First of all, I want to thank everyone for their thoughtful responses. As many of you have pointed out, there are a number of important lessons here.
Some people have asked specifically what kind of gear I was diving. It was dual Steel 100's with BP/W in DIR configuration.
In terms of the quarry, the max depth was around 300 ft. However, the quarry steps down... it isn't a sinkhole. So we had a bottom for our 90ft dive that we could follow up.
Here are some of my lessons learned from this dive.
First of all, as many have mentioned, comfort with your gear is huge:
-Even when diving jacket BC and single alum 80, it is important to be able to operate every single piece of your gear (i.e. back dump valve). As Capt Dale aptly pointed out, if I wanted to use my back dump valve and was having issues with it at 30ft, then why didn't I attach a longer leader and a weighted cap so that I could find it in an emergency? The answer is I kind of forgot about it while trying to get the rest of my gear setup the way I wanted, and blew it off. I knew it was a problem, but I ignored it because I figured the odds of me needing it were fairly low. Big mistake.
-Wetsuit was inappropriate for the conditions. To some extent I trusted the dive shop on this one, and had been told that it should be ok. At 30ft in the quarry, it was perfect. At deeper depths, it was completely inadequate. Nevertheless, I had plenty of time to scrub the dive before I ever left the line (will discuss this further down). As far as wetsuit versus dry suit for this type of diving, I think that there are appropriate wet suits for this type of diving. Unfortunately, I wasn't wearing one. I am not dry suit certified, and obviously given the amount of new gear I was using already, it probably wasn't a good idea to throw that in the mix as well.
-Regarding the ankle weights, I believe they actually improved my buoyancy control and trim significantly. In fact, I think they might have been the one thing gear wise that I did correctly during this dive. I had a bottom weight on the steel tanks previously, and that just tended to make the rig turtle.... it didn't improve my trim or control. The ankle weights actually gave me much better control, and actually were probably quite important in allowing me to arrest my initial out of control ascent. I think things might have been much worse without them. In terms of overweighting in general, the steel tanks already made me too negatively buoyant for the type of wetsuit I was wearing (a separate issue in itself). While the ankle weights made me more so obviously, I think they did much more good than harm.
As far as things I could have done differently leading up to the accident.
First of all, I should have called this dive at 75ft when I realized that my core temperature was being negatively impacted by the thermocline. I decided to try to save the dive by seeing how I felt at the bottom. Gear/prep problems aside, this was mistake #1.
In terms of relying on the down line, I was simply using it as a guide down. It wasn't a crutch for most of the dive, however I severely underestimated the impact of pressure on squeezing my wetsuit and thereby making the steel tanks extremely negatively buoyant at 90ft. By the time I got to that depth, it had become a crutch only to the extent that I didn't want to leave the line if my wing wasn't working properly. Clearly more time spent working up to this depth would have improved my familiarity with wing buoyancy at depth.
Some people have mentioned that the instructor should have called the dive as soon as I signaled to ascend. Unfortunately, another student was in the middle of doing an isolation drill with his tanks, which involves turning off gas and switching regulators. This same student had a problem the previous day with this drill, that had resulted in an out of control (and out of air) ascent from 30 ft to the surface. I believe this same student was doing the isolation drill when I signaled to ascend, and I wasn't under duress at the time, so I don't think the instructor made a mistake here. He wrapped the drill and we left to ascend immediately after.
Given my issues in the water, I should have insisted on returning to the down line to ascend. This was an option that went through my head, but I "went with the flow" when the instructor signaled to do a free ascent up the incline. My mask flooding problems, in addition to buoyancy issues all could have been controlled had I ascended up the line.
I do feel that the instructor somewhat took for granted my request to ascend, as he headed away from me up the incline and signaled for me to follow. Given that I had requested the ascent, I do think he should have stayed closer to me at that point. I think the fact that I was calm at 90 ft gave the instructor the impression that I had a minor problem, and that whatever the issue was it was no big deal. Feeling like I had to catch up to the instructor while following an unknown path to the surface did add some additional stress to an already stressful situation.
Past this point in the dive, my lack of familiarity with the rig made the eventual problem almost inevitable. Some made the comment that the instructor shouldn't have inflated my BC, but this is ignoring the reality of the situation, which is that once someone is out of control, there are no more good options, or truly correct decisions. You are only doing what you think is best at the time to help that person out of an already very bad situation. The instructor just as easily could have not inflated my BC, at which point I could have sunk to the bottom (about 55-65ft on the inclined ledge), landed head first, and sucked in a bunch of water and drown. I was negatively buoyant at the time and heading face down, couldn't see anything, and was clearly panicked. I also believe the instructor was having a hard time telling whether I was breathing normally still, or having some other pulmonary issue (probably difficult to tell given my hyperventilation). While we had gone to 90ft, I had called the dive in less than 5 minutes, so we had no deco obligation. We were in 50-60ft of water when I lost control. So in truth, hindsight aside, the decision to send me to the surface was probably one of the more correct things to do. I will admit that I was a little annoyed when I first learned this was how I ended up ascending, but after some reflection I realized that the instructor was simply trying to make the best of a bad situation that I had created. At the end of the day, we all have to take responsibility for our own actions while diving, and I wouldn't have ascended that way had I not created the situation in the first place.
Anyway, I would appreciate further comments on my thoughts, and hope the discussion continues. This was a very scary experience for me, and I hope to use it to make sure I don't put myself in this situation ever again. There is probably something to Capt Dale's comment that you can't be half in on tech diving, and that having your own gear and knowing how to dive it is more than worth the investment (certainly a lot cheaper than your life). I admit that I am guilty of wanting to try it out without making the investment of $3-4k minimum to have all my own gear, but at the same time that seems cheap compared to drowning in a quarry in the future.
This was an Advanced Nitrox/Decompression Procedures class, for those who wanted to know.
