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>is 12c. Visibility is a whopping 20 feet. Your diving with a family member, >wife, son, daughter etc. (pick your soul mate). Both of you are experienced >divers and in addition there is another diver along with you, who you trust >and care about. After a lenghty bottom time you decide to head up, your >family member and friend decide to stay for 5 more minutes to get those last >pics or yank that last piece of scrap. Their at the anchor line so you >decide to head up. You make it up to your third stop at 15 feet and First off, it's difficult to say depending on what you mean by lengthly bottom time, exactly HOW much deco penalty you have, exactly HOW MUCH gas is left, etc. It's good to think of these scenarios BUT the important thing to determine are what I call the "knees" or "decision points". i.e. if I have "x" lbs of air left I'll descend and look for "y" minutes, etc. Given the depth and the fact that you planned some nitrox somewhere in there (travel gas I presume), with O2 deco the planning for this is non-trivial. To simply go back down to attempt a rescue is very foolish. If anything someone on the boat who didn't dive should be sent down to attempt the "recovery". The problem here is that you have multiple "failures" in your scenario. #1 problem with at least one diver at depth - and state of other unknown. #2 n2o2 gone (you didn't say why and didn't say how this fit inot the dive planning) #3 air low due to the dive #4 splitting up a dive team (you ascended) is what I call a *failure* even though it may have been a conscious decision. Having THIS MANY problems is inexcusable and a recipe for disaster. Sometimes shit just happens but I'd say that this dive had many potential problems before it was executed and as such it's not one that *I* would have planned or performed. *WHEN* either of my sons dive with me (I have a few years to ponder this given that one is a week old today and the other is 2.75 yrs - but he already knows about 1st and 2nd stages, computers, masks, etc!!! ) they will be limited in what they can do. Since *I* am the senior diver I would *insist* that they stay with me at all times and when *I* head up, THEY headup, especially to a dive of this depth. You left out the larger potential for a problem with the *lone* diver in which case HE has no one else to assist HIM... In other words, this scenario would *NEVER* have happened with me, period, end of story. I'm sur others will agree with me on this. I would most likely by using a gas usage pattern such that the turning point of the dive was much more conservative. I don't know if I would go as conservative as the rule of thirds (assuming this wasn't a penetration wreck dive at this depth) I think that I would most likely limit the turning point to 1/2 gas remaining, which is basically what I use for this type of dive anyway. I could go on and on about what if this and what if that but, I think the major point from this is to not put yourself into a scenario like this. Kind of like the ounce of prevention/pound of cure idiom. I *hope* that this wasn't a scenario taken from real life somewhere. If not, how did you come up with the circumstances? For people that say "I'd go back down", I'm curious as to how people answer differs if you take away the "relationship" out of the deal (i.e. how much is thinking with your heart vs. your head)... -Carl- *************************************************** The best way to avoid a punch is to not be there... ***************************************************
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