How those idiots (us) run out of air

[MXGratefulDiver]

I slept on it and I am beginning to come around. See what y'all think.

I agree that it was a mistake to think that "I don't have enough air to do what the DM wants but I am going to stick with her". I did think that at some point. Stupid me.

At 50' stressed, when to start for the surface? -- when we know we have enough air to make a it safely, with some reserve. Maybe 500 lbs? I can do an unstressed ascent from 50' next to the line with abt 300 lbs incl. a safety stop -- unstressed. So 500 sounds maybe about right.

Assuming that we had done this, she probably would have noticed us and followed. Actually by the time I was at 500, we were together with her, heading for the mooring line. She should have led us up at an angle, at a minimum at that point. I will mention that to her.

Here's the kicker -- you'll love this. She is a DM in training, with 80 dives. We have about 60. Note to self -- find out the training level and number of dives of everyone I dive with BEFORE starting out.

Am I making progress?

Bill

Yes ... that's progress.

Everyone makes mistakes ... I like to call them "I'll never do that again" moments ... and they are an important part of learning what it means to be a safe, competent diver.

... Bob (Grateful Diver)

 

[danvolker]

Yes ... that's progress.

Everyone makes mistakes ... I like to call them "I'll never do that again" moments ... and they are an important part of learning what it means to be a safe, competent diver.

... Bob (Grateful Diver)

I'll say!!
From my own list :

• I'll never "tie" a broken weight belt on again, especially when using a tank without a BC
• No more night-time spearfishing with inattentive captains that will leave you on the surface for 30 minutes or more with a bunch of fish on a stringer....---and absolutely no night dives where the only illumination source is a dive light that will run out of battery juice not so long after the dive is over !!!
• No more allowing an instabuddy to be considered a buddy...If you or your wife are given an instabuddy, you ARE SOLO diving....with someone else nearby who may well do really stupid things --- you don't want to be responsible...
• no booking a dive boat WITHOUT doing some homework on what the typical divers are like on that boat, and what their normal dives are like...ie., choosing a diveboat and captain is almost as big a deal as choosing a buddy....almost.

 

[fjpatrum]

Thumb. End of discussion. I don't trust guides to keep me alive... they are just guides, not saviors.

 

[MXGratefulDiver]

Thumb. End of discussion. I don't trust guides to keep me alive... they are just guides, not saviors.

... especially a dive guide with just 80 dives. Crikey, she's probably been diving since ... March ...

... Bob (Grateful Diver)

 

[Jim Lapenta]

Or worse has been certed for a few years and dives 10-12 times a year. Except this year. She did 20. 15 of them with an instructor having her do skills. And 5 of those were in the pool.

 

[dumpsterDiver]

At 50' stressed, when to start for the surface? -- when we know we have enough air to make a it safely, with some reserve. Maybe 500 lbs? I can do an unstressed ascent from 50' next to the line with abt 300 lbs incl. a safety stop -- unstressed. So 500 sounds maybe about right.


Bill

That is not enough air to start the ascent (for you). You MUST ALWAYS reserve enough air to get you AND YOUR WIFE to the surface. If you need 300 when unstressed and we assume your wife needs the same... then you need 600 psi for both of you... AND if either (or both) of your air consumption rates increase, then you will need MORE air... Of course.. if you skip the safety stop, it will save you air, but these are all things to carefully consider, even with simplistic planning. I would suggest 8-900 psi until you figure out what is reasonable for you.

It is great that your are contemplating planning your dives, but the biggest change (you need) is to master the free ascent. This ability will (I think it has to) significantly reduce your feeling of vulnerability during the actual dive. This will translate into a much more relaxed dive and it will probably reduce your air consumption and extend your dives (not to mention the huge safety benefit).

 

[maniago]

Speaking of rock bottom....we found the rock bottom number indicating us to ascend to a shallower depth at just about the time everyone else is halfway through poking around the deck of the wreck (maybe only slight exaggeration here).

Its a religion with some who post a lot around here and they have their own valid reasons for that. But Rock Bottom to me (and as you've eluded to) is better used as a tool in your bag to make you aware of the risks you must accept in the dive.

I know I know, I'm a heretic for not being a convert. So burn me at the stake.

 

[Hepcat62]

Its a religion with some who post a lot around here and they have their own valid reasons for that. But Rock Bottom to me (and as you've eluded to) is better used as a tool in your bag to make you aware of the risks you must accept in the dive.

I know I know, I'm a heretic for not being a convert. So burn me at the stake.

Nobody MUST accept a significant risk, and I would argue that nobody should. You can choose not to do the dive, or you can mitigate the risk by managing it down to statistically acceptable levels. If you know how to determine the gas required to get you and your buddy safely to the surface from a given depth in an emergency, and you choose to stay at that depth past the point where you have that gas available to you, I guess that's your choice, but you're choosing to ignore risk - not managing it.

Personally, when I am concerned about rock bottom I prefer to plan my dive to ascend a bit and continue my dive shallower, or bring more gas. Both are easily manageable, even at tropical dive resorts. I spent a lovely week in Roatan with an AL80 on my back, and another slung as a stage bottle, so that I had the flexibility to spend the time I wanted at deeper depths with an acceptably managed level of risk for my similarly-trained buddy and I.

 

[Tortuga68]

Speaking of rock bottom, my wife and I started experimenting with this concept on some recent dives in the Keys (Spiegel Grove, etc.) to see how it would work out in practice. What sadly became clear to us is that, under strict rock bottom planning principles, we do not take enough gas for many of the dives we do. (What, none of you are surprised?) I'm sure this has been discussed ad nauseam in other threads, so I don't mean to divert this one. But many of the dive ops we use don't even offer 100 cf tanks as an option, and when we used the ubiquitous AL 80 like every other diver on the boat, we found the rock bottom number indicating us to ascend to a shallower depth at just about the time everyone else is halfway through poking around the deck of the wreck (maybe only slight exaggeration here). I can just picture a DM reacting to our request for 100 cf tanks to dive a wreck in 90 feet of tropical water: "You crazy, mon?--you don't need that and we don't have that." I also understand that whether rock bottom or rule-of-thirds or still some other alternative is the more appropriate way to plan a dive may depend on the dive profile.

Again, no intent to divert the thread here, but when I saw rock bottom brought up, it piqued my interest because we have been delving into this concept. In many ways, my wife and I are still inexperienced divers. Only after 200+ dives is "gas planning" becoming part of my vocabulary. It's good that Bill is getting the lesson early on.

RB is like insurance; if you never make a claim, it's a waste of money. But you have it in case your house burns down

 

[billt4sf]

It is great that your are contemplating planning your dives, but the biggest change (you need) is to master the free ascent. This ability will (I think it has to) significantly reduce your feeling of vulnerability during the actual dive. This will translate into a much more relaxed dive and it will probably reduce your air consumption and extend your dives (not to mention the huge safety benefit).

What are the steps to master this? What we are doing now is to use the line as a visual aid and ascend next to it. We consistently do well except when there is current -- we don't want to get blown offline for the sake of practice.

Bill