Overhead environments and open water scuba divers

[tstormdiver]

Comparing the average OW diver, in the average overhead environment you would normaly find said diver, to a one in six shot of death is rediculous.

I am only saying, a diver (& I don't care what level they are at), going outside of their training is playing the odds, whether 6:1 or 1,000,000:1. Whatever the odds are, they are more greatly stacked against the diver without the knowlege or training.

OK, using the gun analogy,.. I'm not shootist, nor a gun owner, nor have I ever fired a gun. But if I where to just pick up a gun, without any training, & just start firing (if I even could), wouldn't you say the odds of myself or someone getting hurt or worse, be greater?
On that note, I ask you to cut me a little slack, just because I don't know the proper terms, I think you can get the gist of what I'm saying.

 

[Racer_X]

Using the gun analogy - it depends on what those odds INCREASE to. If they increase by .1% and go from 0.01% to 0.11%, it's a DRAMATIC increase - 10 fold. However, what that really means is the odds of hurting someone go from 1 in 10,000 to 11 in 10,000 - it's not a big deal. Put it another way - if the odds of losing your money in vegas were 11 in 10,000 versus 5002 in 10,000, why would you ever leave?

It's not just understanding the odds change, but how much they change and where they change from - everything has to be understood as much as possible to make a value decision. That includes probability and impact. Just one isn't sufficient to make an informed decision.

BTW, if you've seen a cop show, you know how to fire a gun - insert clip, rack it back, and start firing. The bullets come out going very fast, so be careful where you point it.

Regarding an overhead environment - one thing we have to remember is we effectively dive with an overhead environment on dives below 40 feet. That surface looks really tempting when you breathe all 3000 psi from your 100s at 75 feet, but that's just as lethal as out of air in a cave - and a situation well within the OW parameters. I'll leave the "worse way to go" discussion for another thread.

Having gotten back from cenote diving in an overhead environment, I'd say the factors for danger for me would be:
Max and min visibility
Bottom conditions
Map availability
Route marking and familiarity
Quality and experience of guide
Previous safety/track record of site
Previous safety/track record of diving organization

All of these factors were determined by me before I got on the plane. I memorized the routes and had my own back up gear that I knew and trusted, and did field checks prior to the dives. In fact, the dive guide used my materials to do the group briefing because I accessed information that wasn't easily available to them.

That being said, I'll get cave certified before I try a serious wreck penetration course. But for cavern dives, even in low vis? Give me my lights, a line, compass, and the natural experience of 6 inch vis in the lake in my backyard, and I'm good.

 

[Darnold9999]

Regarding an overhead environment - one thing we have to remember is we effectively dive with an overhead environment on dives below 40 feet. That surface looks really tempting when you breathe all 3000 psi from your 100s at 75 feet, but that's just as lethal as out of air in a cave - and a situation well within the OW parameters. I'll leave the "worse way to go" discussion for another thread.

????? OOA at 75 feet is nowhere near as lethal as out of air in a cave within recreational limits. Not sure what you are talking about here???

 

[Kingpatzer]

I think that part of the issue lay with instructors who have bought into the notion that we should sell students on how safe diving is. I actually make it a point to tell my students that this activity is safe "until you start doing things you don't know how to do." And I use entering a cave and a wreck as examples where they have the potential to get dead (along with a deep dive without adequate air).

I wish the standard OW course contained a few more of the scary stories about what happens when you don't follow the guidelines. Not because I want people to feel like diving is some extreme sport, but to instil in the average student a healthy respect for the limits of their knowledge and to get them to spend some time thinking about what the limit really is.

 

[boulderjohn]

Regarding an overhead environment - one thing we have to remember is we effectively dive with an overhead environment on dives below 40 feet. That surface looks really tempting when you breathe all 3000 psi from your 100s at 75 feet, but that's just as lethal as out of air in a cave - and a situation well within the OW parameters. I'll leave the "worse way to go" discussion for another thread.

????? OOA at 75 feet is nowhere near as lethal as out of air in a cave within recreational limits. Not sure what you are talking about here???

I think he means that if you go OOA below 40 feet, it is not possible to get to the surface alive. If so, I'm confused as well and wonder what is wrong with CESA's and Buoyant Emergency Ascents. Back in the days when there were no SPGs and the J-valves would malfunction, people did OOA ascents from 75 feet with some regularity.

 

[jmneill]

????? OOA at 75 feet is nowhere near as lethal as out of air in a cave within recreational limits. Not sure what you are talking about here???

I assume he's talking about the deco problem this could present if he just sucked two 100s dry at 75'? However, I think this would fall a little outside OW perameters. (even ignoring the depth)

 

[ianr33]

I assume he's talking about the deco problem this could present

You can fix bent. You can't fix dead!

 

[jmneill]

You can fix bent. You can't fix dead!

I hear ya, don't shoot the translator!

 

[wtcreaux]

This is what I classify as "low-probability, extremely high consequence event"........which means I take as many precautions as I can........

I've too many years in Emergency Services to tempt Lady Luck (YMMV)

BTW - Racer X......Haven't seen too many "clips" in a pistol....... magazines yes, clips no. Maybe you can enlighten me which pistols have clips, yes?

 

[stairman]

We call these, trust me dives, and they can be your demise if you fall for one. Its all good till an o ring blows or any number of things that can cause one to panic in a minute. You gotta be smart about your hobby.