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on 8/12/01 9:51 AM, Thom Hadfield at thom.hadfield@ho*.co* wrote: > Being new to tech diving and looking at different gear configurations I have > developed a question? If I go to doubles for deeper and longer dives but do > not use a manifold (cost) what are the major drawbacks? I would assume the > major draw back would be if the right tank and the left reg went bad at the > same time? not being to isoloate one tank off and using a different reg? > Would I assume this would be an acceptible risk while diving with a buddy. Or > are their other reasons that I am just not seeing at the moment. Thom, do NOT go down this path. Independants require you to constantly switch breathing from one bottle to the other to maintain your rule of thirds. ie if you need the second tank in an emergency and for some reason it malfunctions, you are fornicated. Abdicating to your buddy, your own responsibility for true redundancy is not an acceptable plan (for me) And what if HE has the same CF setup as you ! It requires two SPGs to be worn and monitored, which to me is an unnecessary clutter. There has NEVER (to my knowledge ... others feel free to chime in) been a fatality involving a manifold failure. That was a common objection from the old timers who dived independents before the invention of the Benjamin manifold ... and then later the isolator manifold. However there have been numerous deaths where independents were implicated with divers failing to manage this situation at depth. (Mostly involving narcosis and task loading) On the "deeper longer" dives you are planning for this setup (an air presumably ?) narcosis becomes a major contributing factor in the developing CF that independent bottle management fosters. Also, while the backup short hose is on a bungy around your neck, you now need to clip off the long hose reg each time it is switched, which is more often the better on independants. This is asking for danglies or some other CF resulting from constant deploying/stowing of that reg/hose. Since you are using both bottles/regs equally how do you deal with donation of a long hose ? You are just as likely to have the short hose in your mouth when the "ship hits the sand" and your long hose is clipped off ... the short hose gets ripped out of your mouth ... can you even REACH your clipped off long hose reg with the panicked diver pulled tight up against you ? .... MAJOR! CF :-( You need to be able to donate the long hose at any time and have the backup always within the safety triangle The extra task loading (at depth + on air) of independents will detract from your ability to do whatever you went down there for in the first place, either tasks or just enjoying the dive. With your recent comments on handling high currents and use of "river sticks" this is madness. > If I go to doubles for deeper and longer dives but do >not use a manifold (cost) Tom ! :-( Never, EVER ... let cost be the deciding factor in choosing whether or not to implement any part of your dive equipment or plan. If you can't afford the right gear at the time, hold off on the dives that require that gear, until such time as you can afford it and most importantly the training that goes with it That above thought process shows you are prepared to do something that you know is not right, because of money ? ... not a good idea (imho) Wait, and then do it right. Apart from the above I think it's a great idea ;-) btw I remember your first posts here some months ago regarding purchase of trimix and the flurry of replies asking you to slow down and get proper training. Have you been able to get into some training program and find some experienced buddies ? Please tell me this list is not your primary source of knowledge and advice for technical diving ? regards *** dean laffan real world productions melbourne, australia ph +613-9419-3966 Mobile - 0418-525-315 It said on the box: 'Requires Windows 95 or better' ... so I bought a Mac ! -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
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