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> > Secondly, "Huge bottom times" is an accident waiting to happen, or at > best, a disappointed customer. so true, and my point at the nassau drager deal, duing the round table raimo made an ignorant remark, something to the effect of: "i can sell 20 of these things", and that is true, one probably could, but then the buyers would be pretty pissed after they dived them for a couple of days, and found out how limited they are. While semi-closed systems are more gas- > efficient than open circuit, "huge bottom times" are not possible without > "huge cylinders" and/or helium compatibility. Closed circuit systems, in > general, are more gas efficient than semi-closed. > really... > Thirdly, saying that one can take a rebreather to "extreme depths" > without qualifying the statement is, IMO irresponsible or misinformed. > agreed. > >With closed circuit, you rebreathe *ALL* the gas,...(emphasis added) > > Technically, Dan this is not correct. May be a nit-pick, i would say so.. but you have a point about mis information. but there are > some folks reading this who may not know much about rebreathers. For > their benefit; the diver does not rebreathe either CO2 (hopefully) or > the metabolized O2. The CO2 is removed in the scrubber (to be replaced > by heat and moisture in an exothermic reaction) and the metabolized O2 > is replaced from the cylinder. And if you really want to nit-pick, a > very small amount of nitrogen (assuming a nitrogen based gas) is also > absorbed by the body. In semi-closed systems some amount of gas is > always vented, and therefore, not rebreathed. > > >The real issue here would be the probability of an electronic failure, > >and if planned redundancy will work if electronically based. Some day > >this will be the answer---we don't know if it is today or not. > > Dan, we think it is in the PRISM II which works in any of these modes: > ----------------------------------------------------------------------- > Electronic | Electronic monitored, | Manual > control | manual control | control > --------------------------+----------------------------+--------------- > Closed circuit | Closed circuit | Closed circuit > Semi-closed, constant % | Semi-closed, constant % | Semi-closed > Semi-closed, constant PPO2| Semi-closed, constant PPO2 | bail-out > | | Open circuit > ----------------------------------------------------------------------- > The PRISM II comes with an independent PPO2 monitoring system that, in > the event of a main computer and/or mechanical controller crash, allows > the system to be flown manually. It also comes with a completely > independent dive computer for depth, bottom time, and air-based deco > computations. Available as an option is a completely independent backup > PPO2 monitor/dive computer with deco computations based on the actual gas > you are breathing and redundant data logging capability. Of course, you > can always fly the thing by the seat of your pants. > don't you really mean that this is how you "hope" the P2 will work, isn't it true that your unit doesn't really work in a fully closed mode as of yet. > There sure seems to be a lot of mis/dis/information and outright BS > being flung around about this rebreather subject. would be the first one to agree with you on that subject, especially the bs part. btw m2, i'm ready to answer your questions.. all of em. dp
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