When does PADI teach gas planning?

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LG Diver

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I've completed the following certs: OW, AOW, Rescue, Nitrox, Deep, DPV. I've already bought and scanned the course books for Nav and Wreck- all from PADI. After hanging out here for a while now, absorbing the collective wisdom of SB, and educating myself a bit on "rock bottom" and gas planning, I'm growing alarmed that nowhere in any of the above-mentioned courses does PADI teach gas planning. The closest they get is a half-hearted attempt at calculating depth consumption rate in the Deep specialty.

In preparing for my Deep specialty dives (one of which was planned for 130') I did some calculations of rock bottom, and came up with a figure of 2100 PSI for an Al 80 with padding for surf exit on air. The day of the dives comes. We're all gearing up and the instructor goes over rough surf entry/exit procedures, objectives, etc... no mention of a gas plan. I ask "what's the gas plan?" Huh? "At what pressure should we start our ascent?" Huh? Oh, uh.... 1500 PSI. "what? Excuse me, but my rock bottom calculations say we should be starting to ascend at ~2100PSI." And the reply was....

"if we started our ascent at 2100 PSI, we wouldn't have a chance to see anything down there!"

OK, fair enough, but I'm not particularly keen on trading sufficient emergency reserve for additional bottom time. Perhaps an Al 80 isn't adequate for this dive. Oh no, I'm reassured, it's done all the time. We ended up not doing the dive due to increasingly bad surface conditions, and in thinking about this afterwards I was quite relieved that we didn't do the dive because I was very uncomfortable with this discussion.

Now, mind you, this is not just a PADI instructor, but a PADI Tech instructor. So, this has me wondering. Does PADI not teach gas planning anywhere- not even on the tech side, or is this instructor just choosing to ignore gas planning when dealing with recreational students? In either case, I'm not comfortable with the notion of continuing to dive with people that won't carry enough gas to get me to the surface in the event I have an equipment failure, and I'm sure not keen on getting into overhead situations with an instructor/curriculum that doesn't address gas planning at all. I know I could buy a pony but I don't want to compensate for lack of training with gear.

I realize that this has been more of a rant than a question up to this point, but I'm torn. I really like the instructor and am VERY excited about doing some wreck diving but I'm not willing to do it in an unsafe/untrained manner. Should I a) address the issue with the instructor and ask that he add this to the curriculum of the wreck course, or b) go seek out some better training from another agency that covers this topic. If I address it with the instructor, does he have access to PADI content (perhaps from the tech side) that would cover this topic?
 
I would bet you could count the PADI tech divers here on one hand.

You KNOW the right choice in your mind. Stop fooling around and get some training. Not to say GUE is the only way to go, but you've taken HOW many PADI courses and not done gas planning? GUE's is Day 2 in the first course. This should be taught in OW, or at a minimum, AOW.
 
I agree. Consider tech training somewhere. TDI, GUE, IANTD, it does not really matter.

The sad fact is that in 1985 when I got certified, PADI taught gas laws, gas planning and the math and theory that went with it in OW. Since then OW, AOW and related deep and wreck specialty courses have all been watered down to the point where it is seldom convered in any depth if at all.

What the new standards do is create "herd" divers that go forth into the world and rely on DM's to keep them from running out of gas. The scary part is that often the new crop of DM's and instructors are more ignorant about gas planning than a newly minted OW student would have been 25 years ago.
 
I'll skip the whole PADI thing and simply say this: NEVER do a dive you're not comfortable with. You lucked out on the weather this time. Next time you're not comfortable with something, the weather may not be so cooperative. If you don't want to "chicken out" or something, make up some excuse (e.g. you're congested, sick to your stomach, whatever).

I feel one of the most important skills in all of "tech" diving is knowing when not to dive.
 
PADI doesn't teach rock bottom. Sounds like your instructor was using the rule of halves. If you are making an ascent straight to the surface as opposed to making a multilevel dive with varying depths, the rule of halves is not a bad rule, but he should have explained to you what he intended and how he decided to use it over the rule of thirds, which is what your rock bottom figure is.

I'm sure that PADI Tech teaches gas planning, but I haven't taken any of their courses. I have to wonder about making 130 foot dives on an AL 80. Why not a 100 cube instead?
 
PADI and "gas planning" don't necessarily go in the same sentence together...

While we didn't cover rock bottom in my NAUI OW/Nitrox course we did cover SAC rates and how they related to how quickly your gas is used up at depth, so we did have some elementary gas planning.
It was, however, covered in my NAUI rescue course, which was actually a huge conglomeration of things.
 
TheRedHead:
I'm sure that PADI Tech teaches gas planning, but I haven't taken any of their courses.


OW and AOW completed a few months back, here- they don't cover it there. I scoured the texts one night- it ain't there, period. My buddy just finished PADI DM, and he says they cover it there. I got angry about this at first, then I decided to simply learn the stuff I was interested in myself and take responsibility for my own dives. I'll probably pursue some advanced certs, as I would like to dive tech when I'm ready for it, and I probably won't do it through PADI. But I'm not angry they don't teach stuff like gas planning- they want people to be able to do resort dives w/ DM's and stuff like that; which is fine, I mean, someone has to do it, right? Those of us that take diving more seriously will search out more thorough training, naturally.
 
Odd. Just finished PADI AOW and deep. SAC rates are covered, including estimating your SAC from your dive history. We covered rudimentary gas planning in OW - nothing formal, but we set turnaround pressures based on there and back + 500 reserve. I don't have my deep or OW book handy, but check pp. 83-84 of AOW manual for the (very brief) discussion.

My instructor also discussed rule of thirds and rule of halves, and other planning issues (for instance, gas planning when there is a current, or other stressors that might effect consumption rates going out differently from coming in), but I have a feeling that that was not PADI talking. He required us to participate in planning every dive, including our OW cert dives.

I think the curriculum may not include extensive discussion of gas planning, but good instructors may enirch the curriculum from time to time.
 
PerroneFord:
I would bet you could count the PADI tech divers here on one hand.

You KNOW the right choice in your mind. Stop fooling around and get some training. Not to say GUE is the only way to go, but you've taken HOW many PADI courses and not done gas planning? GUE's is Day 2 in the first course. This should be taught in OW, or at a minimum, AOW.

I've got your back, GUE ftw. I'm overly excited for fundes in August.
 
TheRedHead:
PADI doesn't teach rock bottom. Sounds like your instructor was using the rule of halves. ...

What is the rule of halves for rock bottom calculation? The rule of halves I know is for computing turn pressure in cases where the team doesn't absolutely need to make it back to the entry point. Turn Pressure = Rock Bottom + (Total Pressure – Rock Bottom)/2

I am not advocating diving to 130 on an AL80 nor am I suggesting that what your instructor told you is a good way to plan a dive but his answer may be correct according to the PADI tables. I don’t know the exact rules for diving the PADI tables but the math would go something like this (it’s late so don’t beat me up if I’ve made a stupid mistake):

Time to go from 130 to surface at 30ft/min = 4.3 minutes
* 2 divers emergency SAC of 1.0 each
* Average ATA for ascent ~= 3
~= 26 cubic feet of gas for the ascent.
3 minute safety stop
* 2 divers emergency SAC of 1.0 each
* ATA at 15 fsw ~= 1.5
~= 9 cubic feet of gas for safety stop

35 cubic feet of gas should be around 1400psi in an AL80 so a rock bottom of 1500 should get you and your buddy back to the surface with 100 psi in your tank. It’s not a very good number as it doesn’t give you any time to sort out a problem at depth and it rushes you to the surface but it isn’t completely out of line.

Again let me say that I don’t advocate diving the way I described above and I think you are absolutely correct in your concern about the lack of attention given to this topic. If you like the instructor I would speak to them privately about the topic and decide for yourself if they have enough knowledge to continue as your instructor. In the meantime you might want to contact NWGreatfulDiver on this board. He has his own AOW material that will fill in where your manuals may be lacking. Dive planning is not a “tech” thing it’s a diving thing. You should be able to get this information from any qualified instructor.

Safe diving,
Ed

P.S. Add one more vote for GUE training.
 
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