Nwbrewer wrote:
Bob, they turned the dive at 1500, but is that when they headed for the surface? How deep were they at that 1500psi mark and on what kind of tank? I'll make the assumtion that since they were newer divers, that they were using al80's. For new divers on an al80, out from shore a ways at ~100fsw, 1500psi may be very unconservative. It depends largely on topography of the site. At someplace like mukilteo, where you're gonna start upslope immediately, I'd say 1500 is fine for turning from 80' or so. Not true if you're at some place like redondo, where I know from experience, you can spend a looonggg time kicking at 80' before you ever start upslope. For me, 1500psi in an al80 with a new diver, who may be a little narced and a little stressed at 80', that's leave the bottom for the surface time, not swim accross slope or follow a gently countour time. My "new divers" rock bottom numbers actually put them behind the curve at 80 fsw with 1500psi in an al80. Giving the benefit of a HP100, they would be at RB at 80fsw. I wouldn't try this dive with a new diver on an al80, and an HP100 would be marginal. Maybe that's just me.
I got another e-mail from my source that suggests his cylinder was empty ... they were unable to inflate his BCD or drysuit, which is why they dumped it. Given the depth at which he was found, this suggests to me that either he turned the dive too late, or they were deeper than 100 feet when they turned it. Most likely scenario is that he ran out of air, bolted to the surface, held his breath, and embolized. That would also account for him sinking back to the bottom after passing out. Purely speculation, based on what I've been told by people who were there or were involved in the rescue, but a plausible theory of what happened.
Jake, as you know, I do not recommend that anyone go deep on an AL80 ... and I have no idea what size cylinder he was using. What I do know is that he was a pretty new diver, and most new divers go through their air pretty quickly. This is one reason I recommend people get more experience before they experiment with deep. Also, you need bottom time and practice to sublimate that "instinct" to bolt for the surface in an emergency ... especially an OOA, since the natural response if you don't actively think about it will be to hold your breath on the way up.
I agree with you ... I would not do this dive on an AL80. I'm not even sure I'd recommend it on a 100. It'd depend on the diver. This is why I have my students calculate their actual consumption based on a dive plan before I ever take them on their AOW deep dive ... there have been times when consumption and rock bottom calcs recommended a 119 or larger, even for a routine dive to the I-beams. Depends on the divers involved.
Unfortunately, too many divers don't get that stuff in their AOW class ... they get a puzzle. Butt lot of good that's gonna do if they go too deep and suddenly realize they don't have enough air to get back safely.
Please understand that I am not blaming this diver ... I don't know what he was taught, or what the specifics of his dive plan were. I DO know that too many new divers set their priorities on going deep ... often well before they're adequately prepared for it. And as long as everything goes right, they'll be OK. But if something goes wrong ... will they be prepared to deal with it safely? Sometimes not.
My advice to new divers contemplating deep dives ... ask yourself a few questions ...
- Why do I want to go?
- Do I know what the risks are?
- Have I prepared adequately to deal with them?
- Do I have the skills to handle an emergency?
- Am I diving with a buddy who can handle this dive safely?
Be honest with your self-assessment ... and with that of your buddy. Don't let concern for "ruining your buddy's good time" factor into your answers ... the best way to ruin a dive buddy's good time is to put them in a situation where they have to rescue you ... or recover your body.
If you have any hesitancy coming up with appropriate answers to those questions, you're not ready to go deep yet. Be patient ... diving isn't the place to be taking shortcuts to achieve your goals.
... Bob (Grateful Diver)