Cave Certs Expiration

[PfcAJ]

If we know rule of 3rds is wrong why even use this terminology? I contend that 3rds needs to be removed from our lexicon just like 1/2+200. What would the replacement be- good question,but there is a solution with as much cave diving experience that is out there.

Its also possibly to plan yourself right out of a dive. Might as well stay home and hide under the covers.

Looks like 4x the gas needed to get out was barely enough for Ainslie. So do we teach 5ths? What if he didn't make it? 6ths? Probably need some margin for error. So 7ths?

The real issue isn't gas.

 

[rjack321]

Its also possibly to plan yourself right out of a dive. Might as well stay home and hide under the covers.

Looks like 4x the gas needed to get out was barely enough for Ainslie. So do we teach 5ths? What if he didn't make it? 6ths? Probably need some margin for error. So 7ths?

The real issue isn't gas.

Which is exactly why I threw down diving 1/4ths in classes and enough failures to illustrate that 1/3rds would have killed one or more of you.

We dove 1/3rds minus 200 in many of my full cave course dives. In a team of 2, no flow. We barely "survived" escalating failures. I think I hit our O2 bottle with 150-200psi after one OOA which turned into a blind OOA. Drove the point home.

 

[karstdvr]

Its also possibly to plan yourself right out of a dive. Might as well stay home and hide under the covers.

The real issue isn't gas.

There is "win-win scenario" in there for gas planning where you don't need a bailout stage every 100ft, but don't have to be critically close gas quantities without enough reserve. So yes,it isn't about gas at all but adequate planning, and that is the root of the problem. But hard to have good planning skills when entry level training starts with teaching bare minimums as the standard.

 

[tbone1004]

There is "win-win scenario" in there for gas planning where you don't need a bailout stage every 100ft, but don't have to critically close gas quantities without enough reserve. So yes,it isn't about gas at all but adequate planning, and that is the root of the problem. But hard to have good planning skills when entry level training starts with teaching bare minimums as the standard.

but we can start circling round and round because in order to do adequate planning you have to have some sort of planned penetration to find out how much gas you are going to need. It's an endless and vicious cycle. Do you encourage them to have planned penetration based on rough cubic footage required, or try to find some sort of rough absolute pressure limit and then teach them how to modify it based on your dive plan. The shallower you are the more aggressive you can be, i.e. going up the Peanut line to thirds is much less aggressive than say Orange Grove because of time. 5 minutes on the Peanut line is going to use a lot less gas than 5 minutes in OG because of depth and that time to stabilize is what is going to cause you to eat it. The deeper you are, the more conservative you have to be because of time needed to fix a situation, and that is how I was trained to plan my extra gas reserves and pad my dive plan.

 

[boulderjohn]

Andrew Ainslie's dive plan did not look anything like one of my typical dive plans. Look at the cascade of things that went wrong. Most of those things would not be a remote possibility for a dive I do. Isn't it possible that the rule governing that dive might not be suitable to the way I plan my dives?

I was part of a dive team that had a fatality this past spring. I was not on the dive that included the fatality, and I would not have been because the dive was well beyond my ability. I would not have dreamed of doing what he was doing given my present level of training, so any rules that govern my dives were irrelevant to his dive.

When I talk to open water students about the rules that govern dive planning--including all usable, rule of halves, and rule of thirds, I say that those specific numbers are just starting points for planning. "Rule of halves" actually means, "It would be nice to get back to my starting point, but if not, it's OK." You then look at the exact circumstances and decide what you actually mean by "halves" in terms of actual turn pressure. What makes sense in one situation makes no sense in another.

The rule of thirds means you and your buddy must get to a certain point on your return. What does that mean in actual turn pressure? It depends upon the circumstances, and a thinking diver will consider all the factors involved (flow, etc.) before deciding what is the proper decision to do the dive with reasonable safety.

As for Ainslie's dive, all of that stuff is meaningless. A diver doing that kind of dive must toss out all preconceived planning axioms and think it all through carefully. A dive like that will not fit into any norms. He is taking risks that invalidate all planning, because you cannot plan for the challenges of fitting through restrictions you might not be able to fit through at all. That is the lesson from the incident I mentioned in the second paragraph--it doesn't matter how much gas you have if you are thoroughly stuck and can't move.

 

[karstdvr]

in order to do adequate planning you have to have some sort of planned penetration to find out how much gas you are going to need.

That is exactly right, some type of planning is needed. Set that planned penetration, and use a conservative gas plan, for example 1/4ths as a starting point. If you make the distance, then note the amount of extra gas, and then build on that basis. Conversely if you are short, then this will help with planning. Over time as you learn the system and are aware of certain features eg passing a bail out sink, small cave that is silty and numerous other variables, then alter your plan to something more suitable. Are entry level cave diving students exposed to planning like this or are they exposed to 1/3rds to start with, which has been noted as being too liberal and potentially unsafe? Hence you are right, with multiple uses of the word "plan".

 

[karstdvr]

Andrew Ainslie's dive plan did not look anything like one of my typical dive plans.

Your are right, he was doing exploration type diving which goes outside what a large majority of the what average cave divers do. But, once we let complacency set in such that these things can't happen to me because eg I just swim the mainline 1000ft and exit, then our risk level goes up. Maybe I am unlucky person and born under a dark cloud,but I have had large rock movement in JB that silted out the cave, got under a fissure at Lafayette that dumped a debris mound of material on me and silted out the cave, and even had a sand banks shift at Pineland and Vortex which trapped me and required digging to exit. These weren't exploration dives,but typical dive plans,but something went wrong big time. You can't plan for these events,but have adequate conservatism in the plan to address the problem.

As for Ainslie's dive, all of that stuff is meaningless. A diver doing that kind of dive must toss out all preconceived planning axioms and think it all through carefully. A dive like that will not fit into any norms

I really think his dive has meaning and there are some very important lessons to be gleaned from his narrative. When things go wrong, they tend to cascade and multiply, this is true for the explorer or the average cave diver. When that adrenal gland kicks in, breathing elevates, CO2 retention occurs our focus diminishes, which helps this cascade of events. You do this long enough there will be a dive in your future that will really go wrong, the key is are you prepared either from a skill/experience stand point, or a planning stand point (preferably both).

 

[boulderjohn]

I really think his dive has meaning and there are some very important lessons to be gleaned from his narrative. When things go wrong, they tend to cascade and multiply, this is true for the explorer or the average cave diver. When that adrenal gland kicks in, breathing elevates, CO2 retention occurs our focus diminishes, which helps this cascade of events. You do this long enough there will be a dive in your future that will really go wrong, the key is are you prepared either from a skill/experience stand point, or a planning stand point (preferably both).

What I got from this account and from the fatality I mentioned is the difficulty of knowing your limits when you extend your diving beyond that which is commonly done. We are all told not to dive beyond our limits, but how accurately can we judge our limits when we have no sure way to measure them? We have to push the edge of those limits if we want to grow as divers, but how do we know the difference between a reasonable step forward and an unreasonable leap into danger? For me, things are pretty clear in terms of cave diving. Because I have to travel significantly to dive in caves, I don't do it often and so have not progressed to the point that I am doing anything more than the most basic stuff taught in my training. I don't have to make decisions outside of those norms because I don't do those dives. The people that are doing those dives have to make pretty big decisions without a lot of guidance from the experience of others who went before.

I tried hard to write an article about knowing how to extend your limits without exceeding them after the aforementioned fatality. I even started a thread in the instructor to instructor forum asking for suggestions to help me get started. I tried a number of different approaches, and I eventually stopped working on it. It isn't easy.

At some point, the people who are doing those difficult exploration dives have to recognize that they are taking risks that include the possibility that something can happen that is beyond their most careful safety plans. I was talking to a very well known cave diver/explorer who described a time that he was solo diving and got so thoroughly stuck in a restriction that he did not think he was going to get through. He finally did manage to worm his way through, all the time knowing that the fact that he was able to get through going in that direction did not mean he was going to be able to get through coming back. He accepted that risk when he did that dive. In doing so, he was working with norms that have no relation to the way I dive.

 

[Jack Hammer]

My take away from the article isn't that things happen while explorering. It is that when problems happen they can escalate quickly and if it can happen to a highly trained and experienced diver and explorer it can to any of us.

 

[rjack321]

My take away from the article isn't that things happen while explorering. It is that when problems happen they can escalate quickly and if it can happen to a highly trained and experienced diver and explorer it can to any of us.

Exactly, nothing happened on that dive that hasn't happened to a novice cave diver as well. There are a long long list of fatalities and near misses due to silt outs leading to delays or various stressors leading to not checking other equipment and the stress compounding and making itself worse and worse.