PADI Deep Diver course- gas management

[jadairiii]

Capt Jim did not quote all the relevant parts of the Instructor Manual for Deep Diver.

Appropriate gas management is talked about multiple times in the class. For example, one of the performance objectives of Deep Dive One -- which, by the way, is also the Deep Dive for AOW -- is this:

Plan and manage gas use, including determining turn pressure, ascent pressure and reserve pressure. Establish no stop and dive time limits.​

In the briefing for Deep Dive One, it is suggested to:

5. Have buddy teams plan their turn pressure, ascent pressure and reserve pressure for the dive based on gas supply limits.​

6. Have buddy teams establish maximum depths and bottom times, and plan and plan contingency profiles for longer and deeper dives than planned.​

A performance standard for Deep Dive One is specifically about gas management:

a. Before beginning the descent, remind divers to check their starting pressure and make a note of their turn pressure.​

b. During the dive, check cylinder pressures at irregular intervals to confirm appropriate gas management.​

Deep Dives 2-3-4 have similar statements.
Other parts of he IM and the Deep Diver Student Manual discuss gas consumption rates, and how to determine if you have enough gas for the dive.

So what are the PADI parameters to "determine if you have enough gas for the dive"?

That was my initial question.

 

[tursiops]

So what are the PADI parameters to "determine if you have enough gas for the dive"?

That was my initial question.

That's physics -- not PADI -- plus it depends on the dive, plus Instructor input.
If you want recipes, go to PADI Tec.
There is nothing wrong with thirds, back on the boat with 500 psi, leave the bottom at 800 psi, etc, depending on the situation, right?
Remember, this is NDL recreational diving, not deco or tech diving.
I refuse to play "gotcha" with you in your incessant questioning on this issue.

 

[jadairiii]

That's physics -- not PADI -- plus it depends on the dive, plus Instructor input.
If you want recipes, go to PADI Tec.
There is nothing wrong with thirds, back on the boat with 500 psi, leave the bottom at 800 pso, etc, depending on the situation, right?
Remember, this is NDL recreational diving, not deco or tech diving.
I refuse to play "gotcha" with you in your incessant questioning on this issue.

I am really not trying to play "gotcha". But this is called a "deep diver" course, and in this thread PADI instructors were taking students down to 130'.

But your response, along with Capt Jim's (and the rest of the people that posted) was enlightening as it related to my question. From my first post, I now know what to expect when my friend's son takes his Deep Diver course. Thanks, this was what I was looking for.

 

[inquis]

Remember, this is NDL recreational diving

As such, I would hope the gas planning would include calculations to get 2 stressed divers to the surface, along with reasonable assumptions of what a stressed RMV might be.

Does the PADI Deep specialty include the above in its standards, or is it on the instructor to go beyond standards for a student to be taught this?

 

[Lorenzoid]

That's physics -- not PADI -- plus it depends on the dive, plus Instructor input.
If you want recipes, go to PADI Tec.
There is nothing wrong with thirds, back on the boat with 500 psi, leave the bottom at 800 psi, etc, depending on the situation, right?
Remember, this is NDL recreational diving, not deco or tech diving.
I refuse to play "gotcha" with you in your incessant questioning on this issue.

Now that you put it that way, in retrospect, I think "recipes" are exactly what I had envisioned getting out of the PADI Deep Diver course I took years ago. Instead, as I recall, I got a lot of "it depends on the dive," and we didn't plan out a variety of different dives. Diving in the 100-130 ft range really is on the transition between rec and tech. I didn't care for my course because I felt it kept my feet firmly planted in rec, while suggesting that because we're trying to reach farther it is difficult to mitigate the risks. Only later did I appreciate that the ways to mitigate the risks are taught in a straighforward, even formulaic (recipes!) way in tech diving courses.

 

[tursiops]

As such, I would hope the gas planning would include calculations to get 2 stressed divers to the surface, along with reasonable assumptions of what a stressed RMV might be.

Does the PADI Deep specialty include the above in its standards, or is it on the instructor to go beyond standards for a student to be taught this?

It is Parr of the discussion: exactly how it is discussed is up to the instructor. The standards are silent on the details of the discussion, so going into great detail, for example, is not going beyond the standards, but no discussion of SAC/RMV and "when to leave the bottom" would indeed violate the standards, IMHO.
As always, good instructors matter more than good Instructor Manuals.

 

[Cthippo]

Sounds like the whole coirse could really be consolidated down to one or two dives. Gas planning can be taught in the dry. What I feel is really needed is a controlled experience of "when do I personally get narced and what does it feel like".

 

[Capt Jim Wyatt]

The gas management planning for this class is the responsibility of the instructor to "teach".

The class requires four dives over at a minimum two days. Dive one max depth = 100 feet. Dives 2, 3 and 4 max depth = 130 feet.

No stage decompression dives are allowed. Required equipment includes an emergency backup air supply. To meet this standard the instructor carries an AL40 with him/her.

It would not be an unreasonable plan for divers with AL80s filled to 3000 psi to leave the bottom with no less than 1200 psi and head to the 15 foot safety stop.

 

[tursiops]

Sounds like the whole coirse could really be consolidated down to one or two dives. Gas planning can be taught in the dry. What I feel is really needed is a controlled experience of "when do I personally get narced and what does it feel like".

I don't know why the course is 4 dives, except that it is far too much to do on 2 or maybe 3 dives, and four nicely fits a 2/day schedule for 2 days, plus classroom time (if done in a classroom).
All dives must be >60 ft. dive 3 is recommended to 130, and dive 4 is planned and executed by the student(s), with the instructor in attendance and having input-if-needed and veto-power over the plan.
The BIG take-away for the students on all four dives is how much faster their gas gets used up.
A secondary take-away is narcosis, possible on all four dives but likely on Dive 3.
Planning and execution to the plan is an overlay on all four dives, and paramount on Dive 4.
Another overlay -- and emphasized in the classroom work -- is the much higher possibly of DCS on deep dives and how you recognize it.
An emergency decompression stop is simulated on Dive 3.
Dive 2 includes a navigation exercise, away from and back to the descent/mooring line, which tests multi-tasking when possibly narced.

 

[Capt Jim Wyatt]

Capt Jim answered it, PADI does not define what "appropriate gas management" is, in the Deep Diver course.

That is true if you expect the numbers be laid out in the standards. But as @tursiops pointed out when he pasted:

Plan and manage gas use, including determining turn pressure, ascent pressure and reserve pressure. Establish no stop and dive time limits.In the briefing for Deep Dive One, it is suggested to:
5. Have buddy teams plan their turn pressure, ascent pressure and reserve pressure for the dive based on gas supply limits.6. Have buddy teams establish maximum depths and bottom times, and plan and plan contingency profiles for longer and deeper dives than planned.A performance standard for Deep Dive One is specifically about gas management:
a. Before beginning the descent, remind divers to check their starting pressure and make a note of their turn pressure.b. During the dive, check cylinder pressures at irregular intervals to confirm appropriate gas management.

Planning is done and I can defend that as appropriate gas management as is described.