Well I had a pretty interesting weekend. Saturday July 28th, 2007 I went to Pennyroyal Blue Springs Scuba Park located in Hopkinsville, KY. I had just had my 2 low pressure steel 85 cu ft air tanks doubled up together. With the tanks, isolator manifold, bands & back plate I have roughly 90lbs on my back. I met up with a couple of guys form a local diving web site that have been diving double tanks for a while & have recently earned their full cave diver certifications. I`m still an open water diver, but interested in technical diving. The first dive was short & terrible. We decided that we would descend on a sunken cabin cruiser near our set up tables that rests at 95ft. I have dove this boat before & it has never bothered me before. Anyway I geared up & jumped in. As we began to descend, I became very negatively buoyant & started dropping like a rock. I was also struggling to balance the tanks to keep them from taking me down on my back, trying to inflate my wings, inflate my drysuit & clear my ears all at the same time while making like a dart to the bottom at 100ft. It was all too much for me to handle at once as I was also probably suffering from some nitrogen narcosis. As I neared 90` I finally stopped my free fall, but my breathing had gotten really rapid & was quickly turning into hyperventilation. Unable to get my breathing under control, I immediately aborted the dive & started ascending with my buddies who had followed me. They helped me as best as they could & I finned like crazy. When I reached about 40ft, my head finally cleared, my breathing slowed & I was able to continue the ascent without assistance. Once my buddies & I surfaced, we discussed at length that it was a poor plan to have tried such a deep dive with me diving twinned tanks, for the first time. It was agreed that the next dive would be in the shallow end of the quarry. I decided to sit out for a few hours & collect myself while my buddies went on a deep dive of their own. The second dive was much better in that I seemed to have better (although still not great) control of my buoyancy. I found it still to be quite a trick to balance all that weight on my back. One moment I would start going to my left, then my right, then feel like I was nose down, then heads up. I must have been quite a sight to my buddies as I worked to settle myself out. We checked out some of the attractions in the shallow end & I worked on my hovering & was starting to get the hang of it a bit. Between the first dive & the second, I sucked down my tanks pretty good in a short time. I will say it was a lot of work to do what I did & I was sore & worn out by the end of the day. Now I can`t wait to get the chance to try again (in the shallows for a while, I guess). Although not a great day of diving, I certainly learned a lot & will work to perfect the skills I need to handle these beasties on my back