Overhead Environment DPV Use

What kinds of gas math will UTD be suggesting for DPV use? Will you offer courses in FL, and will those of us with a current "full" cave rating and be able to crossover? I'm thinking of taking the NACD course here soon, but would be open to suggestions. My buddy for the class is GUE/Cave 2 if that matters.

Do you plan for 2 scooter failures and 2 divers sharing gas? 1 scooter failure and sharing gas? 2 scooter failures and not sharing gas?

Seems there's no simple way to solve the problem. High/low flow, depth, huge deco penalties, a fluctuating rock bottom, etc all shift the math around much more than the standard 1/3rds taught as a starting point for swimming a cave.

I would be interested in hearing what you guys do, both those of you who have been scootering for a while, and what the official agency stance will be. I apologize if this isn't a topic that should be posted, I know there's always risk of misuse when you start discussing these things in the open.

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Permalink Reply by Richard on October 28, 2009 at 1:03pm

You really think there can be an "official agency stance"?

At some point you have to keep yourself alive with a combination of good judgment, common sense, wits, team, and equipment, not "standards" or "protocol" which could never cover every life threatening situation you might encounter underwater. This would include contingency gas volumes, safety bottles, scooter choices etc etc. See the video blog 'protocols are a stopgap'

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Permalink Reply by James Garrett on October 28, 2009 at 1:17pm

I'm not sure....I think there has to be a starting point. Maybe that starting point is 2x the gas needed to swim out if you don't have a tow scooter, but now we're planning for L/R post failures and 2 DPV failures all on the same dive. A bit unrealistic, but it certainly gets the risk back to roughly the risk of swimming.

Planning for no DPV failure certainly isn't an option....you can always tow out, but silt would immediately render each scooter useless until you could swim into clear (enough) water. You're now left making the judgment call of how bad could a silt-out possibly be? In recent years, JB and Madison Blue have both had cave collapses that blitzed the viz through the whole thing. Parker Turner's death at Indian could have been prevented by a little bit more gas, but then again it might have taken 5 hours worth of gas, and now we're getting unrealistic.

There seems to be a fairly consistent view that you should have 120-130% of the total burn time you THINK you need when doing a DPV cave dive, with various logical reasons that reserve is required, both towing a buddy and possibly search time if you get split up. That's about the ONLY consistency I've gathered.

Maybe once you factor in the rock bottom differences in plans, various scooter reliability, high/low flow, etc there's just too many factors for an agency to write out on paper, but I have to assume there's some sort of logic or baseline....Similar to 1/3rds, we all know it's not enough for swimming a low flow cave, but it can be used as a planning reference.

One thought we had while brainstorming was 1/4ths....since for every 1min in on a scooter you need 3min to get out assuming you scooter 3x as fast as you swim, but then the sac rate would increase on the way out and make that theory fall apart.

Just hoping for an open discussion here, hopefully everyone understands that no one plan works EVERYWHERE.

Richard said:

You really think there can be an "official agency stance"?
At some point you have to keep yourself alive with a combination of good judgment, common sense, wits, team, and equipment, not "standards" or "protocol" which could never cover every life threatening situation you might encounter underwater. This would include contingency gas volumes, safety bottles, scooter choices etc etc. See the video blog 'protocols are a stopgap'

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Permalink Reply by Teppo on November 1, 2009 at 8:33am

Not being a UTD instr, but another agency instr. I would say one possible accident could be lose of gas and tangled/broken DPV, by hitting ceiling and tangling the DPV, thats 2 failures. So for 3 person team 1/6 rule is still working

The question i like is about staging and how much gas do you need get back to "working" stage and if you leave back up scooters in cave

Teppo