Transition to CCR - YOUR experience?
Hey all rebreather divers,
I'm looking for opinions from people who had fair cave experience on OC, THEN went to CC. How did you handle the transition? How many dives did you do in OW first? Did you do deco in OW first? Did you take any instruction?
It seems nuts to do a full 8 day class all over again, so another question is, did anyone do a crossover with someone that was shorter? Was it a sanctioned class? There seems to be no official crossover class - strange that you can do a sidemount crossover but not a CCR one!
I'm hoping that by seeing what others did I can make an informed decision on what to do myself. I ain't doing 8 days of training, that's for sure!
THose of you with an... ahem, agenda against one or another agency, please let's keep this civil!
Transition from OC to CCR.
I am not sure how fair is defined, but I had about 50 OC cave dives and about 40.5 hours on my Meg before I went cave diving with it. I had been doing open water deco dives and wreck penetrations with it in New Jersey. And felt very comfortable. I am IANTD certified on the Meg for Open Water to 145'.
I had originally been committed to getting Cave CCR trained, however after moving to Mexico the 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 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 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.
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.
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, you don't know what you don't know, until you learn it. And your never really sure what the payout will be. So, I am really torn, normally I am all over getting the training, here I am having trouble seeing the value.
I went for a nice 2:40 dive at Naharon today on the Meg. That place is perfect, the passages are larger, 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 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 break down 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.
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.
I don't know whether you should go for training or not. I do know it is a challenging process, that I have to practice at a lot. Sometimes I just want to sell the unit, sometimes I want to hug it.
Hans
I added some more information and cross posted this to my cave diving blog here: http://www.quietdiver.com/46/transit...ve-diving.html
