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Chris Parrett wrote: >>>The concept being the you will plan out the dive. Upload the plan into the computer (containing all planned gases etc..) Then make your dive and move between the planned gases in real time. The point here is that with the plan we will be able to Forcast TRUE time to surface and total deco time from any point in the dive forward. This is what is currently missing from all other computers. SInce we have the plan. we can compute in the future gas changes and display real info to the diver to make decissions with while still on the bottom.<<< Interesting concept, Chris - I'm not sure if you're saying that it will work for me or now, so let me give you MY reasons for wanting a dive computer to work with rebreathers, and see if this fits into your computer's plan: John and I make films. We usually have a plan of what we're going after before each dive (i.e. whale sharks, tigers, etc...). However, we really never know how long we'll be down there, or even how deep we will go (beyond the tolerance for narcosis - if we KNOW we'll be going deep, we mix gas accordingly). For example: We go out to film sharks in Fiji. We figure we'll find 'em at about 130', and it'll take us about a half hour to shoot the film, so we come up with tables to reflect that, with additional tables for longer bottom times. We're diving Nitrox (i.e. compressed air as Diluent - not mixed gas). While we are down there, John (who is the Director of Photography) sees something that is really cool, like one of Pyle's counterlung eating fish. He's been pursuing this beast for years. Since we are partners, I follow him as he pursues the fish. We go down to 170, where I start feeling too narced for my own good (we're both at 1.2 set point). So I stop. John, who is a much more experienced diver, follows the fish down to 200, where he is perfectly comfortable. It takes him about 10 minutes to get just the right shots. He ascends up to me at 150, where I have discovered the largest cleaning wrasse on the planet - 10 feet long, and full of life. Handing off his one camera for the other, he begins to film this beast. He follows it back down to 180 for just the right shots of it cleaning remora's off of Farb, who is looking for the long lost Flying Dutchman. With that accomplished, and no more film in the cameras, we all decide to begin our ascent and deco. Only one problem: Our dive plan (in terms of deco) is now shot to hell. Each one of us has a different deco obligation. Farb is fine, since he designed the computer that Marco built for him, and has it with him. But his profile does not match mine (I probably have less deco than they do), nor John's (who probably has more than all three of us). In that particular case, I'd just follow Rod's deco schedule, and be extra safe, whereas John would have to do some quick mental calculations to determine his deco, then add a significant fudge factor for safety. Each of us, having a computer that tracks deco obligations, much like the current air and nitrox computers, would be the best bet. The fact that it constantly monitors ppO2 against depth to come up with the N2/Inert Gas uptake is even more helpful. Now add the possibility that we knew we were going deep, and were using trimix, and the same scenario happens, the problem becomes even more complex. Will your unit be able to deal with situations as described above? Now (for all you geniuses out there), the easy answer in the above scenario is "Just Dive Your Plan" - but we are talking real world, here. These are "working" dives that involve the pursuit and capture on film of animals, some of which don't realize they are destined to be stars, and as such are hard to get close to, or don't stay at fixed depths. Also, we have rebreathers, so bottom time is not a big issue - i.e. we're not limited by the amount of gas we carry. Our true limiting factors are the amount of film in the camera, and how much deco we are willing to become obligated to. Calculating deco on the fly is possible, but not really the most dependable method, nor the most accurate, especially with large saw profiles during the dive. So, with all that in mind, what do you think? Kevin. HeyyDude P.S. I've posted this to the techdiver list, since I believe that it is a subject that a lot of future CCR divers would be interested in reading.
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