Cave Certs Expiration

[Jack Hammer]

Losing just one cylinder in sidemount can still leave people in a bad spot if they are far back, get stressed, and have loss of visibility. Everything is simple when you first start out and stay in the front of the cave, it quickly gets more complex the further back you go and the longer you stay inside. Plenty of Intro divers have died diving sixths because they lacked the experience to make good decisions. Cave diving isn't open water resort diving on a reef... you can get dead really easily.

 

[Germie]

I have never seen a loss of ALL gas, but I have seen: an Oring popping out between cylinder and valve. That means a non fixable failure. So closing the manifold and then you have 1 cylinder left. If you are fast of course.
I have seen a blowing manifold.
I had another failure myself: the loss of a valveknob on a stage cylinder. That means if the cylinder is closed that you cannot access the gas. Not a real loss, but gas is not usable, but quite non fixable (or you have to take stuff with you to fix this under water).
I have had a free flow on a decogas, followed by closing cylinder, so normally not a problem, but followed by getting no gas anymore because of a block somewhere in the second stage. Really nice if you are coming from 340 ft and doing deco. I solved this problem not by changing regs under water, but got the decogas from a ccr diver in our mixed team group.
Just some examples of partially lost of gas.

I had a panicing diver with a twin12 liter and he drained his twinset in 30 minutes. No failures, he was just in panic. Experienced diver with around 350 dives.
I had a buddy who lost a fin and he used much more gas to swim back (we could not go back to surface directly due to ships above us).
Just some other examples.

 

[syntaxerrorsix]

Swapping regulators underwater is not my idea of a good time and I've not found much cave where I need to to use sidemount on a regular basis.

 

[Imbodie]

Not if you lose one of them, and now you have no way to donate air.

OK...
you guys are being ridiculous..... IF I LOOSE ONE OF MY CYLINDERS.... I AM THE ONE WITH THE ISSUE AND I am exiting the cave... on MY GOOD 2/3 full cylinder...
If my dive buddy ALSO lost one of their cylinders... THEY TOO would be exiting on their good cylinder with 2/3 of the fill they started with...

 

[Jack Hammer]

I'm side mount... I have 2/3's of my gas in EACH of my cylinders IF I pushed it all the way to full 1/3 of my gas before turning... that still leaves my dive buddy with seemingly 2 times the amount of gas to get out as it did to get in... assuming we're both using same cylinders...

But we're not talking about divers with experience and who are pushing 3rds to the limit... we are talking about training standards which should be universal....

No offense intended here... this comment seems common in newer side mount divers and shows a fundamental lack of understanding gas management planning planning. Please take a calculator out and redo the math.

 

[tbone1004]

I'm side mount... I have 2/3's of my gas in EACH of my cylinders IF I pushed it all the way to full 1/3 of my gas before turning... that still leaves my dive buddy with seemingly 2 times the amount of gas to get out as it did to get in... assuming we're both using same cylinders...

But we're not talking about divers with experience and who are pushing 3rds to the limit... we are talking about training standards which should be universal....

not quite because while the pressure in each may be 2/3's of your starting pressure, each tank is only holding a third of your total gas volume, so theoretically just enough to get out.

Now, this whole discussion of boom total gas loss at max penetration and you are right at thirds and you're going to die is a little ridiculous because I don't know of any realistic scenario where you are going to miraculously lose everything, but if you ran the reel on the way in that usually chews up a good bit of gas so you should have a bit of a safety margin there. Unfortunately many of the popular caves have pulled the gold lines out so far that it doesn't matter, and we have seen instances of idiotic people scootering through places they shouldn't have and shearing both valves off, but come on.

@syntaxerrorsix you are being completely ridiculous now implying that you have 3 catastrophic failures in that situation. No one plans for that many catastrophes to happen because you have to draw the line somewhere. In sidemount we still carry a long hose because you plan for two catastrophic losses of gas. Either both regs on one diver, or one on each so you can share air, but literally no one plans for those kinds of failures.

Certifying divers to dive on thirds is no different than certifying them to dive air to 130ft at the recreational level. You should advise against it as it is a hard and fast rule not to violate, but that doesn't mean that is where you should stop at every dive. The instructors have the responsibility to discuss the rule of thirds, the history of that rule, and why it is the absolute maximum limit of gas planning as opposed to a rough guideline. Why should the certification limit you to what you can do instead of your own brain? The instructors have the power not to certify someone they don't think is capable of making good decisions so let them have the choice to limit themselves further so they make the progressive learning and if you don't trust them, don't certify them. Simple as that

 

[syntaxerrorsix]

It seems as if conservatism isn't a big deal to some of you folks. Progressive penetration, progressive depth limits are all designed to allow the diver to gain experience closer to the entrance or closer to the surface. I'm not sure how I could better instill that lesson.

I suppose when you've been doing it long enough to have one of those "oh ****" moments it just seems so much clearer.

 

[Imbodie]

I have never seen a loss of ALL gas, but I have seen: an Oring popping out between cylinder and valve. That means a non fixable failure. So closing the manifold and then you have 1 cylinder left. If you are fast of course.
I have seen a blowing manifold.
I had another failure myself: the loss of a valveknob on a stage cylinder. That means if the cylinder is closed that you cannot access the gas. Not a real loss, but gas is not usable, but quite non fixable (or you have to take stuff with you to fix this under water).
I have had a free flow on a decogas, followed by closing cylinder, so normally not a problem, but followed by getting no gas anymore because of a block somewhere in the second stage. Really nice if you are coming from 340 ft and doing deco. I solved this problem not by changing regs under water, but got the decogas from a ccr diver in our mixed team group.
Just some examples of partially lost of gas.

I had a panicing diver with a twin12 liter and he drained his twinset in 30 minutes. No failures, he was just in panic. Experienced diver with around 350 dives.
I had a buddy who lost a fin and he used much more gas to swim back (we could not go back to surface directly due to ships above us).
Just some other examples.

NONE of that has to do with CAVE diving... give me cave examples since this is a cave conversation....

You are also talking backmount, which yes is used in caves... but doesn't personally have ANYTHING to do with the way I or a lot of other people dive in caves.... Yes there are back mount cave divers but the percentages are swinging to side mount from what I have seen.

I HAVE seen knob's fall off.... and that would really be a bummer... and maybe a nylon valve tool might be a great addition to add to a diver on person tools... Know an instructor that had a 2nd stage failure... you can ALWAYS GUT THE THING and manually control the air flow (assuming you dont have one of the 2nd stages that has a stupid pin holding the face plate on)

 

[Germie]

The blowing manifold was in a cave.
And all failures can happen in a cave and in open water. If you think such things never happen in caves, you are wrong.
I have been lost in my sportsdiver career in a wreck, will that mean this could not be happen in a cave? The reason of getting lost was group pressure, no need to take a line according to others. It ended up with a buddy in panic, and no way out. At the end I had just 15 bars left in my cylinders and my buddy has drained its tanks. I always use this example for cave diving too, always use continous guideline to the exit. Oops, wrong example as it did not happen in a cave.

 

[Imbodie]

It seems as if conservatism isn't a big deal to some of you folks. Progressive penetration, progressive depth limits are all designed to allow the diver to gain experience closer to the entrance or closer to the surface. I'm not sure how I could better instill that lesson.

I suppose when you've been doing it long enough to have one of those "oh ****" moments it just seems so much clearer.

Been there, Done that... and yes... ONLY 25 cave dives to my name.... I TOTALLY understand stress and air consumption... my reaction was appropriate for the amount of penetration on the dive... my stress level dropped considerably when I dealt with the situation rather than letting my buddy make it worse (which is what happened... it was intensified).... had I been further into the cave I would have dealt with it from the start and exited the cave.... rather than relying on a buddy and consuming precious breathing gas...waiting for them to help resolve it.

ALL I'm saying is make a training standard STANDARD for everyone...