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Wow! Thanks to all who responded... I got more private e-mail to this question than anything else I have ever posted! Very sorry I don't have time to personally respond to everyone. But here I will try to touch on issues that have been brought up. I think the bottom line is that little research has actually been done in this area. I do not know if anything has been published in the UHMS journal, or if the Navy has done research. Yes, I did take a look at Bruce Wienke's thermodynamic chapter last night. This is the best theoretical source I have come across, and yes, the change in off-gassing efficiency is due to the changes in tissue and venous tensions. He doesn't really get into just how much temperature affects these, however. Perhaps it should be the subject of a future research project? Integrating this into a decompression model I think would be a fascinating constrained optimization problem. We would try to maximize deco efficiency given real-time changes in our constraints. What new profile would get us out of the water the fastest and with the most off-gassing, given the continually reducing off-gassing efficiency? I thought that Chris Parrett had an excellent response... what would the software do in a situation like this, where the ongassing is positive and the offgassing negative? Would it abort? Recalculate different stops? I would be very interested. Now on the practical side. Yes, I knew about wearing a wetsuit under the drysuit might be a good idea for mega-dives in cold water. I wanted to take this out of the equation. And for most recreational- technical divers, an on-sight chamber is not a practical option. I like the idea of grabbing someone else's suit and going back to do an in-water recompression if a large deco obligation is blown off. I really asked this question with more of a deco solution is mind, however. Could a more "Wienke-ish" profile reduce the amount of time in the water, where shorter, deeper stops are required? Some of you who wrote had experiences similar to the one I described, where the dive was warm and the deco very cold. How feasible would it be to do a crude drysuit patch job underwater? Even though it probably be very leaky, could it reduce the flow into the suit just enough to work? Could carrying a few extra strips of duct tape somewhere be used? I actually know someone who did this - patched up his suit between dives with duct tape, then went back in for a second dive! I also got this one mean-spirited response from a person in the UK: ----------------------------------------------------------------------------- >> I have been pondering this question for a while now. Please consider this >> scenario: >> >> You're on a deep dive in cold water. You're wearing your drysuit with >> normal drysuit underwear. When you have incurred a significant >> decompression obligation, you accidently rip your suit on a jagged piece >> of metal, and it floods. You immediately abort the dive, but still must >> do your decompression. On the deco line you start to become very cold, >> and due to the cold, your off-gassing efficiency is significantly reduced. > > serves you right ! ----------------------------------------------------------------------------- Oh well. I hope that this isn't the general attitude over there when someone has an accident such as this. Thanks everyone, Christina
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