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Actually, what this should have convinced you of is that you can't deco dive safely with a Cochran computer... Cochran has a terrible reputation on the net, in my opinion richly deserved. Search the archives under their name, or "cockring", another common alias... Cam ----- Original Message ----- From: <Deep1dave@ao*.co*> To: <techdiver@aquanaut.com> Sent: Tuesday, June 13, 2000 1:49 PM Subject: Deco diving: Dive Computers vs. Bottom Timers > > Greeting list, > > Lately there has been a lot of posts regarding computers Vs bottom timers for > deco. I found a good summary that was posted by Jarrod Jablonski last > February. > > I have recently switched to diving with decoplanner tables, and a bottom > timer. At first, it was awkward to have to look at a table during deco. Now > I have many of our typical profiles with the appropriate mixes memorized, > and my deco doesn't depend on a computer. Even if I loose my slate, I can do > the deco. > > During my normoxic trimix class, I dove with both a 2 gas Cochran Commander, > and a bottom timer with tables. I wanted to see what the Cochran would do > since it only new about the 50% switch at 70fsw. Well, on shallow dives, say > to 160fsw for 20min, the cochran would clear at about the time the table had > me out of the water. However, on the 200fsw for 20min dive, the Cochran > would bend it self, and lock me out, at the 20fsw stop. In addition, on one > of the dives, the Cochran really went south and gave me a ceiling of 20fsw > when I actually hadn't completed my 50fsw stop. That's when I really became > convinced that we can't safely deco on dive computers. > > Deep diving is not a "by the seat of the pants" event. One is forced to plan > the dive for gas consumption and deco. Understanding and familiarizing your > self with your deco is just part of it. > > Below is the post of Jarrod's. > > Hope it helps, > > Dave > > > > " 1) Dive computers tend to induce significant levels of diver dependance, > eliminating the awareness so common and essential to all diving but > particularly obvious when diving tables > > 2) Dive computers do not allow proper planning as divers can't properly > "study" the impact of various mixture and decompression choices. > > 3) Dive computers are of very limited educational benefit as they do not > induce questioning, or proper planning discussions as can be found with > tables and most particularly with deco programs > > 4) Dive computer programmers often play games with computational process so > that they can take insulate themselves from the risk of taking largely > square profile data and utilizing it on a multilevel dive. These games tend > to result in odd and often ridiculous levels of conservation. > > 5) Dive computers are expensive and in some cases leave divers with limited > resources carrying equipment that is of far less benefit than other > equipment that may have been purchased. > > 6) Dive computers significantly limit the likelihood that divers will track > their residual nitrogen groups. > > 7) Dive computers do not allow for Helium diving in any formats but the > bulkiest and most questionable format. > > 8) Dive computers will often generate longer decompressions than could be > figured by an astute, well educated diver with experience. > > 9) Dive computers often create confusion by giving the user to much useless > information, sometimes even obscuring depth and time in favor of blinking > CNS and/or deco limitations. > > 10) Dive computers can become very difficult to properly if a deco stop has > been violated. Some computers lock up completely while others just beep or > generate erroneous and distracting information. Divers using mixed gasses > are likely to often violate computer profiles. > > 11) Dive computers do not allow for the educated diver to properly modify > their decompression to account for advancing knowledge such as the use of > deeper stops in a decompression profile. > > 12) Dive computers do not offer divers as much flexibility in the > generation of profiles with varying conservation. For example the right mix > would allow 100 min at 60 vs 60 at 60 but I might prefer to do one or the > other and indeed might like a compromise. Computers confuse this issue by > not providing divers with the proper information. > > 13) Dive computers users often ignore table proficiency and therefore do > not learn tables properly. When confronted with a situation where they > can't dive the computer (failure, loss, travel etc) these divers are at a > serious handicap. > Jarrod Jablonski > > President- > Global Underwater Explorers www.gue.com > CEO Extreme Exposure www.extreme-exposure.com > VP Halcyon Manufacturing www.halcyon.net, www.browniedive.com, > www.tankfill.com" > > Global Underwater Explorers www.gue.com > GUE is a non-profit educational, research, and exploratory organization > with hundreds of dedicated members around the world. > > Extreme Exposure www.extreme-exposure.com > Extreme Exposure and Halcyon manufacturing produce some of the scuba > industries most novel and robust diving equipment designed by many of > diving's most active explorers. > -- > Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. > Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'. > -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
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