Cave Diving, Cave Exploration and Cave Mapping in Yucatan, Mexico
Gran Cenote, Tulum Mexico

Category — Equipement

Back on the loop

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.

Patrick Widdman on DPV and CCR

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.

Howard pushing a tank through....

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!!!


July 25, 2009   4 Comments

Interview with Steve Bogaerts: Part 3 of 3

In February of 2009 my wife and I got pregnant with our first child, which is a wonderful joy as we were trying.  The pregnancy set off a chain of events which resulted in us moving back to the United States.  Well, that move created mass chaos in my life and the fact of the matter is I just didn’t have the bandwidth to maintain the blog.  I was busy moving, buying furniture, going to the doctors and getting my life restarted.  Luckily, some of the insanity is dying down and I can get back to some of my recreational activities like blogging.

Before we get to the third part, I want to thank Steve for being a wonderful instructor and for taking the time to participate in this interview.  His responses were well thought-out and I think will help people when they are considering instructors.  You can find Steve’s new web site at:  So, without further adue….

I asked, “You have a new harness on the market called the Razor, what can you tell us about its development?”

Steve answered, “Well as they say “necessity is the mother of invention”.

I originally designed the Razor Harness for use on Side-mount / No-mount exploration dives in very restricted cave where every piece of extra equipment tries to kill you.

The problem was that in many cases to get to the part of the caves where I was exploring required long penetrations using DPV’s and multiple stages thus increasing my equipment load considerably. But when I got to the area I wanted to explore I needed to be as small and streamlined as possible. I wanted some way to integrate these disparate requirements in one system.

Over the years I have dived just about every Side Mount rig on the market as well as various homemade versions.

All of them worked to a degree but none were ideal.  Like most Side Mount divers I spent a lot of time making modifications to improve the various rigs but was always constrained to a certain extent by the original design and never had a Side Mount harness that I was 100% happy with.

As my exploration dives became more and more challenging, particularly over the last few years, I started to run into the limits of both the equipment and the equipment configuration I was using.

Trying to squeeze myself into ever smaller places was pretty rough on all my gear. I was getting hung up and stuck quite often and in fact in the year of exploration leading up to the connection between Sistema Sac Actun and Sistema Nohoch Nah Chich I managed to destroy 3 different Side Mount rigs. I was running out of equipment to dive in.

I ended up making a simple No Mount harness to go under my Side Mount harness so that when the cave really started to get small I could ditch the comparatively bulky Side Mount rig and carry on No Mount.

The problem was managing all this equipment a long way back in very small cave usually in zero visibility while trying to run a line or survey.  I was spending too much time dressing and undressing while underwater a long way back in the cave and not enough exploring.

Also trying to make sure that I had all the stuff I needed on the right harness at any given moment was a problem and at various times I forgot line arrows or survey slates for example because they were attached to the Side Mount rig I had left behind me in the cave and not my No Mount harness.

Additionally having passed through a section of No Mount cave sometimes it would open back up again and then having a Side Mount harness again would have been an advantage so that I could swim more efficiently.

As well during this period I started exploring from a tiny Cenote called Por One which lay between the Sac and Nohoch systems.

Por One has a nasty no mount entrance where you have to descend down a very tight chimney in the shape of an S.

There was absolutely no way to enter wearing my Side Mount harness, even with both tanks off, so I would begin my dives just in my simple No Mount harness.

Once through the entrance the cave continued in no mount sized passage for quite a distance and often I had to crawl, wriggle and dig my way through to make progress.

Eventually the cave opened up a bit and again a Side Mount harness would have been good to have but there was no way to get my existing Side Mount rig through the entrance and beginning section of the cave.

I needed a simpler more flexible system that fitted my current, more demanding needs.  I decided to start from scratch and design a completely new harness for myself.   It had to function as both a No Mount harness and a Side Mount harness. It had to work with multiple stages and with DPV’s.   The harness also needed to accommodate a totally separate and removable modular buoyancy system.

Ideally the harness also had to meet the following criteria on my rather extensive wish list as well:

  • Small and light so as to be easy to carry on long treks through the jungle.
  • Comfortable to wear and easy to get on and off on the surface.
  • A simple design with no stitching or fancy hardware.
  • Rugged to stand up to the most challenging dives in the most challenging environments where it was going to take a beating.
  • Safe and reliable because my life depended upon its performance.
  • As low profile and streamlined as possible to allow me to fit in the smallest areas possible.
  • Easy to use in very challenging conditions.
  • Easy to adjust.
  • Easy to repair if and when it does get damaged.

Over many hours of brainstorming, lots of test diving and various “Eureka” moments in the middle of the night the Razor Harness finally evolved into what you see today.

There were several prototypes along the way but the final version that I am currently using meets all of my requirements and is by far the best and most flexible Side Mount / No Mount harness I have ever used and has made my exploration dives far more efficient and productive and safer too.

I finally have a harness I am totally 100% happy with and that level of comfort is directly translated into the difficulty level of the dives I can now undertake that I would have hesitated to do before.

After years of experience diving in Side Mount I really thought I knew what I was doing but the last  few years spent experimenting with the Razor Harness have completely redefined my approach to, and philosophy of, Side Mount diving.

It has been like an evolution for me and I feel like I have learned so much and become a much better Side Mount diver along the way and that has been a really enjoyable experience.

I soon realized that if it worked so well for me then the Razor Harness would work just as well for other divers as well.

I started teaching all my Side Mount students in the Razor Harness and noticed a dramatic improvement in their skills, abilities and comfort as well.   Their pace of learning accelerated considerably.

One of the best ways to really understand something is to teach it to someone else.

Teaching other divers to use the Razor Harness really forced me to think deeply about, and refine, all the skills sets and procedures and this has been a really helpful process for me personally as well as a lot of fun.

The current system I teach is the distillation of all that trial and error. That experience refined and streamlined equipment, skill sets and procedures.

Each of the components in the system is designed to fit together seamlessly and work as part of an integrated whole.  The Razor Harness is at the heart of this system and is the foundation of all my “Bogarthian” Side-Mount procedures.

My philosophy is holistic in approach and is designed from the inside out so that as additional layers of equipment are added there is no change in the core equipment, equipment placement, procedures or skill sets.

“Less is More”

The Razor Harness itself is simplicity and elegance personified with only 2 continuous pieces of webbing and 1 closure point.  It is simple, strong, rugged, reliable, low profile and extremely minimalist in design. It fits like a glove and is very comfortable to wear.  The Razor will fit anyone no matter what their physical size or shape and is quick and easy to set up and adjust so that each individual diver gets a custom fit using standardized hardware.  It can be adjusted at several points to ensure the optimal fit for each individual.  All the attachment points such as D rings on the Razor Harness can be adjusted quickly and easily to allow personalized positioning of equipment placement.  Extra attachment points can be added easily if required.  Weight can be added to exactly where you need it on the Razor Harness to optimize trim.

You can easily use any BCD you want with the Razor Harness either wing or jacket style or no BCD at all if using a Drysuit or light tanks and lung volume.

The beauty of not having an integrated BCD is that you can add whatever level of buoyancy is required according to tank size & material, total equipment load, environmental factors, exposure suit type etc.”

I asked, “Are there any other related developments on the way?”

Steve answered, “Yes I am currently working on a modular buoyancy control system specifically to go with the Razor Harness.

When I first started using the Razor Harness I was diving it without any kind of BCD, controlling my buoyancy with just lung volume.

That worked out okay just diving with 2 AL80 Side Mount tanks although at the start of the dive, when the tanks were full, I had to dive at the top of my lung volume and it did not really become comfortable until the tank pressures dropped 500psi and the tanks became a bit lighter.

I really needed a small amount of lift to compensate for the weight of the gas in the tanks at the start of the dive but did not want to add a large and bulky BCD.

In one of my “Eureka” moments I decided to try out a 2l Camelbak hydration bag that I had lying around as a BCD. The 2l volume gave me 4.5lbs of additional lift.

I wrapped the Camelbak horizontally around my lower back over my Razor Harness and held it in place by attaching a bungee cord to one side, running that around my waist and through the front loop of my crotch strap and clipping it off to the other side of the Camelbak with a small snap bolt.

I inflated it orally through the bite on mouthpiece of the drinking tube and dumped air out of it by pinching the mouthpiece between my thumb and forefinger while holding the drinking tube up.  You can also suck the air out of it if you want to really empty it or are in an orientation where dumping will not work.
This is a real advantage when I find myself head down twisted like a pretzel in a restriction!

The concept was so simple and yet it worked fantastically well.  I called it the “BAT Wing” which stands for Buoyancy And Trim Wing.

The BAT Wing is designed to be worn over the Razor Harness. In my opinion sandwiching the BCD between the harness and the body is not ideal for the following reasons:

  • You cannot remove the BCD underwater.
  • The harness restricts the BCD.
  • You need to use a bigger BCD to cope with the reduction of usable volume.
  • The harness may cause air trapping in the BCD making control of buoyancy, trim, gas dumping etc more difficult.
  • Inflating the BCD restricts the harness.
  • When the BCD is inflated it can make the harness uncomfortably tight.
  • If you leave the harness loose enough to allow comfortable BCD inflation the harness will not be as snug and streamlined as it would otherwise.
  • Layering BCD’s for redundancy is more difficult and compounds all of the other issues above.

The most important reason for me to have my BAT Wing over my harness is the ability to easily and quickly remove/replace it underwater while diving if necessary.

Having the buoyancy so low down on my body was the ideal position to help maintain horizontal trim and the fact that it is so close to my center of gravity helped to optimize control when changing orientation in the water.

The BAT Wing is positioned in the small of my lower back and the super low profile meant that I could enter very small areas of the cave with no problem at all.  If needed it was very simple to remove the BAT Wing underwater as it was worn over the Razor Harness just being held in place by a single small bolt snap.

When I got to No Mount areas I could either take it off altogether and leave it behind or wrap it around my butt mounted tank to get it neutral and make towing the tank easier.

When I get to No Mount areas I have 3 options; leave the BAT in place but suck all the air out of it to minimize the profile, take it off altogether and leave it behind or wrap it around my butt mounted tank to get it neutral and make towing the tank easier.

I quickly upgraded to a 3l version that gave me just enough lift (6.6lbs) to dive with a single AL80 stage in addition to the AL80 Side Mount tanks.

I have recently upgraded again to using the MSR Dromedary Hydration Bags instead of the Camelbak’s as they are better made, more rugged and durable and come in a larger range of sizes 2L, 4L, 6L and 10L.

The beauty of not having an integrated BCD is that you can add whatever level of buoyancy is required according to tank size & material, total equipment load, environmental factors, exposure suit type etc.

I am currently using a 2l for No Mount dives, a 4L for Side Mount single stage dives and a 6L for Side Mount multi stage dives.

In addition it is very easy to layer the bags one on top of another for redundancy.

While this system is very, very good I have a few ideas that I hope will improve it further.

At the moment I am in the process of developing a commercially viable modular BC system along the same principles specifically for the Razor Harness and hope to have something available very soon.”

July 15, 2009   3 Comments

Update to My Cave Diving Helmet

About a year ago I wrote my original Cave Diving Helmet article.  Since then my diving has rapidly evolved calling for ever more refinement in my helmet.  Following are some photos of two revisions of my helmet.  The photos with the yellow backup lights is what I call revision two.  It was sufficient for sidemount diving.  I used it to do a bunch of survey and 100 sidemount dives.  It was still a little too bulky and presented a lot of drag.

The photos with the single light head holder is revision three.  This came about when I started to scooter deep cave with my CCR and realized I needed the minimum amount of drag and tightest fit to stop the helmet from moving when I was zipping along.  Additionally, I learned that my backup lights interfered with my T pieces on my over the shoulder counter lungs.

The things to notice are:

  1. I changed the shape of the helmet by slicing it down the middle and clamshelling it.  It sits very tight to my head now and doesn’t move at all.
  2. I got rid of the flimsy black PVC and created a nice new holder out of white pvc.  I also created some wedges for adjusting the focus of the light for scootering.  Also, I rounded the edges of the PVC to allow easier insertion of the light head.
  3. The teal helmet is the original helmet, I have a backup encase I blunder when cutting.  You can see the difference in fit and shape.  And a serious lack of holes.
  4. Like all things in cave diving, my helmet and my needs have gotten very specific.  For CCR, I need one light configuration.  For sidemount/survey/exploration I need a different configuration.  I have not reconciled how I am going to switch back and fourth.  Maybe the teal helmet will fill one role and the purple one the other role.
  5. I am migrating away from the SL4 LED lights to the Intova light.  Having 8 C-Cell batteries on your head is heavy.

I think that is all, just wanted to write a quick article.  Enjoy and I look forward to you comments!

March 24, 2009   3 Comments

Surveying While Cave Diving is Difficult

Alain and I spent the day developing a protocol for team tape survey.

On Friday, Alain and I spent the day working on protocols for team tape cave survey.  It was Alain’s first attempt at underwater cave survey and it was my first attempt as part of a team.  When I took my survey class, I learned solo knotted line survey (KLS).  A knotted line survey is the process of using a knotted guideline to measure the data needed for the survey.  For those of you who haven’t surveyed before, here is the simplified process:

  1. Talk to locals and dive a lot.  Eventually a good project will come to mind.  Do some test diving to make sure it is a meaningful project, get permission, and create a plan.  If you need a team to do the work, recruit them and train with them.  And before you start, check your motives.  (This one I got from Matt at Protec).  Ask yourself if the exploration is for your ego? Does it contribute to the cave community?  Are you going to follow through and give back to the community?  How much impact will it have on the cave?  Does the data exist and can I collaborate to minimize risk and impact?  Remember, exploration and survey is a high impact activity and conservation needs to be a close second only to safety.
  2. Sitting at home or in your refrigerator box, use a knotting machine to put knots ever 10ft in some guideline.  This is the really tedious part.  Spool the knotted line onto your reel.  My exploration reel holds about 600ft and my exploration spool holds about 250ft of 18guage twisted nylon line.
  3. Make some survey slates.  A survey slate has a compass and 4 columns for data:   depth, distance, azimuth and comments.  I attached my compass directly to the survey slate.  Trident makes these great slates that are 6in x 8in and have a nice slot for a pencil.  I choose to use a Suunto M3 compass  it has +-2 degrees of accuracy which is the minimum required for the grade survey I am interested in.
  4. Put all the stuff and your teammate in your vehicle and go diving.
  5. Once on site and to the area of cave you want to explore, install some guide line.  When you lay it, make sure you have nice straight level shots and the line isn’t kissing off anything.  Also make sure it isn’t a risk to other divers.  Installing the line is critical; if you do a lousy job here the rest of the job will be very difficult.  My advice is to spend a lot of time looking at existing lines and analyze their placement and their impact on the cave and the dive.  Do they look easy to swim?  Are they safe?  Can they be surveyed?  Then practice putting line into benign situations.  A tight or pristine spot isn’t the place to learn to lay line.  Be prepared!    I have heard some funny stories from Steve about him finding reels and lines that were obviously left by someone who had gotten in over their head.  And remember, take your time and enjoy yourself.  The joy is in the journey.
  6. This is where you have a choice, conditions permitting and gas permitting you can survey the line you just put in on the way out.  Or, if you don’t have the gas or conditions are too nasty, you can exit and survey the new line on another day.  Collecting the data and staying alive are critical to the success of your project.  Drowning with a slate full of survey data is stupid and will curtail any further exploration. We witnessed this recently in Ginnie Springs and it was really sad.  It impacted me and everyone else in the cave diving community, whether they realize it or not.To collect the data you need to record the depth, distance, azimuth and notes at each station.  There is a fine balance between precision and speed and as you practice you will get faster.  I am still pretty slow and I make minor mistakes pretty regularly.  Usually those mistakes are a couple of degrees one way or another, I forget to write a number down such as 16 instead of 163, or I loose count when counting the knots.  Minimize your mistakes by taking your time.  Resurveying kind of sucks and robs you of time to make real progress.And now we have come full circle, it is called a knotted line survey, because you are counting the knots between stations.  When you get to a line segment that doesn’t span two knots you use arm spanning to estimate the remaining lengths.  I know the length of my forearm, tip of finger to tip of finger and tip of finger to the middle of my chest.  Using this method I can get 95% of my data within 1ft of accuracy.
  7. At the end of the dive, immediately record the data from the slate to a notebook.  Slates have a way of loosing data by getting erased or rubbed off.  I have already lost data to this villain, you don’t need too.
  8. When diving is done for the day, I go home and enter the data into Compass.  Compass is a cave mapping program.  If I have GPS coordinates, I place the new survey into Google maps so I can see my relative progress.
  9. Rinse and repeat as necessary.

What I just described is greatly simplified and doesn’t really capture the difficulty or investment required to do a survey project.  Please do not use my instructions to go out and start a survey project.  I suggest that you seek training or mentoring from instructors who are experts in survey/mapping and actually do it themselves.  There are MANY tricks and ways to make it more efficient and I can’t really imagine learning to do it on my own.  Survey is the essence of tasking loading and perceptual narrowing.  I think it could be described as a right brain activity and it can blot out your sense of time and reprioritize things for you.

Moving right along, I learned to do KLS solo so I didn’t really have to deal with any of the complexities of communication or team logistics while surveying.  Recently, Alain and I decided to work on a project together.  The cave has existing line and the line needs to be resurveyed so we could continue our work.  The line is not knotted.  So he and I decided to do a tape measure survey and leave the existing line.  We decided to leave the line to save the impact and time of relining.  Additionally, leaving the line in maintains some of the history of the cave.  I would be sad to see my line taken out, someone placed that line with love and care and it should be respected.  I know I enjoy looking at the arrows and seeing the names and dates.  It gives me a real sense of who was there before me.

A tape survey is when you use a tape measure to measure the line segments instead of knots.  Almost everything else I described is the same.  A tape survey is much more accurate, however it is more difficult.  It requires two people or it requires one person to swim back and fourth repeatedly.  Alain and I selected a 100ft nylon tape measure.

To begin with, Alain and I practiced our survey on dry land.  I set up a circuit and we each set about surveying it solo using KLS.  I walked Alain through the process and we each took the data down.  Then we decided to attempt a tape survey with me as diver one (D1) and Alain as diver two (D2).  We decided that D1 would swim the end of the tape out and fix the guideline as he made progress.  When he reached the next survey station he would signal diver one with a BIG X.  While D1 swam away, D2 would take the depth.  Once D2 received the X, he would take the distance and the azimuth.  After completing the circuit, we switched position and tried it again.  We neglected to create any other signals.  I bet you can foresee what is going to happen. We were happy with our progress so we entered the water.

For Friday’s surveys, Alain was D1 and I was D2.  We planned to survey into the cave and we started at the beginning of the line.  The line at this location starts in 20ft of water and then drops down to 40ft and into halocline. It runs for about 300 feet at that depth and then rises out of the halocline.

Alain and I got the first 2 stations pretty easily.  Then we got into the halocline and I realized that light signals just were not going to work.  I couldn’t tell when he was giving me an X.  And I couldn’t signal to him that I needed to repeat the distance measurement.  Work really slowed down at this point, it was a real trial by fire.  Our communication protocol was short a couple of commands.

The first dive provided many excellent lessons.  I learned that we would need to develop a protocol for communicating through the tape.  I also learned that the process was going to be pretty slow and our SAC rates would be much higher as we settled into the new level of task loading.

On the first dive we collected about 500ft of survey.  It took us 54 minutes surveying and we only penetrated about 10 minutes into the cave.   At 54 minutes we both hit our thirds and had to call the dive.  Our gas consumption was through the roof while surveying.  I can tell you that I was stiff in the water and tense all over.  I could see how I was burning through the gas.  Plus, I was paying attention to surveying and not my breathing.  Luckily, surveying in adds conservatism to gas management.  I survey much slower then I swim, therefore if I use a third surveying in, I should use a 1/6 or less to swim out.

During our surface interval we worked on our protocols for communication.  We developed a system to communicate through the tape.  I also developed signals to ask him to repeat the tape measurement.

For the second dive we swam to the end of the first survey and started surveying.  At this point the cave got much smaller and the condition and placement of the line deteriorated.  The new signals worked out great.  We were a bit more efficient but covered less ground due to the conditions.  The second survey only netted about 300 feet of data.  I was still really stiff, but at least I was aware of it.

When I got home Friday night, I fired up Compass and put the data in.  The stick map started to come together.  I spent a couple of hours and learned how to put the stick map into Google Earth which was a real thrill.  The stick map super imposed on the satellite photos really pumped me up to go back and collect more data.  Overall it was an excellent day with a great dive buddy and friend.  We laughed a lot and got to improve our skills, you really can’t beat that for a Friday.

November 23, 2008   5 Comments

A Tattoo, A DPV and Another Way to Waste Your Employeer’s Time.

It is good to be back in Mexico!  I went back to the states for a week and let me tell you, it was cold cold cold.  I was wearing a hat and a winter jacket; My friends thought I was crazy.  I have to admit, my blood has gotten very thin living in Paradise.  Unfortunately, I didn’t do any diving while I was in the states, however, I did bring back some gear which was sorely needed for us to continue our deep work.   The list of new gear includes new climbing pulleys from Petzl for the lift system, a bunch of caribeaners, tank bands, regulators, hose retainers, mouth pieces and some valves.  I am feeling well stocked now.  I also finished my back tattoo. hans-back-tattoo.jpg

On Friday, I visited my friend Jay at Electric Lotus Tattoo in Boonton, New Jersey and sat for two hours.  This was the easiest sitting yet.  The first two sittings were absolute torture.   Both sittings I was in a terrible spiritual place and exhausted when I arrived.  This time, I was spiritually centered, well feed and relaxed.  I was ready. I only got out of the chair once, about 20 minutes in to look at the first new color in more then a year. From that point on, I just sat there, ate Good & Plenty candy and drank a Coke.  I am super stoked about the art and I am glad I kept my head in the game and finished it.  There were times when I was sure I wasn’t ever going to go back and finish it.

Now on to the DPV portion of the story. After many discussions with Steve Bogaerts and Patrick, I elected to purchase a Silent Submersion N19 DPV. In the end I selected it because it was near my price range, though very expensive, and it was a known quantity. Plus, I hadn’t seen the Tahoe DPV (Scooter) Benchmarks which placed the Cuda as the pack leader for a small technical scooter.  I am still happy with my purchase, although it hasn’t been in the water.  I will have to wait a week for my back to heal before I can get wet.  The suspense is killing me. n19-closed.jpg

And now for a good way to waste some of your Employeer’s time, not that you aren’t right now.  David from Cancun turned me on to the Ejido Jacinto Pat Documentation web site this morning.  He wrote,

If want to see more photos and videos of Nicolai and Gang check this “old site”

There are some interesting dive reports about Nahoch Na Chich and Dos Ojos check it out and let me know what you think!

I hope to get back to diving the first part of next week.    In the mean time, we have an article coming from Patrick about his DCS and another article about me not passing my multi-stage course.

November 12, 2008   1 Comment

Cave DPV with Steve Bogaerts

Editor’s Note: I want to apologize to my readers.  I posted this story in the middle of the night with some errors.  Particularly, I got my sac rate calculations wrong.  I checked my notes today and discovered I used more gas then I first thought and I checked my X1 average depth and realized I was using a deeper depth then it recorded.  — Hans

When I arrived in Mexico last winter, Steve Bogaerts and I developed a rough plan for my training. The training would include: Basic Sidemount, Advanced Sidemount, Cave Survey, Cave DPV, Stage/Multi-stage and CCR Hypoxic Trimix.  As of today, the only class I have left is stage/multi-stage.

We planned to spread the training over the course of a year and to pace it based on my progress.  My progress would be reflective of the number of dives I complete and the focus I put on practicing.  I am glad that I am a little ahead of schedule.  Today, I finished my 12th training day with Steve and we completed Cave DPV.

The Cave DPV course was a lot of fun.  I wasn’t as difficult or as stressful as some of the other courses, such as Advanced Sidemount.  Riding a scooter is like flying.  It is super cool to zip through the cave.

The DPV course took three days. The first day started with three hours of lecture.  We discussed:

  • Why to use a scooter
  • Safety issues
  • Gas planning
  • Emergency procedures
  • Team dive execution
  • Staging the scooter
  • Choosing a scooter
  • Batteries
  • Charging
  • Conservation
  • And a host of other topics.

After the lecture, we broken down Steve’s Silent Submersion UV-18 DPV and prepped it for diving.  The prep went something like this:

  1. Check the voltage of each battery. (13+ volts)
  2. Check the voltage of the combined batteries. (26 volts)
  3. Inspect and clean the o-ring and sealing surfaces on the motor end of the scooter.
  4. Inspect the motor compartment through the window.
  5. Ensure the cap is secure on the motor compartment.
  6. Attach the battery.
  7. Check to make sure the propeller is clear and the trigger is locked.
  8. Plug in the main connection.
  9. Plug in the secondary connection.
  10. Test the motor for less then three seconds.
  11. Attach the body of the scooter.
  12. Remove the nose cone, inspect and clean the o-ring and sealing surfaces.
  13. Disconnect the secondary plug for transport.
  14. Install the nose cone.

After a couple attempts, this ritual it becomes second nature.  I found it was best to work from the bottom of the scooter up.  If the scooter isn’t on a flat surface, like in the jungle, make sure to flip it over on the nose cone before testing the motor.

We also discussed predive check and break down of the scooters.  I am not going to give you all the procedures, because you will learn them when you take the course with Steve.  About noon, we got the gear loaded in his truck and we headed towards Tulum.  In Tulum, we stopped at Xibalba Dive Shop and picked up another UV-18.  I repeated the prep procedure and loaded the DPV in the truck.

Our first dive was at Cenote Car Wash.  When we arrived the water was tea colored.  I guess with all the rain we have been having, the swamps are unloading tanic water into the Cenote.   The first thing I needed to do was to get my scooter trimmed and weighted properly.  Steve walked me through the process and provided some helpful tips.  He recommended that DPV should be slightly positive with the nose slightly up.  If I was going to spend a lot time below the halocline then I should set it up a little negative at the surface with the same trim.

I was doubtful due to the limited visibility; however as soon as we descended we broke into clear water.  It was like coming out of the clouds.  The tannic ceiling provided a virtual roof and looked exceptionally cool.

We started off by doing figure eights and driving around.  Immediately I noticed how easy it was to manage this scooter.  I had driven a bunch of scooters including UV-18s and always felt awkward and hated it.  I felt like I was fighting the DPVs and I would be exhausted before we finished the dive.  This DPV was different.  It was balanced and I didn’t really have to hold the handle.  I could set the trigger lock and finger it.  I couldn’t believe it.  I had arrived.  It made scootering so much easier.  I just didn’t know it should feel this way, I figured you always had to fight them.

After I got over my euphoria, we moved onto staging drills, lights out touch contact and team communication.  After a couple of hours in the water we headed back to Steve’s place to break down the DPVs and charge them.

The second day we went to Ponderosa.  We made two cave dives.  We practiced installing/removing the primary reel, staging the scooters, team communication, low on air (tank swaps), exit on secondary light, zero visibility touch contact and other skills.  The first dive I wasn’t all that confident and kept stopping to wait for Steve to catch up.  This repeatedly broke rhythm and I blundered the scooter stage procedure.  I had forgotten the hand signals and couldn’t figure out what he was asking me to do.  After a minute or two of watching him do them louder, it came to me and we carried on.  The debriefing was insightful and to the point.  After diving we went back to Steve’s place, broke down the scooters and burn tested mine.  I had 7 minutes of burn time left.

Today, we went to Chac Mool.  Chac Mool is a big power cave with the largest known underwater stalactite.  It is about 90ft tall.  It is a 30 minute (1500ft) swim from the entrance.  I normally use about 42cuft of gas to reach it.  It is about the perfect scooter training dive because it provides an excellent benchmark to test again.  On the scooters pitched at 5 we reached the Monster in 14 minutes.  This included me bumbling with the reel and getting the tow strap entangled around my sidemount tank.

My swimming sac rate, in sidemount gear, is a .7 cuft/min.  I ran some calculations for my swimming dives to the monster and came up with .66.  Tonight, I calculated my sac on the scooter and was surprised to learn that my first dive was a 1.5 and my second was a .97.    Both of those are pretty hideous and leave huge room for improvement.  I think the task loading with the scooter during the installation of the primary reel really afected my sac rate.   I am definitely going to go and make some practice runs with the scooter to try and improve those figures.

A great example of the differences in our sac rates was our gas consumption at Ponderosa.  We scootered the River Run to the change in direction in the line arrows.  It took us just shy of 20 minutes.  In that time I used 450psi out of each tank and Steve used less then 200psi out of each tank.  I was shocked when he handed me his tank and he had used 200psi, I couldn’t believe it.

Besides keeping close track of our trigger time and gas consumption, we towed and towed some more.  Which is good because towing efficiently is harder then it looks.  Being towed is challenging because you have to stay out of the wake, control the scooter between your legs, maintain orientation to the guideline and not annoy your buddy.  Towing is challenging because you are like a semi truck moving through the cave. A semi truck with a failing tail that is apt to hit things if you are not careful.   It is like dragging a plow though the water. This is another skill that could use practice.

At the end of the day we headed back to Steve’s house to break down the scooters and burn test mine.  The burn test went 17 minutes and the Watts Up Meter showed we had 4ah remaining.  This correlated nicely, because the UV-18 has 16ah batteries and I had recorded about 60 minutes of trigger time.  That means we had about ¼ of the battery remaining and the total burn time would have been 77 minutes, which is in the middle of the 45-90 minute range.

Overall the course was a blast.  I really enjoy working with Steve.  He does a lot of this diving and spends a lot time thinking about the procedures.  Luckily, they are born of direct experience and you can feel that as you put them to use.  They just work.

I am glad to be qualified to use scooters now.  They will be an invaluable tool at The Pit.  I already have some other dives in mind.

Tomorrow, I start the stage/multi-stage course.  Since I dive in sidemount, we will do it in sidemount.  Hopefully, on Friday I will have something entertaining to report [Read more →]

October 8, 2008   7 Comments

The Trimix Odyssey

Becoming a Trimix Rebreather Diver with Andrew Driver of Blue Foot Diving

On May 17, 2003, I was certified as an Advanced Open Water diver.  The following Christmas I got “The Last Dive” from my in-laws and I read it cover to cover on Christmas day.  My in-laws thought I was nuts, maybe I am.  I purchased every narrative I could find on deep diving.  Each story deepened my interest; the characters and the dives captured my imagination.  Allie noticed all the books and asked me if I was interested in diving the Andrea Doria?  She wanted to know where this was going.  I admitted was and I estimated it would take me five years to reach the that level.

When I made the decision to pursue deep diving, I had a couple of principles in mind:

  • Be safe and take it slow.
  • Maintain a positive mental attitude.
  • Be young enough to be fit to not hazard my health.
  • Do it using a rebreather.
  • Seek the best instruction possible from a range of instructors.
  • Ensure my wife understands what I was doing and the risks involved.
  • Surround myself with people who would guide me and help to pace me.

Five years later, I have executed just shy of 500 safe dives. 350 of those dives have been technical dives, either North East Wreck Diving or Cave Diving.  Eighty of those dives have been with my Megalodon rebreather.   In January, I moved to Mexico for diving. I started running 3.5 miles three times a week and going to the gym.  And I have continually sought training from some of the top instructor in the world.  All this culminated in a trip to the United States to take my Rebreather Trimix Diver course with Andrew Diver of Blue Foot Diving.

Book One.  Incomplete Normoxic Trimix.

Completing the CCR (Rebreather) Trimix course has been an odyssey.  In fall of 2007 I met Joe Z., Fabrice, Eric Goldstein and Andrew in Alexandria Bay.  Our plan was to do some DPV diving and start the Normoxic Rebreather Trimix course.  I started class with 50 hours on my Meg.  We did a handful of Normoxic Trimix dives and lots of drills: High PO2, Low PO2, Solenoid Stuck Open, and deploying a lift bag.  We had a ton of fun and laughed a lot.  We visited the Islander, the America, the Key Storm, the Vickery and the bow of the Jodrey.  Max depth on that trip was 197ffw.  Of course we got to spend time with Mo Hunt.  Mo is a local legend who has been diving for 55 years.  They were all awesome dives and I learned a ton.  Hanging around with people like Eric, Joe Z. and Fabrice is amazing.

Andrew’s style of teaching is to teach as you do.  Consequently, most of the lessons are very practical and are derived straight from experience.  He has two philosophies that really struck me, I am paraphrasing:

“People come to dive not sit in a classroom.  So, I get them out diving as fast as possible.  It gives me a chance to assess where they are at and it gives them a chance to dive.  It helps me to structure the course and helps to focus on the student’s needs.”

“If the basics are solid, the rest will follow.  With a solid grasp of the basics, situations which might have posed a substantial hazard will become second nature to identify, troubleshoot and resolve.”

These ideas are reflected in his teaching methods.  The three times I have been to Alex Bay, as the locals call it; we dived on the first day.  We hit the water, did some basic drills and started the process of getting comfortable.  I could see Andrew watching us as we did the drills; his debriefs were short and never belittling.  On the days that I looked like a spasm in the water, he told me I looked like a spasm.  We would laugh a little and then talk about what I could do better and how I could develop processes to deal with each task.  On the days I did what I was told, he didn’t tell me I look like a spasm.  I guess part of his British nature is not to celebrate when you do what you are told.   We spent a lot of time on the basics and by nailing them, the rest of the diving became easier.

Unfortunately, we didn’t plan to finish the class that weekend.  I walked away certified; which was fine, because the rest of that fall I didn’t do any diving.  Work had gotten out of control and I was preparing for my move.  I wanted to put some more medium depth dives together before moving on.

Book Two: False Starts

Before moving to Mexico, I met a fellow name Patrick Widmann.  Patrick is skinny (way skinny), a cave instructor, a deep diver, my mentor, my dive buddy and the motivating force!  Once I arrived, I learned Patrick had designs on exploring The Pit.  If you are a regular reader of this blog you will have seen his posts.  One day Patrick and I got to talking and he told me about his plans.  I thought they sounded interesting and wanted to participate.  The problem was that I was not Trimix certified and I only planned to be in Mexico for one year.  I needed a solution for both.  I went home and declared to Allie, “We need to stay for two years at minimum.  I want to explore The Pit and I estimate it would take me year to work up to it.”  Luckily, Allie agreed.

I was anxious to complete my Hypoxic Trimix Rebreather Course.  As luck would have it, there are not many instructors who are qualified to teach it on the Yucatan.  To be exact there is one, Steve Bogaerts.  Luckily, Steve is already my instructor so we scheduled the course for the end of July.  Steve did a lot of the deep exploration at The Pit on double redundant Inspiration rebreathers; I thought his practical experience made him an excellent candidate.

July started with my parents in town for 10 days.  The trip was stressful, my bed frame broke and my back went out in a BIG way.  It required acupuncture and three shots in the ass.  We elected to cancel the course because we agreed it would be a terrible idea to do deep mix diving with an inflamed back.  I guess that is where the health hazard principle comes in.  I was totally bummed, because Patrick and I had a bunch of dives to do during low season and I lost my chance to get qualified.  Luckily, Patrick and I were able to work around it and he made significant progress.

Book Three.  Don’t Change Your Configuration.

As the gods would have it, my back didn’t get better for a couple of weeks.   When we attempted to reschedule my Trimix class in September, it conflicted with the arrival of Steve’s new baby.  The next opportunity wouldn’t be until October.

I couldn’t wait any longer!  Fortunately, I had a wedding the first week in September in NJ.  I contacted Andrew and asked if he could arrange a course.  Bingo!  Andrew put a course together for three of us.  With some skepticism I packed the Megalodon in my hand luggage and a 120lbs worth of dive gear and cloths in my checked luggage and headed for the states.  Luckily, I am a frequent flier and was allowed more then one heavy bag.  I got home with zero charges or difficulties.  The only real challenge was at security in Cancun.  They closely examined the Meg, but let it pass.  Promptly, I removed the red and yellow warning labels.

When I went to my storage unit in NJ to fetch my dry suit, I discovered the neck seal had melted and the edge was dry rotted.  I put some duct tape on the seal and used it the whole week.  Amazingly, it was dry and didn’t rip.  I am eternally grateful.

When I arrived at Andrew’s house, I learned the third man had bailed out.  It was down to two of us.  Andrew loaned me some steel tanks.  I decided to invert my tanks this time.  I thought it would be easier to reach the valves, normally I dive de-inverted.  This was the first mistake, changing my gear configuration.

We went for a shore dive on the Islander.  I was super wonky!  I hadn’t been in a dry suit for more then a year and it showed.  I was over weighted and out of trim.  My feet were down and I looked like a stroke!  Luckily, I survived.  We finished the dive and my classmate quit; he hit his limit.  This was his second attempt at Hypoxic and he just didn’t have the juice.  Andrew and I did another dive and that ended day one.

Day two arrived and Eric Goldstein showed up.  I was grateful to see him.  I really like diving with Eric because he is an excellent diver, very knowledgeable and funny.  We planned to go out on the boat, but with so few people it didn’t make economic sense.   We did another shore dive, this time to 140ffw.  This dive Andrew gave me two Al80’s to manage, which shouldn’t have been an issue.  I was closer to trim head to toe, but my lateral trim was shit.  Normally, I side mount my tanks balancing them.  I decided to emulate Andrew and Eric and wear them on the left.  This was the second big mistake.

I know what works for me, but I elected to do something different.  I assumed I could adapt.  That was a lapse in judgment and the dive was shit.  There was a decent current and we had to pull and glide.  My gloves had holes in them and my fingers got sliced to shreds.  I could see the blood in the water.  Plus, I was swimming with a 45 degree list.  I looked like a COMPLE STROKE.  It took me until the next dive to sort out my lateral trim.  I needed to make changes in the placement of weight and the way I clipped the tanks in.  I was still over weighted.  Luckily, I get through all the skills.

For the next two days we dove the Jodrey.  There was a lot of drilling on High PO2, Low PO2 and bailing out.  We completed a partial ascent off the loop.  I spent a lot time on my Golem BOV, and I convinced.  I didn’t notice any WOB issues on it at 220ffw. Throughout class, I tried the drills in a couple of ways: faster, slower, and blundered.  The conclusion was that I need to take my time when I perform the drills and think it through.  I had a tendency to go on autopilot and do the flush too fast.  I need to spend more time verifying the cells.

The last day was spent in the class room talking about gas selection and other technical issues.  Andrew’s lectures are factual and to the point.  As a bonus, I had examples from The Pit.  Andrew and I worked through the gas selections and the deciding factors.

The course was challenging and a lot of fun.  I learned a substantial amount and I got a chance to tune up my skills again.  Upon reflection, I would have liked to have had a day or two more in my dry suit diving before starting class.  It would have given me an opportunity to perfect my trim and buoyancy, thereby allowing me to concentrate on the skills rather then basic issues.  The expectation is buoyancy and trim should be in the bag on arrival, however, the change in environment really through me for a loop.

I should have stuck to a configuration that was similar to the one I use in Mexico; even if I had to explain it to the team.  The addition of the dry suit, the tanks on the left and the inverted tanks added a noticeable level of task loading, which robbed me of cycles to use on performing the tasks on the dives.  The lesson is, don’t change things before class! I should have learned that lesson already.  Ironically, I had a similar issue during my Advanced Sidemount Course.  I got a new 9MM wet suit the day before class and it killed my buoyancy and trim, creating a terrible problem on the first day of class.

The joy is in the journey.  The truth is that the experience of diving and spending time with friends is so much more fulfilling then getting a Trimix Card.  I am glad I passed, it is important to me to do well.  But more important is the opportunity to dive with people I like.  People I can share the joy with.  Diving is a supremely social activity for me.  I like to solo dive, but I really like to dive with a good buddy.   Luckily, I have that buddy and we have some big dives planned.  In the coming months I look forward to opportunity to put my training to use as we dive The Pit, The Blue Abyss, the cenotes near Merida and the local walls.  I will keep you in the loop.

September 24, 2008   6 Comments

Minotauro: The other upstream. And video of the Nomad and Razor Sidemount Harnesses

Thursday brought the return to more normal diving for me.  I met up with Alain, a swiss tech instructor, helped him through some issues with his Nomad Sidemount rig and drove down to Minotauro for a leisurely cave dive.  Minotauro is nestled in the jungle near the Zero Gravity Dive shop.  The landowners are super nice people and there is always a laugh when we meet with them.

Alain getting ready for sidemount cave dive at minotauro

Which brings me to another related topic.  There is a rumored connection between Minotauro and Taj Ma Hal.  I haven’t found it if there is.  Maybe it is like the swimming pool at my grammar school.  You know, the one in the basement.   Every once in a while we get the feeling like we should go looking for it.  The entrance to Taj Ma Hal and Minotauro are less then 2000 apart.  I need to make a general survey of each system and see if they trend toward each other and how far apart they might be.  Could be an interesting project if I were bored.  If you have any information on this rumor, let me know?  Might save me some heartache.

Back to the dive!  Alain and I suited up in our side mount rigs and got in the water.  Alian asked me to look at his rig and check it out.  It looked pretty good, there are some danglely issues like his pressure gauge, his crotch ring and his regulator.

If you are wondering what sidemounting looks like, here is a little video.  The first part of the video is Alian in his Nomad Side Mount rig.  The second part of the video is me in my Steve Bogaerts’ Razor Sidemount Harness.

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The primary complaint with the Nomad is that it is a recreational side mount harness.  It is very general purpose.  It takes a lot of work to get the configuration correct and in the end you may not ever get it.   This complaint is handled completely with the Razor.  The Razor harness is a custom side mount/no mount harness worn under an open water bcd.  I was fitted for my harness when I took my basic side mount class with Steve Bogearts.

Taking the class and getting a custom harness provides two huge benefits.  First, the harness and the bcd fit me perfectly and put me in very good trim and my gear in the right places.   I made two adjustments after I left class.  The first was to add more give in the bcd for more lift.  The second was to add more weight when I got a 9MM suite.

Second, Steve very closely analyzed my configuration and diving for a couple of days providing constant feed back including video.  This feedback accelerated my adjustment to sidemount by 10-15x.  In 5 dives, I was more comfortable then many people I know with 50-100 sidemount dives.  Side mounting just takes a lot of tweaking, and people would rather dive then spend time in open water analyzing and tweaking.  Taking the class enforces a little discipline and starts you off on the right vector.

Ok, back to the dive now.   The entrance to the ‘other upstream’ is at the back of the cenote under a duck under.  I have dove about 60% of this section in backmount, however, it is tight and hard to not have some impact in that configuration. In sidemount it is much more enjoyable.  This dive includes a very cool carousel formation.  The line passes around the carousel and up into a highly decorated air dome.  After the carousel, it is easy diving until you pass the second T.  The two T’s are actually of two circuits of the main line, sort of.  If you go left at each T and then swim to the end of the line, you end up a the second T.  Just prior to getting back to the main line there is a jump to the left.  That is the end of the line from the first T.  it all sounds very confusing and the first time I was up there it was a little confusing.  But now I have a pretty good mental picture of the area.

I should warn you that after the second T it becomes sidemount sized passage and the chance for zero or no visibility, if you are careless, is pretty high.  Please tread lightly and stop when you hit your limit.

I do have one question, there is a mystery arrow at the back of the loop of the main line.  Alian and I searched for the jump for a couple of minutes and couldn’t find it.  If you know where to look, email me at:

When we reached the cenote again, we had plenty of gas remaining.  This dive has a max depth of 20feet (6 meters).  So, we decided to recalculate and extend the dive again.  Near the duck under there is a line arrow, the jump is 50-60feet and hidden.  That line leads to a very silty side mount section.  This isn’t the down stream section.   The line and its branches are pretty short but a lot of fun.  When we arrived the line was in bad shape.  It was loose and the rock it was tied to was broken in lots of places.  Someone trashed the line and left it.  I guess they were a little freaked out.  It goes to zero visibility pretty fast.  In any event, we took some time and restored the line.  It was a good exercise to work on the line in reduced visibility.

The dive was 110 minutes long and we had a great time.  Minotauro is still one of my favorite places to dive!

August 3, 2008   3 Comments

8000 Feet, One Spool and One Total Loop Failure

A traverse from Naharon to Mayan Blue on rebreathers.

This past week has been very busy for Patrick and me.  With the arrival of “Slow Season” here in Playa Del Carmen, we have found more time and more opportunities to get ourselves into some serious dives.  We have made two trips to The Pit and one trip to Sistema Naranjal with our Megalodons.  Luckily, the dives at The Pit were relatively excitement free, other then Patrick reaching the restriction at Jill’s Chamber at 105 meters.  However, the dive at Naranjal was anything but boring.

Patrick had finished up a full cave class at Mayan Blue on Sunday.  Unfortunately, the student didn’t complete the A Tunnel / Death Arrow circuit, so we had to retrieve the remaining gear, one spool.  We decided the only reasonable way to do the clean up dive was to traverse from Cenote Cristal (Cenote Naharon) down to the Death Arrow jump, pick up the spool, and swim back.  The swim from Naharon to Mayan Blue typically takes about 2 hours.  We decided to cut the swim a little short by only going to the end of the Death Arrow passage.

When we were planning our bailout gas, I was worried about having enough.  I hadn’t swum this distance and I wasn’t sure of the depths.  Patrick and I agreed to take 2 Aluminum 80’s each.  We ran some calculations and it was enough to get us out if we needed it.  Patrick’s calculations showed that two 80’s would last him 4 hours at this depth.  My SAC is higher, so I didn’t have same cushion.

When it came time to decide on our gas mixes, I asked Patrick what he was taking?  He told me Air.  And then we got into a discussion about bailout.  He very sternly explained to me that the choice of bailout gas didn’t really matter.  He didn’t believe he would ever have to bailout.  However, if he did he would only be punished with deco time.  He explained that he follows a checklist and is meticulous about assembling his unit.  I told him I was going to take 32% regardless of his feelings on the topic and I was going to drop a tank of O2 in the cavern for good measure.  You really never know when something unexpected is going to happen.  Isn’t that the definition of unexpected?   We agreed, or I decided in my head, I can’t remember, that if someone bailed out, they would get the 32% and the Air would be the gas of last resort.  At this point, Patrick’s attitude really concerned me and I decided that I was going to have a sit down with him, but I was going to wait until after our dive, as to not mess with his head.

Wednesday arrived and we got on our way.  The dive was going according to plan.  We passed the restrictions heading for Mayan Blue.  At the T, I wanted to “drop” a cookie.  As I got my markers out of my pocket, I dropped my safety spool. I reached for the safety and lost control of my buoyancy and started to fall.  I reached for the inflator, but no luck!  I ended up rolling down the windows saving myself from crashing into the mud, but creating some silting.  I could hear Patrick laughing as he watched this comedy of errors.  I finally got my act together, marked the T and proceeded.  I am sure it looked hysterical, you know how things happen in super slow motion, I know I was laughing about it.

We arrived at the spool at 80 minutes.  He retrieved the spool and we rested briefly.  When we finally got going on the return trip I was in the lead.  We were singing into the DSVs and just enjoying the dive.  After about 10 minutes we settled into a decent rhythm and pace.

At about 20 minutes, I saw a quick flash of the light head of me.  I instinctively turned and started to swim to Patrick.  We were about 50feet apart.  It took me a second to process the situation.  What I saw was one of the breathing hoses from the KISS Classic just floating in the water and I saw Patrick deploying a bailout reg.  My first thought was, ‘Oh shit, what do I do?  My bailout regulators are really secured and are not quickly accessible.’  Before I was close enough to help, he got his regulator out.  I arrived and assessed the situation.  The exhale breathing hose had disconnected from the canister.  At Patrick’s request, I reattached the hose.  We thumbed the dive, changed positions and started swimming.  This is when my heart rate finally picked up and I became aware of the gravity of the situation.  This was a real live catastrophic loop failure way back in a cave.  This is the exact type of unexpected situation we train and prepare for.  I knew we had enough gas, but I still got hit with some adrenalin.  I had to stop and think about my breathing and heart rate for a second.  My heart rate really isn’t under my control sometimes.  The base of the brain just reacts.

As we swam, I stayed near to Patrick in case something else went wrong.  I checked my computer and marked the time.  We had 60 minutes of swimming up stream to exit the cave.  Patrick cleaned up his hose routing and attempted to go back on the loop.  As I watched him attempt this, I just kept thinking, “You can’t recover a KISS from a total flood.  Don’t try.”  He found out in short order it was a done deal.  Then I offered him my 32%.  He waved it off, and he started to play with his X1.  Patrick later told me he thought he would be fine on air.  However, a couple of minutes later when we reached the T, he realized he was running out of no stop time and asked me for some 32%.

He asked at the worst time for me.  I was about to pick up my cookie and had too many things going on at once.  I struggled with my tank for a minute and finally told him to start swimming.  It would be easier to make the switch underway instead of hovering.  At this point I made a mistake, I think I was a bit overloaded and my brain was fried.  Instead of doing one thing at a time, I had the tank neck out of the bungee in the left hand.  I reached down to get the cookie with my right.  Now I was swimming with both hands full trying to get my tank completely off.  Ug! What a nightmare!

I finally stopped and stowed the cookie.  Then I passed the tank to Patrick.  He reached down to pull the regulator off the tank and the mouth piece came off!  The irony is that Patrick recently told me it was stupid to put the bungee necklace under the same zip tie as the mouth piece and that the mouth piece would come off at the worst time.  I defended my choice and didn’t change my configuration.  The bungee was wrapped around the tank neck and under the single zip tie.  When he showed me the regulator without the mouth piece, I could hear his voice in my head and I laughed.  I have since changed my configuration for CCR diving.  I removed my 120 degree swivel and the necklace on the bailout regulators.  I want them to be as accessible as possible.  Now, I believe that I will need them at the worst possible time.  He replaced the mouth piece and started to enjoy the joy that is 32% EAN.

Patrick swam off and I struggled with his tank.  This dive taught me my sidemount bungees are too short to be useful in an emergency.  As I struggled with the tank, I swam into the ceiling with my rebreather.  It got a little hung up so I jerked my head down.  I immediately realized my head was way heavy and I was heading for the floor!   A huge rock had broken loose and was on its way to pinning me.  I rolled to the right and the rock fell off my head before I hit the ground.

Again, I laughed.  I couldn’t believe how many things had happened to us on a single dive.  We have been diving for seven months together and all of those dives had been incident free.  A series of walks in the park, including cave dives to 300ffw.  The type of diving that breeds complacency.

I caught up to Patrick and we continued to exit.  We decided to pull our gear.  As I pulled my spool from the jump between Southern Sacbe and Southwestern Sacbe, I created a nasty knot around the main guideline.  I ended up cutting the spool free from the guideline.  It was the last in a row of incidents.  We exited safely with a total run time of 180 minutes.  I estimate the total distance at around 8000 feet.

Patrick and I agreed that we handled all of the situations acceptably.  We did a serious review of the dive and have both made changes to our rigs and attitudes.  As I mentioned, I changed my regulators and I lengthened the sidemount bungee.  Patrick also made some changes to his regulators to ensure they are accessible.  We adjusted our bailout gas attitudes.  And we agreed to take better care to avoid team separation.

Once the stress started to pile on, it made simple tasks like a tank swap more difficult.  A task he and I normally can handle in a minute or less took a couple of minutes.  My overall awareness decreased and we got a good distance apart more then once after the main failure.

I feel it was an excellent dive!  We both returned and no one was hurt.  We tested our abilities as a team, and as individuals in a stressful situation.  We both stayed calm and controlled our breathing.  We reacted instinctively and completed the tasks at hand.  We realized our performance wasn’t perfect but it was acceptable. The whole dive confirmed to me the following idea.  Bailout is for unexpected situations and it does matter.  No matter how bullet proof you might think you are or your procedures, unexpected shit happens and it will happen at the worst time.  And these situations never happen alone, they are always compounded by other events.

Patrick used just over 2000PSI from one Aluminum 80 to exit from 60 minutes into the cave.  I hope you learn a little from this, I know I have learned a lot.

As always, your comments and criticisms are welcome here.  If you want to know more about the incident, leave a comment and one of us will respond.

July 29, 2008   13 Comments

Spy photos of Rob’s Sidemount Prism Rebreather.

Okay, they are not really spy photos.  I emailed Rob after I saw his post on his wreck diving blog about his new sidemount rebreather and asked him some questions and if he had any other photos.  I thought that my “valued” readers would love to see more of his unit.   And I have my own selfish motives, I really wanted to learn more about his unit.  I think it is totally RAD!

One of the most popular questions I am asked is, “When are you going to sidemount your rebreather?”  My standard response is, “I am not planning on it anytime soon.”  That is followed with, “Why not, Hans?”  I usually answer, “Any place I would want to use my rebreather sidemount would require too much bailout to sidemount effectively.  It might work for survey where I need a lot of bottom time, but I might not be covering a lot distance.  However, I just haven’t felt the need.”  I think at some point, I might change my mind, just not today.  But I digress, the point here is that you want to see photos of Rob’s sidemount Prism rebreather.  Here they are.  Click the images to see a large version.

Rob ready to gear up with his Prism rebreather.Rob all dressed for the show in his sidemount Prism rebreatherRob entering the water at Dutch Springs with his Prism rebreatherRob in the water with his sidemount Prism rebreather
The unit is still in development in these photos.  Rob had some issues to work out, like the wing and the placement of his light canister.  My understanding is it is progressing nicely.  I asked Rob a couple of questions and here are his answers.

Hans: Have you dove it in the ocean?

Rob: I have indeed taken the sidemount rig into the  ocean.  Did two nice dives on the Arundo last Sunday, 100 minutes and 70  minutes.  Big bag oflobsters, 3.5 dozen scallops, plus an old  bottle.

Hans: How hard is it to kit up on the boat?

Rob: Kitting up is definitely different.  Put on the harness/counterlungs,  cinch everything up.  Sit down, butt clip both sides, hook up manual O2,  display and hud on one side, adv and wing on the other.  plug in the hoses  and connect, a bit of a pain but a one-click manifold is in the works.   Then bungee both sides and I’m set.  Easiest thing is on an engine cover,  barring that to just sit on the ground.

Hans: What modifications did you make to the Prism?

Rob: As you can see from the pics, I’m still wearing the standard counterlungs, just customized – Y-pipes, meg adv, inspiration opv, stock prism drains.

Hans: How is the work of breathing?

Rob:  WOB is the same as a stock unit.  The counter lungs are in the standard position, so I still get all the benefits of over the shoulder counter lungs.

Hans: What kind of weight do you need to trim the unit in the water?

Rob: Weight wise I am using:

  • Two 2lbs on top of the harness
  • A 3lbs and a 4lbs in the counterlung pockets.  (Prisms have these on the back.  Very convenient.)
  • A 5lbs in my right side weight pocket.  Nothing in the left.
  • The rig itself has a 3lbs and a 5lbs weight zip tied to the base.

I am possibly a bit heavy in this configuration, but not terribly so for salt water.  I can also use an AL80, in which case I can drop a few pounds.

Hans: Is it hard to turn off the O2?

Rob: It takes nothing to shut off the O2 as the knob is pointed right at my  hip. Can also unclip either side and swing it around in front of me to get through restrictions.

I want to thank Rob for allowing me to post his photos and his response!  And now for the extra special treat.  Here is a photo of a Prism (Right) and a Megalodon (Left) rebreather.  Both are sidemounted in the same fashion.  Click the image for a larger version!

Megalodon and Prism Rebreathers (CCR) Sidemounted at Dutch Springs NJ

If you want to see a video, I posted a link to Rob in his sidemount rebreather. If you have any questions you want me to ask Rob, let me know by commenting. I will follow-up and get responses as fast as possible. Safe diving and keep on pushing.

July 23, 2008   3 Comments