Category — Rebreather training

I just come out of a pretty busy run full of teaching and exploring, tiring but fun and now as things slow down a little bit I can take the time to write about it.

When I had finished the basic sidemount course with Wayne I was off on three weeks vacation. First I had planed to travel to Dominican Republic and everything was set until my travel partner had to cancel due to work obligations. I was pretty bummed out about the whole situation but when Mauro asked me to join a project he and Alex where pursuing I forgot about the situation and was looking forward to go and explore with the two.
In the same period of time I also got the second draft version of a sidemount rig I help to design which instantly outdid all my expectations and gave me great motivation to go out and dive again daily. So besides exploring I also dedicated a good amount of time to testing the rig in various different diving environments as well as techniques ranging from wet to dry suit, stages and scooters in backmount and sidemount seized passages.

With Mauro I was exploring in Cenote Balan Ak where Alex had established the relationship with the landowner and out of Cenote Palomita to resurvey and push some lines. A great pleasure to hang out and dive with the two guys who are both so passionate about the exploration there.

After that it was back to work and I started my first course right away with Mark who came in to do a deep/advanced nitrox combo course. A cool start that gave me also the rare possibility to dive in the ocean. After one day in a Cenote for confined water training and another day in the sinkhole Angelita we lost a day to sickness. Having only one day of diving in the ocean left, we couldn’t finish the training but Mark has already booked his return in September where we will not only finish but also integrate the advanced recreational trimix course.

Before the next course I had the great opportunity to help Nadia a cave explorer that lives down in Tulum with her mapping project of Cenote Dos Pisos. It was a super experience, first of all since I had never attempted to produce a large scale cave map (besides stick maps of course) and second it was cool to hang out with her and talk about different projects she is pursuing with her husband Dave in the area as well as some of the history of  the Cenote and the Cave System.

After that I almost instantly went into a CCR cave course with two Germans, Dirk and Thomas who came equipped with an Inspiration and a Megalodon CCR. Dirk had already done his course in Thailand some time ago and already visited Florida and Mexico for cave diving but wanted to sit in and train with his buddy. Dirk was one of my really first advanced nitrox students back when I lived in Egypt and to see him now as a very skilled trimix/cave ccr diver puts a big smile on my face. Thomas being a very experienced trimix ccr instructor himself made for a great team and hard for me to challenge the two.

Thomas and Dirk back from a dive in B Tunnel

The first two days we spent in the open water working on buoyancy, trim and fining techniques as well as looking at the units and trimming them down to minimal seize. We also went through all of the ccr related exercises followed by zero visibility training and touch contact and touch and go procedures.
Third day had us in the cave ready to go and trying the first time all ccr skills while staying horizontal within arms reach of the guideline. We realized quickly that doing those skills in a dark place with limited space while staying perfectly trimed with neutral buoyancy is not a quiet easy thing to do =)
The next five days we were working on many different scenarios including hyper and hypoxia drills, boom scenarios, hypercapnia, long hose gas sharing of bail out, passing restrictions in zero viz, complex navigation, surfacing in zero visibility, solenoid stuck close and open during a cave dive, lost line and lost diver and many combinations of the above.
During the entire course we had lots of fun and a general relaxed atmosphere and shared many stories of diving the cold lakes in europe =)
Both of them came very open minded in the course and with a lot of experience which gave us many interesting topics and point of views to discuss, all in all a great time!

Dirk and Thomas tired but happy!!!

After that Dirk who had brought his own scooter enrolled in a three day basic cave dpv course. We were using Bonex(dirks), Silent Submerge as well as a Divex Cuda during the training to see different performances and characteristics of the models.
First day we were doing theory all morning discussing pros and cons, gas management, emergency procedures, conservation and other topics before driving to Cenote Ponderosa to do our initial training. We were practicing different towing techniques, how to keep neutral bouyancy while driving, touch contact, touch and go and runaway dpv failure which especially on the bonex is an easy scenario due to his master switch.
The next day we were in the cave all day long going through lots of complex exercises involving lost line and lost diver during a dpv dive, computing different RMVs and times which are essential to dive planing, zero visibility drills including picking up gear, dpv failures, time awareness and so forth. Dirk realized very fast that there is more to scootering in a cave then pulling a trigger =)
Last day we implemented all of the previous learned in complex dives in cenote Mayan Blue which turned out to be just amazing! The previous long days payed of and we could use our rebreathers and scooters effectively. We did long dives covering an amazing distance while relaxed sight seeing knowing that at all times even with two catastrophic failures we would still be able to safely exit the cave. Now Dirk must get some more experience using his new favourite tool so that next time we can bring out the long range dpvs and take it to the next level. =)

The next day I went straight over to a OC cave course with Yamil a local diving instructor who had started some time ago but couldn’t finish due to work obligations. Again we were not able to finish his training due to a bad cold that knocked him out after the first two days.
At least that gave me the opportunity to squeeze some days of exploring in and even a fun dive with friends from Utila (Frank and Andy). We were a big group consisting of Dirk, Thomas, Mauro, Frank, Andy and myself and were diving in separate teams in Cenote Muchachos. Dirk and Thomas on CCRs, Mauro sidemount and stage, the Utila gang after finishing their basic sidemount training with Nando in their new rigs and me CCR also and dpv. A great day with 3h+ dive time =)

The following day I welcomed Nick who came in to “upgrade”  from GUE Cave 1 to Technical Cave Diver. We had met before to discuss exactly the expectations that he had in the course and that I had from him as a student. Nick came in as a highly trained, skilled and experienced diver which made my job both very easy and difficult. Easy in a way that he learned extremely fast difficult in a way of bringing him close to the edge of his comfort zone to establish some limits. The main new information and skills we had to cover were navigation, restrictions, deco bottel and stage tank use in the overhead environment and reviewing the stuff he had already learned and all of that on a tight schedule which ment early mornings and late evenings, especially for me as Nick stayed in Puerto Aventuras…
Nick is an avid deep and wreck diver from Australia which made the lunch brakes very entertaining as he shared some insights on the local wreck and cave diving in the land down under. I really hope I will get the chance one day to visit him there and check it out!!!

So that was part one…part two will be up in some days…I hope you enjoy =)

cheers

Taking the CCR Sentinel cross over 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.