In Late August I had the chance to go down to Tulum Mexico in the Yucatan peninsula to explore Cenotes and underwater caves with OpenROV #420. The the Yucatan peninsula is dotted with thousands of these Cenotes; open sinkholes that result from eroded and collapsed limestone that exposes the groundwater underneath. The Maya considered the Cenotes to be sacred sites; they provided the potable water that served as the lifeblood for their civilization, and were the very gateways to the afterlife and the underworld.

In the last 20 years or so, many of the Cenotes along the Yucatan peninsula have been found to connect together. Passionate underwater cave explorers, such as those in the Quintana Roo Speleological Survey, have gone out and mapped out over 208 different cave systems, amounting to over 900 kilometers of underwater caves. Yes, you read that right. 900 kilometers. These cave systems are still being continually explored, and one of the intents of my trip down to Tulum was to join some of these explorers to test the OpenROV’s capabilities for exploring this challenging environment.

I (an amateur ROV hacker/pilot) had the awesome opportunity to hang with some of the most experienced cave divers in the world; Bil Philips, one of the first divers to start exploring the underwater caves in Quintana Roo, Robbie Schmittner who was part of the team that mapped out Sac Actun, once the longest underwater cave, and Fabio Amador an Archaeologist, science communicator and visual artist who works for National Geographic by day and is an explorer by night :P

We were able to dive at three locations; a previously unexplored underwater cave in the back of a humongous dry cave we called “Monkey Cave”, Naval Cenote, and Aktun-Ha Cenote.


Monkey Cave

The very first day after I got to Tulum, we went down to a massive dry cave that Robbie had discovered a few months back with a fully intact Mayan artifacts, and a wet cave in the far reaches of the cave that had not been explored before. I was very nervous about the ROV, since this would actually be its first deployment outside of a test tank, and I would be hiking it into the jungle a fair distance. I was able to rig up the ROV to my backpack with some paracord and two carabiners, and stuff a laptop+100m of tether into the backpack! We almost weren’t able to find the cave entrance again (Robbie was going off his memory of the location, and we were pretty far off a trail), but after a few unfruitful forays into the jungle, Robbie pulled a lucky hit and barely missed the edge of the entrance. By then it was already mid-afternoon so we didn’t have much time to explore the cave, but we made the most of it.

I took a quick dip with the ROV into the cave, just to see how well it would do in the overhead environment. I didn’t venture in too deep ( It was the very first dive of the ROV after all), but even just the cursory glimpse of the spindly ivory salagtite formations underwater was enough to entrace me. Word do no justice for this otherworldly and beautiful environment.

The next day we got up early and hit the road, hiking back to the cave in no time. This time I was more ambitious (since the vehicle performed nicely in the last dip), so I went down into the cave as far as I could

I was able to dive all the way down into the deepest end of the cave. If you notice at the end of the video, I got a little carried away trying to chase the blind shrimp! However at the end of the dive, when i started to turn around to head back, Comms cut out. I was able to reboot and gain control of the OpenROV intermittently, but by them the OpenROV had gotten a little stuck. Thankfully Robbie was able to free-dive into the cave and get the OpenROV loose and back! All in all it was a successful dive in that the OpenROV was able to be the first to explore a new underwater cave, and demonstrate that it could be used to explore caves!

After some debugging, I figured out that there was a slight leak in the ROV (pressure from the depth was forcing water through a nick in the tether jacketing and shorting out the Homeplug power on voltage between the two lines).


Stay tuned for the part 2 post and pretty pictures of the OpenROV in Cenotes! I gotta finish a problem set, and catch up on grad school work.


I wrote up a full expedition log of all the dives which can be found here: Expedition +Dive Log