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07-20-2004, 09:16 AM,

WTF is wrong with saying National Lamp00n > Sad

?

Omicron · (This post was last modified: 07-20-2004, 09:35 AM by Omicron.)

Hey Chuck,

Thanks for the info on the gas planning and such w/ the rebreathers. That kind of answered my question!

I watched the show last night. I'm probably going to order the DVD, just so I can watch the footage of the caves again.

Their technique was a good example of what I hope I don't look like in a cave. I'm hoping that they just got caught on film at a bad time. I couldn't help but cringe when I saw them pounding the stake into the ceiling. Their technique wasn't all bad, but I saw a few things being done that I know I would have gotten nailed for by my instructor.

But besides that, I was mesmerized. Some very cool footage of the caves - I've only dove dissolution caves, that show really made me look forward to getting down to the cenotes sometime.

And it was a blast watching someone else suffer the land drills ;D

igotoofar · (This post was last modified: 07-20-2004, 12:45 PM by igotoofar.)

The thing that hit me was they were 2hrs into the dive when they got to the opening. Correct me if I am wrong, but doesn't the inspiration scrubber have a 3hr limit? If they didn't know they were able to get out, that would have left them with a problem :o

It was intereasting to see the caves and visibility :o I was expecting to see more of a mineshaft like space.

I would say that they really didn't discover to much stuff out on the show. They made it sound like they did, but that's TV.

john j · (This post was last modified: 07-20-2004, 12:59 PM by john j.)

Standard limit of the Inspiration caniser is 3 hours as quoted by the manufacturer, if the standard, recommended grade of Sofnolime is used, in warm water, with nominal diver working conditions. Some folks use chemicals other than Sofnolime and some folks use Sofnolime much longer than 3 hours. I'm not advocating anything here, just stating facts that I have observed.

I didn't see the program, nor do I know about it so I don't know as a fact what they were doing. They could have even been using a larger cannister or something. If I was going to make a guess, I'd say that the probability is high that they were running standard scrubbers for longer than 3 hours. This is quite common.

ghosch · 07-20-2004, 02:52 PM,

Not knowing anything about the dive, I didn't watch the show, but looking at it from a "rule of thirds" standpoint if they went an hour in, turned around, and took an hour out, leaving them with one hour on the scrubber, that would make sense to me. Combine that with the fact that the canister is rated very conservatively, and that you still have other bailout options and it seems like reasonable dive planning.

Now, if after exiting the entrance of the cave they still had a bunch of deco., that's a different story.

igotoofar · 07-20-2004, 03:02 PM,

They were 2hrs into the cave when they "Found" another opening. This allowed them to start the dive while cutting out 3500' of penetration.

ghosch · 07-20-2004, 03:34 PM,

So, if I understand you correctly, had they not "found" another exit they would have had to turn around and go another two hours back out? Which we mean total dive time would be four hours? What if they hadn't "found" another exit, how long would they have kept going?

Guess I should probably just watch the show rather than have you give me a play by play on the entire thing.

07-20-2004, 03:53 PM,

The max depth in that system is 67ft - average depth is 35ft. A squared away diver can do a 3500ft penetration at that depth on a set of AL80's without even needing a stage - add a stage and you easily can go a mile. Chatterton's comments about needing a rebreather for this dive is complete BS - WKPP and other teams do SETUP dives thousands of feet farther into the cave at a depth of 300ft on OC - go figure!

Chuck_Northrup · (This post was last modified: 07-20-2004, 04:22 PM by Chuck_Northrup.)

Are you talking with a scooter or unassisted? What are you assuming a "squared away diver" would have for an RMV? Is this following the standard rule of thirds?

07-20-2004, 09:05 PM,

No scooter - just swimming. Let's assume an RMV of .4, which I would consider still somewhat on the high end for a diver who's comfortable in the water and who works out on a regular basis. With slightly overfilled AL80's you're looking at 55cf of gas going in on thirds, RMV of 0.4, average depth of 33ft gives you a little over 68 minutes to swim 3500ft - that's a very doable pace. The key is to work out (but most people would rather buy any piece of equipment instead of committing to running 5 miles twice a week) and streamline (the increase in effort with increased drag is just ridiculous - what the HC showed was definitely not a great example of streamlining).

D