Category — Rebreather

…The very next day I was back in the water with Yamil and this time we couldn’t finish again as I had another course already booked but we could get another two days done.

Then Ritch came in who I had taught previously during his cave diver course to do some training in deep diving and expand his horizon in cave diving with a basic Sidemount class. As Ritch was already a cave diver his basic skills just needed a little brush up but we were ready to go and introduce new information and skills such as SMB deployment, gas switches, team formation in open water, ascent protocols, and so forth. We did a deep diver and advanced Nitrox combination and so the theory was focused on gear selection, dive planning in regards to decompression, gas volumes, oxygen exposure, emergency procedures and plenty of real life examples. During our dives we saw different environments as we used a Cenote for confined water, a sinkhole for our first dives and then moved over to dives in the ocean. During our dives in the ocean we went down to Xpu-Ha and then drove down a bit south to the deep reefs. After arriving on the bottom I have to admit I was surprised how cool the reef was. Anybody that knows me, knows I am not super keen on ocean diving, but I have to say that I really enjoyed the dives there as it was full of life and colour.

Right after that we were back in the caves (juhu) and our first objective was to built a rig that Ritch would feel comfortable in. Being that Ritch is a bit larger then life it wasn’t quiet that easy but not that hard either, and I think at the end we came to a total price on his rig of like 100usd or smth =) The next two days we were training first in open water to get familiar with the equipment and to understand 3 dimensional diving, fine tuning here and there and working on gas management and emergency procedures the basic game. After that we started with cave diving in passages that he could have passed in backmount but only with serious effort but now in sidemount were manageable with ease. It was cool to see Ritches smile after the dives because he felt so comfortable and free under water as never before with a set of doubles especially since the normal backplate simply doesn’t fit on his back. We even had a day to spare and go for a fun cave dive down in Chan Hol which we both really enjoyed!!!

Ritch in a basic harness with a modified BCD

The days after that we could finally finish Yamils cave training with two last spectacular days in Taj Maha and Xunnan Ha. It was kind of funny since I went from the biggest person I have ever trained (Ritch) right to the smallest one (Yamil). The same way I like to challenge my students during training I like to be challenged myself, and so it was really cool to look for ways to make the two comfortable in the water although they had slight disadvantages due to their seize. At the end of the day the two of them really came around during the course and I was more then happy to sign their certification!!!

Right after that it was my time to be student again, Yipi!!! I had enrolled in a GUE fundamentals class with Fred who I know and respect for some years now. I am constantly trying to evolve as a diver and as a diving instructor and part of that is to take classes myself not only to see again how it feels to be watched and critiqued but also to see how the instructor teaches and relates information. All in all it was a great experience and lots of fun and I am looking forward to do further courses with Fred an hopefully also with Danny and Chris!

At the same time my dear friend and dive partner Hans (with family) was is town and so of course we had to seize the opportunity to go cave diving. He had spent the last couple of days exploring with Mauro while I was teaching and now that I was free the three of us went to Cenote 307 adding some 600ft of line in small unstable but awesome cave!!! The day after that we went down to Dos Pisos for a three hour swim around since neither of the two had been there before. There is really hardly anything better for me then going cave diving with a couple of friends and just enjoy a day out in the nature!

Little Hans

The day after that I was back teaching, finishing Anneleens course that she had started with Nando. We had only the last three days left to go from intro to full cave. Anneleen is a local diving instructor who finally after living here for more than a year gave in and started cave diving. It was fun to watch because she instantly was so fascinated and stunned by the caves that she was still smiling hours after ascending =)))))

Finally the last couple of days I had the great pleasure to dive with Dr. Mel Clark and show her around a little bit which was great. Of course it is always cool to dive with another CCR cave diver especially one that is in the hall of fame!!! We did some really amazing dives and finished with an insane trip from Cenote Dos Palmas to The Pit and back. Some 4h of non stop scootering…I don’t know what was better the dive or finally getting out of the water releasing the pressure in certain areas =)

Mel with a 42 ... without batteries in it though =)

After that I got another two former cave students in, Jojo and Chris from the french part of Swiss. We started of doing a stage, multistage course which was really super fun, since I had to teach in french which always kind of makes me look like a stand up comedian. In the evenings my brain was so much in knots that I started to mix all sorts of languages and simply was not able to communicate anymore. Moments like this always make me think of my polish chemistry teacher in high school, being that chemistry isn’t the easiest subject in the first place, only being able to understand every third word of the teacher doesn’t really help either But they both assured me that I was doing great and that they really understand what I am talking about (yeah right…)! Thanks god hand signals are international!!!

Jojo and Chris still suited up to avoid the bloodsuckers

After that Jojo continued with a Normoxic Trimix class which brought me back again to dive in the ocean. After the confined water session in a cenote we dove out of Xpu-Ha, mostly hanging out at the drop off =) Jojo really enjoyed the training especially the ratio deco which was a new concept to him and as he told me changed completely the way he looks at dive planning now! I am always happy and glad to get such a reaction from a student!

So I hope this little report shows why I didn’t post too much in the last 2 months but I was simply too busy living the dream and going diving every day, hahahah! I hope you enjoyed the post nearly as much as I enjoyed the dives!!!

cheers Patrick

Most cave divers may wonder at the beauty of cave maps and may even use them for cave dive planning but few have learned how to make cave maps. I recently taught yet another survey and cartography cave course with Dirk from Germany. We both used CCR Rebreathers as our primary breathing device during the survey portion of the training program. The goal at the end of the program is to have a published map in your hand, made from your survey data.

cave cartography

Most people would think cave map making and the process of surveying is only for cave explorers but if you have a cave in your neighborhood that is already explored, if there are already permanently guide lines installed but no cave map does exist you many want to consider a survey and consequently producing a cave map. Permanent guidelines do not have to be taken out in order to conduct a re-survey. Knotted line can be used for the distance measurement or fiberglass tape for greater accuracy. The NSS-CDS published a great book called Underwater Cave Survey by John Burge with all the details needed to survey and cartography.

Besides cave divers for dive planning there are other parties who may show interest in cave maps might be the land owner for him to see what he has and locations of potential wells, local governments to decide where certain installations such as gas stations and landfills may not be placed, developers to decide where not to construct due to danger of collapse and environmental agencies for natural reserve planning just to name a few.

cave cartography

A cave survey is a slow process and there are at least two ways to go about it 1) survey in and 2) survey out. 1) During the survey in technique the first diver is laying the survey line and the second diver is taking the survey data. The big advantage on this technique is that in case there is a problem the team can exit much faster than entering the cave and no survey data is lost. The survey in technique is a team effort and requires at least two divers. 2) During the survey out technique the line is laid on the way in and the survey is done on the way out resulting in a delayed exit and if the dive needs to be aborted then the survey is ‘hanging’, meaning the survey date is not connected to the starting point. The only advantage of the survey out technique is solo diving situations, with all of their particular advantages and disadvantages.

A cave survey as well has the potential for negative impact onto the cave environment as the dive is very slow and we need to get very close to the survey stations (tie off) as well as the line in terms of potential entanglement or breaking the guideline. Very good buoyancy, trim and propulsion techniques are a must for a cave survey. If a cave map does already exist for a particular cave one should not conduct a resurvey of the cave in order to protect the cave environment. There is no reason to fuck up a cave just to get the survey data and destroy what we love so much.

cave cartography

Once the survey data is collected the data needs to be saved on paper (my favorite) or electronically, or both. Line maps or stick maps can be produced in free software programs such as Compass. The data then can be imported into software programs such as Corel Draw and the map can be produced electronically.

cave cartography

My favorite way of making a cave map is the traditional drawing technique as I see the map as a artistically expression of the cave surveyor and cartographer. The first step is to draw a working map with all the cave information drawn onto milimetric paper. The second step is to draw a copy onto onion paper with all the cave information drawn onto the paper. The third step is to print out all the information shown on a cave map such as names, locations, index, scale, symbols and notes. The last step is to go to a copy shop and have your map copied and ready you are to publish your art work. You even can send a copy of your cave map to the NSS-CDS as they do a yearly competition for the most beautiful cave maps.

Taking the CCR Sentinel cross over course when the opportunity arose in March of 2010 when Nader Quarta from Switzerland came to Mexico to do some fine cave diving in the Riviera Maya. When we were setting up his dive trip he mentioned that he was coming with his Sentinel CCR Rebreather and I asked him if he is an Instructor on the unit. With a positive reply coming back I asked if he could do a cross over course with me while here and he was happy to do one for me while here in Playa del Carmen.

prior diving

The Sentinel CCR Rebreather is made in the U.K. and is the little brother from the larger Ouroboros CCR Rebreather. The Sentinel has a manufacturer depth rating of 100 meters / 330 feet and a very unique Co2 sensor detecting a rise in Co2 in the breathing gas should the scrubber material fail. The Sentinel is designed as a back mounted counterlung Rebreather, meaning you have the front of your body clean and the counterlungs protected within the casing on your back. 

manual oxygen and diluent injector blocks

Back mounted counterlung Rebreathers are used to be not breathing so well compared to front mounted counterlungs due to the harder work of breathing effort as the counterlungs are a bit shallower then your real lungs, making inhalation a bit more difficult then exhalation. During the last years a number of new Rebreathers with back mounted counterlungs came onto the market with quite good work of breathing besides being a back mounted counterlung design. Keeping the front clean protects the counterlungs in case you want to penetrate small caves or wrecks. For photography and filming it is quite nice too as it gives space to bring the camera close to your face. Smaller people with not so much real estate might find it very comfortable as they are not so cluttered with the counterlungs in front.

solenoid assembly

The Sentinel is a bit bulky compared to other Rebreathers but is packed within a rugged design package, large bore breathing hoses and meaty construction components. All parts are fitted together in a way they can be individually replaced at a reasonable cost. The unit looks it is made to last a life time. A nice feature of the Sentinel is the location of the manual oxygen and diluent injector buttons located left and right on the chest within switch blocks allowing the plug in of additional offboard gases.

The two day cross over program started off with the unit itself, learning how to pack the scrubber and work the electronics, which are very different from all others I have used so far in terms of going through an electronic checklist that will let you only dive when completed poperly. In the afternoon of the first day we went to cenote Eden to get through a nice and long confined water session where I had ample time to get used to the Sentinel and work my way through emergency scenarios such as the three H’s of Hypercapnia, Hyperoxia and Hyperoxia as well as a boom scenario, SCR bailout and various electronic features.

unit in pieces prior diving

The second day we went to cenote Manati to complete the cross over program with two long dives where all emergency related drills and skills where repeated multiple times. When we started our diving that day the water was flowing quite strong out of the cenote through the tunnel and into the ocean. The current was so strong that we had to swim very hard against the water flow in order to get further into the open water area of the cenote.

BOV

I was very happy to be on a Rebreather as I had all the breathing gas in the world and was able to check out the work of breathing while swimming very hard for a longer period of time. At the beginning of the second dive I took the time to go through the complete handset menu various times. Very comprehensive, very sophisticated, very capable.

sensors inside the head

As Nad had asked me quite a view questions about the Classic KISS CCR Rebreather we have in the store I packed my unit in the morning and took it with me to the dive site in order to give Nad an introduction on the Classic KISS CCR. The water current was still very strong, actually the strongest I have ever seen in 15 years. While I was on an open circuit single tank Nad was happily on the KISS CCR and off we went for another dive, this time me being the instructor and Nad being the student.

pre-breathing the unit

I had a great time with Nad to learn once more something new and meet new people. The cross over program was very thorough with Nad being very knowledgeable about Ouroboros and Sentinel CCR Rebreathers.

In mid January 2010 I took the rEvo CCR Rebreather cross over course from Mel Clark. The rEvo is a relatively new CCR on the market and is produced in Belgium. There are three versions of the unit as the standard, mini and micro in the physical size of the unit. The unit is designed as a back mounted counterlung Rebreather, meaning there are no counterlungs on the front of the body, keeping it nice and clear for photographers, people with little real estate, meaning space in front or people who do not like front mounted counterlungs at all.

Matt on rEvo looking at Blue Crab

Etienne, a good friend of ours was so kind lending me his rEvo CCR in order to do the cross over course. The new rEvo owner has the option to have the unit configured as either a manual CCR, electronic CCR or a hybrid with the manual and electronic version combined. Etienne’s unit was configured as a manual CCR while Mel’s CCR was configured as a hybrid version, so I had the opportunity to look at them both in detail.

Matt on rEvo Cenote Manati

The rEvo is a very thin and streamlined Rebreather with the counterlungs protected within a metal box on the back, protecting them from damage if diving within wrecks or caves. Each rEvo has 4 oxygen sensors and two controllers or po2 display’s. Depending on owner preference and made to buyer specification they can be both rEvo oxygen po2 displays called Dream, or a Dream and the Canadian manufactured Shearwater electronics hand set display that are either just a po2 display of full blown decompression computer laced into the oxygen sensors keeping the decompression information up to speed and in real time. Again I was lucky that Etienne’s unit had one Dream and one Shearwater po2 display while Mel’s unit had two Dreams and a Shearwater decompression computer wired into the sensors to display the oxygen po2 while calculating the inert gas intake.

Matt on rEvo Cenote Manati

The reason there are 4 oxygen sensors as to the regular 3 sensors seen in most CCR Rebreathers is that one dream is always on only one sensor, not sharing any wires, battery, cables or whatnot, making that one display truly independent and redundant, and great for cross reference to the other display that still has the regular 3 sensors with voting logic. One particular feature on the rEvo is the two independent absorbent canisters configured in line, one after the other. This allows to change only one of the absorbent canisters when staying within two hours of bottom time. This feature is particular nice when doing Rebreather try outs when not the whole load of absorbent is used, and the unused absorbent does not have to be thrown away.

Matt on rEvo Cenote Manati

As Mel was dragging me through the pool of pain (Cenote Eden) I went through all the CCR related emergency drills, learning them from the rEvo unit point of view, with new buttons to use on different locations as the oxygen and diluent manual inflator buttons are located at the but of the unit. The work of breathing is quite nice for a back mounted counterlung Rebreather. Once done with the pain part we went the next day to Cenote Manati. Due to strong winds in the salty ocean stuff we could not dive the ocean but enjoyed some really nice diving, full of emergency drills and scenarios found in a regular CCR Rebreather course while floating through the mangroves of Cenote Manati. The cross over course is a couple of days shorter then the regular CCR course as I did not have to learn the basics of Rebreather diving part but just the unit specific drills, details, ins and outs including pre dive unit preparation, maintenance and post dive care.

Matt on rEvo Cenote Manati

Once I had completed my training dives and bottom time Mel took her camera in the water and squeezed some nice images through her lens of Cenote Manati with me blocking the view. The reason I am still taking courses is that I do not want to lose the feeling to be a student. I still want to learn new stuff and still enjoy the learning experience. Additionally I can now teach CCR cave courses and CCR normoxic trimix courses with my students diving the rEvo as I have completed the diver training program allowing me to understand what my student is doing on his unit. 

Matt on rEvo Cenote Manati

It was great to meet Mel and hang out some days with her, and learn a bunch. It’s always good to see how other Rebreather divers dive in other regions or other environments such as the cold water environment. I truly enjoyed the experience. All images within this article are authored, copyrighted and published with permission from Mel Clark.

A little while ago I was teaching a CCR Cave course down in Tulum. Besides the daily driving it was definitely nice to teach in different places than I usually do. To change the air conditioned classroom and PC with the mosquito infested jungle and a white board didn’t appeal to me at first but having the water and breathtaking nature right next to me had definitely its advantages!

My student was Enzo, an Italian Megalodon diver who had already plenty of experience diving CCRs and after having done plenty of deep and wreck dives finally became interested in cave diving. He also managed to combine his training with a relaxed vacation together with is girlfriend in a romantic hide away hotel right on the beach.

The first day we met with all the gear at Cenote Carwash (Aktun Ha) to start of with paperwork, some theory and gear configuration. It was also the first opportunity to chat about different point of views on CCR diving, Bail out Strategies and Dive planning. After agreeing on important points and trimming and streamlining the gear as much as possible it was time for the first splash. Checking if all the gear works and getting comfortable in the configuration and the new environment. Carwash is really a perfect place for that with its easy entrance and exit possibilities. The first session was only focused on buoyancy, trim, and fining techniques to create a stable platform from which we would be able to perform more complex tasks. At 6pm we left the water and it was time to pack up and head home.

Next day we were back in the same place, this time though less talking and more action. The day was split in two water sessions and a brake with some theory and dry line drills. First up we were working on the CCR related skills. Now most divers when they enter the course have a good understanding on the principles of the ccr skills but never tried to do lets say a diluent flush while staying in a horizontal trim and within an arms reach from the guideline. You also cannot lose your depth control while performing the exercise since that would mean crushing into the sediment covered floor or ceiling which could result in loss of visibility and the danger of damaging a vital part of your equipment. So the main goal of this session is to “cave modify” the already learned skills.
In the afternoon we were working on the cave related skills which added new things while still perfecting what was learned before. The exercises are dealing with zero visibility scenarios and are meant as well to teach the student to deal with task loading in stress full situations. Always with the eyes closed to train other senses and the means to navigate underwater in total darkness.

The next day, after some more line drills, we where finally ready, to depart on our first tour in the overhead environment. The first dive is always a demo dive where the student is walked through the pre dive checks and later shown how to use the reel and how to install the guideline. Being second gives the opportunity to observe and focus on buoyancy, trim, and propulsion techniques.
After surfacing and debriefing we stayed in the water to drop back down and run once more through the CCR skills while maintaining our position in regards to the line, the floor, and our team. Most accidents don’t happen because of a single problem but an accumulation. A key element in avoiding accidents is to cut the chain of errors as fast as possible before it gets out of hand.
After hours in the water we left, tired but happy and satisfied!

The fourth day of our training was here and we were off to a dive site south of Tulum which to cave divers is known as Naharon. A very dark but beautiful place just perfect for conducting training dives.
First dive of the day and the first time for Enzo to be the team leader. On the way out we simulated a zero visibility situation and exited using touch contact and touch and go communication. All in all a good success which just confirmed that all the time we had invested training in the open water was not wasted.
On the second dive we ran through some CCR skills, same as the day before, just this time in the cave in darkness. Bailing out gave us the first chance to confirm our calculations with real numbers from a simulated emergency.

After a day brake we were back at the Cenote for some more fun. On the first dive we repeated the bail out scenario and changed donor during the exit and then continued into a zero visibility simulation to further the complexity of the exercises and to simulate worst case scenario.
Second dive we introduced the lost line scenario after practicing it on the surface. Not on the first try but after conducting a systematic search Enzo found the line and I could here his enthusiastic scream into the mouthpiece.

We continued our training in Jardin Del Eden aka Ponderosa so that Enzo would have the opportunity to see a different type of cave. I generally do at least one dive in Tulum when I am teaching around Playa Del Carmen and Vis Versa.
This day we started complex navigation introducing Jumps, Gaps and Ts as well as techniques to negotiate restrictions with and without visibility. To round the whole thing up we had lost diver scenarios and CCR failures.

The last days we were back down in Tulum diving in Zazil Ha and Grand Cenote to further complex navigation, restriction training and completed an entire dive flying the unit manual amongst other things.

All in all a great course, fun time and awesome dives.

After that Enzo also booked some guided CCR cave dives to enjoy the caves without being hassled by an instructor all the time =) and to simply use the learned in real life.

What I like and what I don’t like – A personal view 

I bought my first Inspiration e-CCR Rebreather back in 1999 and back then there was no choice between Classic, Vision or even the Evolution. It was plain and simple the Inspiration, now known as the classic version of a range of Rebreathers offered by AP, and manufactured in the U.K.

As it was my first Rebreather I ever purchased the choice, and my knowledge about choices, was rather limited back then so I had not much to pick from in terms of other units commercially available to the public … or at least I was not informed enough to know about them. The unit was purchased in Singapore by a friend and then came to Mexico. I did a number of deep cave dives on the unit and sold it about 3 years later to a friend residing in Utilla, Honduras where I believe the unit is still up and running. 

Late last year I took the chance and offer to purchase a used Inspo from a friend of mine who was willing to part from his Vision Inspiration e-CCR Rebreather with only about 40 hours on the unit. The unit was living in Canada at that moment. When the unit came to Mexico it was in a still spanky shiny new turtle box with no scratches on it as the unit was housed during its 40 hours in a aluminum travel frame. 

The things I like on the Vision & what I left as is

Decompression capability – I am actually an advocate of having the dive computer and Rebreather separated but have to say that it is quite nice to have the decompression computer tied into the actual Po2 from the sensors. My CCR capable dive computer (Liquidvision X1) is the primary dive computer and the inline Vision decompression computer housed within the handset my backup.

Handset – I like to be able to put the handset on the wrist as on the classic they were hanging somewhat below my profile and dragging in cave sediments a view times. To have only one hand set on my wrist instead of two is quite nice as well which leaves space on the other wrist for my CCR capable dive computer. 

Sensor changing and placement – They changed the design of the head and now you can actually change the sensors without breaking any water sealing o-rings and need no tools anymore in order to do it. The way the sensors are connected now is better as well as on the Classic Inspiration where corrosion and conductivity issues frequently plagued my diving excursions. They changed as well the metal battery housing screw who is now not located directly opposite the second sensor anymore and does allow the unit being laid on its back without condensation water droplets dripping directly onto the second sensor. 

Tempstick – I have to say that I like the temp stick display even if I do not use it as a reference on how long I can still stay and use the absorbent.

Hydrophobic membrane – I like the hydrophobic membrane on top and bottom of the absorbent cartridge which gives a bit of protection to the absorbent in case we have some water in the can. 

Calibration – I got used to it how easy calibration is on the unit.

HUD -I like the HUD even if the placement is not entirely right for me … because of my big head. I guess. 

The things I do not like on the Vision & what I changed

Softpack – I do not like softpacks with all of them straps and plastic buckles. After all these years of cave, wreck, tec as well as dry suit diving I have to say that I do prefer a stainless steel backplate with all through standard webbing and a sturdy crotch strap. With the use of my standard Dive Rite ss backplate I have all the d-rings exactly where I want to have them, and can use the same backplate for oc and cc diving. This is one of the modifications to make the unit right for me. 

Wing – The original box wing I do not like. With the softpack went the original box wing which was replaced by a Dive Rite 55 lbs Rec wing, but can be changed for any brand, any size wing either single, double or sandwiched. This is one of the modifications to make the unit right for me. 

The inflator and bailout regulator – With the old box wing went the complex and prone to leak (at least mine) inflator and second stage assembly. Not only did I have some leaks but it was hanging below my profile and is in the way of streamlining myself. It makes deflating and sharing gas with another diver at the same time a bit more challenging too. I am an advocate of having my CCR and my bailout gas separated so I am carrying always a separate bailout tank with me. This is one of the modifications to make the unit right for me. 

DSV – I did not ever like the original DSV. Somehow I had a problem to remember which way is open and which way is closed. From my prior CCR diving experience I came to like a BOV quite a lot and it was a much welcomed change on the unit. My BOV is attached to the inboard diluent tank. The BOV access to the diluent tank is only a step in-between in my bailout procedure. It allows me to get off the loop very fast and convenient while I am getting my bailout regulator ready. On deep dives I change to larger onboard diluent tanks. The BOV allows my dive partners intervene externally as well in case I am unconscious or behave erratic. I attached a Golem Gear BOV to the unit. This is one of the modifications to make the unit right for me. 

The box – The yellow and black plastic container I do not like. While traveling a lot I found the large plastic box a bit too cumbersome. The other aspect was that I had to drag half of it around to get my countelungs disinfected. The cover in my point of view has the potential disadvantage that it can trap gas bubbles underneath in case of a leak with either O2 or diluent, quite a bit of gas actually. I first changed that while drilling little holes into the cover. In the end I placed the unit into a steel frame which did a couple of things for me. The ability to travel light and disassemble the unit into individual pieces, to change the backplate and wing fast with any brand and size, as well does the frame allow for a wide variety of back plate and wing mounting positions helping with trim. The open design of the frame I use does allow my dive partner to see all components of the rebreather in order should a leak arise, as well the amount of gas that can be trapped below the cover is very minimal. This is one of the modifications to make the unit right for me. 

Non-detachable counterlungs – Pain in the butt to keep clean and dry. Keeping the unit sanitized seemed to be a drag literally as I had to drag the plastic shell with me to the water source and then somehow place it in a way so the lungs can dry while on the floor or table. I live in a humid environment and want to hang my lungs up to dry, so I cut them off the attachment point and sewed on a d-ring each on top. The top of the lungs are now attached via a quick link to the frame while the bottom part is attached via bungee and a clip to my crotch strap scooter d-ring. The counterlungs are not attached in any way to my harness to allow me to move them around to get to my backup lights, d-rings for bailout or stage tanks or my dry suit inflator. This is one of the modifications to make the unit right for me. 

Tank size restriction – The original plastic box allows only one tank size with one particular valve design to be used. As I travel a lot I may choose to travel with small aluminum tanks or don’t pack tanks at all as I rent tanks at my destination. As my destination provider may not have the tanks I like to have the plastic box is limiting me in my choice of tanks. With the steel frame mounted to my unit I can use Alm 13, 19, 30, 40 and 80 cft tanks mounted to my unit as well as 2, 3, 4, 5, and 7 ltr steel tanks. This option is quite useful when traveling. This is one of the modifications to make the unit right for me with the installation of the steel frame. 

Special sensor – I do not like the fact much that I do need special sensors for this particular unit but another sensor for all my other units which puts me into a situation that I need to stock two different sensors. However, with the new connector a lot of my old sensor connectivity and corrosion issues have been addressed, and all I can do it stock special sensors for the Vision. 

Plastic buckles – I do not like plastic buckles and fast clips at all. In my experience they break way too many times and always at the wrong time, the time I am ready to go diving. With the change to an ss backplate with standard harness and ss buckle this issue has been addressed. With the counterlungs now detachable and connected with metal quick links and clips got me to get rid of all plastic attachment points. This is one of the modifications to make the unit right for me. 

The things that don’t bother me much on the Vision 

Plastic bucket – The bucket where the absorbent cartridge is living inside is made out of plastic but has hold up very well so far including the metal threading embedded in the bucket walls. On the Classic Inspo you could actually rip them out while over torqing the screws that hold the lid on the can but with the Vision you have them little black rotary clips with a lesser or no chance to rip out the metal thread rods.

Single o-rings – The unit is been designed and sealed with single o-rings in all locations only while other Rebreather manufacturers are using a double o-ring design with at times large and thick diameter. So far I had no problems and the unit is tight with excellent positive and negative checks.

Mesh webbing over counterlungs – The new counterlungs have a partial mesh webbing over the inner and actual counterlungs. Especially in cave diving sediments can fall in there and with a lot of time and rubbing action can damage the inner counterlungs but I have had no issues so far.

Battery life – The battery life is not too bad, could be better but could be worse too. I run the unit fully electronic and just carry extra batteries with me. Fortunately they are readily available in most photo stores anyways. 

All in all I am quite happy with the unit after I have done the changes as outlined above. The unit is streamlined, light, is reliable (at least my electronics are), has a very good horizontal trim now with the changes done and is user friendly … at least for me.

Greetings

Matt

While reading this article please keep in mind that 99% of my diving takes place in the caves of the Yucatán Peninsula, Mexico. The opinions expressed in this article are based on my observations of the combined experience of Matt here at Protec, Hans Kaspersetz from Quiet Diver and myself.

Patrick decoing after deep dive in the Pit

I have found the X1 to be an extraordinary tool, considering the environment I dive in and the type of diving I pursue.  The X1’s design and features are both robust and easy to use and facilitate the type of diving I do on a daily basis.

I have used the X1 for: shallow cave diving, teaching and exploring; both in open and closed circuit modes; in environments from huge power passage to tight sidemount cave; for air, Nitrox, Trimix and Heliox; and for up to 7-hour long decompression dives with in water decompression as well as in a habitat.

There are certain aspects that make the X1 the perfect choice for me and here are some of them:

1. The computer is unbelievably small: I think this is a very important factor because of various reasons such as, less entanglement hazard while working with reels and lines, less crowded forearms especially while deep diving and the general minimalist approach of equipment in cave diving. The unit is nicely streamlined and can be carried on both arms with the option of flipping the screen. In cave diving, seize matters!!!
2. The solid body: Anyone that dives in caves will be able to tell you that it is extremely demanding on your equipment. Sharp edges and fine silt that enters even the tiniest orifice put your equipment to the test. The solid body, button less design and wrist mount from Deep Sea Supply combines to make a durable unit that securely attaches to your person.
3. The OLED display: Well, who ever has seen one under water or in pictures knows that the display is very powerful and also readable from almost every angle. A fantastic feature especially for exploring because you can still read the depth reading in extremely low visibility which facilitates the collection of data. In fact the display is so bright that I call it my 3rd back up light.
4. The compass: Honestly I would not use the compass for surveying BUT, you can use it to follow the general trend of the cave while laying line for example. It safes another spot on your arm, two birds one stone.
5. The integrated stopwatch: Very useful for timing decompression stops, low Po2 brakes in the water or habitat, slow final ascents, distances between way points in the cave, runtimes of DPV and many more.
6. The constant updates: Another awesome feature and they are FREE, when you use Ross Hemingway’s V-Planner Live. It is like getting a new computer every couple of months. The new software versions are announced by mail. To download and update your computer takes about 10min and it is easy even for somebody like me who is very inexperienced with computers.
7. The user elected menu list: The new software 4.25 gives you the option to choose the order of the menus. Meaning you can swap things around depending on their importance during the dive. Depending on the type of dive you maybe want to have the compass on first place followed by deco mixes and maybe then the lost gas option or maybe first stop tables then ceilings and display. Before every dive it’s your choice in which order they appear.


Hans preparing for a 325ft / 4.5hours cave dive

8. Plan your dive, dive your plan: I am a fan of Ross´ software since I first used the Z-Planner for deep diving projects in the Egyptian Red Sea. When I got my hands on the first multi-gas computers the calibration nightmare started. I don’t know how often I “bent the computer” because I followed the tables and my computer did not agree…what a nice back up?!? Anyway it always took some time to tweak the settings of the software with the ones of the computer to get them to more or less agree. Now having the same software in the laptop as in the dive computer makes really for nice straight forward dive planning.
9. The use: If this computer was any easier to use a monkey could do it, on a second thought maybe the ones at NASA can. But seriously the menu set up and programming is really great. You still should READ THE OWNERS MANUAL before you use it though. But after sitting and playing with the unit for like 20min you know it inside and out.
10. Customer Service: I have worked in the dive industry for about 8 years and purchased a lot of gear.  Unfortunately, my customer service experiences have been less then satisfying and I rarely have something positive to say about dive equipment manufacturers.   Most will invent the weirdest stories or blame you no matter how something brakes or doesn’t work as advertised. Sometimes it is even insulting.  However, I am happy to report that for the case of the X1 where you have to deal with two manufacturers: Liquivision and HHS Software, I received OUTSTANDING support from Margaret at Liquivision and Ross from HHS. They are incredibly fast when it comes to answering emails, are super professional and very helpful.  I had to deal with them for equipment failures and after a dive accident.

Patrick during Deco

Unfortunately, I cannot report only good things about the X1.  We suffered some hardware failures; however they were dealt with quickly and without cost to us.

1. Problem with depth sensor: There is a known problem, as stated by Liquivision, where the pressure senor port is filled with too much protective white goo.  When the computer is heated up by being in direct sunlight or in the sweltering jungle, the goo expands and the unit senses that it is under pressure and will not turn off.  There are fixes for the problem listed on the Liquivision web site.  If it occurs while on site, Hans discovered that he could just take the computer in the water and the goo shrinks and display the correct numbers.  Liquivision offered to replace the computer.
2. Missing pixels on the display: Matt and I both had some missing lines and missing pixels on the display after only a couple of dives. Liquivision replaced them at 0 cost and we kept the computers (since they were still absolutely usable) until the new units had arrived. The same day after sending a mail to Ross we had a new key to install V-Planner Live again at no cost.

All in all it is really a great tool with a wide range from exploring tiny caves in OC sidemount and getting good readings even in low viz which is crucial for collecting good survey data to several hour long deep cave dives utilizing CCRs with 20 different Bail Out mixes and habitats. The X1 with V-Planner Live is a great product that really jump started a new generation of dive computers. What a great time to be a diver ))

Photos by Matt and Hans

Kreislauftauchen in Höhlen – Das Cross Over Ausbildungsprogramm 

Ich bin gerade mit einem Rebreather/Höhlen cross over Kurs fertig geworden, den ich mit Bill aus Hawaii gemacht habe. Der Grund für ein solches cross over Ausbildungsprogramm ist die Fertigkeiten des „Kreisel“ Tauchens mit den Fertigkeiten der Höhlentauchens zu verbinden. Das Wort cross over bedeutet hierbei, dass der Schüler schon eine Ausbildung für das Höhlentauchen, sowie als auch eine Ausbildung zum Tauchen mit einem geschlossenen Kreislaufgerät (CCR) abgeschlossen hat und nun „Kreisel“ und Höhlentauchfähigkeiten vereinen möchte.

Soweit ich weiß (und ich kann da falsch liegen) gibt es nur drei Ausbildungsorganisationen die die Ausbildung im Höhlentauchen mit Kreislaufgerät ermöglichen IANTD, TDI und NSS-CDS. Um sicher zu gehen,                dass der Taucher bereit ist die beiden Taucharten gleichzeitig auszuüben, wird eine abgeschlossene Höhlentauchausbildung und ein Minimum von 20 Tauchgängen mit 35 absolvierten Stunden auf dem Kreislaufgerät vorausgesetzt. Beides sind äußerst komplexe Aktivitäten in sich selbst und natürlich doppelt so sehr wenn sie mit einander verbunden werden.

Das „Kreisel“- und Höhlentauchausbildungsprogramm beginnt mit einer Diskussion über die sogenannten „Bail Out“ Techniken. „Bail Out“ ist hierbei der alternative Weg zur Oberfläche, sollte das Kreislaufgerät aus irgendwelchem Grund auch immer nicht mehr tauchfähig sein und uns somit keine sichere Rückkehr aus der wassergefüllten Höhle gewährleistet. Ein weiterer Teil der Diskussion, ist die Tauchgangsplanung und die Vorteile eines Kreislaufgerätes im Gegensatz zu herkömmlicher Tauchausrüstung in Bezug auf komplexe Navigation in verzweigten Höhlensystemen. Der Alternative Weg zum Höhlenausgang und ultimativ zur Oberfläche kann in drei Kategorien unterteilt werden, abhängig von den Fähigkeiten und Vorzügen des Tauchers. Die meisten Taucher nutzen das traditionelle „offene System“, Flaschen mit Lungenautomaten, da es am einfachsten zugänglich ist und auch einfach aufgebaut ist. Die zweite Möglichkeit besteht darin ein mitgeführtes halbgeschlossenes Kreislaufgerät (SCR) zu nutzen und die dritte Möglichkeit ist die Nutzung eines weiteren geschlossenen Kreislaufgerätes (CCR). Wenn die 1/3 Regel des Höhlentauchens in Bezug auf Atemgas strickt umgesetzt wird besteht auch die Möglichkeit mit drei Kreislaufgeräten zu tauchen (Jochen Hasenmaier, Olivier Isler).

Die nächste Frage in Bezug auf „Bail Out“, ist das Individuelle oder Gruppen Konzept. Die vor- berechnete, benötigte Gasmenge die nun entweder von jedem Taucher komplett selbst mitgeführt wird (Individuelles Bail Out) oder von der Gruppe als Gesamtvolumen auf die einzelnen Taucher in der Gruppe (Team Bail Out) verteilt wird. Es ist darauf zu achten, dass genug Atemgasreserven vorhanden sind, um einen Atemkalkdurchbruch mit eventueller Hyperkapnie und den damit zusammenhängenden Atemgasbedarf Rechnung zu tragen. Im Team Bail Out wird eine Minimum Reserve von 50% eingebaut die es erlaubt 1 1/2 Taucher sicher an die Oberfläche zu bringen.

Die komplexe Ausbildung umfasst alle höhlentechnischen Ausbildungsschritte wie das Austauchen aus der Höhle mit Köperkontakt in Nullsicht, das Austauchen aus der Höhle mit Ersatzlampe, Atemgas in null Sicht teilen, eine verlorene Leine in null Sicht wiederzufinden sowie das Leinenprotokoll, Aufmerksamkeit gegenüber den Tauchpartnern und Schutz der Höhle, all das, nur eben mit einem Kreislaufgerät.

Zusätzlich müssen die Kreislaufgerät bedingten Notfallübungen wie teilweise- und voll geflutetes Gerät, Hyperkapnie, Hyperoxie, Hypoxie, manuelle Bedienung eines elektronischen Kreislaufgeräten sowie als auch langes horizontales austauchen aus der Höhle während man von seiner Bail Out Flasche atmet.

All diese Übungen sind dem Höhlen – Kreislaufkandidaten nicht neu da sie schon eine Höhlentaucher- und eine Kreislauftaucherausbildung absolviert haben wo diese Übungen schon viele male lediglich separat durchgeführt wurden. Der “Kreisel“ – Höhlen cross over Kurs führt die beiden Taucharten mit Diskussionen und Übungen im Freiwasser zusammen und endet schließlich mit Übungen die sicher für den Taucher und sicher für die Höhle durchgeführt werden. 

Was dem Kurskandidaten hilft ist, so viele Höhlentauchgänge und so viele Tauchgänge auf dem Kreislaufgerät wie Möglich absolviert zu haben. Die Handhabung des Kreislaufgerätes sollte automatisch ablaufen da wir von der einfachen Handhabung auf eine komplexere Handhabung übergehen die es uns ermöglicht trotz Problemen mit dem Kreislaufgerät zumindest ein wenig beziehungsweise komplett aus der Höhle auszutauchen oder das Gleiche mit Hilfe der Bail Out Flasche(n) zu tun.

Das Tauchen mit geschlossenen Kreislaufgeräten (CCR) in wassergefüllten Höhlen ist eine sehr komplexe Art des Tauchens und der Taucher braucht deswegen Zeit um die komplexen Übungen in der Höhle sicher und geübt durchzuführen. Neben den vielen Vorteilen wie zum Beispiel das vermeiden der Dehydratation, dem warmem Atemgas und der besseren Nutzung von Atemgasreserven bei tieferen Tauchgängen liegt der große Unterschied zwischen „Offenem“ und „Geschlossenem“ Tauchen darin das man längere Höhlentauchgänge machen kann, solang der Taucher sich innerhalb des vorausberechneten Bail Out Radius befindet. Der Bail Out Radius ist einer der vorausberechneten Limits, genauso wie die benötigten Sauerstoff und Diluent Gasmengen, der mitgeführte Atemkalk und dessen Nutzungsdauer.

Geübte Deutschleser werden sich sicher wundern was mit meiner Grammatik los ist. Ich kann zu meiner Verteidigung leider nur sagen, dass ich seit fast 20 Jahren nicht mehr in Deutschland lebe und es mir deswegen ein wenig abhanden gekommen ist. Deutsche Sprache = schwere Sprache.

Gruß und viel Spaß beim „Kreisel“ und Höhlentauchen.

Matt

CCR (Closed Circuit Rebreather) cave cross over

I recently conducted a ccr cave cross over with Bill from Hawaii. The reason and purpose of the ccr cave cross over program is to combine ccr rebreather diving with cave diving. The term cross over is coming from the fact that a diver who had a cave diving education in open circuit as well as a ccr rebreather diving education who wishes to combine his cave diving experience with his rebreather experience.

The ccr cave cross over program to my knowledge (and I could be wrong) is only offered by two training agencies, IANTD and NSS-CDS. The prerequisites to participate in the ccr cave cross over is to be a trained cave diver with cave diving experience (75 cave dives with Bill) and to be a ccr rebreather diver with at least 20 dives and 35 hours on his unit (30 dives and 35 hours on his Classic Inspiration for Bill) to ensure that the skills of cave diving and rebreather diving a well rehearsed before bringing the two together.

The ccr cave cross over training program starts with a long discussion about bailout techniques and concepts as well as the advantages of diving a rebreather in water filled caves in terms of time we can spend and complex navigation we can do. Bailout is the alternative path to the surface in case your rebreather is non operational for whatever reason allowing us to return safely to the cave exit and surface. Bailout can be organized in three ways: open circuit (o/c), scr rebreather or ccr rebreather depending on a diver’s preference and recourses. Most divers opt for o/c as it is the easiest to obtain and simple. Team bailout concept versus individual bailout concept is a question about how much gas is carried by each individual, if the needed bailout volume to bring at least 1 ½ divers to the surface will be split in-between the divers or carried by each individual diver.

The complex and task loading training for the ccr cave cross over is coming from the fact that all cave diving related skills such as touch contact in zero viz, backup light exit, sharing gas in zero viz, lost line in zero viz plus the line protocol, team diving awareness and cave conservation have to be done using the rebreather doing them in the cave. The rebreather related skills such as partial and complete flood recovery, hypercapnia, hyperoxia, hypoxia, flying the unit manual as well as long horizontal o/c bailout swims have to be done in the cave.

All drills and skills are not new to the cross over student as he has done them many times before, only in separate environments and different breathing sources. The ccr cave cross over program is to bring the two together by first discussing the drills, then practice in openwater and then to practice them in the cave environment with safety and cave conservation in mind.

What will help the student is to have done as many cave dives as possible before the cross over as well as have done as many as possible rebreather dives on his unit. The basic operation of the rebreather should be second nature as we move from basic rebreather training and diving into a more advanced form of rebreather diving where we have two choices after an event on the rebreather which is either to stay o/c or go back onto the loop if we have figured out what is wrong with the unit, and go back onto the loop after a diluent flush to do a full or at least partial exit out of the cave using the rebreather.

Ccr rebreather cave diving is one of the most complex forms of diving due to the complex and task loading skills that need to be mastered by the ccr cave diver. To dive a rebreather in a water filled cave takes time to learn but can open new doors into the art of cave diving as we are not just going in and out of the cave anymore but are freed to stay much longer, as long as we stay within our bailout range and within save diving parameters including our consumables such as oxygen, diluent and Co2 absorbent duration and time limitations.

Save diving and greetings

Matt

Bailout is the alternate path to the surface if our rebreather does not work anymore for any given reason such as a full flood, not trusting the unit anymore, flooded handsets, malfunctioning mushroom vales or electronics failure. The CCR Cave Diver has a variety of options, scenarios and approaches that will get him back to the surface safely.

In an open circuit ( O/C ) bailout scenario the minimum breathing gas that is needed and to be carried by the team is the breathing gas volume needed to get 1 ½ divers back to the surface. In a rebreather bailout such as a SCR or CCR bailout rebreather a second rebreather can be used as bailout to bring us back to the surface in case of our primary unit malfunction. If we think in overhead environment terms gas planning , in particular the rule of 1/3’s a second rebreather might not be the end of the scenario but a third rebreather might be considered.

In the 1 1/2 diver to the surface scenario, diving in a team of 3 we calculate the gas volume needed for 1 1/2 diver and can separate the needed gas into 3 tanks, carried by three divers. The needed bailout volume is seen as a total carried by 3 divers. The team-bailout approach may work in most cases but it does not factor in a team separation, particular for the diver who is on its own who does not have sufficient bailout gas to come all the way back to the surface.

I believe that having and major rebreather problem that forces me to take drastic actions or even may force me off the loop, and due to that major problem in the cave environment we may create bad or zero visibility that could result in a team separation is not something I personally would like to leave out of the equation and my dive planning.

CCR cave diver with bailout tank

As the individual bailout approach is allowing to have for each CCR diver sufficient bailout gas to bring every diver separate to the surface, plus a margin of reserve the CCR cave diver has a larger bailout gas reserve. During later dives this can be practiced and then expanded upon to further penetration and team bailout approach as larger bailout gas volumes are needed if depth or penetration is expanded.

The whole bailout concept needs to be understood by the CCR cave diver in terms of not having all the time in the world anymore when on open circuit bailout as we are breathing our life support away, a breath at a time. Potentially we need to deal with some 25 – 30 % more decompression due to falling Po2´s on the way up and or poor bailout gas choices, depending on dive profile. Teaching a CCR cave course or diving with a rebreather in a cave without proper bailout planning capability to the student or diver is nothing else then giving the student or diver a loaded gun.

On open circuit bailout tanks a long 5 or 7 foot / 1.5 or 2 meter hose is a must and the deployment of the long hose from the always open and turned on bailout tank must be well practiced during predive safety drills. That will be a life saver and in some environments the only way to deal with a failed CCR while diving in a cave. Handing over the bailout tank in a fluid motion while sharing gas now on o/c and being under time and mental pressure will only lead to further problems, delays and stress. The hand over and sharing of the 7 foot hose, and not the handover of a stage tank will be the key to some real emergencies. However, the hand over and exchange of bailout tanks in-between divers must be well rehearsed to enable proper execution in case the skill is needed in earnest.

The choice between team or individual bailout, the balancing of bailout gas volume within the team, within all present bailout tanks must be discussed and rehearsed within the team prior diving and followed in either 1) team approach because the needed volume is split up in-between the team members and the out of CCR diver need their gas to make it back to the surface alternating between bailout tanks when the gas pressure reached 50 % of the initial starting pressure or 2) individual approach to have enough gas for oneself but not breathe the bailout tank totally empty and loose all redundancy when still with other team members, alternating here as well on the 50% rule. Larger bailout gas supplies are present with the individual approach, even when diving as a team allowing for delays exits such as restrictions, zero visibility, potential team separation and increased RMV due to stress.

When talking about the furthest point of penetration o/c bailout versus right before deco or close to exit bailout it is the furthest penetration that would be most problematic, as the divers still have to do the exit out of the overhead environment and then potentially have to deal with decompression. As we are talking about cave diving and not ocean drift diving we are able to stage the deco gas bailout if needed at the cave entrance. Having planned and carried sufficient bailout gas traveling horizontally through the cave will be the trick. Potential air hogs that go CCR to have more time in the cave still need to sling them large bailout tanks or they going to be running out of bailout gas fast. Taking a bailout tank without proper volume planning and reserves is like Russian roulette, and must not be done.

Besides opting for O/C bailout different options have been developed as Jochen Hasenmaier, Olivier Isler and the Wakulla II team went to SCR or CCR bailout for at least two reasons. First the bailout gas volume and the ability to carry it, drag and streamlining, second is time pressure of diminishing gas supplies and associated stress levels translating in potential errors and elevated RMV. If diving in deep caves the decompression obligation and related gas volume requirements are a factor too.

The bailout gas and volume planning will bring with it a change of breathing gas and Po2 at the bottom, changing decompression schedules and breathing gases needed to finish the warranted decompression. A dive computer capable of switching from O/C mode to CCR mode will help to control inert gas loading either wired into the loop with a separate sensor, or separate from the rebreather. Breathing gases as well as CCR and O/C operation of the rebreather can and must be changed when going from CCR to O/C in a bailout scenario in order for the dive computer to give us the correct inert gas load information. Diving with only one of such dive computers has no redundancy, that is where submersible tables or dive plans come in. Bailout gas volume calculations are a must and are done prior diving and separate to insure sufficient breathing gas bailout volumes.

In my opinion we need to take submersible bailout tables with us underwater in order to recalculate potential changes in dive plans as long we stay on our CCR. Submersible tables need to be designed for the breathing gases used during proper function of our CCR as well as the O/C bailout gases we may use. Planning dives with deco planning software including the calculation bailout scenarios with to deep and to long profiles as well as having them on a slate works well when diving known caves and profiles.