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Pat Moran wrote: > I am a Northeast Atlantic wreck diver and am looking for insight into > different setups for decompression tanks and appropriate regs. I am > diving intermediate depths (130-170), using air (will be switching > to mix asap), nitrox for hangs (1.4 PO2 max), and still limiting myself > to hangs of around 30-40 min -nothing fancy- but will be extending my > depth/range at some point. > I have recently gotten some cash together, and would like advice about > the various characteristic of > various setups used for decompression (ie: OMS 45s, aluminum 40s or 80s, > steel 72s, etc. and appropriate regs that will carry me eventually into > more extended hangs -read bottomm times). > What are the advantages/disadvantages of the tanks, what do you (all) use > and why, are there other options that I am not aware of???? > Any and all advice would be greatly appreciated There is no equipment configuration I know of that works in all environments. (I know some would hold this tantamount to sacriledge....) Since you've asked about North Atlantic wreck diving, here's what I'd recommend: first, whichever stage bottles you decide to use, **practice in a friendly environment BEFORE going on an ocean wreck dive***. A quarry is a good place to practice, although you'll have to keep in mind (for weighting purposes) that you'll be in fresh water, as opposed to salt water.... If you can have an experienced friend or instructor go with you and lend you bottles, try the smaller bottles first (30's or 45's). Get the hang of carrying the stage bottles, rigging your regs so they don't dangle, putting the regs back in place, and taking them off in the water (which you may want to do at the end of a dive to unclip them to a gear line, saving you the hassle of climbing up the ladder with extra bottles). Work up to larger tanks, as you see fit. Generally, steel 72's are great because they don't get positively buoyant at the end of the dive, which aluminum 80's will do. Also, steel 72's are a little smaller than 80's and less cumbersome, plus less of a drag. In any case, the more you practice before a **real** dive, the better off you'll be. I've used various stages for cold water wreck diving and prefer smaller tanks that can be overpressured (arghhh...did he say that??) but there are definitely times when your dive plan will call for the biggest stages you can manage. Obviously you shouldn't just start off with huge stage bottles, but should work up to them. Remember: you have to get yourself and the tanks back onto the boat at the end of the dive, when you're the most tired. I haven't seen the following addressed yet: In carrying stages, especially during deeper dives that may require multiple gases carried in stages, a concern is redundancy: should anything go wrong with one of your bottles, you'd be up the creek unless you provided for redundancy. (Of course, in the case of a reg failure, you can always switch regs from one stage to another, but that's no fun in rough seas, believe me.) I've done dives where I've had twice the gas I needed in my stage bottles, eg, either stage bottle would have sufficed, and opted for only one gas in both bottles. Although deco was a little longer than using a two gas combo, I felt it safer to use this method, especially since I would be doing a drift hang for an hour. I'd like to know what other wreck divers are doing on deep multi stage dives. Is anyone using "Y" or "H" valves and two regs on their stage bottles? What concerns do other divers have regarding redundancy in travel and deco gasses? Oh, one other thing: **way too many** experienced deep air divers have died in the last few years as a result of breathing a high content oxygen mixture at depth because **they changed to the WRONG reg at depth**. PLEASE DON'T LET THIS HAPPEN TO YOU! For high content oxygen mixes, I recommend marking the reg and CLIPPING it off, preferably well away from where you have your bottom mix regs. Billy Deans went one step further and came up with an idea that many divers have subsequently used: he has a brightly colored pouch that goes over the reg; when you want the reg, you have to unclip it AND take it out of the pouch. Conclusion: start with smaller stage bottles, practice, get used to them in open water and go over this process again when you want to use bigger bottles. Remember to mark and clip off any high content oxygen regs so you don't accidentally switch to the wrong reg at killer depths. Bernie Chowdhury bernie@in*.ne* Bernie Chowdhury bernie@in*.ne* __________________________________ Your message, to which I am replying, follows:
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