Naharon – Or Cristal? The next favourite cave

Second day of MCEP project week, we were assigned to go to Naharon today! It was the first time I was diving with Yvonne, new dive buddy, I barely knew her before this dive, but as always, being GUE Cave 2 diver, we didn’t need that much of a talk regarding procedures, only about the plan, what did we wanted to do and where we would like to go, basically, where everybody recommended, this is one of the jewels of the GUE community, when a 3 hours dive with decompression, complex navigation and scientific tasks involved, only needs a GUE PLAN and a GUE EDGE on the cenote surface.  

Cenote Cristal – Entrance to Naharon on the back right side

Our task was fairly simple: have fun, and upon exit from the cave, take some algae and water samples from the cenote, so we could establish a baseline on the cenotes network of how is the status of the water. They wanted to compare both samples and the nutrients concentration on them, including the chemical components and water quality.  We took our twinset with Nitrox 32% and a stage tank (S80) with 32% as well, so we had enough gas to truly enjoy the cave.

Why is it called cristal? the cave actually is not even remotely similar or resembles anything related with a crystal; then I learned, that Cristal is just the cenote from where you entry Naharon cave. It is the same situation with cenote Escondido and Mayan Blue cave, which are connected through one of the tunnels.

Naharon cave map with our diving path

It was believed to belong to Sistema Naranjal, and then discovered that it is actually part of Ox Bel Ha system, the world’s largest underwater cave. Some local Maya history says that people used to threw their gold on this cenote to avoid being captured by the invading forces during the Caste war (1848 – 1902).

Cave entry from the inside, the first tie-offs are set up on the wooden sticks

Cenote Cristal, entrance to Naharon, is South of Tulum, on highway 307, on the right hand side as you are coming from town. There is a small parking lot at the entrance for snorkelers, swimmers and basically everyone who is not a diver. To entry you need to pass through the gate and pay the Mx $200 fee for the day. If you’re a diver, you can drive up to the cenote, which has a few papayas with toilets and picnic areas, including tables to gear up comfortably, and some platforms to get in the water.

STOP sign at the entrance of Naharon
One of the thousands of columns inside

The cave entry, is just opposite side of where you park, on the right hand side (North), so you need to swim across the cenote to find it. The main line is around 70 m into the cave, after the typical STOP sign, and it is on the right hand wall as you enter (North side), so you need a proper primary reel for it. There are some sticks placed on the entry for secondary tie-off and the rest are easy to place on the left wall. The cave is mainly fresh water, with the halo cline in 18 meters.

Going through one of the passages
A detail of the rock formations inside

We went through the main tunnel, taking the first T to the left, continuing through Desconocido Dome, jumping to The Jump Side, and then to the Dutch Connection. We continued towards the west, until we hit turn pressure on our back gas, leaving the stages just before jumping to the Dutch Connection tunnel. The Chac’s Room is an amazing area, bull of huge formations and a really big space, which will blow your mind wth the ceiling stalactites, all dark and pointing towards you. To get to this part, through our path, you will need five jump spools.

Detail of one of the cascades inside the cave
It has huge rock formations, all in dark colours
More speleothems with different rock composition

We took everything back on our return, coming through the same tunnels. It’s amazing how the cave changes with different perspectives. When we got to our stage tanks, we decided to continue on back gas for a little while on the previous line tunnel, as we still had some gas to explore, recalculate and go!

One of the passages full of stalactites, stalagmites and columns
Thousands of needles!!!!

Black or dark caves absorb the light tremendously, needing several sources along the way to iluminate the same area as you would do with other caves. Also, if there is too much light, you will have backscattering, due to the particles on the fresh water.


One of the tight passages

The area is more tight (red on the map), but is completely decorated with columns and other speleothems as well, completely incredible to be floating there. You can tell as well that this is not such as transited area, because of the amount of percolation on your way, specially yo can see the mist on the way back.
Our dive profile is shown below, having, where you can see where we turned back because of the symmetries, and also the depth profile of the cave.

Screen Shot 2017-12-14 at 17.38.05

On our exit, we cleaned the primary reel, and went to two different locations on the cenote to collect some algae and water samples.


Me, collecting algae samples
For each site, one water sample and one algae sample

Clean up, and have lunch at the cenote under the sun!!

And at the end, we had a special visitor from the jungle!!! they are actually really cute 😃

My new friend from the jungle!!!

 Dive Technicalities

  • Distance travelled: ~1200 meters
  • Upstream time: 53 minutes
  • Downstream time: 98 minutes (including excursion second branch)
  • Total diving time: 151 minutes
  • Maximum depth: 19 meters
  • Average depth: 13.8 meters
  • Gas: Nx 30.2 stage and Nx30.5 back gas
  • Tanks: 2 x S80 + S80
  • Temperature: 25ºC 
  • Dive base: Zero Gravity
  • Team: Yvonne & Belen

Cenote Minotauro – Breathe

Close your eyes, take a breath, and feel the Earth.

There’s nothing more you can ask to a Cenote. Minotauro is a rather dark cave, on the freshwater side, with an halocline that gives way to a bright white cave when you encounter the sea water. It has many jumps and paths that you can follow, fully decorated or not, with restrictions, tight pales, T’s, gaps, and exits to other cenotes.

Outdoors at Minotauro

It is located at coordinates N 20.481868,  W 87.271091, only a 10 minutes drive from Puerto Aventuras, in Yucatan peninsula. The site is prepared with some picnic tables and entertainment for snorkelers, but the really important area sits behind the cenote: a huge cave system. The entrance to the cenote is Mex$300. The parking spots (if you get there soon enough) are really close to the stairs that take you down the cenote. We geared up and ventured there, on a team of 2 this time. The plan was to close the circuit  on the main line and if we have enough gas, recalculate at the end to check some jumps around.  The site breathes peace.

First dive distance travelled

For the first dive, we followed the main North line, starting in open water, so there is no need to install a reel now.


The first jump left is around 15 minutes into the cave, where you closes the loop. We jumped to the left and continued clockwise. Between the halfway mark of the circuit (chase of direction) and the first jump, there is a gap to close. Just half way, on the arrows that mark it, you can jump to Cenote Escalera, we left this for the way back. The halocline starts at 12 meters, and you can start floating on top of the river before and after the change of directions, and enjoy yourself playing with the lighting and different colours. Swimming between waters feels like being between two worlds on the same planet. The salt water is slightly warmer, and  you feel it in your body, just slightly enough for the dive computer not to notice it.  

Colors on the halocline at Minotauro

We reached TP on the stage almost at the end of the loop, around minute 40 on the dive, completing the circuit in 53 minutes, when we turned back. With the cave going up and down, you can find yourself either in fresh, salt or between waters, where one can play with the densities and light speed changes to see the colours of the cave.

On the way back, at the change of directions, we decided to drop the stages and go with back gas (no hit of TP yet) to cenote Escalera. It is only a 3 meters swim there, and you can see the light coming down, using only 10 bar to go and back, including the switch to and from back gas. On the way back, we picked up the stages and continued with them to the exit.

Exiting the cave
Dive profile for the first dive

Upon surfacing, we still had enough gas to do another dive, so why not?!

This time we chose the Eastern line (on the right looking at the cenote). The area of the cave is shallower than before, therefore no thermocline here. That means that most of the passage is highly decorated with dark brown speleothems, stalactites, stalagmites, column, flowstone, needles on the ceiling pointing towards you, and more restrictions and keyholes. It is a very technical fun way to go. The needles give you a feeling of being pointing down ready to pinch, with thousands of years waiting for you.

It is good not to go to this part with an almost empty stage, as one needs to be really careful of not hitting any part of the cave for its delicate formations. This time, you need a reel to connect from the open water to the main line, which starts 10 meters inside the cave part. After our recalculations, and considering we were a team of two, we had 30 bar usable for penetration, the good part is that it is really shallow, so we gifted ourselves another 80 minutes of marvellous cave.  

Part of the travel on the second dive

The first jump is located 20 meters from the beginning of the mainline, where we turned left. We found another T after 25 minutes, and we ventured through a tiny tunnel, full of stalactites and stalagmites, columns, and keyholes again. It is such a wonderful passage, when you really feel like being part of the Earth.

One of the keyholes on the North Passage

We encountered a break on the line, which would be a gap, just when we hit TP. On the way back, as we didn’t have enough, on the closest T from the entrance, we recalculated and swam 10 bar into the other side, T to the right!

Detail of one of the passages


Second dive profile – North mainline

All this part, as it is in fresh water, is covered with dark speleothems, giving you the darkness and mystery of a gloomy area.

Close your eyes, take a breath, and feel the Earth.

  • Dive 1 Technicalities
    • Distance travelled: 700 meters
    • Upstream time: 55 minutes
    • Downstream time: 65 minutes (including excursion to Cenote Escalera)
    • Total diving time: 120 minutes
    • Maximum depth: 15 meters
    • Average depth: 9.2 meters
    • Gas: Nx 31.7 stage and Nx30.1 back gas
    • Tanks: 2 x S80 + S80
    • Temperature: 24ºC (and maybe 24.5ºC in salt water)
    • Dive base: Zero Gravity
    • Team: Britta & Belen


  • Dive 2 Technicalities
    • Distance travelled: 400 meters
    • Upstream time: 30 minutes
    • Downstream time: 50 minutes (including 1st jump Right)
    • Total diving time: 80 minutes
    • Maximum depth: 6 meters
    • Average depth: 4.4 meters
    • Gas: Nx30.1 back gas
    • Tanks: 2 x S80
    • Temperature: 24ºC
    • Dive base: Zero Gravity
    • Team: Britta & Belen


Zero Gravity in Gold and Black Sapphires

The day started slow paced, even though we were going diving, we didn’t have any rush, and on these situations, it’s convenient to double or triple or quadruple check everything, and take with you as many spares as you can!

First good sign that the day was going to be good, crystal clear water.

The preparations started the day before, it took us about 3 hours to put together two full sets of equipment, including gas fills, analyzing and all checks. One of the nice things about diving GUE is that we can arrive at the dive location with only our pigtail with cookies and arrows, and we are sure that our buddy will have all our usual gear for us, as standard configuration. On the day to the cave, drive, coffee and start with the usual site check and topography review. On the way to the cave, we talked about plans, what’s the main goal for the day, obviously HAVING FUN!!, but to have some others in mind, we wanted to assess different video possibilities along the cave, to be prepared for our next projects.

Alviela provides nowadays 10% of the consumable water in Lisbon, and it is one of the biggest aquifers in Portugal. The area is also known as picnic and family area, with plenty of visitors during the summer to calm down the hot temperatures in Central Portugal. It is located between the Estremenho Karst Massif and the Tertiary Basin of Low Tajo. There are close to 140 million years difference between each of the rock systems. They are dated from the same orogeny that formed the Alps and the Pyrenees. The cave systems in the Massif are being documented as part of a Project Baseline initiative.

The entrance to the cave, already a two passage system.

First, site survey: before starting to gear up, we needed to check the site status, like water level, way to the cave (for me) and possible water flow: which is  not common in summer time, of course, but it is something always to be checked.

I have never been there, so it is mandatory to check the procedures and ways to gear up, carry all the gear to the cave, and usual tricks that only locals could give you.

To enter into the wet cave, you need a couple of ladders, specially if you’re going to carry gear, I don’t see how can I climb a bare rock with my twinset on the back! Thanks to the people at SPE, everything is organized with the ladders and tools to safely access the cave.

Access to the water

My first cave dive after GUE cave 1 class in Sardinia!! I was super excited!! We were a team of two, and we planned gas (double thirds) to do three dives on the cave. The first dive would be just to get a first impression for me of the cave, and to make up the topography of it in my mind, get used to the change of depth and smoothness and get some waypoints. That was not the case for my buddy, who knew each of the cracks that you can find there, but both of us needed to have that clear idea of the topography.

We started to carry all the gear, so it was ready just for when we got into our drysuits and jumped in the water.

Gear ready!

After gearing up and the pre-dive checks we descended into the tunnel which gives entrance to the cave, following the main line. The beginning of it is a wide and tall tunnel, which starts to get deeper with a very smooth slope. As happens with a lot of caves, your brain can’t really imagine what’s going on just by reading the topo, specially the diving technicalities.

Tunnels naming with depths

Suddenly you realize that you are swimming in golden walls, with black cracks all along it, which look like black sapphires crusted in gold. The cave splits into two tunnels in 30 meters from the entrance, but they are not independent, they are connected through windows, which give a lot of room for imagination to play with lights and have some unique scenarios for photography.

Tunnel A top view

We had a depth limitation due to gas (32%) and to deco of 30 meters, so we concentrate our dives on tunnel A. within GUE C1 limits, and after three 50 minutes dives, I would say, it is still not enough time to “explore” it all, if you really want to enjoy its colors and features. The tunnel has a couple of jumps on it, towards other passages, but we’ll keep those for other dives. I entered the cave with my eyes wide open and all my senses alert, as you do anyway when you go into the unknown, it doesn’t matter how much brief or study you do before.


When we reached the -30m depth limit we turned back to exit, following the main line, and sloping back up to the entrance. The feelings that you, or at least I have before diving a new cave are always a mix between vertigo, excitement and curiosity, and that remains on the way back, as you have a complete different view of the cave, with a new perspective. That famous knot on your stomach remains until you take the first breath of uncompressed air out in the surface.


After some surface discussion and a questions, mainly from my side, of course, and first impressions, we started the pre-dive checks again and went back. The goal this time, was to record some footage of one of the side passages, to build a 360 degrees virtual reality video of it. Also, we needed to figure out how to play with lights, and get some good photos for the project that is coming up next September, more information here

Start of the windows passage

On the second dive, as I had in my mind a general overview of the topology and some way points, I couldn’t resist just to enjoy it and keep on blowing my mind up getting the personality of the cave. The visibility was of 30 meters at least, having the feeling of flying on it. It is a rather dark cave, so the illumination is a bit more trickier than for example caves in Mexico, it absorbs most of the light, making illumination a challenge. Playing with the windows and lighting, we got a clear idea as well on what to improve for next expedition.


Before the last dive, we took a break from the cold water, and went to the daylight for some time. I can’t really described the feeling of going from a completely dark and peaceful atmosphere to mid-day sun and kids playing on a pool in summer. After having a breath, we went back into the cave, ready to fill up our twinsets with some spare tanks we brought, so we could have them top up for the last dive of the day.


Being the third dive, I already had on my mind way more waypoints and the cave topography so I could focus on lightning and some new ideas to take footage. We went back to the -30 meters range, trying to get a long clip with different angles, so we could trace some strategies next time. It turned out to be one of the most amusing cave dives I’ve ever done, what it was going to be a short dive to wrap up some of the shots turned into 47 minutes of darkness and brightness, peace and giggles.     


Dive technicalities

  • Coordinates: 39.445617, -8.712091  
  • Dive 1
    • Dive time:  28 minutes
    • Max depth: 29.6 meters
    • Average depth: 15.9 meters
    • Gas: 32%
    • Water temperature: 17 degrees
  • Dive 2
    • Dive time: 31 minutes
    • Max depth: 24.6 meters
    • Average depth: 14.0 meters
    • Gas: 32%
    • Water temperature: 17 degrees
  • Dive 3
    • Dive time: 47 minutes
    • Max depth: 29.5 meters
    • Average depth: 15.1 meters
    • Gas: 32%
    • Water temperature: 17 degrees

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