Cave Certs Expiration

[kensuf]

Jack and Jill dive Peacock Springs. They are both on 85s pumped to 3600 psi. They both hit 2400 PSI at the same time, but Jill loses all of her air in a catastrophic gas loss. They will die.

Why?

Think about your own description of burning through more air at the beginning of a dive when you're stressed out.

It took them 2400 PSI (1200 each) to get to that point when everything was good and calm. It will take them 2400 PSI to get out if they remain calm and relaxed, but the likelihood of them remaining calm and relaxed is low -- one of them just had a gas loss and they're now sharing air. Additionally, in most cases a tank becomes very difficult to breathe from when it's below ~150 PSI, so they don't even have the full 2400 PSI.

 

[Jack Hammer]

I don't understand how rule of thirds is aggressive... 2 times the amount of gas to get out as it took to get in.... seems to be a good rule...

If you have a problem that gas goes away very quickly, especially if you have to donate at max penetration. Unfortunately there are plenty of people who found this out the hard way. I'll look for a link to Andrew Ainslie's account of how quickly his gas went away

 

[Germie]

If you are a beginning cave diver (and lot of experienced have same), there is just a small amount of stress needed to make your gasconsumption make go up. If there is really stress, your consumption will be much higher. Have you never felt a little bit uncomfortable?
That can be because of really minor issues, or there can be a bigger issue. Never lost a line because of a small time thinking/looking at other things? Never went in with good viz and went out with less viz or no viz? Such things will happen, and that is reason that you always have to be conserative and always have to consider what amount of reserve is needed. Having an OOG will make you slower and every diver will have stress, so 1/3 will not be enough to get out.

After 10 successfull cave dives you are not the most experienced cave diver. But some think. Same as 10 dive ow divers think they are gods.
It is true that some divers are more talented or a natural then others and can use their talent, but even the most talented diver need time to become experienced. Some divers will feel earlier stress or panic than others, but it can happen to every human. And the less experience you have, the thinner the line between some stress and panic if you go too soon too fast.

 

[Imbodie]

Rules of thirds is aggressive in may ways. If it it's a low/no flow or syphon system you swim in and then out. It is very likely that you are not going to go out as fast as you go in because you've already been working.

It SHOULD NOT be universal for ANY level or EVERY dive.

It's part of gas management that should have been thoroughly discussed in class.

New cavers have NO business using the max allotted gas for penetration.

It should be univseral for certifications.... if its' going to be 6ths... then it should be 6ths for ALL certifcations

I DID NOT SAY for ALL DIVES.... if you are not capable enough to determine that you are going to use MORE AIR coming out of a siphon than going in... AFTER you have been certified... it is on YOU the diver..

If you are a NEWLY certified cave diver.... you should never be pushing the limits... but your limits should be the same as ANY other cave diver...

In MY experience people limited to 6ths are violating the limitations to do longer dives anyway... obviously staying under thirds, but violating 6ths...
Why not just make it universal and be done with it. People get pissed at me because as a Cave1 certified diver I can dive 3rds... (rarely do push it all the way to 3rds).

But to say it again.... 3rds should be universal for ANY certification level.....

 

[syntaxerrorsix]

It should be univseral for certifications.... if its' going to be 6ths... then it should be 6ths for ALL certifcations

I DID NOT SAY for ALL DIVES.... if you are not capable enough to determine that you are going to use MORE AIR coming out of a siphon than going in... AFTER you have been certified... it is on YOU the diver..

If you are a NEWLY certified cave diver.... you should never be pushing the limits... but your limits should be the same as ANY other cave diver...

In MY experience people limited to 6ths are violating the limitations to do longer dives anyway... obviously staying under thirds, but violating 6ths...
Why not just make it universal and be done with it. People get pissed at me because as a Cave1 certified diver I can dive 3rds... (rarely do push it all the way to 3rds).

But to say it again.... 3rds should be universal for ANY certification level.....

Because we don't advocate new divers using the max allowable gas for penetration. It's called conservatism and safe planning.

It's the same with depth. We don't certify everyone to 300' it's progressive.

 

[Imbodie]

Having an OOG will make you slower and every diver will have stress, so 1/3 will not be enough to get out.

Maybe I'm frustrating you.... rule of 3rds is 1/3 going in... 2/3 coming out... (if they are following the rules, why are they out of gas????)

I'm not saying every diver SHOULD push straight up to that first third of their breathing gas before they turn a dive.... I AM saying the standards should all be based on thirds when training new divers...

 

[syntaxerrorsix]

Maybe I'm frustrating you.... rule of 3rds is 1/3 going in... 2/3 coming out... (if they are following the rules, why are they out of gas????)

I'm not saying every diver SHOULD push straight up to that first third of their breathing gas before they turn a dive.... I AM saying the standards should all be based on thirds when training new divers...

Because they had a catastrophic gas failure and you seem to be overlooking the fact that it's not all YOUR gas to come out on.


(OOG=out of gas)

 

[Imbodie]

Jack and Jill dive Peacock Springs. They are both on 85s pumped to 3600 psi. They both hit 2400 PSI at the same time, but Jill loses all of her air in a catastrophic gas loss. They will die.

Why?

Think about your own description of burning through more air at the beginning of a dive when you're stressed out.

It took them 2400 PSI (1200 each) to get to that point when everything was good and calm. It will take them 2400 PSI to get out if they remain calm and relaxed, but the likelihood of them remaining calm and relaxed is low -- one of them just had a gas loss and they're now sharing air. Additionally, in most cases a tank becomes very difficult to breathe from when it's below ~150 PSI, so they don't even have the full 2400 PSI.

So your saying BOTH of her cylinders just dropped ALL their gas?? I don't know much about back mounted cylinders so that might be a possibility... Diving side mount I'm not sure how that could happen.... and then I'm wondering where that safety cylinder is...

 

[Imbodie]

Because they had a catastrophic gas failure and you seem to be overlooking the fact that it's not all YOUR gas to come out on.


(OOG=out of gas)

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....

 

[syntaxerrorsix]

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 if you lose one of them, and now you have no way to donate air.