Posted by Kevin Metcalfe on September 03, 2003 at 15:31:37:
“Bing, Bam, Boom, Pow” was the theme of the GUE Rec Triox class I took over the Labor Day weekend. Everything we were shown was amazingly simple once it was explained. All of the calculations that we would need to make throughout this class were easily done in our head once we got the hang of it. I took the class along with three other students. Our instructor was GUE Training Director Andrew Georgitsis, and he was assisted by Michael Kane, Marc Hall, and Joe Talavera who were interning and Gina Castillo helped with the video. Gina and the interns worked LONG AND HARD helping with fills and logistics for this class and deserve our thanks!
There has been a lot of talk on the various bulletin boards about this class. One of the common themes that keeps getting brought up is that “it’s not really about the helium as much as it’s about proper deep diving skills”. In my opinion, that is correct. Sure, we were shown how to mix 30/30 Triox. We were taught the advantages of helium when doing deeper dives. We were also taught how to treat 30/30 Triox when considering depth and time limits for NDL dives. (Same as 32% nitrox.) But what they really taught us was how to properly plan and manage a deeper dive.
Among the concepts we learned was Rock Bottom. How much gas do you need to get yourself and your buddy to the surface from your deepest point? Assume 1 cu ft/min SCR. 1 minute to deal with the problem, 30 ft/min ascent rate to your stops, 1 min each at 30, 20, and 10 ft. (50, 40, 30, 20, 10 for deeper dives, 100’+), figure average ATA’s. “Bing, Bam, Boom, Pow”, you need 32 cu ft. to get you and your buddy to the surface from 100 feet. What’s your tank factor? (used to convert cu ft to psi). Your tank factor is 2.5 for an AL 80, “Bing, Bam, Boom, Pow”, your rock bottom for a 100 ft dive on an Al 80 is 1300 psi. (800 on an lp 95 or 104, 1100 for an HP100, etc.)
So now, we’ve learned how much gas we need to safely make it to the surface if things go pear shaped, how about the dive? Once again, we use our SCR (your real one, not the emergency value of 1), average ATA’s and tank factor to figure out how many PSI we will burn every five minutes. Back to our Al 80, SCR=.75, depth 100 ft. 4 ATA’s => 3 cu ft/min, 15 cu ft/5 minutes “Bing, Bam, Boom, Pow”. You will burn 600 psi per 5 minutes. Since you started with 3000 minus your 1300 rock bottom, you have 1700psi for the bottom. Hmmm, slightly under 15 minutes on the bottom with an Al 80. Maybe MHK is on to something when he says that a single Al 80 isn’t the best tank choice for deep dives… Once our dives started, we were trained to check our gas consumption every five minutes to see how we were doing compared to our plan. Am I really using the xxx psi/5 minutes I planned on? Is it more? Do I need to revise my plan? etc.
We also learned a little bit about how to shape our “deco”. This was an NDL class, but none the less, we want to make our decompression/safety stops work for us to minimize problems. We learned how to quickly in our head calculate the EAD of our gas, then use the Air tables to calculate our NDL times using easy to remember tables. We also learned a little bit about how to use “depth averaging” to calculate our NDL for multi level dives.
But what about the diving? Well, the first two days we dove at Folsom Lake. The water was warm (mid 70’s) and the vis was poor (5’-15’). We practiced, S-drills, valve drills, ascent drills. We did dives where Mike or Andrew would throw failures at us to see how we dealt with them. We had situational awareness drilled into our heads. For instance, if the instructor noticed that we weren’t checking our SPG every five minutes like we were supposed to, we might find ourselves doing an OOA drill, and then when we went to show our SPG to our buddy, we couldn’t find it… Because it had been unclipped from our D-ring and put up around the manifold. Because we weren’t paying proper attention to it!!
Since we had all professed the desire to take Tech 1 in the future, we got a turbo charged version of the course. One particular dive sticks out in my mind. (Please note that valve failures were simulated by the instructor indicating which valve was broken. When we shut it off to solve the problem, we were supposed to then open it back up while playing along that it was still closed and failed. If we forgot to open the valve, the instructor would open it for us and tell us so in the debrief. Also, OOA’s were always communicated to us, not forced. i.e., we’d get a signal telling us that we were OOA.) Anyway, I got a right post failure. I shut down and went to my backup. Then I got a left post failure (OOA!), my buddy donated his long hose. Since I was the person having “troubles”, he was going to shoot a bag, but then his mask disappeared :-0, so I did it. But when I shot the bag, not much line went out. Hmm, well, I’m kind of busy now, so I’ll just ignore that. Next thing I know, that bag has disappeared, by now my buddy has his spare mask on, so he shoots his bag. I finished the dive with my bag clipped to my butt d-ring. Andrew took my bag because I should have realized that it only went up a couple of feet and must be tangled on something.
This all may sound excessive, but it’s not out of the question. Consider the following: You have an OOA situation, your buddy kicks off your mask in the confusion, there’s a current and you need to shoot a bag because you can’t swim back to the anchor line. That’s a lot to deal with. And of course we need to be able control our buoyancy when things are going wrong.
Anyway, my buddy and I got the official “Triox Blessing” from Andrew on Sunday morning and we drove up to Lake Tahoe for our experience dives. Vis was good (40-50 feet) and the temps varied (64 at the surface and 46 on the bottom.) For our first dive we did 120’ for 20 minutes on 30/30. All went well except I had problems dumping on gas on the ascent. This was a perception problem on my part as I was deceived by the slope we were diving on and only thought that I was putting myself in an attitude that would dump gas. Andrew jumped in and to my undying humiliation helped me out. Not that I didn’t greatly appreciate it! There were no drills on this dive, but we did have real failures. My buddies argon reg and mine above, froze open (it was 46 degrees on the bottom) and he had to shut it down to avoid doing a Polaris missile impression. Also, his light failed.
For the second dive, my buddy was tired so it was just me and Andrew with Marc Hall doing video. About half way though our dive (100’ for 15 minutes) I realized who my buddy was. Only with GUE would I get buddied up with a diver of Andrew’s skill and experience!
This class was worth every penny and then some. This class will help me when I dive doubles in the cold water of Monterey. This class will also help just as much when I do warm water, single tank drift dives in Cozumel. The information I learned in this class is invaluable.
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