PADI Deep Diver course- gas management

[jadairiii]

And in the classroom my instructor likely mentioned the rule of thirds as a "good" option,

When they discussed the thirds, was it to terminate the dive when someone hit thirds?

 

[Lorenzoid]

When they discussed the thirds, was it to terminate the dive when someone hit thirds?

I would assume so, but ... My course was in 2012, and as I said, my recollection of the classroom portion is not as good as my recollection of the dives themselves.

 

[steinbil]

Not specifically in the material; it is up to the instructor.

And therein lies the problem. This means an instructor can teach how to calculate reserve gas in a sensible way or completely botch it. It's surprising to me that there is no industry standard for gas management.

 

[tursiops]

And therein lies the problem. This means an instructor can teach how to calculate reserve gas in a sensible way or completely botch it. It's surprising to me that there is no industry standard for gas management.

Because dives are different -- depths, conditions, missions, etc -- gas management differs. A simple set of rules only applies to a very constrained kind of diving...for example training dives with square profiles.

 

[johndiver999]

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And therein lies the problem. This means an instructor can teach how to calculate reserve gas in a sensible way or completely botch it. It's surprising to me that there is no industry standard for gas management.

There is no standard for ascent strategy and a disparity in the acceptance of pony bottles between organizations, so it seems impossible to agree on a standard.

This means to me anyway, that it is essential that the student understand some basic math equations, understand sac or rmv and be able to logically develop a plan for themselves. Thirds or 500-psi-on-the-boat are both simplistic and somewhat arbitrary short cuts.

 

[steinbil]

Because dives are different -- depths, conditions, missions, etc -- gas management differs. A simple set of rules only applies to a very constrained kind of diving...for example training dives with square profiles.

That sounds like a cop out to me. A simple reserve gas calculation based on getting two divers back to next gas source (ie the surface) can easily be applied to any dive within recreational limits and most technical dives. Of course you need to allow for different scenarios in a complete gas plan, but at the very least every diver should be able to calculate reserve gas for whatever dive they make.

 

[steinbil]

There is no standard for ascent strategy and a disparity in the acceptance of pony bottles between organizations, so it seems impossible to agree on a standard.

You can adapt the following calculation to any ascent strategy:
2 divers * conservative sac rate * minutes of ascent * optional safety factor

 

[tursiops]

You can adapt the following calculation to any ascent strategy:
2 divers * conservative sac rate * minutes of ascent * optional safety factor

And what number do you come up with?

 

[johndiver999]

You can adapt the following calculation to any ascent strategy:
2 divers * conservative sac rate * minutes of ascent * optional safety factor

Exactly my point, you are doing calculations that are relevant to you. Not a cookbook approximation or rule of thumb.

 

[steinbil]

And what number do you come up with?

I'm saying there could be an industry standard for calculating it, not for the answer to the calculation.