosted, hydrogen and CCR diving are compatible, a strategy to introduce hydrogen on descent was successful, a decompression dive was successful, a low setpoint at depth did not practically affect total dive time, strategy to reintroduce a high PO2 on ascent was successful, and HPNS and narcotic impacts were subjectively favorable.
“In introducing hydrogen we have addressed the issue of gas density, but we certainly have not established it is safe to use in terms of explosion risk, decompression, or the thermal hazards,” Harris said.
Among his conclusions, Harris pointed out that he also managed to evade the nickname “Hindenburg Harry.” “Fortunately that was avoided,” he said, “but remains an ever-present risk.”
The Future of H2
Harris warns not to read too much into what his team achieved—a single data point that should in no way encourage others to repeat the dive. “David Doolette’s comment should be heeded,” Harris said. “All we have shown is that we got away with it on one occasion.”
Provided it can be safely proven and built upon, Harris said he thinks of his hydrogen dive as a window into the future that would enable tech divers to continue exploring into the 250 to 350 meter/820 to 1148 feet range. “Imagine the wrecks and caves that lay unvisited around the planet,” Harris said.
YouTube: Wetmules 245m Cave Dive in the Pearse Resurgence, New Zealand (2020)
InDEPTH: Hydrogen, At Last by Michael Menduno
InDEPTH: Density Discords: Understanding and Applying Gas Density Research by Reilly Fogarty
InDEPTH: Playing with Fire: Hydrogen as a Diving Gas by Reilly Fogarty
InDEPTH: High Pressure Problems on Über-Deep Dives: Dealing with HPNS by Reilly Fogarty
InDEPTH: The Case for Biochemical Decompression by Susan Kayar
John Clarke Online: Hydrogen Diving: The Good, The Bad, the Ugly (2021)
InDEPTH: Diving Beyond 250 Meters: The Deepest Cave Dives Today Compared to the Nineties by Michael Menduno and Nuno Gomes.
Undersea Hyperbaric Medical Society: Hydrogen as a Diving Gas: Proceedings of the 33rd UHMS Workshop Wilmington, North Carolina USA (February 1987)
InDepth Managing Editor Ashley Stewart is a Seattle-based journalist and tech diver. Ashley started diving with Global Underwater Explorers and writing for InDepth in 2021. She is a GUE Tech 2 and CCR1 diver and on her way to becoming an instructor. In her day job, Ashley is an investigative journalist reporting on technology companies. She can be reached at: email@example.com.
Earlier this summer Jake Bulman and the Protec Team launched their 2023 expedition to Madagascar’s formidable Malazamanga cave known for massive tunnels, formations the size of buildings, and its unbelievable cobalt blue water. They then journeyed to Anjanamba, which despite enormous passageways, consistently turned into tight, restrictive spaces before opening up again. Having appeased the cave spirits and returned safely, Bulman offered up this account.
by Jake Bulman. Photos by Phillip Lehman. Lead image: (L2R) Jake Bulman, Patrick Widmann and Ryan Dart motoring through the first mega-room after Ryan’s Chamber, Malazamanga.
Deals made. Plans Laid
As I sat in the Paris airport working on my computer, Patrick Widman gestured to me to remove my headphones. He and Phillip Lehmann sat across from me and asked if I wanted to make a deal. Assuming I was walking into some kind of joke, I replied with a hesitant “Sure.” “Next summer you come with us to Madagascar, if you…“ “Yes! Deal, ” I answered before he finished explaining my end of the deal. It didn’t matter, the answer was yes. Patrick finished laying out his already agreed deal, headphones went back in and everybody went back to what they were doing, except for my thoughts, which went to “Holy Shit! I’m going exploring in Madagascar!”
Now nearly a year later in June 2023, we were back in Paris, this time packing all of the bags for the flight to Antananarivo (“Tana”), Madagascar’s capital city. When we got there we met up with Tsoa, who is the local contact, translator, organizer, and overall critical part of the team. Our bags headed to Toliara with the drivers while we spent the day doing some errands.
The next day was important to me, not because i turned 30, but it marked the end of a bet Patrick and I made in 2020, for which I had now won $100. The victory was short lived, however, as I spent that day stuck in my hotel room violently sick. Welcome to Madagascar!
After a short flight, overnight in Toliara, then an hour long boat ride along the coast, we reached Anakao Ocean Lodge. This place is a bit of a shock to the senses after traveling through the poverty stricken cities. Luxury in the middle of nowhere; it would be our basecamp for the trip. As Patrick and I posted a photo of the place, Phillip sarcastically mourned the loss of any “hardcore expedition” image people would imagine.
The next day we planned to meet up with the National Parks’ representatives, organize porters, transport all the equipment to the site, then get in the water and place all of the deco tanks and scooters we would need, and finally be out by dark to avoid being stranded overnight. This may seem overly ambitious, and it was, but is a good example of the overall approach of the project. Always go all in, no shortcuts or laziness, and if it was not possible in the end, no worries at all. The goal is to have fun with the group and do awesome stuff, which we always did.
”This is the most epic cave ever”Phillip Lehmann on Malazamanga
Musing on Malazamanga
Malazamanga, a cave of indescribably massive tunnels, formations the size of buildings, and amazing blue water dominated the first part of the trip. We set up a little basecamp in the mouth of the cave, each of us with our own spaces to change, hang up our suits to dry, and change sorb each day. The entrance swim is a tediously frustrating one for rebreather divers: 20 minutes of low ceilings, bouncing from 20 m to 5 m/66 ft to 16 ft and back several times, never allowing space to sit “in trim”, and no flow to remove any of the inevitable silt that came from passing with multiple scooters, stages and divers.
However, once you reach Ryan’s Chamber, the first big room, you find a staging spot for leaving scooters and tanks for the following day, and a small tunnel leading to the real, intimidatingly massive, Malazamanga.
Patrick and I went to the deep section right away (45-50 m/138 to 164 ft) and spent three days trying to find the way on, while Phillip and Ryan Dart looked around the shallower parts of the cave (20-30 m/66-100 ft) for any leads that had not been checked. Patrick laid line while I surveyed behind him through a wide but low space that became swirling silt and clay by the third tie off. We reached a vertical shaft, Patrick asked me to hold and ran a line into a smaller tunnel below us that led to a restriction. In spaces like this where zero visibility is guaranteed, diver two will be pushing through restrictions blind, having no idea the shape or size of the space around them, which is a recipe for disaster, so I waited on the line for Patrick to return and started a timer.
As fifteen minutes showed on the timer, it started to feel like a long time. How long do I wait before doing something? Five more minutes rolled by, and my mind started to run… What if he has a problem? Does he need help? Memories of having to get somebody out of a similar space once before came to mind. But this time it was Patrick though, if he truly needed help it would be a serious situation. I decided to give him until 30 minutes from when he left, and then I would go in (slowly). With four minutes remaining, a glow appeared before Patrick explained that “it’s tight, but it goes.” It was a long wait that meant a bunch more deco, but this could be the way on.
The next day I was tasked with pushing the End Of Line (EOL) while he and Phillip looked elsewhere. After twisting, turning, removing tanks, and wondering if this was a good idea more than a few times, I pushed through a few ups and downs, but the cave unfortunately ended in a basement section at 52 m/170 ft. No going leads. Time to head home.
Breakthrough and Packing Techniques
Our daily routine started at 06:30 with a breakfast of bread, fruit, eggs, tea and espresso. We’d leave the garage at 07:00, meet the porters at the bottom of the hill in the national park and send the equipment with them. Phil would then educate us on the risks of breakthrough, importance of proper packing techniques, and the impact of dwell time. All of which are critical to making espresso.
After making espresso, the handpresso is put away, we hike the 30 minutes up the hill, get dressed, dive four to six hours, then head home. Back at the garage by 08:00 pm, fill tanks for an hour, eat dinner at 09:00 pm, and then sleep. All the while making jokes, sharing stories, talking about life, trying to blind each other with lights, and being shown the same photo of Rosie, Phillip’s pit bull, with a “look at this awesome photo” preceding the photo display by a few seconds.
All in all, going diving required some effort, not to mention the week of traveling with piles of luggage to get there, the week to get home, and all of the time spent organizing beforehand. In terms of “cost (time/money/effort) per hour underwater” it is some of the most expensive time I’ve ever spent underwater.
One day, after a significant amount of problem solving in the hot, muddy entrance tunnel of the cave, we finally got everything sorted and started doing checks. Halfway through, Phillip said, “I’m not into this. You guys go. Nobody is paying me to do this,” and started to remove his tanks. Considering the “cost per hour underwater,” I think many of us would go whether we wanted to or not, giving in to a sunk cost fallacy-like sense of commitment.
We reformed a plan for the two of us, a few angry birds levels were completed on the surface, and everybody went home excited to see the survey data. There is a lesson to be had here for many of us, about what is actually important and ignoring those perceived, often self-induced pressures to carry on even if it doesn’t actually make sense.
We scoured every corner of the section we were in, until a hole underneath a formation showed a large room on the other side. I tied in at ~40 m/~130 ft, headed down the slope to where floor met wall, removed my tank, locked the reel, threw it through the hole, and headed in. Once my torso passed the squeeze, still inverted in the water, I put my tank back on, grabbed the reel, and swam the direction that I remembered it went. I passed the cloud and made a tie off. Turn, tie off, into a bedding plane, tie off, big room, tie off, and stop.
The floor suddenly featured huge, wavy marks that everybody recognizes as signs of flow. A lot of it. Massive clay bricks fit together like tiles in the riverbed resembling floor. A promising development, I tied off and ducked my head under the lip of the ceiling. Instantly the ceiling met the clay bed and the cave ended. Water unfortunately doesn’t consider human size in its choice of direction. Back to the drawing board.
“Fuck it, let’s just see what happens”Patrick Widmann
To Breathe or Not To Breathe
At the time, the furthest reaches of Malazamanga was an enormous collapse with no way beyond it except a few air domes. We were aware the air domes may not be breathable, but lacked a proper analyzer for that. After some thought, Patrick decided that we would just give it a go one at a time. We surfaced and knelt close together as Patrick closed his DSV and took a short breath of the gas. Wearing an expression resembling somebody tasting less-than-appetizing looking food he took a second breath.
Watching intently, I saw the expression quickly change from hesitant but ok, to uncomfortable to concerned as he put his DSV back in and opened it. I was ready for him to pass out as we sat there breathing, but nothing happened. We knew it was likely not breathable, but I wanted to see what it felt like! I removed my DSV and took a breath. A humid, thick, shockingly hot breath filled my lungs and I was not going to take a second one. No way that was safe, I thought, as the burning in my lungs slowly faded.
Patrick climbed out with just his rebreather (and flowing oxygen) and took a quick look around, but no luck. As he was getting dressed again, I popped my head into a few holes and found a passage that looked to slope downwards on the other side of a tight squeeze. I ran a line in with Patrick behind me, and tried to push through but couldn’t fit. After removing myself and the cloud of unavoidable silt surrounded us, I grabbed the rock that was in the way and flipped it over. If you have ever moved a big rock in a collapse, in a never-before-dived cave, you can imagine the visibility afterwards. We backed out, went to check a few other places, then returned hoping for slightly better visibility.
Patrick was the next one in, leaving a tank on the line with me this time, and he extended the line down the slope on the other side. I heard rocks falling, tanks banging on rock, grunting, laughing, bubbles moving along the ceiling, and then he returned with his hands shaking like crazy. Whatever was over there, was not for the faint of heart it seemed. After a bit of cooling down, he went back into the cloud, which was followed by loud yelling. Excited yelling. We exited, and planned our return for the next day. What lay beyond the 6 m/20 ft deep, vertical, awkward, tank-off restriction was an open space that continued downwards to what appeared to be 40 m+.
The next day, I was going through first. We rehearsed the shape of the restriction and the series of movements needed for passing it on the surface. It was weaving through the space where collapsed boulders met the sloping ceiling, and any extra force on the wiggling rocks meant possible collapse. The plan was for me to pass, tie into the EOL, and head off. Patrick would pass behind me with the MNemo and survey in. Adding tie off after tie off, I headed deeper, then flattened out, then up through an opening to my right. Now it was my turn to yell, the cave had returned to its previous enormous size!! This celebration lasted three tie offs, as we climbed yet another collapse that was quite clearly the end. Cut line, put reel away, look around knowing that nobody will ever be here again, and head home.
On to Anjanamba
Several options lay ahead of us, which Patrick and Phil weighed over dinner. Continue searching in Malazamanga, or get the filming done then head north to Anjanamba, or spend the next two weeks surfing. The last option was apparently way more valid than the joking suggestion I had taken it as. Fortunately, the second option was the choice. We spent a day scootering around with lights in hand and on the DPVs. Screen grabs of the video were used as photos for this article.
We also had two surfing days, where I (having never surfed before) mostly tried to not get annihilated by the waves. My second goal was “not to kill anybody” as Patrick and Phillip repetitively warned me not to do it with my oversized board (only a stand up paddle board was available). Fortunately I’m a very strong swimmer, as I spent large chunks of time crashing and burning, then being tossed around by the ocean.
”This is the most epic cave ever”Phillip Lehmann on Anjanamba
Heading up to Anjanamba featured a boat ride, a seven hour drive that resembled one of those truck commercials trying to show how tough its product is, and a journey through the Mikea National Park which had no paved road either. During lunch break everybody commented how much better it is now than it was several years ago, describing it as “pretty smooth” and “less violent” in the same sentence.
We visited the local village, where residents are the spiritual keepers of Anjanamba, to talk to the chief and say hi to a friend of Tsoa who had just had a baby. While there we got a tour of their newly built school, joked with the children a bit, took a photo and headed home. For a lifestyle that is so drastically different to our own, with so much less of everything tangible, the village seems a happy, lively place with kids running and playing. However it is easy to see the need for food, schooling, health products, and basic medical care to name a few.
Appeasing the Spirits of Anjanamba
Anjanamba is the location of the filming of the “Spirits of the Cave ” series (see DIVE DEEPER below). Described as a much more dendritic, Mexican-like cave with a blue color that puts the famous Mexican salt water tunnels to shame. The name of the series doesn’t come from nowhere; this cave is home to several spirits. In order to appease them, a few things need to be accomplished.
First, we must visit a big, double trunked baobab during the walk there. We remove our hats, gather near the meeting point of the trunks, place a pointer finger on one tree and pinky on the other (think bull horns hand shape), bow our heads and ask the spirits for two things. One, that they allow us to find an epic cave that goes. Two, that they grant us safe passage and everybody returns home safely. The ever-present, always watching lizard that lives there looked down in approval. The locals however, who had no idea what we were doing, waved us back to the path with a smile and laugh.
Once that is done, a ritual must happen with the Mikea people (in which the National Park is named after). Patrick and Phil have already been through it, so it’s just me. The chief started the ritual, as they each took a sip from a bottle of rum we had brought. Tsoa explained to me afterwards what they had been saying (asking the spirits to accept me, safe passage etc). Notably, it included nothing about finding mega cave, but we had already covered that during the lizard tree ceremony I guess.
The guys had warned me about the second part of the ritual, which had me eating a part of the cave – sand, dirt, rock, whatever. The chief continued speaking, and Tsoa told me it was time. I pinched some sand, put it in my mouth and swallowed. Phillip verified it was all gone. In the background I hear Patrick stifle a laugh, and my long-held suspicion was proven true, this was not actually part of it. The locals found it hilarious, and it wasn’t as if I was going to say no in any case. Diving time.
As usual, we were quite late and had made very ambitious plans which didn’t quite pan out. But we did as much as we could, then headed back to our new home at “Laguna Blu.” Like in Anakao, we had great food, friendly staff, beautiful views and comfortable sleeping.
Having laid less line than we had hoped in Malazamanga, we were keen to “bash some reels”. Anjanambas current EOL lay at more than 2287 meters/7500 feet with an average depth of 18m/60 ft or so. It featured enormous tunnels and decorated rooms, yet consistently turned into tight, never-quite-ending spaces before returning to vast rooms with pristine formations all over the place.
Patrick and I each carried a stage, and I carried the back up scooter. Passing through the 30 minutes of sideways swimming, weaving up and down, belly scraping, up and down cave with a negatively buoyant scooter in between my legs meant it was not always smooth sailing. Fortunately it usually got stuck when I was in the back so nobody saw. We reached the end of the line, Phillip tied in and headed off with Patrick recording and me surveying behind them.
From my POV, it looked likely to end every 10 tie offs only for the line to weave into a little corner of the room and continue, with nothing but a light dusting of silt at each tie off as signs of my team ahead of me. This repeated for another 457 meters/1500 ft of line until the reel was emptied, everybody cheered and fist bumped with excitement and then decided that we really needed to head home.
Our DPV charging plan didn’t pan out, so after each day Patrick and Phil drove over to a neighboring location and ate lunch while the scooters charged. I went back to Anjanamba and swam some of the closer lines checking for any going cave. After extending a few EOL’s, the sections had been checked without much luck. After a few days of exploring in Anjanamba, which mostly featured a repeating pattern of restrictions then big rooms, we finished our last diving day with nothing clearly going, but a few hopeful areas left.
End of the Line
As we reached the end of the trip, instead of feeling tired as we expected, we found ourselves ready for more. We had lots of sorb left, but had used every last liter of oxygen. Unfortunately, it was time to take a group photo with the locals, dry our equipment and start the journey home. Not only did we have flights to catch, but we had classes to teach less than 12 hours after landing in Mexico.
After five weeks of expedition, we had managed to get the most out of every day, be on time almost never, and explore some amazing cave. More impressively, I don’t recall a single argument or bad mood at all, which is rare when you spend 18 hours per day with the same people. Until next time, the villagers return to their normal lives, we go back to the Caribbean, and the spirits of Anjanamba can rest again.
We did have one last day before heading home, in which we would make a discovery. What will come of it is yet to be seen, but I’m sure it’s going to be a mega-epic either way. In fact, probably the most epic cave ever.
The Protec Team‘s past Madagascar Expeditions:
YouTube: Spirits of the Cave (2017)
YouTube: Spirits of the Cave 2 (2019)
YouTube: Spirits of the Cave 3 (2020)
Originally from Canada, Jake Bulman is a full-time cave diving and CCR instructor at Protec Dive Centers in Mexico. The last several years of teaching have been almost exclusively sidewinder focused, from try dives to CCR Cave classes, 4C to 24C, and in several countries around the world. Outside of work, he can be found on exploration projects in local caves of a wide range of depths, distances, and sizes.