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> > I can be a bit of a bonehead as I seem unable to remember something. I would > like to find out the following: has a manifold with or without crossover > ever failed underwater? If so when, where and who? Two seperate manifold failures are documented in Martin Farr's book "the darkness beckons" (as I remember). One was an isolation valve shearing off. The diver didn't die because his entire gas supply vented in a couple of seconds, and formed an air bell in a pocket above him. I understand that he waited there till his companions returned. (Perhaps manifolds are ok if you only dive where there are pockets in the roof?) The other one was in a lava tube. The diver was with Sheck Exley, but I don't remember his name. He had a free flow (before reaching thirds) and by the time he shut down the isolation valve, and the bad reg, he had vented nearly 2000 psi from his doubles, leaving him with 300 psi. Apparently his RMV did not return to normal after his excitement, as, despite the fact that this occured *before* reaching thirds, he totally consumed Sheck's supply before they reached the staged gas. Fortunatly, the staged gas was within sight, and the pair reached it by holding their breath and swimming fast. The excitement wasn't over then! This guy's RMV must still have been elevated, as he cosumed the whole stage cylinder, dropped it and began buddy breathing the one that Sheck was carrying. This time they used up all the air, and still couldn't see the next stage bottles. Apparently they swam *very* fast, holding their breath, and around the next corner, there were the stages. They then reached the exit, with the remaining stage breathing hard and almost out, with all the deco still to do. This guy then surfaced (the cave was 165 ft deep BTW) and there happened to be someone there, and they happened to have a full scuba set in the boot of their car, which they got, and dropped to the waiting divers. > It was my understanding that the concern over manifold failures is > misplaced. Any tweaking of the high pressure seals in a manifold is likely > to result in a problem that would be evident before the dive when the > internal pressure of the system is at its greatest as would the torsional > stresses to the rig. The real concern should be over simplicity of operation. > > I'm not really offering an opinion since I don't know who tri-mix is ;-), > but I do dive doubles with manifold (w/ crossover) and often solo. Hell, I > swicthed from diving the doubles as independents because I thought my fears > were misplaced (mechanical failures vs. ease of operations). > > Regards, John > > -- > Send mail for the `techdiver' mailing list to `techdiver@terra.net'. > Send subscription/archive requests to `techdiver-request@terra.net'. > Cheers Jason =:) PS, Manifolds *do* make for some exciting stories don't they!
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