When does "Gas Management" get taught?

[vkalia]

Can't you guys read, PADI does NOT teach "Gas Management", end of story!!!!!!!!!

PADI doesnt teach *aynthing*. Instructors do - and a lot of them DO teach gas management.

Vandit

 

[Charlie99]

PADI doesnt teach *aynthing*. Instructors do - and a lot of them DO teach gas management.

One of the strengths of PADI is in the quality of their educational material. You read it, you watch a video about it, your instructor tells you about it, and you do it. It doesn't matter what style of learning you have, at least one of the methods will connect.

Gas planning is one of those areas that just isn't covered in depth like other things PADI considers important.

Instructors may indeed add it to the course. Students may take the Boyles law stuff and extrapolate and figure it out themselves. But is doesn't get the repetitive, multiple media form approach that PADI does for the "important" stuff.

 

[vkalia]

Gas planning is one of those areas that just isn't covered in depth like other things PADI considers important.

Agreed. That wasnt my point, however.

This isnt a discussion on PADI and their training materials, but on the merits of teaching gas planning, and to what extent. Since it is instructors who teach and not PADI, saying "end of story" struck me as being a bit too final.

Vandit

 

[O2BBubbleFree]

I have a friend who's an instructor. He couldn't tell me what size pony bottle he's got. Is that wrong? (feigned innocence)

I, like so many others, first encountered the concept of gas management beyond “back on the boat/shore with 500 psi.” here on SB.

Now that I’m thinking of working toward instructorship, how’s this sound for a plan:

In OW, introduce ‘rock bottom’ type calculations by working an example using an al80, from 100’ with an elevated SAC. I haven’t worked through the calculations, but let’s assume for the moment that it comes out to 800 psi. Point out that this calculation is for an al80, and must be recalculated for different tanks. Give the example as a handout for future reference. For the remainder of the class emphasize ‘leaving the bottom with 800 psi’ rather than the old ‘be on the surface with 500 psi.’ Now the OW students have a simple number that will serve in the vast majority of dives, but have also been exposed to the logic and calculations. My approach assumes that the new divers are unlikely to encounter anything other than an al80. In my limited experience, I’ve seen that it’s really hard to rent anything else. If the new diver ends up with something else (say they go out and buy a different size tank) they have at least been exposed to the logic and calculations, and have the handout to reference.

In AOW start with the above, then further teach the logic and calculations with different size tanks and in different scenarios. Measure SAC rates. Include test problems working different scenarios.

Whata ya think?

 

[rjack321]

Eh? The standard recreational diving safety procedure is - if something goes wrong, you go up. Recreational diving is predicated upon the fact that the surface is 1-2 min away, regardless of where you are in most cases.

Vandit

1 or 2 minutes??? From 120 feet? No safety stops, old school 60' per minute ascents. Yikes!

Actually I don't totally disagree with you. I haven't heard of anyone dying in an OOA situation (at least in this area) in quite awhile. There have been a rather large number of heart attacks and similar UW medical issues recently though.

From a risk benefit perspective, getting someone to lose weight, exercise, stop smoking, lower BP, etc etc. would probably expand their scuba safety factor more than knowing how to calculate rock bottom.

 

[DBailey]

I read these twelve pages of responses, and I still need an answer to my question...

What is gas management?

I think it is a loaded question. I think the answer will vary depending on the type of diving that you are doing.

On an out-and-back dive, is checking your gauges frequently, turn at a half of tank, ascend some, do a safety stop and get back on the boat with 500 psi enough? I think it is, and this was taught in my PADI OW class. Do you really need to know much more?

On a drift dive, is checking your gauges frequently, start deep, work your way shallower, ascend to your safety stop at 700 PSI and get back on the boat with 500 psi enough? I think it is. Do you really need to know much more?

For recreational diving, do you really need in depth gas management? I agree that for other diving activities more in-depth gas management is needed, but for cruising around a reef on vacation I could care less about my SAC rate.

 

[vkalia]

1 or 2 minutes??? From 120 feet? No safety stops, old school 60' per minute ascents. Yikes!

For the vast majority of "real world" situations, the surface is indeed 1-2 min away, even assuming proper ascent rate. And even in the extreme case of someone being at 120-130 ft, and being completely OOA, and with a buddy who also happens to have only 50 bar in their tank (shall we throw in a few killer sharks as well, while we are generating a worst case scenario?), coming up a little faster than 10m/min rate isnt exactly going to be the end of the world.

And I posit that if someone is in that situation, it isnt inadequate gas planning that was the problem.

From a risk benefit perspective, getting someone to lose weight, exercise, stop smoking, lower BP, etc etc. would probably expand their scuba safety factor more than knowing how to calculate rock bottom.

My point exactly. Instead of adding a lot of detailed calculations that the vast majority of the diving population will not remember, it'd be better to focus on the basics instead. That being said, SOME mention of gas planning - and different bottle sizes - isnt a bad idea at all.

O2BubbleFree - re. your instructor friend who doesnt know what size bottle he has - embarrassing though that is, does that automatically make him an unsafe diver or a bad diver? What does he plan to use the bottle for?

Vandit

 

[darkpup]

I have a friend who's an instructor. He couldn't tell me what size pony bottle he's got. Is that wrong? (feigned innocence)

I, like so many others, first encountered the concept of gas management beyond “back on the boat/shore with 500 psi.” here on SB.

Now that I’m thinking of working toward instructorship, how’s this sound for a plan:

In OW, introduce ‘rock bottom’ type calculations by working an example using an al80, from 100’ with an elevated SAC. I haven’t worked through the calculations, but let’s assume for the moment that it comes out to 800 psi. Point out that this calculation is for an al80, and must be recalculated for different tanks. Give the example as a handout for future reference. For the remainder of the class emphasize ‘leaving the bottom with 800 psi’ rather than the old ‘be on the surface with 500 psi.’ Now the OW students have a simple number that will serve in the vast majority of dives, but have also been exposed to the logic and calculations. My approach assumes that the new divers are unlikely to encounter anything other than an al80. In my limited experience, I’ve seen that it’s really hard to rent anything else. If the new diver ends up with something else (say they go out and buy a different size tank) they have at least been exposed to the logic and calculations, and have the handout to reference.

In AOW start with the above, then further teach the logic and calculations with different size tanks and in different scenarios. Measure SAC rates. Include test problems working different scenarios.

Whata ya think?

Actually, that's about what was taught in our DIR-F class. We ran through Rock Bottom in about 30 minutes, another 15 to 20 minutes of 1/2s, 1/3s, all useable examples, and wrapped it up with a Q&A session. The last slide showed examples of RB for different tank sizes to 60' and 100' to be used as a guideline if calculating RB was still difficult for us. A handout also followed this information with the RB calculations and the default RB numbers for different tank sizes. Total time was maybe 1 1/2 hour lecture (depending on the number of questions).

We didn't get into SAC rates and calculating useable gas for the dive until RecTriox. Mind you SAC rates were touched on in DIR-F to inform us of the tool, but we didn't learn how to integrate it into our diving until RecTriox.

Delia posted a Dive Planning Workbook last night that may be of benefit.

http://www.breakthrudiving.com/xducation/pdf/Diveplanningworkbook.pdf

The calculations breakdown each of the steps that are taught in 5thd-x's Intro to Tech and Essentials courses. It's similar to what was taught in my DIR-F and RecTriox class. It takes about 2 to 3 minutes to run through all of the calculations in my head which I usually do after the dive breifing on a boat or on the drive to the dive site. The numbers act as a guideline for the dive, and help me catch when I'm under stress (i.e. higher consumption rate due to stress, current, etc) or if my work out routine is paying off (i.e. lower consumption rate).

Keep in mind that once you calculate RB for a 100', 80', 60', the numbers are the same as long as you're using the same tank. I very rarely calculate RB anymore because I have most of the numbers memorized from past calculations.

Food for thought.

~ Jason

 

[SharkRider]

I manage gas like this... when I want to conserve my gas, I don't eat beans that day. If I want to use it all up and pass it... I load up on baked beans.... Honestly, who cares about gas management?

Gas management means using 1/3 of your tank during the dive... 1/3 to get back to your exit point and one third to ascend and do your safety stop. In other words, start at 3000 PSI... swim around and look at stuff until you have 2000 psi.... then head back to your entry point (should arrive there with about 1000 PSI,) then ascend to your safety stop slowly... you should reach it with about 800-900 PSI... do your safety stop and hit the boat with about 500 PSI.... Wallah... Gas Management 101

 

[darkpup]

Vandit,

You're amazing, add the word math to the conversation, and you go to extremes to put it down. Leave out the math, and you're all for it. Spend extra time on health, fitness, buoyancy, saftey skills, SOME gas planning, etc, you're all for it. Add in 30 minutes of math with a handout outlining the calculations, not so much.

Instead of adding a lot of detailed calculations that the vast majority of the diving population will not remember, it'd be better to focus on the basics instead. That being said, SOME mention of gas planning - and different bottle sizes - isnt a bad idea at all.

If you feel the math is a waste of time because people will forget it, more power to you. I, like many others, find knowing why something is the way it is beneficial, and the "detailed calculations" you mention above are just another tool to help us reach that understanding.

It just seems like an awful lot of passion arguing a point that is really minor when taking everything into consideration. You're arguing math bad, skills good. We're arguing math and skills good. To each their own.



~ Jason