Category — Trimix diving

The days of deep air diving are long gone, helium is our friend now, not our enemy anymore. I always thought of trimix as a deep diving gas, meaning deep as below and beyond the recreational diving limits.

During an advanced nitrox course I taught not too long ago with local student Andrea we planned and conducted dives in the 80 – 100 foot/24 – 30 meter range when we discovered that Andrea was getting nitrogen narcosis around 90 foot/27 meters of water, fresh water in our case.

I could see her clearly getting affected by the inert gas narcosis watching her communication change, her handwriting to change as well. During de-briefs we came to it that she was affected and did not like it, neither did I.

Realizing that we need a reduction in narcosis made me change the breathing gas (and training program) from advanced nitrox to advanced recreational trimix (IANTD terminology for nitrox with helium) bringing helium into the mix. The word “advanced” meaning we are planning decompression dives and using a stage bottle of ean50 for our decompression to have a better quality of decompression as well as accelerated decompression. V-Planner software was used to plan the dives.

So what is recreational trimix? Recreational trimix combines the advantage of nitrox with an elevated oxygen content in the mix to prolong non-decompression times and shorten decompression obligations with the adage of helium to reduce and adjust the narcosis level at any given depth to the users liking, in our case (and IANTD standards) the narcosis depth was adjusted to 80 feet/24 meters.

Subsequent dives where planned and conducted using 30/15 and 28/15 trimix mixtures allowing us to plan and conduct sinkhole and cave dives (Andrea is a cave diver as well as sidemount cave diver) to 120 – 130 feet/36 – 40 meters without the feel of any narcosis as the narcosis level of the breathing gas was adjusted to 80 feet/24 meters, a depth Andrea did not feel any signs of narcosis.

As we were diving within recreational depth limits the implementation of helium greatly attributed to the save and nitrogen narcosis free dives we both enjoyed so much. Trimix is not necessarily a deep diving gas. Yes, diving close to the recreational diving depth limit is somewhat deep but not what most trimix divers would consider deep. There are divers however that might feel the onset of inert gas narcosis at a much shallower depth, well before the recreational depth limits usually associated with inert gas or nitrogen narcosis.

Memorable in particular was our last training dive at the end of her training program conducted in “the Pit”. Awesome diving with a great student. Congratulations Andrea for a job well done.

Matt

Recently I taught a normoxic trimix course to friend and tattoo artist Johnny who liked the idea of learning how to dive deeper without the hinderance and potential danger of nitrogen narcosis.

As we discussed where he most likely will do this type of diving it became clear rather fast that Johnny is an avid cave diver (full cave, basic & advanced sidemount cave plus advanced nitrox) making the move to permanently settle in the Playa del Carmen, Mexico area. A plan was formulated to spend the training dives in the deeper caves and sinkholes within the Riviera Maya such as Cenote “the Pit” and “Angelita”.

The first step was to brush up on theory and dive planning and as we had to do quite a bit of blending to do for our dives it was decided to incorporate the nitrox and trimix blending programs into the technical cave normoxic trimix training program.

The first day seemed to be dragging on in the classroom but we made good progress and by the end of the day we were getting our gear ready for the second day where we spend countless hours in the “pool of pain” known as Cenote “Eden”. It’s called the “pool of pain” as most advanced forms of diver training start right here and new techniques that might take a while to practice, the newly learned drills being polished to mastery could cause some frustration … and some tears. Johnny and me where joking around as we are both in the buiz of dishing out pain. Johnny in physical pain as he is tattooing people (including me) and me as I am dishing out mental pain drilling people underwater. We where both wondering who is leaving longer lasting scars and as I was looking at my arms (tattoo’s) I would have to say Johnny does.

The first deep diving day was down south of Tulum at Cenote “Angelita”. Before you dive you have to go see the landowner, Ricardo, son of Don Pablo who was checking me out how I am this morning. Not so much about my diving qualification as we know each other for 17 years but more how the weather is, how few people show up lately (low season), the lemons that grow well, by the way I had to bring some back to Tulum for cooking.

As we drive down the highway we marvel at the wide sky, few clouds and little traffic. The training dive with Johnny being the first time on trimix went somewhat interesting as the liftbag- smb deployment and communication gave us ample food for thought and discussion. The drive back to Playa del Carmen is easy but I always think the driving is more dangerous than the diving. When back at the shop in Playa the blending Fest starts and mixing is in full swing for tomorrows dive in “the Pit”.

Next morning we are up early, analyzing breathing gases, packing up, checking our dive plans and off we go down the road south to the Dos Ojos cave system, namely “the Pit”. The road is almost a highway now, a vast differences from the past mule train through the bush kinda deal. As we get ready to dive most of the cavern divers coming out leaving the site to us. This is the first time Johnny is laying some line at depth and the time pressure and task loading is showing in communication issues that lead to a shorter than planned bottom time.

As we discuss things in the debriefing we identify the issues to be addressed and formulate a rough dive plan on the way home to our ProTec Playa home base commencing blending as soon as we get there. The realization is setting in slowly that trimix diving is a bit more than just analyzing the tanks and go for it in particular if you have to blend all your gases yourself. I believe every trimix diver should know how the gases are actually made with hands on experience as it is such a vital part of the dive plan. It is decided to repeat the dive of today to get to our target depth in a less then stressfull manner.

As we get to “the Pit” the third day of diving we are greeted by a large 25 member cavern dive team that forces us to wait for about 30 minutes to get down into the water. The large team is almost out when we get in leaving the place once more to us. This time we have a nice relaxing dive with good team procedure and communication. As we get out the parking lot is almost empty.

For the last diving day we choose to get to the bottom of “Angelita”. A beautifull day it is again, the morning chat with Ricardo the land owner anticipated and appreciated. The parking lot is empty, no rain and a light breeze is cooling us down. What a great day.

As we are in the water we do our pre-dive checks including a pre-dive visualization that helps to leave the bullshit behind and focus on the dive at hand. On the way to the bottom of “Angelita” you have to get through the hydrogen sulfide layer about half way down, level out on top of the debris cone and follow it all the way down to the silty bottom. When you look up you can see the gloomy light coming through the sulfide layer illuminating the debris cone covered by old trees. Awesome sight. I love trimix diving!

Johnny was a bit apprehensive at the beginning of the training program as the task loading and time pressure stressed him out quite a bit. But now after this cool and relaxed dive with the c-cards for eanx blender, trimix blender, technical cave diver and normoxic trimix diver in his hand he is a happy camper. Well done Johnny … looking forward to get more tattoo’s!!

Matt