Cave Diving, Cave Exploration and Cave Mapping in Yucatan, Mexico
Casa Cenote near Tulum Mexico

Category — Equipement

Side-Mount Rebreather. A Prism in NJ.

My buddy in NJ, has finally received his side-mount Prism.    Check out how slick it looks!  He says he has a little more tweaking to do to make everything thing streamlined.  I can imagine how much time will really need to be invested in getting something so cool exactly right.

Side-Mount Prisim CCR

He has posted a very cool video of him diving it at Dutch Springs.  Notice all the exposure protection?  If you take a look at his rig, he is wearing his bailout/diluent on one side and the rebreather on the other side.  There is a sphere of 02 at the bottom of the canister.  Overall it is looking very very slick.  Rob, you are a rock star.  Now tell us how it dives!

Side-Mount Prisim Rebreather

The interesting thing about side-mounting the rebreather is that it handles the one cylinder or two cylinder for bailout question.  Now you only need one to balance you, the unit is the other.  If you need more bailout, then you just wear them like you would side-mount stages.  And it just looks so much easier on his back.  Of course there are many other benefits, but I am not going to go through them today.

Rob, answer me this, our hungry readers want to know:

  • Where are the counter lungs?  Are there 1 or 2?  Looks like they are in the standard position….
  • How hard is it to shut down the O2?
  • How is work of breadth in the different orientations?  I know I end up in some strange ones in side-mount.
  • I wonder what the kitting up procedure is like on the boat?  I have tried to mount my side-mount bottles standing and it can be a real PITA.  I wonder if the same is true about the ccr?
  • I wonder how much weight he added to balance that big steel cylinder?

So many questions!  Maybe I will try and score a visit with Rob in September, when I am home.  I would love some detailed photos and answers!

If you have any questions, let me know.

July 17, 2008   Comments Off on Side-Mount Rebreather. A Prism in NJ.

Where should I dive in Mexico, Tulum, Akumal, or the Riviera Maya?

At some point, I asked Steve where I should go diving. He asked if I had been to: Casa Cenote, Temple of Doom or “the cenotes across from Xpu Ha”? At the time, I had to answer no to all three. It dawned on me how many obvious places there are to dive here. Drive down Highway 307 and stop at the places with a Cenote sign and ask to dive. If they allow it, that is a place to dive. Of course, there is risk in trying to dive without a guide. First, the adventure might be a complete diving bust. You might pay your entrance and find the location undivable or unrewarding! Second, you may not get very far at all once in the cave. The first time I went to Car Wash without a guide, I spent the entire first dive looking for the main line. Luckily, I have the opportunity to waste time driving around looking for a Cenote or swim around looking for the main line. If you are a visitor, you may not have the same luxury. Plus, I love to explore! And for me, even if there is line in the cave, every dive to a new site is exploration. How do I enter the water? Where is the entrance to the cave? Where does the line go? What is the geology?

If you are coming to Mexico and you are looking for a guide or someone to dive with, email me at: I will make sure to hook you up with the right people! Having a guide will save you a ton of logistical work and will ensure you have a fulfilling trip. I know guides that specialize in rebreather cave diving, side-mount diving, exploration, dpv, extended range, deep diving, and I even know someone with an excellent boat on Cozumel. The guide will arrange tanks, transportation, food, entrances, sorb and any other special needs you might have. The same applies if you are looking for an instructor. I know it sounds like a pitch, it sorta is. I just don’t like to read posts from people on CDF or The Deco Stop that didn’t enjoy their trips.

June 9, 2008   Comments Off on Where should I dive in Mexico, Tulum, Akumal, or the Riviera Maya?

Valve Feathering and Valve Management

I recently wrote an article detailing my Advanced Side-Mount Cave Diving Class with Steve Bogaerts. In that article I made reference to feathering my valve after a regulator failed underwater. One of my favorite readers, Anna, sent me an email asking me, “What is feathering? I mean I know your valve was leaking and I’m useless at valve drills. So I guess it means you blew a burst disc and just had to let the tank run down?” I thought I should explain and I wanted to provide a brief explanation of a systematic approach to practicing valve drills as it was taught to my wife and me.

Valve Feathering
Feathering is the act of actuating, opening and closing, the valve on a scuba tank to control the flow of gas. I originally learned the skill to deal with a stuck open solenoid on my rebreather. I adapted the skill for dealing with my leaky regulator. The idea is to limit the gas loss from the leak to extend the time you can use the tank. When done correctly, I open the valve as I start to exhale and close it before I am finished; drawing the regulator empty at the end of my breath cycle. This limits the regulator to leaking just when I am drawing gas. This same skill is a prerequisite if you ever find yourself breathing off a tank valve 3000 feet back in a cave.

The specific problem I had was that my low pressure inflator hose had loosened itself from the first stage of the regulator and was leaking from the connection. I was diving brand new Apex XTX 50’s with DST first stages. I had just assembled them, and I didn’t tighten the hose enough. I was diving side-mount and practicing bottle handling skills, so I was forced to don and doff my tanks many times that day. In the course of rotating the tanks out in front and back, the hose came loose. Of course it loosened in zero visibility and I was unable to figure out the source of the leak. Therefore, I was forced to isolate the leak by shutting down the valve and going on my other side-mount tank. Once I handled the priority emergency, being entangled and cutting the wrong side of the line, and I had passed the remaining restrictions, I switched from the fully functioning system to the leaky system. At this point, I started to feather the valve to control the gas loss and maintain the air source as long as possible.

Valve Management!
“Valve” and “Management” are dirty words in the tech diving community. I know many people who have suffered with valve management, including my wife. They all had trouble with it until they learned a logical process for executing them and dedicated time in a pool or on their safety stops to practicing.

I believe there are three primary reasons people have trouble with these skills:

  1. They can’t reach their valves.
  2. No one ever taught them a logical process and gave them the reasons for each step.
  3. People don’t practice.

The first reason is non-sense. Your rig should be configured in a way to allow you to reach your valves. If your dry suit is too tight or your valves are too low, they you have a real problem. It is a problem that may lead to your drowning. Stop diving and fix the problem. Why would you ever enter the water with a system you know if broken? It just does not make sense.

The second reason is reasonable, not everyone has an instructor that has a logical easy to remember system. My Advanced Nitrox/Deco Procedures class provided no methodical instruction on this issue other then, “Let me see you close your valves. It is ok to do it one at a time.” This is where your choice of instructions really makes a difference. It might save your life.

I am going to share with you the system Allie and I learned. Keep in mind this is for a person diving manifolded doubles with an isolator. It also assumes you are breathing off the right post to start:

  1. Close your right post first. Breathe it empty and switch to the left regulator. Why? It is the most dynamic regulator and will be prone to fail first. You breathe it to the end to confirm you have shut off the correct regulator. Switching to a regulator that is off will come as a nasty surprise.
  2. If the leak continues, turn your right post back on and turn your left post off. Breathe the left post empty and switch back to your right post.
  3. If the leak continues, shut down the isolator and try and figure out which tank is leaking.
  4. Turn on the left post and switch to the tank that is leaking. Breathe it empty then switch to the remaining tank.
  5. Open the isolator at the end of the drill.

If you practice this in the same way each time, it will go into muscle memory. It also helps to do an audible gear matching exercise, at the start of the dive, where you call out each piece of gear and touch the post it is attached to. This helps build a reflex to turn off the correct post in the event of an easily identified leak, such as a leaky SPG. As you become more proficient, you can start to close the isolator at the same time you close the post. I would suggest the first couple of times you practice, have a buddy watch you to ensure you maintain an air source. I would also advise you to not practice this if you have mandatory deco and you don’t have a buddy. It would suck to blow off deco because you find yourself without an air source. When you are short on air, one second is forever!

The last reason I outlined, lack of practice, is just that. We all have to do three minute safety stops, it is a perfect time to practice pain in the ass skills we need to survive. For weeks I practiced my reverse frog kick and my lay throwing skills on my safety stop. Prior to that, I practiced my valve drills and buoyancy control on every safety stop I could. There is no excuse for not practicing; you have time built into every dive for it. Use the time; practice a skill that might save your life.

I can tell you from first hand experience, you may need to shut a valve down while entangled in zero visibility. It could be fishing net, monofilament, cave line or the long tail of someone’s snot that grabs a hold of you. You want to be prepared so you can maintain a calm cool collected manner. I promise, when the trouble comes, it is never alone.

May 23, 2008   3 Comments

An Approach to mounting stage bottles or bailout bottles with a backplate.

This morning there was a post on Cave Diver’s Forum asking:

When I’m swimming a stage, horizontal of course, the bottom hangs down too low to my liking. I use an aluminum 80 but the bottom doesn’t float up at all. My lower clip is wrapped around the handle strap to take up all the slack, but I still have to hold the bottle up when I’m close to the bottom. Anybody ever use a bungee to hold it in line with the body? …

To start, I cave dive CCR back mounted, doubles and side mount. The following information focuses on carrying stages or bailout bottles in a back mounted configuration. My current approach has been heavily informed by my experience diving sidemount. I have gone through at least three major evolutions in this process and it is still evolving. This article is based on my personal experience. I have stolen or purchased ideas from a number of people I dive with here in Mexico and in New Jersey. Those people are: Steve Bogaerts, Andrew Driver, Patrick Widmann, Rob Infante, Nando and others. Sorry if I don’t credit you properly. And remember to click on the images!

I remember asking myself the very same question over and over. When I started to sling a bottle, I learned how to do it from my Deco Procedures class and the north east wreck divers. The approach was to buy/make a sling kit for the respective bottle and mount the bottle to your chest d-ring and the waist strap d-ring. Depending on the buoyancy of the bottle, the position of your waist d-ring and the length of your clip lines, this might put it sticking up at a 45 degree angle or leave it dragging in the mud. It was never streamline with my horizontal body. However, in NJ I could get away with this non-sense. I knew it wasn’t right. So I started to look for another solution. When I moved to Mexico and started to dive my CCR in the caves, the inefficiency of this system was magnified. I remember picking up the tank to pass small areas. I remember the tank swinging to and fro as I kicked. It was maddening.

Armadillio Side Mount SystemThe second evolution was to purchase a butt-plate. I selected the ArmadilloCCR Sidemount System. I mounted the butt-plate to the back plate on my rebreather. I decided to use a neck clip instead of the bungee. My neck clip is just a loop of bungee with a clip attached. I put the neck clip on the tank before I install the regulator. I found this easier to deal with then the bungee loops. As soon as I mounted an AL 80 to this setup, I discovered I was woefully leg heavy. The butt-plate transfers the negativity of the tank to your thighs. Neck clip for stage bottle.It was intolerable. It made cave diving frustrating, because I was fighting with my trim the whole time. I like to be able to float in mid water without making adjustments, this was impossible.

As luck would have it, I dropped my CCR head and broke it. While my unit was being repaired, I had to dive backmount which forced me to use a buddy bottle or a stage bottle. I was in sling bottle hell again. However, I started to smarten up. After a couple of dives, I put my butt-plate on my doubles back plate. That failed to live up to the promise. The door handles were in the way. I couldn’t reach my butt ring and my trim was off. However, the tanks were sitting in a much nicer position.

After some discussion with Patrick and going through training with Steve, I finally figured out the problem.Customized Aramdillio Butt-Plate The door handles are the wrong solution. They put the tanks too far back on my body and are inflexible. They can’t help but be in the way.

For evolution three I removed the door handles and installed two d-rings on the butt-plate. The d-rings move the bottle down my body just enough to balance me and put the tank in the correct position. Eureka! The mobility of the d-rings allows me access to my butt ring. Without the door handles gearing up is much easier and the d-rings are much more accessible.

The d-rings are in the correct position when the tanks are negative.Custom adjustable d-ring campared to a standard d-ring. However, when you breathe down the tanks to about 1500, they become buoyant and you need to move their clip position. Or suffer tanks that are bouncing off the ceiling. I use adjustable homemade d-rings on my waist strap for this job. I picked this one up from Steve.

One more thing I learned is, “Balance is key.” I make an effort to always carrying two stages, one on each side. If all I need is 80cuft of gas, then I carry two Al40’s. If I need more gas, then I add bottles in a sequential way. I up one bottle to an 80 and then the other bottle. I have not found a balanced and streamlined solution to carrying only 1 bottle. If all I need is a Al40, then I suffer with one bottle. An AL40 doesn’t throw my balance off wildly.

My rig will continue to evolve as the diving I do demands different configurations and optimizations. I believe there are at least two ways to approach a problem like this: trial-and-error or training. The trial-and-error approach is valid and is time tested, but damn it takes a long time to figure things out and we have a finite number of dives available to experiment. I would prefer to spend my time diving and not hating my gear. If you don’t live in cave country, how will you ever have the time to get it right?

The training method takes years of experimentation and distills it down into the state-of-the-art. It has been demonstrated to me over and over, that this is the most efficient route. I could have gone out and self taught side mount, but after going through training I now know why that is stupid. I estimate that training evolved my skill and gear configuration by at least 50 dives or more.

Find an instructor who is practicing and teaching the state-of-the-art in your desired disciple and schedule a couple of days with him/her. You will be amazed how some of these fundamental issues are resolved immediately and how your diving improves dramatically.

May 11, 2008   Comments Off on An Approach to mounting stage bottles or bailout bottles with a backplate.

How to convert an Apeks XTX regulater for left hand delivery.

Contrary to the title, I am not going to tell you how to convert your regulator. However, a member at The Deco Stop was kind enough to turn me on to a link to the XTX Tech Manual from Apeks. On page 14 you will find instructions for converting your XTX second stage regulator.

I converted one of my Apeks XTX 50 second stages this morning and it took me a total of 10 minutes and I was really taking my time.

May 10, 2008   Comments Off on How to convert an Apeks XTX regulater for left hand delivery.

Travel Time. Destination New Jersey.

The last couple of months of diving have been fantastic but I knew the role had to come to an end.  This week I am back in the states to do some paper work and get some much needed dive gear!

The first stop when I got back to New Jersey on Friday was the dive shop.  For the last two months Nando from Protech has lent me his sidemount regulators, two Dive Rite RG3000’s.  They worked great except for the swivels he used.    For the right tank he mounted a Scuba Pro second stage so the hose routing could be reversed.  The left tank was a standard RG3000.  The hoses were shorter then standard and I mounted replacement  120 degree Scuba Pro swivels.  I want to thank Nando, becuase I didn’t have access to anything but my Apeks ATX200’s and they were sub-optimal.

That has changed!  I purchased 4 Apeks XTX50s with DST first stages.  No more dicking around with borrowed gear and worrying about it.  I am completely stoked to have my own rig and a dedicated set of regs.  Things are really coming together.  I can’t wait to get to Mexico and get them setup.  I love the way new well tuned regs breath, especially Apeks regs.   In addition to the regulators, I got some 6″ HP hoses, some dive slates for making survey slates, some new compasses for the survey slates, plus some other assorted goodies.

While we were at the dive shop, Allie tried on a bunch of semi-dry suits from Pinacle, Camerao and Mares.  NONE OF THEM FIT RIGHT!  The best suit by far was the Mares.  It was really slick.  The problem was the arms and legs were a couple of inches too long.  But it looked very well constructed and the seals were looking sealed.  The Camerao suits just didn’t really fit, water would have leaked in from the neck defeating the purpose of the semi-dry.  And by the time she got to the Pinacle she was so exhausted, she only got through one suit.  She isn’t sure how she is going to solve the freezing problem.  1.25 hours into a dive and she is shivering and her hands are numb.  She is going to keep looking and I will keep you posted.

The only other item of note is that I received my Sartek lights on Friday!   I am looking forward to getting them south of the boarder and in the water.  The new cable looks very slick and I have a new LION battery.  Gotta love the advertised 8 hour burn time.

I have one dive post that is waiting in the wings.  I had a very interesting dive at Pet Cemetery last Wednesday.  But I am going to save that for after I have spoken to the proper authorities.  Remember my advice about not relying on little plastic discs (line markers) to get you home, maybe I should expand that to not relying on the continuous guideline that was there 80 minutes earlier.  More on that in a couple of days.

Remember, in additional to diving the line, you really need to dive the cave.  Your never sure the line will be there when you get back!

May 3, 2008   1 Comment

Dive Number 400! Rebreather Cave Dive at Grand Cenote with John.

John at the trusty dive truckToday was my 400th logged dive. John took the early ferry over from Cozumel. I picked him up and we left for the fill station. At the fill station I asked John to review all of his gear and let me know if he had everything he needed. I told him I didn’t want to get to Tulum and find out we were missing something. He assured me everything was there and we were ready to go.

John getting ready.As luck would have it, once we arrived at Grand Cenote and started to assemble our rigs, I realized I forgot John’s bailout regulator. I was supposed to loan him one of mine, and since it wasn’t part of my kit, I totally spaced on it. I jumped in the car and headed over to Xibalba Dive Center in town and Robbie kindly assembled a regulator and rented it to us. I was back at the Cenote in 10 minutes. Problem solved and we were back in business.
My perfered bailout package.John and I decided to do one long dive. The plan was to head down to Lithium Sunrise and then return to the first arrow and make the shortcut jump down to Cenote Ho Tul and Cuzan Ha. The dive went very well, except that when we got to the second jump on the way to Lithium, there was another team with gear. I started to install our gear and realized I was in the wrong position. So I picked it all back up and re-laid the gear in. I really like nicely placed lines. Messy lines will make for a messy exit and they look hideous. This debacle wasted about 6-7 minutes. I hate to be robbed of the time, but I could just hear Patrick correcting me about my line placement.

Grand CenoteTotal run time for the dive was 2:32 minutes. John seemed really happy with the dive. He pointed out all the hand and body prints and I told him it is the result of being on the top ten list of places to dive. You really have to get off the beaten path and away from the typically guided locations to find pristine cave.

Cooling off in the refreshing cenote water.Diving the Megalodon has been great! In the last 21 days I put in 15 hours on the unit over 10 dives. I finally felt comfortable again, the last couple of weeks have been full of setup changes and discomfort. The only thing that remains is to move the clips up the 40cuft cylinders so they pull a little tighter into the body. I hate the feeling of bottles swinging forward and aft with each stroke. Just feels like it is robbing energy.

The result of a great day of diving.It was a pleasure to dive with John and I look forward to diving with him again. Just take a look at the picture of the scrubber. That is the evidence of two days of great diving. I love the satisfaction of pulling a hot scrubber out and checking to see how much I have burned through.

April 26, 2008   2 Comments

7200 Feet at Naharon

Saturday morning I got up and went to breakfast with a close friend. I still wasn’t sure where I was going to dive. After breakfast I went to The Gym for a run and an ab workout. While I was at the gym it came to me, a eureka moment! I decided I should go to Naharon with my Megalodon and do a CCR length dive.

I went home and pulled together my bailout and my rebreather and jumped in the car. I discovered it is almost exactly 40 miles from my apartment to the entrance of Cenote Cristal. The drive down was uneventful although a little lonely. That is the biggest drawback and the biggest upside of solo diving. The whole thing is solo. I always think of diving as a social activity. Talking about the dive, anticipating the dive, executing the dive and then taking about how big and scary the conquest was all make good memories. Unfortunately, talking to yourself about all those things might get you committed and is just not that entertaining.

I decided on an AL80 and an AL40 for bailout. I have the 80 plumbed into my manifold, so I can use it as diluent or for my BOV. 120cuft of gas gave me a max penetration time of about 50 minutes at the depths I was expecting. This was enough time to cover the distance and areas I wanted. I started the dive by going up the main line and taking the second jump into the Halocline Room. I counted two arrows after the jump, one to the left and one to the right. I guessed the jump to the right might be the end of the main line. I turned the dive in Chac’s Room. On the map it is marked at 1700’. The clock was about at the 45 minute mark and I was starting to feel a little distance pressure. The little man starts to talk to me, when I think about how far I might have to swim on bailout and as far as I know, there are no emergency exits. The Halo-Line is an excellent swim. The first three times I had been to Naharon, I really didn’t see anything. I was focused on the dive and staying a live. This dive was different, my field view really opened up and I saw so much more. One of the striking features of Naharon are the tiny silk covered stalactites. They are really amazing, and with the CCR I took plenty of time to wonder at them.

I returned to the main line and made a left swimming deeper into the cave. I made it to the end of the Main Line in about 15 minutes. It terminated near Chac’s Room as I had guessed earlier. The Main Line is a bummer compared to the Halo Line. The Main Line is a shortcut to Chac’s Room, I would use it as a transit route in the future to cut about 10 minutes off the swim. I turned the dive and headed back to the first jump off the main line.

When I reached the first jump, I was nearly two hours into the dive. I decided to make the jump and swim 20 minutes or so. I counted 4 arrows on the swim and after the 4th arrow the cave takes a hard left and then a right and then you go up onto a boulder / breakdown. On top of that boulder is a gorgeous garden of formations. I was clearly in a part of the cave which doesn’t get a lot of traffic. Even with no bubbles, I was getting a reasonable amount of percolation just from my pressure wave. I relaxed and enjoyed the view for a while and gave my poor calves a break. Then I headed for home.

Overall it was a very meditative dive. My recent tweaks have really paid off. Carrying two BO bottles is superior in a lot of ways to carrying one. More gas rocks and two bottles are so much more balanced then one. My neutral position is not pulled to one side or the other. And de-inverting the tanks really helped my trim.

There are still some problems with my rig:

  • It is too heavy. With two BO bottles, I have to really inflate my wing and it is pressing on my back. This is uncomfortable and inefficient. It wastes a lot of diluent and makes the volume changes that much greater.
  • The door handles on the Armadillo Butt Plate suck! They are all wrong for AL tanks. And they make reaching the butt ring very difficult. And they just don’t seem to be in the right place. Donning and doffing tanks can be difficult with them.
  • My Dive Rite Two Zipper pocket that is belt mounted is also in the wrong place. It is very difficult to get my wet notes out with the BO on.

Here are my proposed solutions:

  • I am going to remove the single tank adapter and strap the tank to the back plate with the hose clamps. That should lower my profile and remove a pound or two of weight.
  • I am going to remove the door handles and attach two d-rings to the butt plate. Like the original Nomad butt plate. This should fix the position of the tanks and make it easier to reach the goods on the butt ring.
  • I may trim some AL off the back plate. However, this is not going to happen immediately.
  • I am going to get a new bellows pocket mounted on my left thigh for wet notes and other spare crap. I want to ditch the Two Zip. Or I will start to hang it from my butt ring, like I do when I am side mounting.

I feel like I have seen some of Naharon. Total run time was 2 hours and 40 minutes. There is at least one circuit I would like to do and a bunch new passage to be inspected. I figure I will need another 10 trips there to feel satisfied.

Dive: 396

April 21, 2008   4 Comments

Transitioning from Open Circuit to CCR for Cave Diving.

I wrote the following in response to someone asking about my experience in making the transition from Open Circuit (OC) Cave Diving to Close Circuit (CCR or eCCR) Cave Diving.

When I decided to take my Megalodon cave diving, I had about 50 OC cave dives and about 40.5 hours doing open water deco and wreck penetrations in New Jersey and the Saint Lawrence Sea Way. By this time, I felt very comfortable in my unit and had dived it in some very demanding environments. I was OC Cave Certified from NACD and IANTD certified on the Meg for Open Water to 145′.

When I moved to Mexico, I was very committed to getting Cave CCR trained. However, draw was just to great to wait for the instructor I wanted to be available. Plus, I was starstruck with my eCCR. I thought it was the perfect solution for everything and I just didn’t want to wait to dive it. So, I talked to a handful of people here and made the decision to go cave diving with it. I started off slow. I did dives I could on a single 80 bailout. Luckily, most of the diving I do here is shallow, less then 50-60 feet, so you can do a lot of diving on a single 80. I dove in very forgiving systems and really put a lot of time and effort into it. I spoke to people who were diving their rebreathers in the caves and came up with my own procedures. Slowly, I progressed into ever more difficult and demanding dives. I discovered that what I thought was reasonable level of buoyancy control was crap when the cave magnified it. I also discovered that as the dives grew in length, my ability to dive the unit degraded as I got tired and my concentration weakened. At this point, I was diving the Meg exclusively and had abandoned OC.

Then I went for OC Side Mount training and my eyes opened up again. I learned my Meg is not the best tool for every job. Really, it is a horrible tool for many many of the jobs. For instance, diving Taj Mahal on the Meg sucks; it is shallow and there is a lot of up and down. Or Joe’s line at Ponderosa, another horrible ride. Or Minotauro, too tight to take the CCR and appropriate BO and be comfortable.

I started to split my time between OC and CCR. Today, I spend more time in OC then I do CCR. It is just easier for me. I try to choose the right tool for the right job. For instance, today I went for a nice 2:40 dive at Naharon on the Meg.  I dove a 1.2 set point and plumbed my 80cuft BO into my manifold to drive my BOV, wing and diluent.  At a 1.2 you get an amazing amount of no stop time.  That place is perfect, the passages are larger and the depth is pretty much constant 50-65ffw. This is one of the places that makes me love my unit. The eCCR is the right tool for that job. I could see a lot of dive sites in Florida being perfect for a rebreather, like Little Rivers.

The short of the story is that I am still up in the air on whether I am going to go for the training. I have a bunch of people around me who have a lot experience and I am learning from them. I get to dive with some really committed folks. Unfortunately, I know that you don’t know what you don’t know, until you learn it. So, I am really torn, normally I am all over getting the training, here I am having trouble seeing the value.

I guess there are some other points:

  1. Everything is more complicated with a rebreather. There is more equipment and more checks. If you dive 3-4 times a week, this can be a burden. I like to throw my regs in a basket, pickup the tanks and go for a dive. The rebreather takes prep and breakdown and care onsite. I had to plan accordingly; I had to build in more time into all my budgets.
  2. I had to become very conscious of mixed team diving. I dive with open circuit divers, like my wife. I need to be aware of that when doing my risk analysis and preparation. She needs to be aware of it and know the procedures. I now mostly dive OC when I am with other OC divers, unless it is a big dive that is eCCR appropriate. If you have to donate your bailout, it is gone. You can’t get it back. You need to think about a solution for that. Are you going to make everyone carry a buddy bottle, or are you not going to be part of the team? Your team needs to decide.
  3. I dive open circuit pretty regularly, so I am maintaining my SAC rate. I monitor it continually to ensure my gas planning is correct. If you abandon OC totally, your SAC rate will suffer and you need to take that into account when gas planning. Plus, diving a location OC, gives you a very clear picture for BO planning.
  4. I have to be willing to pick the best tool for the job. Some times it is OC, sometimes it is CCR.
  5. There is a fine art to loop volume/buoyancy management. I haven’t mastered it yet. I am still working on how much dil or o2 to add given a change in the loop volume. I hate hearing the solenoid fire all the time. You can’t just dump dil in, it will drive down the PO2, you can just dump O2 in, it will drive the PO2 up.
  6. Sometimes air isn’t the best diluent. A little Nitrox can dampen the swings in the PO2 when you have to adjust the loop volume because of the ups and downs in the cave.
  7. If you are a solo diver or reject the idea of team bailout; Diluent/BO is the limiting factor. Every dive turns into effectively a stage dive. You have the CCR on plus you have a bunch of BO tanks. What a pita. Sometimes I can go just as far on my 80’s side mounted.
  8. Your rebreather’s open water configuration may not work in the cave. If you don’t live in cave country, plan on spending the first couple of days figuring out how to trim yourself out. I loved my tanks inverted when diving open water; with two SS backplates my trim was perfect. Recently, I had to deinvert them to fix my trim in the cave. I needed to change the balance point and I didn’t want to add any weight. I am still looking for way to remove weight from the system. I am still working on my bailout mounting. The rails on the butt plate suck and are in the way and don’t work well with 80’s. I need something more like the original Nomad buttplate with the d-rings. Plus, fighting even the slightest problem in trim will wear you down. The loop really magnifies any energy you put into the system when finning to compensate. The change between cold water and warm fresh water can play havoc on your configuration.

Rebreathers are amazing tools, sometimes I want to sell mine and sometimes I want to hug it. I always have to respect it! It is like any high performance piece of equipment, it can harm you much faster then you can imagine.

April 20, 2008   Comments Off on Transitioning from Open Circuit to CCR for Cave Diving.

Rebreather Diving on Cozumel: Dives 380 – 383

On Friday, Patrick asked me if I was interested in joining a trip to Cozumel for a couple of days of CCR reef diving.  I hadn’t been to Cozumel in more then a year and the opportunity to do some CCR dives on our own boat was just too juicy.  The trip was organized by Protech of Playa Del Carmen.  They provided access to O2, Trimix, Air, Sorb, two guides and the boat.  Patrick was on his Megalodon and provided the CCR expertise for the trip.  The other guide was Dario, a native born dive master of 25 years and boat owner.  Dario is a super laid back guide and plenty of fun.  The boat’s name is Eusmilia and it is excellent.  It is about 10 meters in length and has space for 10 divers.  Each diver gets a locker under their seat to store their gear.  The captain is stationed on a tower.  And the boat is plenty fast.

The plan was to pick up the group of Canadians at 9:30, load up the units and go for two dives.  The first day the group wanted to do an 85ft dive for 45 minutes.  I was disappointed.  I didn’t make the trip over to the island to do dives I could do on a single 80.  I am here to make some CCR dives.  We discussed this a little an opened the range up to max depth of 100 feet for 60 minutes.  They were concerned about using Air as a diluent below 100 feet.  The actual dive ended up having a max depth of 120ft with a run time of 83 minutes.  The group elected to extend the dive while in progress.  The dive was made on Santa Rosa wall.  It was a nice dive, nothing extraordinary but beautiful none the less.

The second dive was in the same class but a little shallower.  We dove Santa Rosa reef.  We had a run time of 72 minutes and a max depth of 60ft.  At the end of the day I had to make a decision on whether I was going to return the next day.  I asked the group what they wanted to do the next day.  They answered, “What will bring you back, Hans?”  I answered in my normal manner and explained that I wanted to go a little deeper then we had today and make longer dives.  I suggested we head down to the southern end of the island for the Devils Throat or the Punta Sur area.  We discussed doing a 130-150 foot dive.  The group agreed and the Canadians requested their fills be Trimix 12/35.

Sunday came and the wind was blowing out of the South East.  This was not very promising for a run down to Punta Sur.  The island curves around and the reefs are exposed to the South Easterly wind.  So it can be a rough and wet ride.  Patrick and I made the trip over to the island and we picked up the other guests.  We started to load up the gear and we explained to them that the boat ride would be at least 45 minutes and it would be rough.  The Canadians were troopers and volunteered.

The Eusmilia is a very stable and capable boat.  The ride down was not that bad at all.  When we arrived at Devils Throat the Plan was for a max depth of 130feet and a run time of 60-80 minutes.  We all geared up and dropped in to meet the Dario on the bottom at 100ft.  The first thing that I noticed was my VR3 wasn’t giving me any depth.  It wasn’t in dive mode.  I thought to myself, “F*ck, the batteries are messed up?”  Then I remembered, the night before I was being slick and added a patch of Velcro to the back of the VR3 to keep it from slipping around.  The genius that I am, I placed it over the hole for the depth sensor.  Dur!  Now I am getting ready to enter the swim through trying to remove this piece of Velcro.  I got it off and the dive went as planned.  The VR3 reset and then started working correctly.  Note to self, don’t cover the depth sensor on your dive computer.  The dive ran for 76 minutes.  I had a total deco obligation of about 15 minutes.  It was amazing.  I just hung out off the wall watching the deep blue and the coral heads pass buy for an hour.  It was exactly what I needed.  The current did all the work.

The second dive was a little more eventful.  It was planned for a max depth of 100ft and a run time of 60 minutes.  We dropped in and went our separate ways, exploring the numerous swim throughs working our way back and fourth through the pinnacles.  It was awesome.  When we were ready to surface, I neck clipped my BO bottles to my left hip.  I was using two 40cuft tanks, one with air the other with 70%.  The two bottles got tangled.  I decided to unclip one and work it out of the tangle.  As luck would have it, I bobbled it and it landed on my calves.  I reached for it and it slipped through my legs.  I stuck my head up and told Patrick, I lost my BO bottle.  He just looked at me and told me to go get it.  I dropped down to 30 feet to get the bottle.  On the way up, I did another safety stop and shot my SMB.  While I was stowing my SMB, I dropped my spool.  I thought I had clipped it off, but when I got on the boat, it was gone.  Patrick says the water gods are angry with me for using bright green line.  I just think I am a klutz.  I traded a spool for a BO bottle and regulator.  I guess that was the cost.

If you are traveling to Playa Del Carmen or Cozumel and want to do some rebreather diving, Protech is fully equipped to handle all your needs.  Patrick and Co did a great job and made both days very enjoyable.

April 8, 2008   2 Comments