Cave 1 / Intro Expiration & Limits

[tursiops]

I think there is a misunderstanding that because they are each a "first step into cave diving" that Intro, Apprentice, and Cave 1 are the same program. They're not.

Before I try to illustrate the differences, let's start with a quick discussion about the final outcomes of all cave programs -- Intro, Apprentice, and Cave 1 were never meant to be end points -- the final end is FULL CAVE, period. This comes back to the very first rule of accident analysis -- untrained and incompletely trained cave divers have a poor safety record in cave environments. No amount of openwater experience can properly prepare anyone for the cave environment, heck, even OW instructors have a poor track record in caves. I can give several examples of OW instructors that died cave diving because they didn't know what they didn't know.

So let's accept that Intro, Apprentice, and Cave 1 were designed to each be a stopping point to refine skills and let everything sink in before proceeding to the next block. Let's also accept that if a person is going to regularly cave dive, they need to complete their education and work towards being a full cave diver eventually.

Now, with an understanding that "Full Cave" is the eventual outcome, let's look at the journey on how we get there. As I've said before, Intro, Apprentice, and Cave 1 are different points on that journey and are representative of the amount of training that has gone into the total trip. The differences in the amount of training that has gone into each stop is why Intro, Apprentice, and Cave 1 have different limits (1/6ths vs 50 cubic feet vs 1/3rds).

To illustrate where each sits on the journey towards Full Cave, I'm going to use a metaphor of a 10 mile hike with 0 being OW Instructor (or AOW diver or whatever, zero overhead training) and a full cave diver with stage being mile 10.

Mile 0 - AOW Diver, Divemaster, or OW Instructor - someone with zero training for the overhead.

Mile 2 - Cavern, Intro to Tech, or Fundies. Usually 2 to 4 days, outcome: Understanding of tech/cave gear, propulsion techniques, buoyancy, trim.

Mile 3 - Intro to Cave or old NSS-CDS Basic Cave. 2 days past Cavern/Intro to Tech/Fundies. Outcome: Tying into the gold line, most basic penetrations (1/6ths).

Mile 4 - New NSS-CDS Apprentice. 4 days past Cavern/Intro to Tech/Fundies. Outcome: Tying into the gold line, most basic penetrations but a little more liberal on gas (up to 50 cubic feet, or 1/3rds, whichever is less).

Mile 5 - GUE Cave 1. 5 days past Fundies. Outcome: Extended penetrations (1/3rd of 2/3rds) and navigation beyond one permanent T (and multiple gaps but no jumps).

Mile 6 - NAUI Cave 1 and old NSS-CDS Apprentice. 6 days past Intro to Tech/Fundies. Outcome: Extended penetration (1/3rds) and two navigational decisions (jumps or t's).

Mile 8 - Full Cave Diver. 8 days past Intro to Tech/Fundies. Outcome: Extended penetration (1/3rds), unlimited navigational (jumps/t's/gaps), circuits and traverses.

Mile 10 - Full Cave + Stage, Cave 2 (both NAUI/GUE). 10 (or more) days past Intro to Tech/Fundies. Outcome: Extended penetration (1/3rds) with stage bottle use.

As you can see, the amount of time to get to that first step is different between the agencies and that's why the outcomes (what the diver can do) is also different. There are various philosophical reasons why those first steps are different, but at the end of the day, they all are in basic agreement that the final step is supposed to be full cave and that the first step is simply a stopping point on the journey.

Whew, this is longer winded than I had expected... Hope it makes sense.

Awesome post. Excellent explanation. Congrats.

 

[dewdropsonrosa]

We should get that stickied somewhere. It's a great summary of the cave training sequence and goals.

 

[RedSix]

Is there a need to do "experience dives" in between C1 and C2 at NAUI?

I'm wondering a little bit about the statment: "10 (or more) days past Intro to Tech/Fundies" for a C2 at GUE. In reality it is at least 5 days training for the C1, often even 6 days. Now you need to do at least 25 C1 dives to apply for a C2 class (to gain experience). Two C1 days per day are another 13 days of diving. C2 class is at least additional 5 days of training, more often even 6 days. So you will never ever be able to get "full cave" at GUE 10 days after your Fundies.
Another point to cleary say in my opinion: diving on 3rds is very aggressive and, in a 2 person team, very dangerous. I can not understand that a training organisation allows more or or less "beginners" (nothing els is a C1 diver) to do something like this. Even as I am now C2 diver I will only dive 3rds under perfect conditions. Diving 3rds in a two persons team in my opinion is "Russian roulette".

 

[kensuf]

Is there a need to do "experience dives" in between C1 and C2 at NAUI?

I'm wondering a little bit about the statment: "10 (or more) days past Intro to Tech/Fundies" for a C2 at GUE. In reality it is at least 5 days training for the C1, often even 6 days. Now you need to do at least 25 C1 dives to apply for a C2 class (to gain experience). Two C1 days per day are another 13 days of diving. C2 class is at least additional 5 days of training, more often even 6 days. So you will never ever be able to get "full cave" at GUE 10 days after your Fundies.
Another point to cleary say in my opinion: diving on 3rds is very aggressive and, in a 2 person team, very dangerous. I can not understand that a training organisation allows more or or less "beginners" (nothing els is a C1 diver) to do something like this. Even as I am now C2 diver I will only dive 3rds under perfect conditions. Diving 3rds in a two persons team in my opinion is "Russian roulette".

The days are based on minimum standards. You can do C1 in 5 days.

Yes, NAUI requires 25 dives between their C1 and C2. You can't go zero to hero.

I agree with you 100% on thirds, especially in a 2 man team. This is part of whats covered in training (thirds being designed for a 3 person team in flow). The NAUI material for C2 also covers gas management and how to dive in a siphon.

 

[rddvet]

Is there a need to do "experience dives" in between C1 and C2 at NAUI?

I'm wondering a little bit about the statment: "10 (or more) days past Intro to Tech/Fundies" for a C2 at GUE. In reality it is at least 5 days training for the C1, often even 6 days. Now you need to do at least 25 C1 dives to apply for a C2 class (to gain experience). Two C1 days per day are another 13 days of diving. C2 class is at least additional 5 days of training, more often even 6 days. So you will never ever be able to get "full cave" at GUE 10 days after your Fundies.
Another point to cleary say in my opinion: diving on 3rds is very aggressive and, in a 2 person team, very dangerous. I can not understand that a training organisation allows more or or less "beginners" (nothing els is a C1 diver) to do something like this. Even as I am now C2 diver I will only dive 3rds under perfect conditions. Diving 3rds in a two persons team in my opinion is "Russian roulette".

Although cave 1 allows dives to 1/3s I assume most competent instructors teach that you shouldn’t actually dive to 1/3s. I think it’s becoming far more commonly discussed in the cave community that 1/3s is aggressive as opposed to in the past

 

[CaveSloth]

Just for my knowledge, can y’all please enumerate scenarios where diving to thirds as a buddy team of 2 is “playing Russian roulette”? I can imagine on my own but just want to hear scenarios I haven’t thought of yet. Any case in which there are multiple failures comes to mind. Dive to thirds and then buddy’s gear has to be abandoned and you pass thirds while figuring that out etc...

 

[tursiops]

Just for my knowledge, can y’all please enumerate scenarios where diving to thirds as a buddy team of 2 is “playing Russian roulette”? I can imagine on my own but just want to hear scenarios I haven’t thought of yet. Any case in which there are multiple failures comes to mind. Dive to thirds and then buddy’s gear has to be abandoned and you pass thirds while figuring that out etc...

Thirds gives no leeway for exiting slower (or breathing harder) should you both be on one diver's set of tanks. So if there is any counter-flow on exit, or hangup on navigation or whatever, there is no reserve, especially if either or both of you are a little agitated and breathing hard. Which you WILL be.

 

[tmassey]

It’s simple. 1/3 in means it will take 1/3 out. At that exact 1/3 in, (2/3 remaining) you lose half of your gas (say, debris in the tank valve: gas cannot leave). In THEORY, you have exactly enough gas to get out. EXACTLY enough.

Except you can’t get the last 200 PSI out of a cylinder due to depth and IP. So now you’re actually 200 psi short. And stress bumps up your consumption. Now you’re 300 psi short. Etc.

There are things that work to offset that (like flow) but should not be counted on. That’s why thirds with a team of two is iffy. You’re counting on the out *must* be better than the in to survive in a *single* worst-case failure. Hence the description as ‘Russian roulette”.

And this is why we tell you why what you want (3 days of training to full thirds) is just impractical. You *literally* do not know what you do not know!

Keep asking the questions, but these are not a substitute to training. This really is different than any other type of diving, even other overheads like caverns and shipwrecks.

 

[CaveSloth]

I swear I’m not trolling but please also describe how one diver’s gas totally disappears. If their entire rig is caught in a restriction and has to be abandoned is the only scenario I can think of. If that happens when a pair is at thirds then that absolutely is a likely death.

 

[txaggie08]

Just for my knowledge, can y’all please enumerate scenarios where diving to thirds as a buddy team of 2 is “playing Russian roulette”? I can imagine on my own but just want to hear scenarios I haven’t thought of yet. Any case in which there are multiple failures comes to mind. Dive to thirds and then buddy’s gear has to be abandoned and you pass thirds while figuring that out etc...

Unless my mathematical abilities suck...

A catastrophic loss of a tank at turn pressure(1/3 volume) would mean that AT BEST you had 1/3 of your original back gas left to exit. ANY loss of time, the line, silt out etc that slowed you down or accelerated your consumption rate means OOA short of open water. In all those routinely drilled and very real possibilities, you stand a chance of losing your buddy.... the result is OOA with bored reserve before clear of the penetration.

I dunno if you've ever done true blackwater... I nearly drowned in it 6 years ago recovering a body. I will stick with a more conservative gas plan unless otherwise told I must botnby an instructor.