Cave Diving Survey

[argyris]

The same gas management rule applies to independents as it does with manifolded doubles. 1/3 of your gas supply in, 1/3 of your gas supply out and 1/3 in reserve for emergencies as a minimum.

How you do on independents is only important that each cylinder has the above rule applied separately. IE 1/3 from each cylinder on the way in, etc. How you do it is not as important IMHO. Personally I switch regs every 200-300 psi. It is not needed to switch that often it is just the habit that I developed. I rarely look at my gauges before I switch it just becomes habit.

Bobby

This is why I told you Bobby that your technique (I do not speak about configuration, i speak about gas manangement), is perfect for solo but not for a team emergency. Because you frequently change the regulator for each tank, so when an emergency arises you may not breathe the long hose. Secondly you speak for a personal habit, there is not such in team procedures.

My main concern is:
1. To minimize regulator switches
2. Always have adequate gas for sharing and exit.
3. Most time to breathe from the long hose for tolerating emergencies.

With the minimum gas switch one can do:

a. Initial penetration 1/3 of tank (1/6 of total penetration gas) from the left tank (short hose). If there is a problem with my own regulator (right) at the switch I can return using the 2/3 of the remaining gas in my left tank. The same applies to my buddy.

b. If there is not any problem then I can switch to the right regulator and now i am on long hose. Breathing 1/3 of the right tank and then return back and exit cave. Now if the is a problem at the further point of penetration I have 2/3 on my tanks to return. The same applies to my buddy.

c. Half of return to surface I can switch back to left cylinder and exit cave with 1/3 from every tank.

The same procedures are followed by my team buddy.

I do not think that you can achieve this accurately especially when you do not check your gauges frequently.

You use the world habit and personal remember team diving is a reciprocal process both parts should be able to perform with each other. In the above procedure I am confident with my team buddy about the results, we practice as modified safety drill every dive. Are you and your buddy confident with your way?

I am sorry if my description is not clear (my English is not perfect), if someone can explain it better please do.

Again I am not arguing or confront anyone. We are discussing and within discussions there are different points and opinions, otherwise would be a lecture or monologue.

Regards,
Argyris

[Bobby]

Argyris,
Your English is fine (at least for me). Thank you for your clarification and I do not take it as argumentative in any way. You make some good points. The system you and Larry propose does have its merits. The best that I see is leaving the most amount of gas in the long hose cylinder for the deepest penetrations. You are correct that I am very much a solo diver. I will add to that statement with the mind set of always looking out for any teammate or anyone else that might need assistance.

I also feel that another valid point is the reduction in swapping second stages. For me it has become second nature but we are talking about applying SM in a training situation. Less switches not only reduces task loading in the switches themselves but also makes gas management simpler.

I would also feel that from a training standard going into adverse conditions that will plug the diaphragms or the inner second stages would not be part of the training and considered advanced diving.

Another benefit that I see is teaching new SM divers to properly deal with balancing their rigs. The buoyancy changes in the cylinders should make this easier compared to switching the regs every few hundred psi.

I don't teach SM but I do a good bit of mentoring. I will think about this more and probably incorporate it into helping others adjust and use their SM set ups.

Funny story that kind of relates. A decade ago I was working with a dive buddy that was getting ready for his cave class. I did not have my independent doubles and did not have any dive experience with the brand new isolated BM doubles I had just put together. Not trusting the BM set up from inexperience I opted to put my buddy in my SM rig. Long story short was that we did an OW acclimation dive and worked out his RMV at the same time. He breathed down 2/3's of the first cylinder before switching. We both were trying to figure out why he was side ways in the water during the middle of the dive. I had neglected to mention a procedure for switching regs. He had never dove double cylinders. LOL. I also dove my new manifolded doubles for almost a year with two spg's, closed isolator and reg switches because I did not trust it.

Bobby

[RN]

I haven't had time to read through this entire thread yet. I do want to comment that I do teach in sidemount. In fact, this past weekend I taught a cavern class with 3 students - one in backmount, one in sidemount, and one in a single 120. It went very well. The sidemount student will get an IANTD card. FWIW, there are other agencies that allow students to complete cave training in sidemount. I encourage my students to consider sidemount and more than half go that route. So those agencies are the ones that get the money for student manuals and certifications.

[argyris]

Funny story that kind of relates. A decade ago I was working with a dive buddy that was getting ready for his cave class. I did not have my independent doubles and did not have any dive experience with the brand new isolated BM doubles I had just put together. Not trusting the BM set up from inexperience I opted to put my buddy in my SM rig. Long story short was that we did an OW acclimation dive and worked out his RMV at the same time. He breathed down 2/3's of the first cylinder before switching. We both were trying to figure out why he was side ways in the water during the middle of the dive. I had neglected to mention a procedure for switching regs. He had never dove double cylinders. LOL. I also dove my new manifolded doubles for almost a year with two spg's, closed isolator and reg switches because I did not trust it.

Bobby

Bobby,

It is obvious that proper training give confidence to procedures and diving systems. Your example is very characteristic and true. I see many people diving with the isolation closed or use double spg's. An on the other side I see many people dive on independent twins without understanding Switch or gas process for a virtual redundancy.

What is the outcome of a successful training is learning by heart. Thats why I prefer to develop as a community procedures as a safety blueprint. I believe that cave training in side mount is feasible but we have to define the process and this discussion is valuable. I am sure that we can set a Hogarthian SM rig and procedures.

Although I support personal preference and diversity, when we address life safety procedure there is inevitably only the application of Hick's law.

[argyris]

So those agencies are the ones that get the money for student manuals and certifications.

Personally, safety and comfort of the student is my primary concern. For gad sake a cave instructor is mostly an educator and not a certification machine. We do not train for the money -or at least me, but i am sure there are more that agree with me.

We have to understand that a certain rig or a technique is valid mostly for the specific environment that is aimed.

On that sense I do not use a rebreather or a scooter on short dives. We have to addressed the legitimacy of any option, like trimix rebreather or sm. Educational wise student development is a scaffolding process.

[FW]

I haven't had time to read through this entire thread yet. I do want to comment that I do teach in sidemount. In fact, this past weekend I taught a cavern class with 3 students - one in backmount, one in sidemount, and one in a single 120. It went very well. The sidemount student will get an IANTD card. FWIW, there are other agencies that allow students to complete cave training in sidemount. I encourage my students to consider sidemount and more than half go that route. So those agencies are the ones that get the money for student manuals and certifications.

Be sure to send in the survey.

[RN]

Personally, safety and comfort of the student is my primary concern. For gad sake a cave instructor is mostly an educator and not a certification machine. We do not train for the money -or at least me, but i am sure there are more that agree with me.

We have to understand that a certain rig or a technique is valid mostly for the specific environment that is aimed.

On that sense I do not use a rebreather or a scooter on short dives. We have to addressed the legitimacy of any option, like trimix rebreather or sm. Educational wise student development is a scaffolding process.

You completely missed my point...

[RN]

Be sure to send in the survey.

Done.

[argyris]

You completely missed my point...

Which is?

[Puttzer]

Be sure to send in the survey.

My link isn't sending in the survey response, as best as I can tell.
Hope the link is working for everyone else.

Wouldn't our survey comments be better directed if all cave divers sent their thoughts directly to the NACD?

Our board members should represent all cave divers and cave diving: not just a small vocal group as those that use this forum.
And I believe the board have voted on this issue a couple of times already.