
Originally Posted by
mstueven
I think I was a bit ethereal in my first rendition, so let me try this with a more concrete example and a couple terms defined for the purposes of discussion. "Standard" is something an instructor must follow while teaching. "Limits" are the rules you are to follow once you are certified.
I think that cert limits are a good idea to make more available. That way, we wouldn't all be arguing about this. There'd be a clear cut "This card certifies you to dive within the limits of: No deco, no major restrictions, 130ft max depth, with a buddy, on the gold line, to sixths of two tanks"....or whatever. Then, if someone was diving thirds, double-stages, deco on trimix to 160ft through restrictions we'd know, clearly. They could even reference official definitions of each of those. This could open up some ugly cans of worms, though.
Is an intro diver with a previous trimix certification perform limited to cave dives shallower than 130'? Does being full cave change the limit, or do I have to have a cave trimix certification?
My understanding is that yes, being Intro limits you to 130ft, period. My Intro card also clearly states "No Decompression." I was told that that was true, REGARDLESS of other certifications. I've met Full Trimix Instructors that are Intro certified and weren't allowed to do deco dives in the overhead. And yes, Full Cave does change that limit. Full Cave, the way it was explained to me by an instructor, was the "license to do any cave dive you'd like." My instructors told me that them giving me a Full Cave card meant that I was expected to be mentally and physically prepared for much bigger dives than I should be doing at that time. It was made clear to me that, while I was allowed to be as aggressive as I'd like, I should use my best judgement before making a dive and that they were giving me the card under the impression that I was wise enough to not go straight to a 4-stage scooter dive but that I'd expand my limits gradually. Deco and mixed gas were both covered topics (briefly) but they were topics for another course.
Can an instructor teaching a full cave course to a trimix certified diver do a training dive deeper than 130' and stay within standards?
I'm no instructor, but my understanding is that they cannot. Training standards seem to me to indicate a max depth. My cert limit is 130ft END, which would allow mix....but I don't think the training standards phrased it as END.
In other words, are the limits restrictive (always limit yourself to the least) or cumulative (dive to the limits of your highest level of training)..? What about the standards?
I think it'd be foolish to think they were cumulative, or anything other than restrictive. Same goes for standards.
And yes, I deliberately loaded the question, because I see divers and instructors in real life and on the internet doing it whichever way is convenient or best for them. I also deliberately used trimix rather than AN/DP to avoid the AIR/END arguments, which isn't the point. Although we might throw rebreather in where trimix was at and see what people think then?
I think the CCR case is different because it's my understanding that there are separate courses for CCR divers that lack overhead training to go straight to Cave without separate OC Cave training. I know many CCR divers get OC Cave training and then do a crossover, but I think most CCR divers jump straight to Cave. CCR is something I'm fairly ignorant about, though, so please correct me if I'm wrong.
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