Cave Diving, Cave Exploration and Cave Mapping in Yucatan, Mexico
Scuba Diving with Big Manta Ray in the Coral Sea Austrlia

The Pit: A Personal Quest.

The story of my odyssey to making my first 350ffw cave dive.

In September 2005, I arrived on the peninsula to do my Cave Course with Matt at Protec. I will never forget the first time I entered the classroom and saw the map of The Pit. Part of Sistema Dos Ojos, The Pit is almost 400ft deep and has 1300ft of horizontal distance ending in the Next Generation Tunnel. How cool does that sound?

From that day on, I spent about 15 minutes everyday just staring at the map and planning; getting upset about how far I was from even attempting a dive like that. I did have experience doing deep, mixed gas, ocean dives in the Egyptian Red Sea, including Wreck Penetration. However, travelling this kind of distance, at such a depth, inside a cave, was an entirely different ball game.

In September 2006, I returned to the Yucatan to do a crossover course from the Inspiration CCR to the Megalodon CCR, which I just had bought, and to get certified in CCR Normoxic Trimix and CCR Cave diving. Yet again, I was fixated on the same map, planning and dreaming about how to do such a dive.

In March 2007, I finally decided that my love and passion for cave diving left me no other choice than to move to Playa del Carmen. Another five months past and it wasn’t until July that I finally saw the beauty that is The Pit. I was part of the support team for two divers who planed to dive to the end of the Wakulla Room. Being only certified as a Normoxic CCR Trimix Diver, and not having enough money to do the dive OC, I limited my dive to 50M (165ft) and immediately fell in love with the place. When you see the sun beams hitting the water surface at the small opening and firing down to the hydrogen sulfide layer at 40m (120ft) your jaw drops.

A couple of days later, I went there to join Steve Bogaerts on an exploration dive in the shallow cave passage. There is an upstream and downstream cave at about 12m (40ft). I was there to see his surveying technique and learn from one of the best. This was the last time we parked the cars about 300m (1000ft) away and carried the equipment. Now, with a lot of patience and carelessness towards our vehicles, we can actually park so close to the opening, that we could back roll from the side of the truck.

To get our rebreathers and tanks into the water, we use a rope and pulley to lower the equipment down a 4m (15ft) deep rock face to the water’s surface. Once everything is staged, we JUMP!

July 2008, the day finally arrived when I headed off to do my first deep dive in The Pit. Having passed a CCR Hypoxic Trimix class, executed some deeper CCR dives, and completed long CCR cave dives requiring multiple bailout tanks, I considered myself ready and prepared. I had also just received a Liquivision X1 computer and after test dives, I was ready to use it for its purpose! Last but not least, Hans, a driven guy who is up for everything no matter what, didn’t mind coming along and helping with the equipment load. Without him, what would I do?

Since I had very little, to no, knowledge about the lines, depths or times between levels, the first dive was to get a general idea about the place. I had one AL80 tank on either side with deep bailout and trailed a third AL80 with Triox that was staged along the way. Another AL80 was staged prior to the dive at 12m (40ft). I traversed the cavern zone, which is a huge dome, then descended the yellow polypropylene line to 34M (112ft) and deployed my primary reel to look for the main cave line. Passing by 40m (120ft), I staged the Triox and proceeded to connect the reel with the main line. After switching my set point on the Megalodon and the X1, it was cruising time. Visibility was quite limited due to what I think is bacteria. The line slowly descents from 46M (152ft) to 65M (215ft) leading through a huge tunnel called the Cardea Passage. At the end, it turns left and descends to a T at about 80M (264ft), where you can decide to either dive the shallower Bypass Tunnel (85M / 280ft) or the deeper section, which I still haven’t seen.

The Bypass Tunnel is a pretty cool place because the cave goes from a gigantic power passage to a 1M (3ft) tall & 8M (24ft) wide bedding plane. On the other side, the cave opens up again into a huge room known as the Wakulla room. There you find a second T that reconnects the two lines that had split before the Bypass, and an additional line that runs to Alpha and Skid Row at almost 400ft, the deep sections of the Wakulla Room. Swimming along the line at 85M (264ft), through the intensely huge room, my 10W HID barely managed to light up the far walls. I had already passed 2 Haloclines and due to the salinity the water had this beautiful blue reflection.

Sixteen minutes into the dive I arrived at another T at the end of the Wakulla Room. Thinking that the T to the right would lead me to the BMB passage, I didn’t hesitate to turn right. I found out that the line ends in a dead end at 92M (303ft). Feeling happy about my accomplishment and wondering what waits at the other side of that T, I decided to turn the dive after 18 minutes. I met Hans at the ascent line in 33M (100ft). We celebrated the dive during our uneventful deco. I couldn’t wait to tell him about it.

Four days later, we returned with a better plan, more tanks, and another diver, Victor. This time Hans took the role of support diver, staging the tanks and connecting the lines so I could go full throttle from the start.

Hans and Victor kicked off the dive and I impatiently waited 30 minutes for my planned departure time. When my start time arrived, I swam with a constant kick pretty much till the end of the Wakulla Room, where I stopped for a minute to calm my breathing and chill out a bit before heading further down into the BMB passage (100M/330ft). I met Victor in the Bypass as he made his way out, returning from his dive to 100M/330ft at the back of the Wakulla Room.

The BMB Passage is way smaller than the rooms before it and has quite a low ceiling and slopes slightly deeper. The stone in the BMB is really soft and the slightest contact immediately results in silting. After about 50m (150ft) there is yet another T. The line there is on the ceiling and is pretty hard to follow. The T to the left immediately ascends through a crack in the ceiling that looked really narrow, so I decided to take the T to the right. The tunnel got smaller and smaller and I was feeling confident I would soon reach the end of the line. As minute 21 arrived, I had to hurry. I thought I could see the end of the line, and I started smiling and a felt super happy about another accomplishment.

Just before I turned, I realized that the line didn’t end. Instead, it ascends through a restriction, a super narrow chimney that gave me the shivers just looking at it. I examined the restriction for a moment and turned the dive at minute 22. I was at 105M (346ft) wondering how in the world somebody managed to lay a line through there. It is really a credit to the original explorers.

The whole BMB passage was quite silty, even though I had almost no direct contact to the cave. On the way back I tried to focus, but could only think about this restriction and how horrible it will be to try and negotiate it. The swim back was uneventful. The 2.5 hour deco obligation is a small price to pay for a beautiful dive like that. I met Hans in 12M (40ft) of water where he took all my unneeded tanks and provided me with Gatorade and a Milky Way to re-hydrate and eat a little.

After the dive the three of us hung out on the platform eating lunch and talking about our experiences on the dive and the diving industry. Two hours later it was time to hoist all the equipment back up and load the trucks. The last adventure of the day was getting the Ford Rangers back to the Highway without getting stuck or scratching the bottom.

That’s my story of The Pit and it is to be continued…


1 david { 08.17.08 at 9:08 pm }

wow what a story! congratulations, who laid the deep lines, Bogaerts and Lins? I remember my firt dive there 8+ years ago, was still in place the remains of the explorers camp, the deco habitat( black plastic tinaco upside down) and the hoses to provide warm water to divers on deco.

2 Hans { 08.18.08 at 8:02 pm }

Thanks, it was a pretty exciting dive. We felt pretty good about it going smoothly and we are looking to go back this week for another dive. We will keep you posted.

As for the lines, I believe Steve Bogaerts, Jill Hienerth, Paul Hienerth, Andreas W. Matthes and some others laid the deep lines. There have been some other expidtions there as well. In the future I am going to do a write up of the history of the pit, I just need to put the time into researching who was there when.


3 Mark Chase { 08.21.08 at 2:35 am }

Keep it comming lads i am loving reading this stuff. Well done to all of you.



4 Hans { 08.21.08 at 8:03 am }

From gtzavelas on Rebreather World: …have you made any modifications to your meg for the deep dives? what are you doing for deco?

PS…I am jelous! warm water cave diving…. diving with out hoods… thats really very rare….

gtzavelas, we haven’t made any modifications specifically for deep diving. Although we have spent a lot of time tuning and tweaking, making minor adjustments so we can carry enough tanks, hose routing it tight, ect ect ect… Patrick might have a different view, or I might not be aware of some of the changes he made.

We both devinverted our tanks. I have a manifold to plumb in off-board gas on the DIL side. Patrick attaches his deep bailout to his right CL. I leave that port open. We both have our O2 on our left side. Beyond that, they are pretty standard.

Deco is done in water on the main line or decsent lines. Patrick’s deco is based on VPM and he is using an X1. I am using a VR3 with Bulh and my bailout plans are VPM. I know that isn’t optimal, I am going to be moving over to the X1/VPM in a couple of days when my wife returns from the states. All the deco is done on the rebreathers.

As Deco progresses, I am exchanging tanks for Patrick and bring him snacks and beverages. It looks like there will need to be a habitat in our future. Our total run times are really going to start to increase.

I think the photos are misleading, we both needed our hoods. Patrick dives dry was cold at the end of the dive. I use a 9MM, which I will be trading for my dry suit in September when I can get it from the states. We both wore our hoods for the almost all of the diving. I just happen to take my hood off when I was ferrying tanks around and posing. I think we were in the water for close to 4 hours each day, that is plenty of time to get cold.


5 Janos { 08.21.08 at 11:07 am }

Nice report. I’ll be reading with interest.


PS – Can’t wait to come back…

6 Patrick { 08.22.08 at 5:50 am }

Hey Mark and Janos,

Thanks for the kind words. It is 06:45 in the morning right now and I just quickly checked my mails and am on the way back to the Pit now. Will be an interesting day. We have the dpvs with and a planed 20min bottom time at max depth to really get a good look at the restriction. Total runtime is a bit over 4h. I will do a write up as soon as I find the time…cheers to england…looking fwd to see you guys back here…and bring this cool camera of yours (Mark).


7 Steve Talbot { 08.23.08 at 1:34 am }

Good story ! Please write more ! I was lucky enough to dive The Pit last year, but had to remain in the Cavern zone, which is still an awesome place. Remember talking to my guide about the Wakulla Room and thinking ‘hmmm someday…’ . I’d love to come back and do some more.

8 Hans { 08.23.08 at 11:00 pm }


Thanks for reading! We are going to do our best to publish our progress! The cavern zone of The Pit is absolutely breath taking! I know it takes my breath away, every time. The scale is just amazing, then you get the beams of light and top that off with the hydrogen sulfide layer! It is a true natural wonder.