Sistema Exploradora is a 6.8 kilometer flooded cave system that is unique to the Yucatan Peninsula as it branches out from a sump almost 300 meters into a dry cave, rather than one of the regions many famous cenotes.

Project Report
STARTING FROM THE FINISH LINE

• by Rory O’Keefe, September 14, 2020

"How many dives did this take?" I have finally completed my first underwater cave map, and that is usually the leading question I am asked about the project. I wish I could answer it, but the truth is: I have no idea. We've produced a map that we're very proud of, but the story is missing.

After 18 months of exploration, porters, rappelling, equipment failures, countless side-mount restrictions, injuries, mapping, and sadly, friendships lost, I should be sitting here with a book to accompany our map - but there isn't one and I feel the need to apologize for that fact. As explorers we have the responsibility to do more than just experience new things. We have a responsibility to document those experiences.

The Exploradora Project, aptly named after the landowner, Dora, began in April of 2018. I was headed out to go caving with noted explorer and cartographer, Peter Sprouse. Together, alongside one of his many teams of cavers, we would continue mapping a promising cave they had discovered the previous day.

We met early morning for a quick breakfast at one of the local taco spots, El Arbolito; a miscellaneous collection of old tarps, wood crates, concrete, and a tree all fastened together to form a restaurant. With steam billowing out of giant-cauldron-looking pots in the background, the cooks hustled to keep up with a barrage of orders. The laid-back, Caribbean lifestyle of the Riviera Maya disappeared inside as customers lined-up single file behind the order window. Here, the Patrona, a late-30s Maya woman who stands at the cashbox window, barks, “How many?” Sensing my life may be at stake if my reply is anything over one-word, I shout “Three!” She tears off a corner of paper, scribbles “3” and I hand her my money in exact change. “How many?” She barks at the customer behind me, indicating it is time for me to get out of the way and move along to the taco window.

In a matter of minutes, all ten of us were happily fed and it was time to head out into the jungle. To my surprise, we drove straight back towards the road beside my house. After a 30-minute drive down the dirt road, we turned onto an overgrown ranch. The driveway abruptly ended just beyond the wooden gate at a patchy spot of grass being overtaken by jungle. I had no idea that this would soon become my parking spot for the next 18 months.

Peter pulled out his GPS and we set off into the jungle. Chopping our way through an infinite assortment of spiky plants, he led us out to a small sloping cave entrance covered with brown recluse spiders and piles of dry leaves that I couldn't help but think must have been hiding all sorts of venomous snakes. I suffered through the short crawl-way to find a beautifully clear pool of water. This accessible little cenote right inside the cave entrance was plugged with years of sediment, of course - there would be no easy diving from here.

We continued on past a few more short crawl-ways and a few more promising pools of water. I jumped into each pool to check for underwater cave – oddly snorkeling in blue jeans that day as my jungle pants were at the laundromat. Soaking wet, I slugged on to where the team had left-off the previous day; up a slope, through a hole, and into the biggest chamber I have so far encountered in a cave. There was a picturesque skylight in the ceiling with mot-mots and swallows fluttering around in the sunbeam poking through the tree canopy above us – I later got quite lost in this giant chamber looking for that tiny hole I had crawled out of.

Under the skylight, we regrouped and split into smaller teams. My team would continue on to survey and map the unexplored section of the cave while the others finished up their maps from the day before. It was my job to scout and set stations, while my teammate, Bern, sketched and recorded data. As the only cave diver present, I was also there to continue snorkeling in my street clothes to scout for underwater leads.

We eventually found another pool of water, this time much deeper than the others and I excitedly jumped in. I took a deep breath and dived down to discover a dark underwater chamber that would almost certainly lead to going cave – it didn't, of course, but at the time I was inspired to keep up my blue-jean-snorkeling-adventure, despite feeling like an idiot.

Towards the late afternoon, we reached the end of the cave. There was nowhere else to go except for one final pool of water. It was shallow, with hundreds of stalactites hanging down from the ceiling high above us. I once again dived under to investigate. In awe, I floated below the waters' surface, staring at an enormous underwater tunnel. It was glorious and without question, I had found what I was looking for.

From here we can fast forward to winter when I was finally able to dive the sump we had discovered so many months ago. The lead had been handed off to another team who were already working in a nearby cave system that Exploradora was heading directly towards. Fortunately for me, that project had kept them more than busy and the Exploradora sump had remained unchecked.

With Peter's team of cavers back in Quintana Roo, I soon had a train of people ready to help haul my gear through to the end of the cave. Once I was settled and ready to dive, the cavers headed out to check some new leads further down the road. They offered to come back at the end of the day to help me haul everything out but I idiotically declined. The lead was huge! I would certainly empty my reel in 20 minutes, survey my line, and be hiking back to my car within the hour. I didn't want to hang around for five hours waiting for them just to save myself a trip or two on the way out - I was wrong.

My enormous discovery pinched down to a 50 cm high restriction in less than 60 meters. I passed the restriction, discovered a nice little room, and hit a dead end. I spent another 15 minutes looking around but saw nothing promising. I had two more sump leads to check in the cave so rather than waste gas searching I got out of the water and started hauling my gear to the next sump, alone. After three trips of hiking my gear, in my wetsuit, inside an extremely humid cave in the Riviera Maya, I was ready to dive again. I made it 19.4 meters into the cave and hit another dead end. There was one more sump to check, and so off I went, hiking my gear back towards the exit. I believe it took me four trips this time. Exhausted, I managed to lay 19.7 meters of line before hitting yet another dead end, destroying my unimpressive record by 30 cm. I spent the next 3.5 hours hiking back and forth to my car, contemplating my poor decisions.

The cave once again sat untouched for a few weeks, until I was able to return in February of 2019. My goal was to sketch the remaining 120 meters of underwater cave I had found to finish up the map from Peter's team. This time I brought a friend, Nicholas White, and working together we had no trouble hiking in our gear. As I was sketching the floor details, I noticed a small opening between some speleothems high up near the ceiling. It almost looked like the floor dropped back down behind them! I signaled Nick to check the lead and he quickly disappeared down the drop. The cave continued! Somehow managing to contain our excitement, we spooled up our line and finished up sketching with the obvious plan to come back the next day. Over the next few dives, along with the help of a third team member, Julien Fortin, we began to quickly approach the 1-kilometer mark.

Until this point, the cave seemed to be a series of breakdown rooms, requiring us to constantly pass restrictions along the outside edges to work our way forward. We had been diving as a team of three, and on this particular day, Nick was laying line, Julien was recording wall distances and I was surveying behind them. With my teammates ahead of me, I reached the top of one of these persistent breakdown restrictions and as I came back down I was suddenly floating alone in a massive tunnel. I could see Nicks line running down the middle but for as far as I could see there was no sign of their lights. I knew what had happened, they were excitedly swimming off down the tunnel, laying line as fast as possible, and I was tempted to do the same.

I reluctantly kept surveying, though at a far less-accurate pace due to my own excitement. Shamefully, this breakthrough section of survey is the least accurate stretch of data from the entire project, despite the fact that it's one of the easiest passages we discovered. I eventually reached my turn pressure, with still no sign of light from my teammates, and I stopped to leave a marker on the line with a note to indicate that I had left. Just as I was turning to leave, two lights appeared around the farthest corner and my teammates finally showed up, thankfully surveying their way out so that we would have the complete set of data for the day. The line leading to this tunnel came to be known as Daddy's Little Secret – Nick had been telling his pregnant wife he was working rather than exploring as he didn't want her to be stressed for his safety. He eventually came clean and told her the truth... I think.

With the new knowledge that there was potential to find borehole tunnels waiting for us behind some of these breakdown rooms, we successfully began investigating other areas that we had thought finished. It was around this time that the project really took off, and our workload began to seriously increase. With the help of porters, we were soon hauling 12 tanks and 6 bags of dive gear in and out of the cave every trip – totaling around 800 lbs each way. With Julien's rock climbing background, we were able to build increasingly more efficient pulley systems and began rappelling from the closer skylight entrance. With everyone working together, we were making our trek in under an hour.

Over the next few months, we pushed the Exploradora cave system to over 5 kilometers in length and it is here that my opening apology comes into place – each one of those dives has a story, and we have totally failed to record them. There is one story in particular, however, that I love to tell, and it gives me a chance to speak about our porters; a father and son team, Jose Luis, and Jeremias. They worked tremendously hard, and there would be absolutely no way we could have accomplished what we did without them.

Each morning we would all hike in a heavy bag of gear to the skylight. I would start setting up the rappel ropes while Julien would rig the pulley system. Jose Luis and Jeremias would make two more trips each to hike in the tanks. I'd rappel into the cave and Julien would start lowering gear down the 8-meter drop. Jose Luis and Jeremias would hike through the cave from the farther walk-in entrance and meet me at the skylight. From here, they'd start trekking tanks to the sump while Julien and I worked together at lowering the rest. We'd tie-off all our climbing gear at the base of the cave and carry our last bags down to the sump. The process functioned equally well in reverse to haul the gear out. Jose Luis and Jeremias eventually even figured out how to operate and breakdown the pulley system on their own, just by watching us assemble it.

One day, as we were preparing to climb back up to the surface, Jose Luis paused to ask me, “Can you show us how to use the climbing gear?” I thought for a moment, the system was fairly simple to use and we were only rappelling 8 meters down, but even so, a fall from that height onto the sharp rocks below could easily be fatal. We would be leaving these guys unattended with our climbing gear for up to four hours each time we dive, and I knew what they'd be doing to entertain themselves. Julien and I discussed it and decided it was better that we do a proper workshop to teach them to use the gear safely.

“Oh, no, it's okay. We already use the gear, we just want to know how to do it properly.” replied, Jose. “Oh...” we said. Upon initial inspection, everything was as we'd left it – tied-off to the ficus roots with our harnesses clipped into a loop at the end of the rope. Julien took a closer look at his harness and noticed a few carabiners were not how he'd left them, and the rope itself was rather twisted.

“Horror struck my face. I was looking at a photo of Jeremias, swinging wildly up in the air wearing Julien's climbing harness. His fists thrown up over his head, screaming as if he were riding a rollercoaster.”

“Look, here's a photo I took of my dad!” said Jose, as he showed me his phone. Horror struck my face. I was looking at a photo of Jeremias, swinging wildly up in the air wearing Julien's climbing harness. His fists thrown up over his head, screaming as if he were riding a rollercoaster. Julien and I stared at each other, almost giggling in disbelief with our hands over our mouths. We decided it would be best to show our hardworking porters how to use the climbing gear straight-away, but they were not to use it unattended! They did. And for the next few trips, we would come back to find our gear almost how we'd left it.

After one of such trips, we had returned the following day and noticed that Jeremias was limping. He had had an accident. He claimed that his dog was running and wrapped its leash around his leg. The leash had gotten really hot and burned him quite badly, he said. He showed us the wound. A painful-looking rope burn spun completely around his thigh.

The following day, I returned on my own to clean up a few open ends on our map. Jeremias and Jose Luis joined me to help with the gear. I didn't bother setting up the rappel rope as it was just as fast to hike in from the walk-in entrance if only one person would be rappelling. The only drawback was that someone would end up alone in the dry cave to hook up the gear while the other two worked the pulley system from above.

The cave itself was relatively safe, the hike was easy with a well-worn path and we were all very familiar with the route. Jose Luis said he'd stay down while Jeremias and I went up. “No!” Shouted his father. “You must be more careful Jose, it is dangerous for young men to be here alone.” He looked at me and gave me the same warning. “Rory, in our culture there are spirits here that are very dangerous for young men. There is an X'tabay here. She will lure you into the cave alone, and it will be your death.”

This was odd. I am absolutely not mocking Jeremias's beliefs – to be honest, I've had enough strange experiences in the Yucatan jungle to understand them. In fact, on this very project, a Mot-Mot once flew through the dry cave, pausing each time about 20 meters in front of me, waiting until I caught up. It led me nearly the entire way to the sump, well beyond the daylight zone. I had an odd sense of discovering something ancient that dive and found a bone site nearly 1.3 kilometers from the entrance that day.

No, what was odd, was the fact that Jeremias and Jose Luis had been enjoying themselves and exploring the cave on their own since they had begun working for us. Jeremias was suddenly terrified – something had happened to him. I suspect his rope burn wasn't caused by a dog leash after all. Needless to say, our climbing gear was always as we left it after that.

Around the start of 2020, for probably the fifth time, we believed that we had discovered everything left to explore in Sistema Exploradora. It was time to begin sketching the map. I had already begun a few mapping projects, but they were all on-going, and here I was, starting another. The system by that time was now about 5.8 kilometers in length. I knew that I was getting myself into a colossal amount of work, but the project had become such a huge part of my life that I wanted to map it properly.

It took me a few weeks to work up the courage, but finally, we started sketching. Progress went faster than I expected at first. Julien and I split into two teams so that we could each sketch, with another diver, Jan Schmid, joining us as Julien's partner.

As we began to finish the closer sections of the cave, our dives were becoming longer and longer. We could usually afford to spend about one-hour sketching on our side-mount tanks and used stages as travel gas. I was soon swimming up to 85 minutes into the cave just to reach my sketching location for the day. DPVs would normally be used in this scenario, but the way through Exploradora required us to pass so many major side-mount restrictions that their use would have been impractical – never mind trekking them through the dry cave.

We pushed on, and slowly the map began to take shape. For the next four months, I had muddy boots and dirty clothes hanging from my balcony chair. We'd hike in, dive, hike out, and start digitizing our sketches from that day. Tracing our drawings with Adobe Illustrator each night would sometimes take even longer than the dive itself.

With hundreds of hours now logged underwater, the end finally came into sight. We must have been two dives away from completing our map when a nagging fear that had begun to develop among the team finally came to fruition - we found more cave. This was a wonderful thing, we were thrilled that our adventure would continue but I couldn't shake the feeling that we had reached our summit, only to find a higher one behind it. We discovered two new tunnels, running in opposite directions of each other, both starting over 1 kilometer into the system. Both showing multiple leads branching out into wholly unexplored areas. The exploration continued.

Within a few dives, we had added another kilometer of cave passages to Exploradora. We discussed our options to finish the map and ultimately decided not to include these new tunnels. We had already reached the limit of what could be mapped breathing four tanks each, and triple stage dives would quickly become impractical due to the high number of side-mount restrictions we faced. Our map was finished. Julien and I had brought this new section as far as we could reach on one last triple stage dive, and found that the cave once again began to branch out. Further exploration would require six tanks plus an O2 bottle each to continue on.

At the time of this writing, our end of line from that final triple stage dive is still waiting for us. I ultimately made the decision to not continue. I do not feel like I was diving beyond my abilities, but I could see that our team was getting sloppy.

Working on this project, we have all gained priceless months of exploration experience. We all came into this as excellent cave divers. Buoyancy, navigation, finning techniques, and so forth are simply second nature to us. But exploration is exactly as it sounds, it brings you into places never seen before. And while we can try, it is impossible to plan for the unknown.

Every morning we would make that same physically demanding trek into the cave, and then proceed to explore the most challenging places we have so far encountered. The farther we pushed, the stability of the cave became progressively worse. With every exhalation, the ceiling would crumble down over our backs and the visibility behind us would be reduced to zero. This was not the place to get sloppy with techniques we would normally consider to be the basics of safe cave diving. With so much effort involved to arrive at that end of our exploration line, time became the biggest stress factor for us. I was witnessing the skills and mental control of my team disintegrate in order to save time – and that to me, signaled the end.

There are a few known cenotes very close to Sistema Exploradora, and in the future, I hope to gain access to explore and hopefully connect these cave systems. As it stands, Sistema Exploradora holds 6.8 kilometers of cave passage, reaching a maximum depth of 21 meters.