Category — CCR

CCR Cave Diving – Don’t believe the hearsay!

As an avid rebreather diver, and self-proclaimed cave geek, there is no better environment to combine both of my passions.

There are a lot of people who say that Mexico is not the place for CCR diving. They say it’s too shallow, too decorated, or even too small.  Well let me tell you right now, this is totally untrue!

As we all know, our number one skill when it comes to diving is “awareness”.  Add a touch of local knowledge to this skill, and a little planning.  You can have some of the best dives of your life, and you can totally use your machines to dive these beautiful caves.

When people tell me, it’s too shallow.  I always ask them to explain, and they tell me that diving in a 5m cave is too shallow for the rebreathers.  Well, if you have ever been to Nohoch Na Chich, or Dos Piso you will know that the average depth is 5/6m. With a low set point, and correct bail out planning, you can literally spend your entire scrubber floating around! You can take in the whole cave (in some caves) in one dive.  Doing this on open circuit, would take multiple days/dives.

When the “too small” comes up, I bring to their attention such caves as The Pit, Mayan Blue, Crystal and the list goes on.

Mexico, has an abundance of caves just PERFECT for our rebreathers. Just over this last week I’ve been “working” and spent many, many, MANY hours of guiding our customers on some bucket list dives.

One such dive springs to mind.  For anyone who has ever been to Dos Ojos cave system and seen the “Crocodile and Barbie” well this is the start of many potential EPIC dives.  The LSD section of the cave is as famous as the Dos Ojos system itself.

To even reach this jump is a multi-stage dive in itself.  It is about a 60 min swim or 25min trigger time on DPV. Once you pass the back to back arrows pointing towards Dos Ojos/the Pit,  the first jump after this you will find the LSD jump.

I first dived this line on my DPV user course in 2014, and I was hooked by the pure size and shape of the Cave.  It has the most spectacular rooms, colours and some breathtaking scenery.  Combine this with more jumps than I can count.  What do you have? Well you have the best dive of your life.

This passage (if you can call it a passage) is so big a plane could fit inside it at some points, it will blow your mind!

I’ve been down this jump line so many times OC, DPV with a ton of stages, and every time still not reaching the EOL (End of Line). I say to myself “next time I’ll do it” and never did!!!!

Then along came Henrik, long term guest, friend and CCR Diver. This was the perfect opportunity to use our machines for what they were intended for: cave diving and long run times!  We sat down, planned our bail out, planned our route. We even planned hydration and food breaks, as we knew it was going to be a long day.

We got to Dos Ojos very early and set up all our bail out tanks and the “mighty Meg, and Peg” as we called our units. After completing our in water checks, off we went.

We reached the jump in plenty of time, got into position, and connected line to line and ventured down the LSD passage!!!!

Let me just fast forward to the end of this story. The whole dive was awesome, it was every bit as good as I had dreamed and hoped for.  We reached the very end of line, well before it goes into sidemount passages.  We arrived to the T at the end of the main line in about 3 hours, maybe a little longer.  We celebrated with some high fives (for everyone who knows me, this has a significant meaning ha ha) and some hearty laughing into our loops.

We then started our long swim back, the cave looks different, however, the way home from the LSD section is just as amazing as the way in!

This is just one such dive of MANY that goes to show Mexican cave diving and CCR go hand in hand.  This dive is achievable on OC, however logistically we all know that CCR leads the way when it comes to gas logistics and LONG cave diving.

I will end this short story, and tell you. If you dive CCR and cave dive, then please combine them together and come out to Mexico. This is just one dive of so many I can talk about all day long!

I am happy to answer any questions you might have on this dive or any other, just email me at

Some of your best dives, are just a click away!!!

March 16, 2016   3 Comments

CCR Rebreather cave diving – Complex dive planning

Recently I taught a CCR cave diver program and as we went diving in the local caves here in the Riviera Maya it came to me again how much cave diving you can do on a Rebreather if you just don’t get in and out of the cave in a hurry.

I still remember when going o/c cave diving and the only thing I was thinking of was going in and out. The thought of visiting side passages or just pause for 5 minutes to admire the cave passages was a strange thought indeed.

Since diving on Rebreathers in caves (1997) and teaching it too I come to spend way more time in the cave without the need of long or fast penetration. As long as you stay within your bailout (o/c bailout that is, I am not touching the subject of CCR bailout here) range (bailout range calculation and bailout concepts will be dealt with in a separate article) you can spend the entire scrubber duration, oxygen duration or diluent duration (whatever comes first) on location within the bailout range.


I used to think of the bailout range as a umbrella but changed my way to come to think of it as a bubble as the entrance is in the center and the bubble wall is the edge of my bailout range I can spend the consumable duration within this bubble.

Here in Mexico we are somewhat lucky that our caves are very complex and have multiple passages and entrance that go all over the place. Good understanding of navigation and how to mark your way out is a must and given, a craft well practiced within our complex caves.


When you pre-calculate and verify your bailo0ut range by calculation of RMV, depth and distance traveled by the minute you come to a x distance, hence your bailout range. This bailout range needs to be verified by actual o/c bailouts during a variety of scenarios to see if the numbers match up when underwater. It’s easy to calculate all day sitting in the dry and breathe air all day, it’s a different issue being on o/c bailout in the cave.

Once we have established a close to reality bailout range and factor in high breathing rate factors such as high stress or elevated co2 we are getting to what we want to take with us into the cave and as we are limited to what we can take with us (not so much fun to take 4 bailout tanks with us) we have a limited bailout range.

Recently I did a CCR cave dive with my student Osmo from Finland and we gave us a bailout range of 24 minutes with RMV, tank size and swim speed. Not much you might think but we did a 3 hour cave dive on it. Yup. 3 hours.


The difference in complex CCR cave diving is that as you go in you take way points – time points at jump off locations and as you go in along the primary line you reach your bailout range calculated in time and distance. As you travel back along the line, and you have plenty of time with a 6 hour scrubber and 6 hour oxygen and even more diluent, you travel slowly, having a good look around. As you come to your jump off point where you have taken the time it takes to get out from this point you can add the time it takes from here to come to your bailout range again just on a different line, in a different cave passage.

On that particular dive not to long ago we did 6 jumps on the way out never exceeding our bailout range on any of the jumps of lines we went on. We did see a large chunk of cave on a single tank we would not have been able to see on a o/c cave dive. What a great dive that was.

The things you need to do such a dive is a Rebreather, a good grasp on bailout calculation and procedure, a good grasp on complex navigation and not to forget a complex cave that is nice to look at.


I would like to congratulate Osmo to the passing of his CCR cave diver course. Osmo was diving on a CCR Pelagian Rebreather while I was diving on a CCR Megalodon Rebreather.

Awesome diving and I can’t wait to get it going again !.


October 24, 2013   2 Comments