It all depends on the diver. Doing just intro to cave will invite some divers to do jumps without course and go over gaslimits. Others do a cave class and stay first 50 dives on the mainline.
I see same back in my students. Most are carefull after a course and dont do directly to their limits they are allowed to do, they enjoy diving on a 'lower' level. For example on the mainline, but using more than the 1/6 rule. But the intro to cave is really limiting. And it invites to go further than you have learned. I see it everywhere around me. Then it is much better to do the rest of the course also. People who are unsure or not so skilled will know that in the intro part and will stay for some time at that level, they don't progress in the same week to full cave.
You have to look at the diver. For a really well skilled full trimix diver, the cave course is not that difficult if the diver has no problems with being overhead and realise 1km in is 1km out. The new skills are line work. With good bouyancy it is mostly not that hard. Cave awareness takes some time, but the more skilled a diver is before starting a cave course, the faster he develops the cave diving techniques and cave awareness.
Same you see with ccr. With ccr you can go from mod1 to mod3 if you are allready a full trimix oc diver. When I started started ccr, 2 weeks after buying my own unit I signed up for a mod3 course 3 months later. I would have then around that minimum of 50 hours. The course went to 76m and day after course I went to 100+ with my experienced buddy.The whole week after course we did every day 100-128 m. And I would say: I learned more from my own deep dives with an experienced buddy then the mod3 course.
Then I started ccr cave diving. And dpv ccr cave diving. And sidemount. Long time later I did the user courses. Not really eye opening anymore then, but I had some nice discussions with instructors, the courses where more fun dives and talk about how do you do that than course dives. Yes, I realise that I was a natural with ccr diving, and I had some feeling for diving. BUT, I wanted to learn also, so I practised a lot, read a lot, talked a lot to other divers, etc. Before starting the mod3 course I practised bailouts a lot. So I knew that if needed I can do it from 100m.
So as instructor you have to look to the individual diver and look what is possible. If people say it is not possible to do a full cave course 18 months after open water, that is not true. Some divers find the time to dive a lot and really want to learn. My open water course was just a way to move into tech. So yes, my full cave course was just 19 months after my open water. BUT: my qualifying dive was dive number 390. My first 100m dive and qualifying dive for full trimix was dive 521, 24 months after open water. I started open water diving with the end in mind: technical diving. So from the beginning I was working on trim, bouyancy, etc. Even if everybody said to me you are not ready for it (without ever been with me in the water). 10 months after my open water I bought the wanted twinset. My adv. rec. trimix cert is dated on 1 april, my full cave on 18 or 19 april same year, my full trimix on 20 or 21 october same year. So if the basics are fine, and you dive a lot, you can progress faster. Becoming instructor I waited till I had between 800 and 900 dives and some years of experience.
You have to look at the individual diver. And yes, most cannot progress the way I did. And that is not wrong as long as you have fun. Motivation is the key factor in success. If you have the brains that reading theory once and remember it, then the theory is not that hard. If you really have to learn for it, yes, that takes time. You see it back in the students also. Some have 800 dives and are not ready for a next level because they allways dove 1 way and never practised, others come with not a lot of dives but a lot of motivation. Between 2 course dives they go practising and in a few weeks you see a big big difference. Other divers perform better by doing a 4 day full time course as the repeating factor is high then. But you must realise, they pass, but if they don't practise after a course their level go down fast again.
Every diver must practise, even me. I still learn.
If you see experienced oc cave divers taking a ccr in a cave without course, or a dpv, if this is safe depends on the diver. I teach the courses and most times you see a little bit unsureness in the diver. He needs an experienced coach to bring them on the next level. Others read about it, have the brains to think about things, and then try to do it. When I look back, I learned most in my 'one week nothing to full cave class' (I won't call it zero to hero) and the adv. rec. trimix course and then the full trimix course. The normoxic was disappointed, just a few meters deeper to depths I already had been and still one stage. The full trimix course was with 3 stages, so really great to do. The adv. rec. trimix course was the course I learned how to handle a stage cylinder. And cave diving, yes, I learned how to dive in caves.
With this experience I teach normoxic trimix with 2 stage cylinders. Sometimes a student chooses the easier way with another instructor as normoxic is still allowed with just 1 decocylinder, but most like to do it with 2. I also learn them the 'stage rotation',bring the outside cylinder to the inside. Then later the 3 cylinder stage rotation is not that hard anymore.
In a cave course is not a lot of time to practise finkicks or bouyancy, that must be normal before the course. As student you only have to think about the new things, the bouyancy, trim and finkicks must already be natural without thinking. That is how I select/accept the students.
Another point to think about: I discussed with an IT what I would learn in the 'expedition trimix' as this is not a real course, but you go deeper than 100m. He answered: NOTHING. And then: you already know how to plan dives over 130m depth, you execute them also. It is the most dangerous course to teach, people who want to do it, want to do 100+ with an experienced diver and are mostly not capable to do it on their own. I think this can be seen in cave also.
You cannot stop daredevils (they will say yes and amen in a course and think **** up directly after a course), but to split and split things into smaller levels, this is done for the less skilled divers. But there must be always a way to combine things for the more skilled divers that want to progress faster.
Of course allways with the warning, don't go outside your comfortzone.
And never say to divers who only do mainline dives and enjoy them: this is boring, it is not real cave diving. Diving is fun and everybody does it on their own level. I passed one time a student who never dove to the 1/3 of gas. He allways turned earlier. But he was a skilled diver. His student buddy was not so happy with him and asked my why I certified that diver. I answered: because he knows his limits, he will allways get out of the cave with enough gas, and he has showed the skills he needs to do to become full cave certified.
Not all cave divers will be explorers. Most will stay on the recreational full cave diver level. And that is fine. I still like to dive with some less experienced divers in a cave and just stay on the mainline for a fundive. Or diving with a sportsdiver and just stay shallow in less than 10m.
