Inspiration Cave Dive

[Chuck_Northrup]

The Deep Sea Detectives series on the History Channel is going to be broadcasting a cave dive tonight. Rumor has it the entire team is on Inspirations and they penetrate more than a mile back into a cave under Cozumel.

Jeff Bozanic NAUI rebreather guru and author of "Mastering Rebreathers" aka "Understanding Rebreathers" worked as a support diver for the team.

Should be an interesting show, I believe it starts at 8:00 our time.

[Omicron]

Something I've been wondering about since I got my cave training....

How the heck does one do gas planning on a rebreather in a cave? With open circuit, the thirds and gas matching are easy. What do you do w/ a rebreather? And how do you do an "air sharing" with a rebreather??

And thanks for the tip on the show - I'll definitely be watching!

[Chuck_Northrup]

The rule of thirds would still hold true, the ability to plug off board gas into the unit from any bottles the team is carrying makes sharing gas pretty straight forward.

Buddy breathing with a rebreather is possible, but does require practice and self-control to do effectively. The possibility of a full system failure requiring this type of bail-out is extremely unlikely. As has been mentioned in other posts there are many options to consider before going "off the loop"

[Omicron]

Interesting.

I just dunno how much I personally would trust it. The idea of them seems so very cool. I really like the idea, if things really go bad for me, I have a buddy nearby that has 1/3 for me on a long, long hose

One of these days I'm going to have to learn more. My lack of trust is probably because of my lack of knowledge.

[Chuck_Northrup]

When you start diving rebreathers one of the things you need to learn (or unlearn) is thinking in terms of open circuit. :

With that said there is nothing to stop you from putting a 7 foot hose on your stage bottles so that you can utilize that gas for OC.

[DRE]

Chuck,

excuse my ignorance but don't you still have to plan the dive in terms of available gas to be able to exit the cave on OC from furthest penetration, ie absolute worse case scenario? Or do you plan the dive around the idea that if the entire team is on CC (let's say three divers - the ideal cave team), the possibility of all three divers having to bail out to OC is so remote that you can use lesser gas requirements? If the latter holds true, how do you calculate your contingencies, ie one or two divers having to bailout to OC, having to bailout to SCR mode or flying the unit manually, etc.

D

[Chuck_Northrup]

If you want to check out the standards for CCR Cave look at iantd.com they have (to my knowledge) the only CCR Cave course.

Reprinted from IANTD standards for Closed Circuit Rebreather Cave Diver, section E (equipment requirements)
1. All students must be taught the concept of gas matching based on O2 metabolism
2. Bailout adequate to allow 1 1/2 divers to exit the cave on OC must be carried by the dive team
3. A stage decompression cylinder containing oxygen is recommended for deco as a back up to the system
4. Bailout stages must be configured to ensure easy hand off to an out of gas diver. A 5 foot hose (1.5 meter hose) is recommended.

There are several more listed requirements but I think these are the only standards germane to your query. 8) Alpinists carry less, you could certainly carry more. It will be interesting to see if they cover dive planning on the special tonight.

Hope this helps

PS "If ignorance is bliss, then knock the smile off my face"
--Zach de la Rocha

[rcojr]

I run seven foot hoses on both of my stage bottles.
It's easier than trying to hand off bottles when you are hanging on a line.

[DRE]

Did anyone see the DeepSea Detectives show last night? I'm not sure whether I should keep laughing at this National Lampoon's edition of cave diving or be abhorred by what I saw: divers kneeling doing their skills, ramming a steel rod in the cave ceiling, absolutely horrific finning technique, etc.
This was an abomination of what cave exploration is all about and I hope no one thinks these guys are the real deal!

[tcjtn0]

Eyups , sure did !!! I was watching their finning etc but I guess I was just looking at that clear water...Ah , makes me want to go back to Ginny Springs again!!! ;D
I tried to just watch the show for the U/W photo etc...
I don't have the knowledge to do any judgements.

But it was fun to see the line drills they did (surface) that we did for our cavern course! Brought back some nice memories.

Jean