To become a “full” cave diver, an individual must spend a minimum of 7 days, and more frequently at least 8 days, in training with a cave instructor. As students progress in their training, their dives become longer, their penetrations into the overhead take them further, and navigation gets more complex. Historically, the cave program was broken up into four two day digestible blocks, easily consumed over a weekend, with Cavern and Intro being the first two steps in the program.
Until the late 90s, Cavern and Intro could only be taken in a single tank configuration UNLESS a student was enrolled in the entire cave program. The reasoning was that a single tank limited penetration distance of the student diver, but if a student diver was in doubles, they may be tempted to go too far into the cave. Most dive sites enforced the “single tank” rule and divers that had only an “Intro to Cave” certification were frequently told they could not dive doubles at popular dive sites. This rule was waived if the student diver produced a letter from a cave instructor stating they were enrolled in a cave class, usually the letter said the instructor was allowing them to dive doubles to gain experience on their own before resuming their training.
The policing of the rule worked well, I have very vivid memories of being run out of Peacock Springs when I showed up in a set of doubles and only my Intro certification, and more than a few of my friends completed full cave just to be allowed to dive doubles at some popular sites.
If you’ve never dove in doubles before, the first day of your “full cave” class is probably not the best time to start. Everyone has at least one “bad day” during cave training, my story involves turning turtle and hog-tying myself while trying to run a reel into Little River on what was perhaps my second dive in a set of doubles. I was convinced I had failed the course right then and there, but my instructor just chuckled and helped free me from the mess I had created.
I guess I wasn’t that unique. I’ve been told that frequently, cave instructors discovered that their students were showing up for the last phase of cave training, the part with the longest dives and furthest penetrations, without the ability to properly manage their equipment. In an effort to correct this, the “Basic Cave” certification was created and students were now allowed to take Cavern and Intro in doubles. The caveats with the Basic Cave certification were that a cavern certification was usually not issued as part of the training and in an effort to make student divers continue and complete their training, the certification card expired after 18 months (or reverted to a single tank certification).
Over time, as the rules became more lax, it became common for students to take Cavern in doubles and be issued a certification card. While Cavern was still the bedrock of cave diver education, now we were developing a group of people that had a certification card that allowed them to dive at many restricted (cave only) sites and were allowed to wear cave diving equipment, but without ever having gone into the cave zone with an instructor.
I need to be clear on one point. The safety record of single tank cavern divers staying within the cavern zone, and single tank intro divers within the limits of gold line diving within thirds, is quite good. By being on a single tank, and having a minimal amount of gas for penetration purposes, the temptation to dive beyond their level of training is almost non-existent. Unfortunately, the safety record of cavern and intro trained dual cylinder divers, those that were tempted by the large quantities of gas on them to dive beyond the limits of their training, is not nearly as good.
We have an interesting dilemma. Do we go back to the old model of single tank until the last four days of cave diver training? Do we maintain the status quo? Or do we evolve and move in some other direction?
Although sensible review of accident statistics may lead a person to suggest a return to the single tank tradition, personally, I am loathe to go back to a model that embraces single tank cave diving. The main reason I am opposed to it is I believe the single tank diver lacks redundancy — if the single neck o-ring or burst disk fails, all of the gas reserves will be lost. And while I believe there is a valid place for single tank cave diving, it is my view that place is actually at the more skilled end of the cave diving spectrum — quick recon of a new dive site to see if it is viable, for instance.
I also do not believe maintaining the status quo is sensible either. While I do believe there is an important need for Cavern training, let’s be honest, where is that dual cylinder Cavern diver going to wind up going? If we agree that the likelihood is that a dual cylinder trained Cavern diver is probably going to wind up in the cave zone on their own, then we have a responsibility to make sure they have the proper training and skills to be in the cave zone.
The NSS-CDS has been looking at this problem and is currently in the process of revamping their cavern and cave diver training programs accordingly. As part of the changes, we will soon see new standards that will make Cavern a recreational safety course only and remove it from the cave diver training curriculum. The new program will require a minimum of four complete days (five recommended) with more time spent in the cave zone to achieve Basic Cave certification, and in exchange for the extra cave time during training, the new certification will allow more progressive gas planning rules than simply 1/6ths.
I still believe there is a place for Cavern as a safety course for recreational divers, but I also fully support and embrace these changes and effective November 2018, I will only issue Cavern certifications to single tank students. Students that wish to take Cavern with me in dual cylinders will only be issued a certification card once they have met the requirements for Intro/Basic Cave.