Advanced Trimix for Closed Circuit Rebreathers

June 16th, 2008

Well, this afternoon my good dive buddy Nailer and I (and our new buddy Larry) threw up our caps (hoods?) as we graduated from Advanced Closed Circuit Rebreather (CCR) Trimix class (I believe this is called Mod 3 in Europe). This means that I can use hypoxic amounts of oxygen (less than 16%) mixed with helium and nitrogen, in various amounts, as diluent when mixing with pure oxygen in a closed breathing loop. I am now certified to dive to 330 feet, which opens up a lot of diving options.

It seems like forever ago, but just 7 months prior I started my first CCR class, Air Diluent CCR cert. It did take me months to find the groove on the Meg, but sometime along the way it just clicked. I’m glad I stuck with it because honestly, those first dozen dives or so had me thinking, what have I done?. Now I feel pretty natural in the water again, not as carefree as on OC before I made the switch, but definitely confident, which is huge.

I never thought that I’d be diving with this much crap attached to me. This is coming from a guy who was thrilled when he got an Atomic SS1 because I wanted to eliminate every hose possible on his regulator (I also had a wireless computer). Now, our diving rigs are so complex that we look like we’re going on combat missions and it takes some real planning, preparation and help to go on dives.

My toolbox used to be a big green van (Nailer’s work van) that I hoped would happen to be around when I needed a wrench or some o-ring lube. Now, I not only have my own toolbox with me, I can actually assemble, disassemble and fix most gear-related issues with my rig (which is a very daunting set of challenges when one first sees what goes into a rebreather).

I don’t feel like I have a really high chance of dying on every dive, because I’m not sure if I put an o-ring or part on backward, and I actually know what’s going on with the gas planning, mixes, PO2s, etc. In all, I’m really glad I made the decision to go closed circuit, though it will still be awhile until I’m back at the level of muscle memory and comfort that will allow me to shoot photos like I used to. But, when I finally get there, I’ll have such a wider range of subjects to shoot, given the range of the Megalodon.

Anyway, diving a rebreather is not for everyone out there, and I don’t think that I would enjoy it like I do, had I not taken the time to stop and smell the roses along the way (learning many things on open circuit first). I will always love the simplicity of being able to toss a tank and some basic gear in the truck to go diving on the spur of the moment, but I have to say that I am actually enjoying prepping the rebreather and going through all the various precise procedures one has to go through to make the machine work. It’s challenging, very challenging… but most importantly – it’s fun again.

Anyone who’s interested in learning more about rebreathers should consider checking out the upcoming Rebreather Experience. It was my first exposure to rebreathers, exactly one year ago. What a year of diving this has been.

Entry Filed under: Puget Sound