My (newish) dive buddy makes a good choice...

[davidbaraff]

Hardly rating a note here, but afterward I was impressed by this decision, so:

I was diving with two newer buddies (new in that it was my second day diving with them, though I've known them for a while: they both got certified in April, and their dive count at this point is maybe around 15 dives). Diver D, a male, is 6'1 a good bit larger than diver J or myself; I knew from the first day's diving he went through his tank a good bit faster than myself or diver J (a woman).

We dove the Sujac at Casino Pt. as our first dive; went down to around 80-90' feet for a while, dove through its hull a few times, and then started heading back up, cutting across back to the steps, doing a fairly slow ascent as we angled back up the slope.

I was kind of wondering when diver D would indicate his air was low enough that we needed to come up for a safety stop; my plan had been to arrive at a point on the slope that was at around 20' and do the stop so we could watch the rocks and stuff. Anyway, all of a sudden he indicated he was at about 500 PSI, and I was thinking, "man, we should have been doing a stop long before this." So rather than angle up any more, I figured screw this, we're going up to 15' right this second, we'll just grab the kelp and chill. We were probably at about 40-50' at this point.

Right then diver D got his tank valve tangled in a bit of kelp (not all that badly, but it was faster for J and me to detangle him). We did that, I swam firmly to 15', grabbed a piece of kelp and so did the other two. I was a bit perturbed at this point, and was wondering if maybe I had gotten a signal crossed since diver D didn't seem concerned at the air situation. I asked again for his air, and at this point he made a motion toward my octo.

(I've never had to donate an octo under water, though I've done it in class of course, and once or twice for fun with someone who was making a bet with someone else about air consumption and who decided to cheat...) It's kind of cool, that the lessons come back instantly into your brain: grab it by the hose, offer it with the button uncovered. As soon as he had it and was breathing off of it, I remembered to grab his BCD to make sure we wouldn't drift, which was probably overkill, given that we could hang onto the kelp anyway.

What's interesting is that if I had perceived that D was that low on air (J turned out to be down to about 600, she sucked through some while detangling D, and was stressing though I didn't know that at the time, about D being momentarily tangled), I would have said to just skip the safety stop and go straight up, staying close by, ready with the octo. I'd read the post about OOA being the precipitating factor in like 50% of accidents and would have been thinking that just getting to the top was paramount -- the stop was, after all, optional. (Not even close to a deco obligation.) Not worth making things complicated by trying to ascend on an octo together.

But diver D had made a far better call than I was going to. He knew I had tons of air left (I was at 1600 PSI, he was probably between 400-500), and what he did was breathe off my octo till the *end* of the safety stop, thereby saving his own air --- then calmly switched back to his regulator, and made a perfectly unhurried ascent up the last 15', on his own air, without any worries about complications due to going up together. (Even if he was down to 400 PSI, he figured that a 15-20' ascent on it was just fine, which of course it was.) An excellent choice, since we got to do the safety stop, as well as a perfectly safe and simple ascent afterward.

Well, I was impressed afterward. Not a particularly stressful or exciting incident all things considered, but I found it interesting and educational.

 

[dwhthediver]

Done very well & calmly, good job by all, except diver D should have been more aware of his air before that.

 

[Hatul]

This calls for a review of gas management and the concept of Rock Bottom, and how much air a diver should have at each point in the dive. I know when I got certified this was not covered at all and I'm not sure it is today.

 

[Scuba_Noob]

It's surprising how people run low on air just because they weren't paying attention (and when there's no equipment malfunction or emergency). Even as a new diver, I was always cautious about air, as it would be somewhat disconcerting to run low at a great depth. I'm glad you guys got out of there with no major problems and that everyone remained calm, but I hope you chatted with him about air monitoring afterwards. It seems like you handled everything the best way that you could.

My normal buddy plan is that when the first person reaches 1000psi, we travel to the safety stop and arrive to the safety stop with at least 750psi. If it's with a new buddy, I'll ask for air pressure periodically. But still, sometimes a buddy just doesn't pay attention.

 

[Hatul]

It's surprising how people run low on air just because they weren't paying attention (and when there's no equipment malfunction or emergency). Even as a new diver, I was always cautious about air, as it would be somewhat disconcerting to run low at a great depth. I'm glad you guys got out of there with no major problems and that everyone remained calm, but I hope you chatted with him about air monitoring afterwards. It seems like you handled everything the best way that you could.

My normal buddy plan is that when the first person reaches 1000psi, we travel to the safety stop and arrive to the safety stop with at least 750psi. If it's with a new buddy, I'll ask for air pressure periodically. But still, sometimes a buddy just doesn't pay attention.

I agree that frequent SPG checking is really important as running low on air is probably the most common cause of dive accidents. There's a value in the rec diver using an air integrated computer as it shows the pressure in the computer window which is more likely to be checked, and the computed air time can also help with gas management.

A simple rule of thumb that works in most recreational (non deco, single tank, no overhead) cases is to have a minimum of 500+10*(depth in feet) PSI as a Rock Bottom. This gives 1500 psi at 100 feet. As you come up the requirements decrease and you can stay longer. If you follow this rule you won't run into the problem of the new diver above, and you'll still have enough reserve to rescue an OOA diver.

 

[themagni]

I agree that frequent SPG checking is really important as running low on air is probably the most common cause of dive accidents. There's a value in the rec diver using an air integrated computer as it shows the pressure in the computer window which is more likely to be checked, and the computed air time can also help with gas management.

Or put your SPG on a flexible hose, run that to your wrist next to your computer. (That's what I've done with mine.) All the convenience of an AI computer, all the safety of an analog gauge. (And if the hose explodes, I have approx. 10 minutes to switch to atmospheric.)

 

[gotair?]

Hardly rating a note here, but afterward I was impressed by this decision, so:

I was diving with two newer buddies (new in that it was my second day diving with them, though I've known them for a while: they both got certified in April, and their dive count at this point is maybe around 15 dives). Diver D, a male, is 6'1 a good bit larger than diver J or myself; I knew from the first day's diving he went through his tank a good bit faster than myself or diver J (a woman).

We dove the Sujac at Casino Pt. as our first dive; went down to around 80-90' feet for a while, dove through its hull a few times, and then started heading back up, cutting across back to the steps, doing a fairly slow ascent as we angled back up the slope.

I am glad you all made it out ok. A 90' dive with two divers that have 15 dives under their belt seems a little deep to me.

 

[spc751]

Was any dive planning done before the dive?

 

[davidbaraff]

I wouldn't have gone down there with them (to 90') if I had had any doubts. In fact, we had done that exact same dive before, in their A/OW class (I was in that class as well), one month earlier. We didn't stay at 90' very long. (And let me tell you, with a group of 10 students, some of which were, er, a bit challenged, I'd say that was a less controlled situation than this one was.)

As for dive planning: well, sure, we had a plan. It's just that the plan called for not waiting till you were at 500 PSI to say you were at 500 PSI.

But, seriously: this is a dive in the Catalina dive park. Which means that given that we're in the park, the only thing you need to do is get to the proper depth, if you get low on air -- it's no big deal if you surface in the far corner of the park. (Well, OK, maybe you'd find it a bit embarrassing to surface swim all the way back to the steps, but it'd be a good learning experience, and good exercise, for all of the at most 5 minutes it might take.) I.e. it's fine to just ascend from whereever you are. No currents, no obstacles, no boats to worry about, nada.

I think it's inevitable that when you're new, you do something that deviates from doing everything "perfectly", which is all that happened here. Never any danger -- just the possibly less than optimal of skipping a safety stop, in an extremely low-level nitrogen load situation, was about the worst it might have gotten to -- but didn't, that being the point.

I think it was a good learning experience for the other two divers, in fact --- I've had dives that didn't go according to plan, where I didn't come at all close to any danger --- all that happened was I used up a bit of the planned safety margin, which of course is our goal -- not to eat up the margin. But I don't think anybody is so perfect that this doesn't occasionally happen, and then of course you learn from it.

 

[MegaBMan25]

Other than the fact Diver D didn't manage his air well, i say this sounds like a fairly successful dive. Even when tangled in the kelp he kept his wits about him and so did Diver J. It is a credit to you, that you stayed calm which helped everyone else. I've gotten to about 500-750psi at a safety stop and been worried i would be OOA before the end of the stop (More so that it would annoy my buddy and divemaster that i mis-managed my air). Thumbs up to Diver D. for staying calm in that situation.