Failed CESA in OW
- Thread starter Mosizely
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How are they being more conservative?
If you leave the bottom before NDLs on a table and then do multiple stops on the way up, then you might be OK. Then again, you might not be OK. The fact is, you don't know, because you have nothing to guide you.
I think we are speaking of two different things. I think you are referring to the French guys who have some weird depth-averging procedure on some weird French tables, who insist their results are both valid and more conservative for multilevel profiles. I have not been able to figure out what they have done, and I'm not sure they know either. Have you been able to reproduce their results and show they are more conservative?
I am referring to the demonstrably and unarguably incorrect precure of using square-depth tables like those from the Navy or the RDP and doing a "multi-level dive" by assuming zero surface intervals as you go from one level to the next. It is more agressive, not more conservative, because it ignores the built-in offgassing that takes place during the actual (but now ignored) ascents.
PADI, SSI, SDI, RAID...the agency doesn't really matter so I will answer this being agency agnostic.
No, I do not feel that redundancy should be part of the OWC. Although I know of at least one agency where you can take the OWC in sidemount.
What I do feel should be introduced is something I had to do in my first tech course. The RSTC should implement an OOG swim. This is done in a pool and is set up like this:
1. Diver A is at one end of the pool
2. Diver B is 12-15 meters away and is to remain stationary
3. Diver A establishes neutral buoyancy
4. Diver A then exhales fully (reg in mouth)
5. After full exhale, Diver A is to swim towards Diver B (the buddy)
6. Once they are close enough, Diver A can signal OOG
7. Only once Diver A is close enough to donate may Diver B donate gas.
8. If Diver A inhales at all throughout the swim, the skill is repeated.
Now in my tech course, this is done with a blackout mask. The reason for that is because you see very quickly, even though you can't see, just how far that distance is and many of us signaled OOG after only the first 5 or 6 meters. We did not make it near as far as we had thought. Also, swimming hard towards Diver B only made the distance you could go shorter due to CO2 buildup.
Why do I believe that this should be an important part of all OW courses? This teaches us what it would be like in the worst case scenario. I always hated that we teach OOG but rarely is it discussed that , with my luck, it would happen upon exhale and not when we have a nice full breath. This drill teaches them that 12-15 meters away from a buddy is too far away in case of emergency. It instills better buddy protocols and will typically make someone check their gas more frequently.
I see divers every single day that are "buddies" but are 15-20 meters apart...sometimes even more. Positioning is also important, with many new divers wanting to be behind their more experienced buddy. That is until you tell them that if I look back and check on them and all is good, then turn back and they have an emergency...what happens when I don't look back for another couple of minutes? Who will save them if it is something they can't fix themselves?
I believe adding this into the OWC would be beneficial to all divers and could lead to the CESA being useless. I know RSTC won't get rid of the CESA but they should consider adding this skill to be done in confined water.
I don't believe there is any explicit mention of a CESA in the RSTC standards for Open Water training, so there is nothing to get rid of.
SlugLife
Contributor
(Disclaimer, I'm not an instructor, nor any relation to any scuba agency)
That's a compound question:
1) I think people absolutely should be instructed on what CESA is and how to do it safely. I'll defer to other people on the ideal way to to teach it in the water. In my own experience, I think we did a surface oral inflate, and maybe a mini-CESA like activity in the pool.
2) I'm a strong advocate of redundant air (more info here). I think divers should at least briefly be made aware of redundant-air, what options are available, it's benefits, and limits.
I don't remember redundant air being mentioned in my SSI Open-Water & Advanced Open water classes. I wasn't really even aware redundant-air was an option until later, as I became more active on places like scuba-board and after an air-loss incident with some equipment. I also wasn't aware of what redundant-air options were available, and ended up with some spare-air cylinders (FYI, avoid those, more info at link above).
I also think that there's a subtle culture where I live, which is embarrassed by the idea of carrying redundant air, as if they're training wheels for incompetent divers. I never see other divers carrying it, and when I offer other divers the ability to borrow a 6cu or 19cu pony free, it's quickly turned down practically every time.
Redundant air could save your life, or from a traumatic experience. If you do it right, it mostly have an upfront cost comparable to health-insurance, but then low recurring costs.
Both 1 & 2) Redundant air and CESA are both forms of redundancy. I don't think redundant-air necessarily cancels out teaching of other skills or principles. There are many reasons a diver might not have redundant air with them, and more redundancy or backup plans is usually a good thing.
Excellently phrased. That probably describes most dive-agencies.
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edit: I suspect many agencies would resist teaching redundant-air early, because they would see it as encouraging divers to not monitor their air, or dive without a buddy.
I hate to speak for John, and he can clear this up himself, but @tursiops , I interpreted this comment differently.
Yes, the RDP tables are aggressive, and using them to do a multilevel dive by adding "0" surface intervals to level changes is even more aggressive.
But if, using the Tables, you do an ascending multilevel dive of X total duration and Y maximum depth, your ending pressure group in the Tables will be higher than it would be with the Wheel.
In that sense, the required surface interval for your next dive makes it more conservative.
At least, that's what I interpreted John's comment to mean...
Earlier in the same document it defines:
"independent procedures include: emergency ascent; redundant air supply"
My point is just that your procedure you describe is not an independent procedure, but rater a dependent (on a buddy) procedure. The point is to give some training in an independent procdure.
Not sure of your point; is it that you don't like CESA, or that you just want to add another skill to the training?
For me, the best part of a CESA is to let students know (1) they can do if if needed, and (2) buddies are good but not essential, don't don't freak out if they are 50 ft away. The first steps toward being an independent diver.
I never said my procedure was meant to replace the CESA. My post was directed at the person who asked me a direct question.
Well if you read my post, I believe you have the ability to comprehend what my point was due to me being very clear about it but let me help you:
The above states my point pretty clearly.
We aren't teaching solo diving in the OWC nor are we trying to create independent divers. We are trying to create new divers, introduce them to the joys of SCUBA and show them what is down that there that is worth protecting while making them safe. We should also be working to creating a thinking diver...which is far different than an independent diver. As this post is in Basic scuba, I believe your mention of independent divers is way off topic and not something to be discussed when the OP was discussing the CESA in the OWC.
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