Gas Planning & Management: What Did You Learn, What Do You Do?

[eponym]

At least once a year, especially in March for some reason, ScubaBoard has a thread about gas consumption in Basic Scuba Discussions or New Divers. This year is no exception. A few keepers (for me, at least) include 2005's http://www.scubaboard.com/forums/basic-scuba-discussions/92311-air-management.html, 2007's http://www.scubaboard.com/forums/ne...-diving/182164-air-management-beginner-6.html, and 2009's http://www.scubaboard.com/forums/ne...ving/277809-if-you-new-diver-please-read.html.

These threads have advice, tables, formulas, and links to other info. They often do yeoman's service in supplementing new divers' education. I would like to depart from that pattern and simply ask new divers (let's say just-certified through thirty dives, give or take) what they learned and what they practice or hope to practice. So, new divers, whether you use a PDA to track your consumption between dives, or you just follow the divemaster and don't think much about it, please contribute.

And to better hear what you're doing out there, those of us with more experience will listen rather than offering advice. Okay, maybe that last part's just wishful thinking.

To keep it manageable, let's separate what you learned and what you do into two phases:

Gas Planning: Happens on-the-dry, before the dive. Estimates whether you have enough gas to execute your planned dive, return, and exit. May or may not allow for emergencies of various kinds.

Gas Management: Happens on-the-fly, during the dive. Periodically checks whether gas reserves are adequate, whether it's time to turn the dive, ascend, or take some other action. Might involve checking buddy's gas too.​

Again, new divers, think about the plans you've laid and the dives you've made . . .

1. What types of dives have you done? (Divemaster-led groups, buddies from shore, buddies from boat, solo (gasp!), warm-water, cold-water, low-viz, current, etc.)
2. What do you remember from your open water (or advanced) course about gas planning?
3. What gas planning do you do, for the different types of diving you've done?
4. What do you remember from your open water (or advanced) course about gas management?
5. What gas management do you practice, in the different types of dives you do?

Thanks in advance!
Bryan

 

[HenrikBP]

1) Warm water dives, dive master led, in the Caribbean. A few dives in the local - cold - quarry.

2) instruction in how depth/pressure affects air consumption. Check gauges frequently - more frequent the deeper you dive. No actual planning as in "this many minutes at this depth" etc.

3) My checkout dives and following vacation dives; somewhat blindly follow the leader, while keeping an eye on the gauge. I did no actual planning. Second trip; got a hold of Bob's and Lamont's excellent papers and they are now "required" brush-up reading before trips. Still, no real planning during second trip either. I did however get into a habit of checking air pressure approximately every 5 minutes and jotting down the result on my wrist slate. For instance: "2300 PSI @ 10 min", which gave me a nice impression of air (PSI) consumption in real time. I have also kept track of my air consumption in my log and have calculated SAC and RMV since dive 1.

4) Mostly "check your gauge and be back on the boat with 500 PSI"

5) for an upcoming trip I have called the shop (DM led dives) and got tank specs, volume and working pressure, and will have a laminated card ready with "Rock Bottom" pressures for various depths, along with approximate air consumption in PSI for those cylinders, based on my average (approximate, I know) air consumption calculations from previous dives of similar kind. I will, on the boat ask for approximate dive profile and use my laminated card to approximate what my air consumption will be for the different parts of the dive. I will then compare that "plan" with actual consumption during the dive.

Could be better, could be worse :shrug:

In retrospect, I think my OW instructor did an ok job given the curriculum. I would however have liked much more instruction and training in dive and gas planning/management. I'm currently looking at options for training that'll fill that hole for me, and am doing my own research in the meantime.

Henrik

 

[MtnPlayVA]

What types of dives have you done? (Divemaster-led groups, buddies from shore, buddies from boat, solo (gasp!), warm-water, cold-water, low-viz, current, etc.)

I have ~35 dives in a 6 month period. I was certified OW in July 08, AOW in Aug 08. All of my dives have been with a DM or instructor. I've done shore dives in Cayman, boat dives in Cayman, Belize and FL Keys, and shore dives in a cold low viz PA quarry. A little current and 5' swells on some of the dives in the Keys.

What do you remember from your open water (or advanced) course about gas planning?

I don't remember getting any instruction about actual planning of dives and haven't really done it yet since I've always been following someone else. My husband just got certified so now I'm the more experienced one (scary thought!) and we plan on doing trips outside of the local dive shop planned events so I guess we really need to learn this

What gas planning do you do, for the different types of diving you've done?

I haven't done any yet since I've always been on a dive where I was following someone else. I have a Nemo Air computer so it shows my air consumption but I really don't know how to use this in planning my dives. My husband sucks down air 3x faster than I do so we need to work on planning dives around his air usage.

What do you remember from your open water (or advanced) course about gas management?

Be back on the boat with 500psi.

What gas management do you practice, in the different types of dives you do?
[/LIST]

I check my gauges a lot during the dive, now that he's diving I worry a lot about his air consumption since he ran almost OOA on every training dive. We'll be doing some practice dives at the quarry here pretty soon and we want to learn how to plan dives based on air consumption. I've been reading a lot online but it would be really nice to have training available.

Julie

 

[Randy43068]

and when in doubt, carry a spare air..
J/K

 

[travelpro]

1) Within the last 12 months; OW in Belize with a total of 12 dives that trip including course dives. All done with instructor/DM. AOW in Cozumel with a total of 14 dives that trip including course dives. All done with instructor/DM. That's the only diving I've done so far.

2) Nothing really except that deeper = more air consumption I didn't really think about gas planning until I started reading this board. Oh, and when I ran out at my saftey stop but thought that was bad management not bad planning. Gauge still said 300psi.

3) Researching that now.

4) Nothing really except to check your gauges often. I just followed my computer and instructor/DM who said to tell them when I'm at 700psi.

5) Researching that now.

 

[Randy43068]

gas planning isn't difficult.

This is something that very well should be taught or at least covered in any open water course. If there were a couple of pages devoted to the subject at minimum. Hell, I learned it in a GUE fundies class and could not find even a mention of it in the PADI encyclopedia of diving.

 

[DBailey]

What types of dives have you done? (Divemaster-led groups, buddies from shore, buddies from boat, solo (gasp!), warm-water, cold-water, low-viz, current, etc.)

All of those except solo.

What do you remember from your open water (or advanced) course about gas planning?

I really don't remember any gas planning from my OW class. To be fair, other than my instructor's name, I don't recall much from my OW class. For example, I don't remember doing a single skill in the pool.

What gas planning do you do, for the different types of diving you've done?

A lot of it is based on the turn at 1/2 a tank, ascend some, and be back on the boat with 500 psi. I do this with a "cool" tank though. This is for no overhead diving, or more of the "out-and-back" types of dives.

For example, hit the water and check the gauge. Ok it says 2900. 2900-500 = 2400 psi for underwater use. 2400/2 = 1200 psi for each "leg" of the dive. 2900 - 1200 = 1700 will be my turn pressure. Ascend some to a shallower depth to check out a different part of the reef. At the boat, start the final ascent around 750.

What do you remember from your open water (or advanced) course about gas management?

One of the things I do remember from my OW class is that if you monitor your gauges frequently, then you should never run out of air. At no point should your pressure reading be a surprise.

What gas management do you practice, in the different types of dives you do?

Every time there is a change or significant event during the dive I check my air. Check the pressure when I splash in. Check the pressure when I start my desecnt. Check the pressure when I reach the planned depth. Check the pressure after each picture (or series of pictures) taken. Check the pressure after looking at unusual/rare creatures. Check the pressure when it has been a while since I remember last checking it.

Needless to say, an uneventful dive for me requires a bit more attention to my pressure gauge since I don't have the cues to check it.

For recreational diving (average depth of 50-60 feet), I don't see the benefits of more detailed gas planning or gas management. I view a lot of the more detailed gas planning as overkill for "average" recreational diving.

I do see the benefits of more detailed gas planning when doing more detailed types of diving. When/If I start doing those types of dives, I will start using more detailed gas planning.