Vortex 3-18-2012

[DandyDon]

I bet tri-mix divers like to save all unused gas they can, and it's expensive to discard reserves for common weight checks.

For nitrox and air divers, I don't see a problem - and if you are accustomed to ending dives with 1/3 or more in reserve, therefore negatives - it might be a good idea to plan on more empty tank weight checks.

As a fumbling recreational diver who doesn't get to go much, I do my checks first day of a trip as I commonly end dives with 500# and my pony, but I want to be sure I can get back down and dodge boats even without the pony. I don't have problems, but my home bud who goes less than me often does.

 

[ianr33]

but you're still negative at that point, correct?

why would someone plan to end a dive neutral with all their reserve left? or is it just laziness from not checking regularly?

Yes,still negative.

I don't think anyone would plan to be neutral with the reserve left.

Yes,probably laziness in not doing a proper weight check,easy to get used to always being negative. I can see how it could bite someone on the one dive that goes wrong . That's all I was saying.

 

[TSandM]

Not only do people not do the checks, but cave instructors perpetuate the problem. I tend to be a bit anal, and EVERY configuration I dive has been weight checked for very low tanks, and in the water conditions where I will be diving (fresh or salt). Twice I have shown up for classes and set my gear up the way it needed to be, only to have an instructor INSIST that I take off weight I knew darned well I needed.

Trying to do an unconscious diver retrieval with low tanks and insufficient weight was an object lesson in the fact that the time when you NEED to be most functional (at the end of a desperate exit, perhaps with an impaired buddy) you are most likely to have problems performing if you are incorrectly weighted. PfcAJ, I'm with you!

 

[Jax]

Not only do people not do the checks, but cave instructors perpetuate the problem. I tend to be a bit anal, and EVERY configuration I dive has been weight checked for very low tanks, and in the water conditions where I will be diving (fresh or salt). Twice I have shown up for classes and set my gear up the way it needed to be, only to have an instructor INSIST that I take off weight I knew darned well I needed.

Trying to do an unconscious diver retrieval with low tanks and insufficient weight was an object lesson in the fact that the time when you NEED to be most functional (at the end of a desperate exit, perhaps with an impaired buddy) you are most likely to have problems performing if you are incorrectly weighted. PfcAJ, I'm with you!

Wow. What did you do? And why would an instructor do such a thing?

 

[cruiser]

....EVERY configuration I dive has been weight checked for very low tanks, and in the water conditions where I will be diving (fresh or salt).

This is a true weight check, but I don't think open water classes figure weighting this way. Rather, you do your weight check when you jump in with a full tank.

 

[Adobo]

Not only do people not do the checks, but cave instructors perpetuate the problem. I tend to be a bit anal, and EVERY configuration I dive has been weight checked for very low tanks, and in the water conditions where I will be diving (fresh or salt). Twice I have shown up for classes and set my gear up the way it needed to be, only to have an instructor INSIST that I take off weight I knew darned well I needed.

That's a pretty broad statement. In fact, the post almost comes across as if cave instructors are purposefully guiding you to be under-weighted when your tanks are close to empty.

I've taken cave classes from two different instructors and spent a day with a third (all from the same agency). None of them ever hinted any such thing. At least two of those instructors challenged me on my claim that I had done a proper weight check but were satisfied when I explained the process I used and also after I made a deal to do another check after one of the dives.

I'd say that your experience is at the very least, not universal. Given that at least one of the instructors that "insisted" you needed less ballast is from the same agency as the three I have interacted with, it is quite conceivable that he wasn't insisting that you be under-weighted but rather challenging the results of your weight check. And by the way, I know of at least one other person who was similarly challenged by that instructor. Apparently, that instructor was also satisfied when told of process the other diver used to do a weight check.

I'd say that if tech divers and cave divers are diving improperly weighted, these divers should take responsibility for that. You and I were taught how to do weight checks in fundies. Nothing I have been taught in any subsequent class has changed that process.

 

[Couv]

..... In fact, the post almost comes across as if cave instructors are purposefully guiding you to be under-weighted when your tanks are close to empty.......

I didn't read it that way at all. I've had twits "insist" I must have miscalculated my weight requirements (they usually think I need more) but I don't believe they were "purposefully" trying to overweight me; they simply got it wrong-the same in TS&M's case.

 

[jdfoxjd]

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[SC_Hoaty]

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[Parysa]

...Can narcosis really be so severe that an experienced diver falls asleep and/or becomes so unhinged that he drowns? And this happened at 100ft? From my limited knowledge this seems very unlikely, no?

Zach, between narcosis and panic, yes, it can. I've been narced at just below 80' myself. It's not always 'euphoric'. When it happened to me, it was like hitting a brick wall. I was somewhere I wasn't supposed to be, separated from my buddies, and in almost zero viz. I was starting to panic and was in the process of convincing myself that my regs were malfunctioning (they weren't, I was just panicked and my throat was closing up) and that I was going to die if I kept it in my mouth. I remember sitting there saying, "Don't take your reg out. Don't take your reg out. You CAN breathe," and probably the only thing that saved me from becoming the subject of a thread on this forum was the fact that Kevin Carlisle had drilled into me from day one "If you can breathe, you're ok. Stay calm." It was the only thing that got me calmed down enough to think clearly, realize what was happening, and get myself out of the situation. My buddies were no more than 50' away, close enough that I could see their lights, but had no clue that I was missing (each thought I was with the other) and if I'd panicked, I would most likely have been dead when they found me. By the time they surfaced, I had already gotten calmed down, ascended, did my safety stop, gotten out of the water, taken off my gear, dried off, walked back down to the water, and had a conversation. To their credit, part of the reason it took so long was because they were looking for me, but it probably wouldn't have mattered had I full-on panicked.
Kevin and Tommy also saw a woman inside the cavern at Morrison's remove her reg and scream due to panic.
So yeah, it happens.