Category — Cave Diving Sites, Cenotes and Systems

Well... the last nine months have been pretty exciting!  My wife and I moved back to the US from Mexico during the height of Swine Flu scare.  We jump started our web design business, and had our son Hans Griffin.  As one might imagine all of the associated chaos put a pretty big crimp on my diving, however I was still able to get a bit of diving done. I made a couple of trips up to Thousand Islands and I did my first deep dive in the Mud Hole off of New Jersey.  But that is not why I am writing, I am writing because I am back in Mexico for a short trip to do some cave diving.

On Thursday I arrived full of anticipation and some anxiety.  Sol picked me up from the airport.  I had in tow a Silent Submersion DPV conversion kit, my side-mount gear and some other assorted dive goodies.  I was very glad to not have to ride the bus.   Sol dropped me off at Patrick´s apartment and I kicked back and started my wait.    As luck would have it, I came down with a cold two days before my flight.  The first two days here were spent waiting for my cold to pass and my sinuses to clear.  On Saturday, it finally cleared enough for me to dive.  I prepped my gear for a check out dive. 

Sunday dawned and Patrick of Protec blog fame and I decided to go diving.  We debated where to go for a while and decided to head to Cenote Azul.  I was told when I moved here that divers were not allowed to enter at Cenote Azul, so I never tried to get in there.  I said that to Patrick and he challenged me.  We decided to check it out and see if that was true. 

We pulled into the parking lot and spoke to the manager.  She was apprehensive but decided to allow us in, to my surprise.  She charged us each 100 Pesos.  She explained we could drive to the water, which was behind the shack.  Cenote Azul´s grounds are very nice and well maintained.  The walkways are manageable and the Cenote is gorgeous.  The water is about a 3 minute walk from the car.  The water is about 10-15 feet below the parking lot. 

You want to enter the water in the main cenote which is right in front of the wooden deck.  There are two lines at Cenote Azul.  One line runs to Kantun Ki and the other runs over to Cristolino.  You can swim to Ponderosa (Garden of Eden) by swimming towards Kantun Ki and taking a left. 

The main line to Kantun Chi is about 150ft from open water.  There are at least three viable options once you are in the cavern zone, however only the left one will lead you to the main line.  If you are looking for the line to Cristolino, you have to continue past the line to Kantun Chi.   The end of both lines are in the same general vicinity.

It took us about 4 minutes to get tied in.  We started up the line and stopped a number of times to make repairs.  One repair took the two of us to lift a 4 foot slab of collapsed lime stone  off the line to free it.  Another repair required us to cut a ball of line off the main line.  Lastly, we re-secured the line a number of times.  Every time I dive this area of the system I find numerous problems with the line.  In the past I have found the line slack numerous times and I find small collapses regularly here.   If you decide to dive here, make sure you pay attention to the line.  It is in the halocline and it isn´t in great condition, this is a relatively out of the way part of the system and the lack of traffic shows.

After about 45 minutes we reached Kantun Chi.   We turned the dive and headed back.  The swim home was uneventful and relaxing.  We surfaced at 100 minutes.  Overall it was an awesome dive.  I am really glad to be back here.   Diving in Mexico is much more relaxing then diving in New Jersey, there is no drive to the boat, no boat, and warm water.

The lesson this trip is to check out those old possibilities.  There are management changes, line changes and changes in perspective.

The advantages of a closed circuit rebreather in a shallow cave.

I have to admit that I recently neglected rebreather diving and instead spend most of my time off sidemounting. I pretty much used my rebreather for deep diving only. But recently that changed, I finished crossover training on the Poseidon Cis Luna Mk6 and right after that was with Howard, aka Scubadadmiami for a week of CCR Cave diving. And I am hooked on CCRs again.

The Mk6 exceeded my expectations but this is not what this article is about. What I want to share here is my recent experience diving Ponderosa, Taj Maha, Nohoch Nah Chich, Grand Cenote, Carwash and Naharon. Generally all the dive sites have an average depth of about 30ft and Nohoch even being shallower with Naharon being the exception at 60ft.

In many posts on CCR forums, the Mexican caves are described as CCR “unfriendly” and honestly I do not understand why? Our recent experience illustrated that CCRs can be used effectively in these caves and enabled us to get to know whole sections of systems in only one dive.

Normally when I guide people open circuit I choose a cenote and then guide two dives to the most famous or pretty parts of the system. The dives are usually turned either on time or gas which results in returning to open water. The option to recalculate thirds does exist, however, my opinion is that it should be reserved for experienced divers with experience in the particular system. When divers elect to recalculate thirds, eventually the gas reserve becomes to small to be safe.

The advantage of the CCR is that you have a bail out radius which enables you to spend as much time as the scrubber will allow, normally about 3 hours which is a huge opportunity here in the Riviera Maya.

The cave systems here are like Swiss cheese with many different side tunnels and passages. They are also very shallow. These two characteristics combine to create a situation where divers have a very long range on an 80cuft cylinder. Depending on you gas consumption while bailing out and conservatism factor you want to build in you will have a radius of at least 40min in most places. There are other benefits worth mentioning:

1. Once you come of the frequent traveled passages you will often encounter quiet significant amount of percolation that can seriously affect the visibility.
2. Thinking about the lost line or lost diver scenario, imagine how your chance of survival or the chance of finding your dive partner will increase with an hours long supply of breathing gas.
3. How many accident reports have we seen that speak about people drowning only minutes away from an exit, what would have happened if they would have been on a rebreather.
4. Taking pictures on the way, on a CCR you penetration distance is not going to change because you stop at a place to take some pictures or simply take a brake.
5. Think about a reverse block way back in a cave, how much more relaxed are you going to be, knowing you can stay there fro hours.
6. No time or gas pressure to go to a certain part in the cave and therefore reduced chance of pushing limits due to being goal oriented.
7. And many more

Of course this is a double edged sword and there are as well some negative aspects:

1. Buoyancy is definitely more difficult.
2. It is the perfect tool to bring people that where before limited by their air consumption far into the overhead environment and by that outside of their comfort and experience zone.
3. With most units together with the bail out your overall size in the water column is bigger and therefore you need more effort to travel.
4. Many ups and downs consume Oxygen and Diluent volume.
5. Getting overconfident due to the feeling of having unlimited gas supply.
6. Proper bail out gas and volume is never an issue until it becomes an issue.
7. And many more

To have a real advantage with the CCR we have to change the way we dive in the cave. Instead of using it to go for that record braking long distance penetration why not stay closer to the entrance but get to know all the lines that are in that area.

For example, at Naharon we dove up the main line and did the Jump towards the double domes. We swam up that line until we reached 40min, or bail out distance. On the way we stopped several times to take pictures and simply stopped the timer while we did not go further in the cave. On the way we marked the double set of line arrows that mark the jump towards south western sac be. On our return we arrived back at the arrows and new that from this point on we had 30min for further penetration so now we did the jump and enjoyed the really unreal beautiful sac be section.

On the way there we pass yet another set of double arrows marking the jump that lead down towards Cenote Mayan Blue and again marked it. We continued in the sac be tunnel until we had reached 30min from the jump and turned our dive. On the way back we stopped again a couple of times to take pictures. We didn’t even have to take care about the time since we were well inside our bail out range.

As we arrived back at the Arrows we decided to make yet another jump and check out the line that leads towards Mayan Blue. After some time we turned from there and now did the entire return trip back to Cenote Naharon.

As you can see, we did in one dive what, in conventional OC cave diving style would need three dives. We had an average depth of close to 60ft with a 180min runtime, me carrying an 80cuf and Howard 2 40cuf bail out tanks.

Another example would be Carwash where we could use Lukes Hope to restart the 40min bail out range and therefore had plenty of time to visit the room of tears and all the different Ts in the back. On the way out we did the jump that leads to the back of the room and stayed there for like 30min just doing pictures and enjoying the decorations.

In Grand cenote we went down to the Cuza Nah Loop and could restart the 40 min each time we past a cenote which was awesome since this gave us the possibility to do the jump at the mid way of the loop and take our time while swimming down that line again taking pictures and having a great time. On the way back we continued the loop on the other way since we were still easy inside our bail out range.
And the same was done in all the other places.

All in all I really enjoyed this week especially the possibility to visit lines I have not been too in a long time. I really love to do complex navigation, see different lines and go back and forth and all around.

Another bonus, so to speak, was to get more experience on the Kiss Classic which I really start to like more and more for its simplicity, the 20min prep in the morning and the 5min tear down in the evening, the free chest, constant O2 flow which facilitates buoyancy and the general possibility to keep the same configuration than with a set of doubles.

For Howard it was great too because he really got to know quiet a bit of each system we dove at, although he only did ONE dive there.

Considering all of the above, I would call the caves here perfectly suited for CCR diving if you bring the right set of skills, a good attitude and some creativity to the table.

Of course there are always people that say OC backmount is the only way to go and others believe that OC sidemount is the best, then there are some that believe in multiple stages or scooters or I don’t know what else; Me, I think it all has its use and its just what you do with it that makes it valuable. Try to get the most advantages out of whatever equipment you use and try to work with the right tool for the job!

Keep the loop closed but your mind open!!!

Patrick

I posted a link to my article Last Dive at The Pit - Bailing Out at Depth over on Rebreatherworld.com.  One of the users, zzzzzzzz, commented on it and I thought his comment was worthwhile reposting here with my response.  The indented copy is zzzzzzzz's comment.

Good article.

WRT keeping on schedule, OC trimix should be running a set of schedules, allowing for aborted dive, short, long and maximum schedules. This provides all the needed flexibility in an emergency. Running a single schedule is not great.

Thank you! I write the articles for people to learn from and enjoy as entertainment.

The diver had the appropriate schedules. I am not sure where you read that we didn't have the schedules. Seems like you made a bit of an assumption to the negative. Our desire was to stay on the nominal schedule. As you might imagine, the switch to the next schedule at depth can add an unnecessary amount of decompression and gas usage. Every minute at that depth translates into about 5 minutes of deco. A switch to the next schedule brings a 30 minute penalty, something neither of us wanted to be obliged too. A close reading of the article reveals that my one minute to make the switch was built in to our nominal schedules. We left the switch on schedule.

This is to distinguish the need for time to solve problems versus making an expeditious exit. Since you experienced issues, it is astounding that the OC diver's schedules did not allow flexibility in running schedules. Certainly, a diver targets a nominal run time for a dive, however, not carrying contingency schedules is a fundamental training issue. Recommending that someone executes faster when encountering problems is not constructive since one cannot predict how long problem solving can take, especially in an emergency.

See above.

It is also quite okay to encourage better skills integration for enhanced performance, however, not because it is an inconvenience for the OC diver.

I see his recommendation in a different light. Optimally, I would like to be able to be swimming towards the exit while making the switch. That ability would cut at least 1 minute at depth and 5 minutes off of deco saving a little less then 18cuft of gas. Additionally, it would put me closer to the exit if there were another emergency, which out of respect to Murphy isn't completely unlikely. I can't remember a time when only one thing went wrong when things started to go really wrong. I think Santiago's critic is correct in that I need to work towards the ability to swim and make this switch at depth. I can do it in 100ft, why not in 280ft? That is a valid question and needs to be figured into bail out planning and needs to be trained further to develop better muscle memory. I don't think either of my CCR instructors would have let me walk without being able to do that skill while making an exit. I shouldn't accept it either.

On deploying and stowing regulators, especially on the fly, an added option is to set hose lengths such that the regs drape around the neck to staggered positions. This can allow maintaining several regulators in a deployed condition, allowing more time and options for stowage.

This is not a bad recommendation though going back onto the loop and doing 2.5 hours of deco this way wouldn't have been very comfortable. Again, this is a training and equipment issue and was only identified because I took the time to actually try it out.  I wrote that I have a similar problem when I dive OC with stages.  That should have been a warning to me that it would manifest itself when I dive CCR.  It is interesting that the problems we have in the shallows are magnified under the time pressure that comes with depth.

Thanks for taking the time to read my article and provide feedback! Your ideas help me to better flush out my ideas. Keep them coming

If you have been following Quiet Diver, you know that I left Mexico a couple of days ago.  And while I was in transit, I was torturing you with stories that were unrelated to diving.  Well, this story gets us back to writing about diving!

A month or so ago Santiago and I made a dive at The Pit down the Lins/Walten tunnel.  It was a nice dive to 238ft (73m).   Santiago was diving OC and I was on the Megalodon.   After the dive we had some helium left over and we enjoyed diving together so much we decided it would be cool to do a dive to the back of Wakulla Room as a team.  Additionally,  we needed to pick up some tanks that were staged from the last project and I still needed to do my at depth bailout.   So, we got another tank of helium and decided to do the dive in a couple of days.  Well, as the date approached I was too overwhelmed with work and had to call the dive.  These dives require a lot of preparation and mental focus and if my mind is on other issues, then I can’t do the dive.

Well, it took me more then a month to reschedule the dive between work and social engagements.  But once we got the dive scheduled everything fell into place.  All the gases were blended, regulators prepared and dive plans cut.

The plan was to stage gas at 20ft (6m) and 70ft (21m) on a down line.  Then set the primary reel and stage gas at 150ft.  For bottom gas Santiago took double 80’s and a deep stage.  I took two 80’s of deep bailout and the CCR.  Normally, I would carry one deep bailout for this dive, however since I was going to purposefully bail out, I thought it would be wise to carry extra gas.  As well, I was diving with an OC buddy and I wanted to be able to donate gas in the event of a lost gas situation.  After staging all the gas, we planned to swim to Paul’s Rock, which takes about 16 minutes.  Paul’s rock is about 800-900 (274 – 278) linear feet (meters) from the surface at a depth of 280ft (86m).  Upon reaching Paul’s Rock, I would signal Santiago that I was bailing out.  We would spend one minute sorting out the situation and then make for the exit with haste.  After exiting the Bypass, I planned to switch back onto the loop to conserve gas and do a normal CCR decompression schedule.

I had a several reasons for bailing out at depth:

1. Switch from a rich HE mix to a lighter mix and experience a change in END and confirm our choice of deep bailout.
2. Go through all the steps of bailing out under the effects of depth.
3. Confirm my SAC rate in that configuration and under the environment stresses.
4. Practice bailing out under the supervision of a trusted dive buddy at depth and get critical feedback.
5. Complete the drill because I made Patrick complete the drill and he was riding me about it.
6. Feel the tanks as they get really light with HE in them.
7. Breath open circuit gas at depth while hustling.  (I never dove Trimix OC.)
8. Practice, practice, practice!

The dive went nearly as planned.  We reached our way point at 150ft (46m) a little late, through a little effort we were able to make up the time and we reached Paul’s Rock on time.  I turned to Santiago and gave him an okay.  He replied.  I then gave him the bailout signal.  I reached up and turned the knob on my BOV.  I breathed out a little to clear the regulator of water and took a breath.  As I completed the breath I was immediately hit with a case of nerves.  I felt a shot of anxiety and adrenaline wash over me.  It was totally unexpected because I had mentally rehearsed the drill a pile of times and had executed it in shallower water many times.  My brain went a little mushy.  I reached around and opened the bailout tank valve.  For reference, I have my bailout tank and diluent tank plumbed into a manifold, so I now had access to both.  I had switched from an END of 67ft (20m) to an END of 92ft (29m).  Plus I went from an “unlimited” gas supply to a very limited gas supply.

After opening the bailout tank, I pulled my regulator out to replace my BOV.  As I pulled the regulator to my face, I reached up and pulled the BOV out of my mouth and thought to myself, "Don’t flood your unit - close the BOV."  I reached around and switched the knob, opening the loop!  Dur! I heard the bubbles and quickly stuck the loop in my mouth.  I switched the loop closed and cleared the regulator.  I thought to myself, "You idiot!  That is exactly what you needed to not do."  I took the BOV out of my mouth put the regulator in my mouth.  Confirmed I was breathing the right gas and looked at my set point controller.  I needed to set the set point down to manual.  It took my four tries to get it right.  I kept setting it to 1.4 instead of manual.   Finally, I got it set and then switched my X1 over to bailout, which I achieved on the first try.  I opened the OPV and started to swim.  The whole switch over took about 1 minute.  However, it really felt like a life time.  We swam for 5 minutes exiting the Bypass.  I switched back to CCR and made all the appropriate adjustments.

As we ascended, I picked up the staged tank at 220ft (68m).  The tank had been there for almost two months.  It was covered in billowing clouds of bacteria.  All the hoses were slimy and I was very glad I didn’t have to breathe from it.

The rest of deco went smoothly and was without incident.  Santiago and I had very similar schedules and exited the water pain-free.

As I hovered in deco, I had a lot of time to reflect about the dive.  The first thing that came to mind was how glad I was that I took the time to do the drill!  I wish I had done the drill last fall, when we first agreed that we would do it.  There is no harm in practicing this stuff, except to your wallet!  There is only benefit and experience.  Because my Meg is so reliable, I do not often get the opportunity to bail in a stressful situation.

Bailing out at depth in the back of a cave is different then bailing out in the first 1000ft (309m) of Ginnie, any shallow cave in Mexico or on the Jodrey.  I had bailed out repeatedly in those environments and never felt the anxiety or lack of coordination that doing it in The Pit caused.  I was definitely noticeably more impaired at that depth, even with a 96ft (29m) END.  I was glad to learn that my SAC rate held even at depth with a shot of adrenaline and a hasty exit.  I was also glad that I was able to get all the required tasks completed.  After the dive, I checked my loop for water and there was very little.  The towels in the bottom of the can were just a little wet.  So the open look fiasco wasn’t too detrimental.  I was glad that I identified that problem quickly and resolved it.

Santiago was concerned with how long it took me to bailout.  As he was on OC and run time tables the whole dive, he really needed to stay on schedule.  He suggested that I might have been better off starting to swim earlier.  I don’t know that I agree.  I think it is critical, even if I waste 1 minute, to get everything set and then start to swim.  I can only do one thing at a time in a situation like that, especially if my lizard brain starts to emerge.  In past situations, I really fumbled things by trying to do more then one thing at a time.  I have learned I need to complete one task then move on.

In response to his remarks and my performance, I would like to go through the drill again at depth a couple of times and maybe a couple more times in mid-range water.  I think when I get back to Q. Roo, I will schedule another bailout before I start deep diving activities at The Pit.  I may have the opportunity to give it a try this summer here in NJ.

Santiago said I looked somewhat impaired as I tried to set the handset.  I agree with his observation, I was.  Either it was anxiety or being narced.  I think it was an insidious mixture of both.  I know that when I get scared or nervous, even in shallow water, my cognitive abilities diminish.  Mix that with some depth and you have a nice cocktail.

Lastly, he was unhappy with how long it took me to get back on the loop and the distance I swam off the line when I switched back to the loop.  Both are valid concerns.  I swam off the line to avoid getting entangled.  As the line exits the By-pass it splits in two and ends up above you and below you in ugly spots.  So, I swam away from it.  As for taking too long, he was right.  I had a lot of trouble stuffing the hose back on the tank and as I was about to pick up another tank I needed to sort the bailout first. I think I need to get looser hose retainers and practice with them a bit.  I have a similar problem when I am dealing with my OC stages.

I am very happy with the dive.  It didn’t go perfectly, but I learned a lot and we had a ton of fun.  I am grateful to for my friend’s observations.  When you are in the moment, you miss things sometimes and a neutral observer can add a lot of depth to the discussion.  Santiago is an excellent diver and I look forward to my next opportunity to spend time with him.  I am sad because that was my last dive at The Pit for a while!  I really enjoyed diving at The Pit, especially the deep dives.  The Pit is a spiritual place for me.  I see it as a cathedral of diving.  The spaces are so big and beyond normal scale that it inspires me.  Until next time, I will dream of diving at The Pit.  To be honest, I am going to miss all my friends: Patrick, Solomon, Alain, Steve, Etienne, Ross, Katie and Santiago just to name a few.  The last year and a half of diving has been amazing and I have many fond memories.  Thanks to all of you, my life is forever enriched!

Patrick and I decided that we needed to go for a nice easy dive, one that wouldn’t include a huge pile of tanks or the mixing of exotic gases.  The answer seemed clear, go looking for Cenote Pabilany in Sistema Sac Actun (Grand Cenote).

The journey to this decision started last year or the year before. Patrick was diving his Megalodon in the western end of the Sistema Sac Actun.  He was near the Pabilany section but he was on the Paso de Los Pozos side.  He wanted to continue but found the restrictions a bit tight in the rebreather.  He finally retreated and decided to return in sidemount.  As time passed, the idea of diving this section of cave stayed with him, I moved into town and then we both got scooters.

With all the requisite gear and skills, we decided to scooter up there in sidemount with a single stage to check things out.  We sat down on Tuesday night and spent a couple of hours debating the best gas management rules for a scooter dive of this nature, finally settling on what we believe to be an innovative approach.  Secure in our planning we decided to dive on Thursday.

The dive plan was as follows: scooter up the main line jumping to the Paso de Lagarto. Continue scootering eventually jumping to the line to Lithium Sunset. When we reached our stage pressure or the T at Lithium Sunset we would stage the scooters and the tanks.  We would swim north on the Lithium Sunset line looking for the jump into Pabilany.  Once we found it, we would make the jump and a short foray into that section of cave.

The dive went almost according to plan.  The first obstacle was planning the dive.  Looking at the cave map and estimating the depths it looked like we might get into some deco with air.  Therefore, we decided to take O2, luckily the average depth was much shallower then we anticipated and the O2 was unneeded, which brings us to the irony of this dive.  Patrick and I wanted to make a simple relaxed dive.  Instead we ended up needing 4 tanks and a scooter each.  I guess when you compare that to needing 6 people and 35 tanks, this was a relatively simple and easy dive, but it was still not a no-brainer.

The second small obstacle was an exiting team.  When we got to the jump off the main line, there was a team of three exiting in backmount swimming with double stages.  We gave them the courtesy of waiting for them to completely exit the area before installing our jump.  This ended up taking 4-5 minutes as they lumbered through.  Not a huge deal, but hanging out and waiting, cuts into your stage and scooter time.

When Patrick and I scootered up to the T, our run time was about 23 minutes and we were both nearing our stage drop pressure.  It was serendipity.  We dropped our scooters and then our stage tanks.  In those 23 minutes, we coved about 2300ft, installed two jumps and a primary reel.  It was awesome.  The last time I swam to this spot it took us about 55-60 minutes to reach it.  I felt like we made pretty good time!

We started heading north looking for the jump.  We came to an arrow and decided to make the jump left.  We swam past a T, taking it to the left.  At this point the cave got tight with an aggressive saw tooth shape.  Then the line doubled back on itself and disappeared into a no-mount restriction.  Well, the truth is Patrick made it through with both tanks on and I had to remove one tank to pass.  The line through the restriction was on the ceiling in an awkward position.  Patrick squeezed through first with a lot of silting.  I followed him using the brail method.  The restriction required angling the body and ascending.  It was challenging and doing it in zero visibility made me nervous.

On the other side the cave opens up a bit and then pinches down.  I started to follow Patrick up, but the silting was just too much and my nerves were starting to fray.  Add to that the line was slack when we first entered the room and Patrick was actively fixing it as I followed.  Finally, I ran into his fins and decided I had enough.  I backed out and into the bigger room.  I decided to wait for him and meditate a bit.  When he returned a couple of minutes later I gave him the “Turn the Dive” sign.  By this time I had calmed down however he could tell I was a bit scared by the look on my face.  I hovered for a minute more and meditated.  I wanted to relax and prepare myself for passing the restriction a second time in zero visibility.

I descended back into the restriction and got a little stuck.  After a couple of seconds of fidgeting I popped out the other side and a wave of relief washed over me.

There is something exponentially more terrifying about following someone in extremely restricted silty cave then leading into that same environment.  All I could see was waves of silt coming down the slope, I had no idea where we were heading.  It ends up that Patrick surfaced just ahead of me in Cenote Azteca.  The last jump we made wasn’t to Pabilany at all.  We had missed the jump to Pabilany.

Once Patrick came through the restriction we gave each other the fist and started our return swim.  Our short stint up to Cenote Azteca didn’t use much gas, maybe a couple hundred PSI out of each tank.  So when we arrived at the T, we decided to check it out.  We swam north at a leisurely pass.  The cave was bigger and relaxing.  We passed over at least one jump and finally turned the dive at a single tank no-mount restriction.  We were nearing our turn pressures so we didn’t attempt the restriction.  When we reviewed the map we discovered we were in First Hope.

The trip home was flawless and we used less gas then on the trip in.  When we reached the O2 we had 90min of NDL, which was a comforting discovery.  Patrick and I both found the dive very satisfying.  It included sidemount cave, scootering, no-mount restrictions, and some very beautiful cave.  Our gas planning worked like a charm and gave us additional flexibility in the execution of the dive.  The only shortcoming was that we didn’t find Pabilany, though it did result in the happy accident of finding Azteca.

Patrick and I are happy to announce a HUGE success at The Pit.  After a lot of deliberation yesterday morning and discussions with our partners, we decided to make a single alpine attempt at pushing the end of the line at The Pit.  We came to the conclusion that using the habitat and support was too much of a burden and elected to go to the end of the line with one scooter each, no support, zero VPM-B conservatism and limited bailout.  We decided to not use bailout after we realized that loading 35 tanks into the jungle was more of a risk then the possibility of bailing out.  Additionally, we recently perfected the team skill of CCR buddy breathing.

On Tuesday morning, we packed up our gear and headed to the dive site about noon and were in the water at 1PM.   The decision netted a significant addition to the end of the line.  We are still tabulating our survey data but it looks like we added more then 1500ft of line.  The dive took us about 7.5 hours using 7/70 for diluent.

I want to thank our significant others for supporting our effort and the rest of the team for not standing in the way.  The dive was a huge success and will serve as a model for future dives at The Pit.

If you are interested in learning CCR Buddy Breathing, I can make a video of it available to you directly for $4USD per copy.  In a couple of weeks, we will write a full article on our recent success and we will be posting our raw survey data on line in the name of safety and future dive planning.  We expect Jill's Chamber and Next Generation Tunnel to be a popular dive site with the launch of the new Mark 6 Technical CCR.

Note: This was an April Fools Day post.....  Your milage may vary.

Hello trusty readers!  This week I find myself in South Florida with Andrew Driver of Blue Foot Diving.  I am here for 5 days of wreck diving.   In about 20 minutes we will be leaving for the Lowarance.  It is in about 170ft of water.   The plan is to do a hot drop, swim around the wreck for 40 minutes and then deco out in the drift.  I think it is going to be a very cool dive.  I will write more about it later today.

In the mean time, while you are at work slaving away, enjoy this video by Pietro.  Pietro is a fabulous videographer and photographer in Playa del Carmen.  He is also a super nice guy!  The video is of a dive upstream from The Pit at Dos Ojos.  I think you might find the shots of the road and the gear setup interesting.  It think it provides a little perspective on the logistical challenges of diving at The Pit.  In any event, enjoy it is worth while!

Every once in a while I read about some really cool diving that is going on that reminds me how basic the stuff I am doing is.  Brain Kakuk is continuing to make headway in the Bahamas and has blessed us with a write up about exploration at Dan's Cave on Abaco Island.   Take five minutes are read about it, it got my juices flowing.

Cave Exploration in Dan's Cave on Abaco Island, Bahamas.

When you are done reading about the diving, make sure to check out his photo gallery, the formations are stunning!

Now that we have that out of the way, do you ever dream about diving?  Well, I do!  And last night I had the craziest dream.  I thought you might enjoy a retelling, it is ridicules.  So, the dream started in the middle of a dive at The Pit.  Victor, Santiago and myself were working our way into the BMB passage.  (I haven't been there yet, so I don't know what it looks like.)  In my dream, the passage narrowed down the width of two people and angled down.  Then the passage continued through a hole in the floor.   The line was run was against the ceiling entering the passage, onto the floor and then against the ceiling through the hole and it was slack.  I was the third man.  When we got to the hole, Victor was looking in trying to figure out how to pass the restriction and kept moving the line back and forth forcing me to keep crossing under the line.  This was all taking place at like 330ft in my rebreather with bailout.  To say the least, it was a little stressful.  After sometime of watching them and getting very upset about having to repeatedly cross under the line and wasting my dive time, I hit my turn time and called my dive.

After calling the dive, the dream skipped right to the point I was out of the water and laying in bed continuing to decompress, at which time I noticed I had forgotten to wear my X1 and I never set my PO2 above .4.  Actually, I realized that I hadn't ever looked at my PO2.  I decided that I must have followed Santiago's open circuit schedule and I was freaking out.  (When I woke up my jaw was sore from being clenched.)  I wanted to get out of bed to check how much deco I had omitted, though I didn't know what set points to use.  And I couldn't figure out when laying in bed had become part of deco.  I knew I should be bent in the dream and I kept checking my right elbow.  The dream ended with me thinking to myself that it was awesome that I wasn't bent and that I had gotten lucky.

What a wild dream!  Well, it was for me.  If you have ever had a really crazy diving dream, please post it as a comment.  If it is really long and interesting,  you can email it to me at hans@quietdiver.com and I will post it as an article.

And to tie things off, right before going to sleep last night I watched "Pod Cisnieniem" or "Under Pressure".  It is a movie (DVD) about an open circuit depth record dive by a Polish team in the Red Sea.  I got the movie from Patrick who was teaching Jacek Szymczak this week.  Jacek is the deep diver in the movie.  Watching the movie really got me amped up and I think it inspired my dream about The Pit.  I love the idea of participating in a big project like that and supporting something extraordinary.  With any luck, I will have the opportunity one day.

Unfortunately, the trailer is in Polish.  However, the DVD is subtitled in English and well worth watching. Here is the trailer for the movie:

In another coincidence, Leigh Cunningham, the deep support diver, was Patrick's trimix instructor in Egypt.  It was really cool to see his instructor in action.  I hope you enjoy the movie as much as I did!

Last week I wrote about an awesome cave dive to The Wakulla Room at The Pit.  Well, three days later, Saturday, I returned to make another try.

Over the last two weeks, I also wrote about some oxygen sensor trouble, trouble might be overstating the issue.  My 02 sensors had come to the end of their lives and needed replacement.  Unfortunately, after many hours of preparation for my dive on Saturday including staging all my gear in the water and starting my dive, I experienced another sensor failure, or sensor abnormality.

To recount the chain of events, on Saturday, 1/17/09, I went to Vaca Ha to do some cave diving on the unit.  The night before as I prepared my Megalodon, I discovered the number 2 sensor was dead, no voltage.  I didn’t think anything of it, the sensor was old and I hadn’t fired up the unit in three months.  I replaced the sensor with a new one dated July 2008, calibrated the unit and dived it.  During the dive at Vaca Ha, the number three sensor became current limited.  It wasn’t a big problem; I took the appropriate steps and exited the cave.  In preparation for my Pit dive on Wednesday, 1/21/09, I replaced the number three sensor with a new one dated March 2007.  That sensor was pretty old, but I wanted to give it a go.  Maybe it only lasts 6 months, maybe it lasts a year.  It was vacuum packed from the factory.  I calibrated the unit and went for a dive at The Pit.

During my 2 plus hours of deco I noticed the number 2 cell started to read a little lower than the other two sensors.  I checked to see if was current limited and I flushed, both checked out.  I didn’t think much of it. I assumed that the cell had come out of calibration as it baked in during the dive.  I figured, I could recalibrate the unit and all would be well.  The number one and number three sensors agreed.  Since I calibrate before every dive, it would be taken care of in my next pre-dive.

And that brings us to Saturday, 1/24/09.  I had another dive scheduled at The Pit.  Again, the setup and gearing up process went very smoothly.  I was super relaxed and ready for an awesome dive.  I finished my in water meditation and dropped down the deco line to check my staged tanks.  At the surface I had a PO2 of .4.  At the 20ft station I stopped and gave my gear the “In Water Two’s Check.”  My PO2 looked fine.  But for some reason, I decided to watch my primary handset as I descended.  This is not something I normally do, usually I check the handset and my HUD periodically to confirm the PO2, but I don’t watch it.

As I approached the 70ft station to check on my 50%, my number two sensor spiked to 1.97.  The other two sensors were in range at 1.0.  I had been adding diluent (7/71) on the way down.  I stopped and hovered staring at the handset trying to figure out what I was looking at.  I watched the PO2 fall on the number two cell from 1.97 to .8, while the other two sensors held steady at 1.0.

At this point I made a mistake; I didn’t flush the unit and put a known gas in the loop.  I just stared at the numbers trying to figure out if I should go for a dive.  Luckily on at least two separate occasions in the past week, I flushed the loop instinctually.  This time due to some mental twist, it never even crossed my mind. I think because it was so near the beginning of the dive and I thought I knew what should be in the loop.  The truth is I had no idea what was in the loop!  I wrongly assumed that I started the dive at .4, maybe I started the dive closer to 1.0.  I really didn’t know at that point, and what is worse is I didn’t know that I didn’t know.  I thought I knew.

After less then 1 minute, I decided to call the dive.  I couldn’t see going for a 4 hour 350ft cave dive with a unit that may or may not be broken.  I decided that when I surfaced, I would replace the number two cell again and try and go for another dive.

When I surfaced four minutes later, I hoisted the unit out of the water and changed the number two sensor with a brand new one.  I fired the unit up to calibrate it and the brand new sensor read 9.4mv.  I stared at it for a minute and realized, I couldn’t remember the proper range for an oxygen sensor.  My sensors had always started above 10mv, and that was my mental low limit.  I asked another CCR diver, Victor an Evolution diver, and he told me 8-13mv was the acceptable range, though I wasn’t sure if that same range applied to the R-22D sensors.  Later, I found out that the sensor was in range.

I decided against diving that day.  It was unfortunate that I couldn’t remember the proper range because I would have been able to continue my diving.  It amazes me how the smallest issue can sometimes put a dead stop to something that took hours and hours to prepare for.  It was a case of not being sure of a fundamental piece of information and paying the price.  In any event, I had hit my limit for the day.  Jorge and I packed up the gear, waved to Santiago and Victor and headed back to Playa for an afternoon on the beach.

The next day I called Patrick Widmann and Andrew Driver to discuss the sensor issue.  The very first thing they both did was give me a good flubbing for not flushing the unit.  The lesson is, know what you are breathing and don’t assume.  It was a good reminder that at any point in the dive, I may need to flush the unit to determine what gas is in it.  It may save my life.  As a result of my discussions, the sensor that spiked has been pulled from service. I am going to take it with me to Florida and put it on a cell checker.   The 9.4mv sensor is going to stay for now; however, I am going to watch it closely.  The bull got me.

A solo trimix CCR cave dive to the back of the Wakulla Room.

After our dives at The Pit in October I was pretty rattled about deep diving and CCR diving.  During those three days at The Pit, I lowered my rebreather into the water with the BOV open, twice.  The first time I know I made a mistake and luckily only suffered a little water in the loop, not enough to cancel the dive.  The second time, I double checked the BOV was closed before I lowered it.  After twenty minutes, I noticed the Megalodon was floating kind of funny.  When I checked it, it was flooded bad.  The bottom of the can was full of water and the sorb was shot.  I called my dive that day due to "technical difficulties" and waited on the surface for Patrick.  When he returned in pain, I got rattled.  The combination of making a very pedestrian error, one which I was taught not to make in basic CCR, twice and then seeing Patrick injured me, just put me off CCR diving and deep diving all together.  I just wasn't sure I was cut out to play at that level if I am going to make basic mistakes.  I spent some time considering selling the rebreather and just diving open circuit.

I didn't dive the CCR for a couple of months and concentrated on sidemount/survey diving.  I gave myself some room to rebuild my confidence, see Patrick's outcome and to get some distance.  Finally, with Patrick back in the water and the season for deep diving returning I thought it was time to get back in the saddle.  I had a choice, I could dive the rebreather or get rid of it.  No reason to have it sitting in the corner depreciating.  I decided to dive it with a renewed focus on checking everything twice.  I started with a couple of dives at Vaca Ha.  Both of those dives went very smoothly and I was really stoked to be back on the machine.

Then Victor & Santiago told me they would be doing a week of deep diving at The Pit and asked me if I wanted to join.  I thought, "This will be good."  It will be a chance to get back to The Pit and concentrate on myself.  Victor & Santiago would dive as a team and I would dive solo.  Learning from our October experience, I hired a sherpa, Jorge, to do the heavy lifting.  He would be responsible for raising and lowering the tanks and moving them from the truck to the water and back, which was an excellent investment!  The three of us split the cost of the sherpa and it was the best 80 Pesos I have spent in a long time.

The two days before the dive were filled with the typical work: planning, blending, and double-checking gear.  The rebreather needed a new #3 cell so that went in and was calibrated.  The gases were mixed: 10/60 for bottom and 5 different blends for bailout.  Tuesday night was spent poolside doing bubble checks and assembling the gear.  The tanks were loaded into the 4Runner and the rebreather was assembled.   I cut my dive plans and hit the sack calm and ready for my dive.  I was in bed by 11:30.

Jorge arrived at 7AM on the dot and we loaded the remaining gear and Chico, my Black Lab.  We were on the road by 7:30AM.  It is really amazing how much smoother things go without 3 other divers involved.  Normally, it would take us and hour to get loaded and out of Playa.

We arrived at The Pit by about 8:45.  Jorge and I set to work.  In short order the tanks and rebreather were in the water.  As soon as the rebreather hit the water, I jumped in and checked it.  Everything seemed to be sealed up nice and tight.  About 9:30, I had my wetsuit on and I was in the water.  I kited up and pre-breathed the machine.  I played the dive over in my head a couple of times.  Everything was going so smoothly, I was very happy.  Once everything was on and I was comfortable, I lay back in the water and did my five minute meditation.  I cleared my mind and took nice long deep breathes and listened to my heartbeat.  I could hear it slowing to a nice rhythm.

When the five minutes were up, I waved to Jorge and calmly dropped down the deco line.  At 20ft I stopped and checked the O2 bottle, it had pressure and was off.  Then I dropped down to the 50% and checked it, though I checked it more thoroughly.  I noticed something strange, it only had 2500PSI.  The 50% should be full I thought to myself.  The 02 is the bottle that was short.  Then I looked at the MOD sticker and I realized that I was looking at the O2 bottle.  It was at the wrong depth!  I thought to myself, “Damn it!”  I unclipped the bottle and ascended to the 20ft station.  I swapped the bottles, reconfirming them and then dropped back down to deposit the 50% at the right depth.  All this was handled in the span of a couple of minutes; however the clock had started to run at that point.

I am very glad I checked the tanks before I left.  In the past, we lowered the tanks and assumed they were fine.  It would have been a nasty surprise to arrive at the “50%” and find that I was looking at a bottle of 100%.  Without in water support it would have been especially problematic, because it would have required that I break my ceiling by 50ft to retrieve the 100% while breathing the 30/30.  I know I should have enough gas to deal with the situation, but the fact is it was avoidable and in fact was avoided by double checking the gassed at the deco stations.  During stage class and deco class we are taught to check and recheck the gas we are breathing, the same lesson goes for staging gas on a deco line.  Another lesson learned.
With the gases at the correct depths, I left for my dive.  I started to make up for lost time, though I arrived at the 150ft stage depot a minute late.  By the time I got to the 220ft way point I had slowed my swimming to limit my exertion I let go of the fact that I was late.  I was still a half minute behind.  I arrived at the By-pass and felt great.  The cave is awe inspiring; the scale of it is really remarkable.  The Cardea Passage and Wakulla Room are huge, both wide and tall.

I swam through the By-pass and beyond my previous distance.  This trip I had some time to really enjoy the Wakulla room (Map of The Pit by Nick Toussaint).  I had scheduled 20 minutes for my deepest segment, so I just took my time.  At 15 minutes I arrived at the second T in Wakulla.  I thought for a second trying to remember the way to BMB, I took the left, a moment latter the line drops off towards the BMB.  I had reached my distance goal, but I still had time.  I decided to drop down and try and catch a glimpse of the BMB.  I got down to 317ft at minute 18, two minutes ahead of schedule.  I stopped and peacefully enjoyed the moment.  All of the anxious excitement of my first dive to Wakulla was absent.  By minute 19 I had turned and was heading out, by minute 24 I had exited the By-pass and started my ascent.

The ascent was super peaceful; I was really stoked about my progress and execution.  I had about 2 hours of deco ahead of me and I wasn’t dreading them.

I arrived at my 40ft stop around 11:30AM.  I could see Victor & Santiago getting into their gear.  I was really excited for them; I hoped they would have a great dive.  While I was on my 20ft stop, another team came up from the deep.  After some puzzling, I thought I recognized the diver in doubles, it was Dennis from Aquanauts.  It was nice to see him.  We exchanged glances and hand gestures to pass the time.  At minute 164 my dive was over, I was floating on the surface chatting with Dennis.  It was an awesome dive.

I floated around for 30 minutes just relaxing.  I pulled off my CCR and got it read to lift.  Jorge, with some assistance from Dennis, lifted the CCR and the tanks.  What a luxury to have help.  Jorge and I cleaned up our mess waiting for Victor’s team.  We got them out of the water and squared away.  Jorge, Chico and I headed for home around 3PM.  It was a fabulous day of deep diving.  Almost everything went right and I had a huge amount of fun.  The pay-off was huge for the effort.  With any luck, I will be back there in 4 days to give it another go.

Of course, no dive is executed by only one person.  I want to thank Jorge for his time, he was a life saver.  I want to thank Patrick Widmann from Protec for mixing up some excellent Trimix and loaning me his deep bailout.  I know I need to blend my own.  I want to thank Santiago and Victor for having me a long.  And I want to thank Chico for being the loving attentive friend that he is.

And as a closing treat, a friend forwarded me this video from YouTube.  I thought was great, though unrelated to diving.