Really stupid question... Why dive thirds with doubles?

[DA Aquamaster]

Not me, his classes always silt out Peacock. It's no secret, everyone's seen or heard about it. If he was younger or from out of town it would be a big deal, but his name is on a few maps so it's all cool.

there is a bit of humor in all this as it suggests a larger pecking order than I suspected.

Not only the local zip codes divers versus the out of towners but also the OLD local zip coders versus the younger local zip code divers and the out of towners.

 

[Meng_Tze]

there is a bit of humor in all this as it suggests a larger pecking order than I suspected.

Not only the local zip codes divers versus the out of towners but also the OLD local zip coders versus the younger local zip code divers and the out of towners.

Cave politics 1-0-1

 

[ucfdiver]

there is a bit of humor in all this as it suggests a larger pecking order than I suspected.

Not only the local zip codes divers versus the out of towners but also the OLD local zip coders versus the younger local zip code divers and the out of towners.

My usual dive buddy/mentor is about your age and took c2/t1/DPV back when Tyler Moon was still teaching it, so a while ago. I have no issues with older divers.

When you see breather teams kneeling on the floor to tie into the crossover tunnel (and you can see here, this isn't a well kept secret), and NAUI Cave 1 classes being taught by someone who's not a NAUI Cave instructor (a NAUI instructor did sign off on the card for them however) in blatant disregard for the NTEC gear config, you start to realize there's different rules for different people.

 

[LiteHedded]

My usual dive buddy/mentor is about your age and took c2/t1/DPV back when Tyler Moon was still teaching it, so a while ago. I have no issues with older divers.

When you see breather teams kneeling on the floor to tie into the crossover tunnel (and you can see here, this isn't a well kept secret), and NAUI Cave 1 classes being taught by someone who's not a NAUI Cave instructor (a NAUI instructor did sign off on the card for them however) in blatant disregard for the NTEC gear config, you start to realize there's different rules for different people.

well in their defense, by the time you swim all the way there with that kind of trim you really need to take a load off and relax for a bit

 

[Doc Harry]

...If you do lose all gas at max penetration in a low/no flow cave - you better stay calm and make an quick exit - because in theory you have "just enough".

You mean make a SLOW exit.

In water, the drag (and gas consumption) quadruples with a doubling of speed.

If you've never done some speed/gas trials, it's quite enlightening. I actually get the most distance for the least amount of gas by flutter kicking at a slow, leisurely rate. Slow frog kicking is a close second. Gas consumption increases exponentially with increasing speed.

I don't have the numbers available right now, but I'll start another thread and post my raw data later today.

If I were in a cave in a low-gas situation, I would relax and take my time getting out. I get more distance per cubic foot that way.

 

[Meng_Tze]

You mean make a SLOW exit.

.....
If I were in a cave in a low-gas situation, I would relax and take my time getting out. I get more distance per cubic foot that way.

I would also not dive to 1/3 in a low/no flow system, it is cutting it too close if there is ANY delay in exit.

 

[Reg Braithwaite]

You mean make a SLOW exit.

In water, the drag (and gas consumption) quadruples with a doubling of speed.

If you've never done some speed/gas trials, it's quite enlightening. I actually get the most distance for the least amount of gas by flutter kicking at a slow, leisurely rate. Slow frog kicking is a close second. Gas consumption increases exponentially with increasing speed.

A little free diving teaches this immediately and vividly. As part of my Recreational Trimix certification (all bow before my l33t sk1llz!) I had to do an out of air swim at 120'. The key was to relax and swim slowly and calmly, like a free diver. I would have failed if I had become anxious and tried to swim quickly to my instructor.

(It was an interesting test to include as part of learning about trimix: You need a clear head to relax and stave off panic. Mind you, the real divers on this thread would have no trouble keeping a clear head at 120'.)

 

[Meister481]

I haven't ever heard of anyone dying because they carried too much gas. The alternative sucks though.

There was that cat that stroked out on the Doria?

My usual dive buddy/mentor is about your age and took c2/t1/DPV back when Tyler Moon was still teaching it, so a while ago. I have no issues with older divers.

When you see breather teams kneeling on the floor to tie into the crossover tunnel (and you can see here, this isn't a well kept secret), and NAUI Cave 1 classes being taught by someone who's not a NAUI Cave instructor (a NAUI instructor did sign off on the card for them however) in blatant disregard for the NTEC gear config, you start to realize there's different rules for different people.

Very different rules. Some people get to scooter Peacock and Madison, the rest of us don't. Some people get to dive with the Big Gator and the rest of us don't. No biggie, they will be gone some day and the rest of us will still be here, making rules of our own! Until that time I will enjoy what I can.

As far as gas rules go, start at twice needed to exit plus deco obligation, and work up from there. It also depends on the cave, how busy it is, are there additional exits, Etc.

For scootering it's far more complicated, and I'm not posting it here where every wanna be cave diver comes to learn to dive. I don't wanna see another guy in a Rec rig scooter into Jackson Blue on a Sea Doo scooter. I'm tired of hearing horror stories about OW divers dying in a cave, on a scooter or not.

The rule of thirds is the MINIMUM gas plan for overhead, and not a good idea for many environments, including some OW dives where current/visibility is a factor.

 

[marchand]

You mean make a SLOW exit.

In water, the drag (and gas consumption) quadruples with a doubling of speed.

If you've never done some speed/gas trials, it's quite enlightening. I actually get the most distance for the least amount of gas by flutter kicking at a slow, leisurely rate. Slow frog kicking is a close second. Gas consumption increases exponentially with increasing speed.

I don't have the numbers available right now, but I'll start another thread and post my raw data later today.

If I were in a cave in a low-gas situation, I would relax and take my time getting out. I get more distance per cubic foot that way.

and I get the most distance for the least amount of gas when I swim as fast as I can and still control my breathing.

 

[scblade27]

You mean make a SLOW exit.

If you've never done some speed/gas trials, it's quite enlightening. I actually get the most distance for the least amount of gas by flutter kicking at a slow, leisurely rate. Slow frog kicking is a close second. Gas consumption increases exponentially with increasing speed.

I was tagging along in a Full Cave class one time because the student need a buddy. We used half as much gas coming out doing a lights out air share drill than we did going in. The drill forced the lead guy to slow way down and thus we used way less gas. It was kind of funny seemed completely backwards.