Mailing List Archive Mailing List Archive
>USN Dive manual quotes about 75% O2 for the standard purge (breathing down 2 >bagfuls, exhaling through the nose), so I'd imagine you might get that 90% >you mentioned if you wanted to do the three of four purges. Yup. >Of course, >nitrogen is racing out of your system the whole time, so you'd have to >re-purge a few times during deco. Now, -that- is not something I had even contemplated. -cool-!. I'll store that gem in the brain cells for future use. Hmmm........ >And the electronics you add (the analyzer) just increased the complexity, >and decreased the reliability. Err.... Not really. A oxy sensor is just a battery. Read the voltage and convert to percent. When was the last time you stressed out over using your analizer on the surface? One trick is to measure the output voltage pre-dive and keep a record of the voltage so you can watch the cell degrade over time and replace it as needed. This is simple stuff. But not the stuff that is so mainstream so that everyone is comfy with it. >While I know next to zilch about mixed-gas >rebreathers, one common complain I hear is that the electronic monitoring >system, that controls the addition of O2 to the loop, is the catastrophic >failure point. Rebreathers are the sort of thing that one approaches like a high performance airplane. They are not for everyone. But there is essentially no failure mode that cannot be dealt with by a -trained- diver with intimate knowlage of the system. In the event of a total loss of electronics one can convert to semi closed mode by simply exhaling every 3rd or 4th breath out of your nose, insuring a constant addition of diluent gas into the loop, thus saving gas use while insuring a breathable mix. This is a long topic and worth your research if you are interested. It's funny that most complaints are made by people that have never used them. To me, the system is totally understandable and completely intuitive. >As for the Russian rebreathers, I've never dove one, but talked to a few >(spetsnaz) who have - the one guy who was the most garrulous told me it's >nickname was the widow-maker, or something like that. Whether that was the >IDA-59 you're talking about or not, I don't know - I'd have to see a >picture. I'd still be interested in one for shallow stuff, I'd just be >hesitant to use it with mixed gas. The IDA-71 has some interesting issues involving automatic purging of the bag with EAN 40 at about 50 feet and then automatically repurging upon ascent with 02. But the IDA-59 is a far different animal. In it's simplest mode it's just a pure 02 loop, nothing to break at all and stone simple. I'm going to play with the IDA-71 as a nitrox rig, but I may end up replumbing it completely. The IDA-59 is staying as-is. There is also an IDA-72 which I'm scrounging also, which is designed for trimix semi closed work and may be OK as-is. I'll report when it's in hand. >As for the advantages of a Draeger for deco, which you described below, I >agree, but my one reservation is that, even though it is a good system, it >is still more likely to fail than OC. Not in the basic pure 02 mode. No moving parts, manual add valve. How can it be any simpler than that? The 02 monitor is just for grins. >Of course, since my deco diving is done in >caves, I'm not too concerned about the size of my O2 bottle. Different arenas require different tools, eh? Understood perfectly. Best, Dave Sutton -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
Navigate by Author:
[Previous]
[Next]
[Author Search Index]
Navigate by Subject:
[Previous]
[Next]
[Subject Search Index]
[Send Reply] [Send Message with New Topic]
[Search Selection] [Mailing List Home] [Home]