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>Heres a question to think about for all those idle people out there!! There's a *lot* of gotchas on this one. >You are diving on a wreck at 30m and you are finishing your dive. >The vis is about 15m. ( A fantasy in U.K. waters) >You have located the shot line, and have approx 100bar left. >Your buddy is by your side and in a simalar state to you. >Your are the more experienced diver.. >Your No Stop time is one minute away. ( Than is to say that if you stay >longer at that depth you will have to do stage recompression, which you >have not planned for). If you haven't planned for stage deco, you really shouldn't be diving within 1 minute of NDL - 5 would be more the rule, but I won't belabor this point. Diving this deep on a wreck also would mean that some type of redundant air supply is a *very* good idea... Oh, a computer would be a good idea too. >You look over the side of the ship and spot a diver 7m below you, as you >observe him you notice that he is motionless ( and no he is not a photo- >grapher), and that his breathing is eratic. So, he's in 37 m (~122 ft) of water, BUT, he is still breathing. >There is spare cylinders on the shotline, but there is in the boat. I assume you meant *no* spare cylinders on the line. Well, since I dive with a 40 cu ft pony on all dives in the 100+ ft range, air would not be a problem in this case. Let's assume that, for some reason I do not have my pony (which in reality means that I would not have done this dive, but let's continue the exercise anyway). >What do you do??? >Ps The first question you should ask is, where is his buddy. >BUt let us for the sake of interest asume that his buddy is no ware to >be seen. Did you know that there were other divers down there in the first place? that is, if you were on a boat, were there other boats in sight or other buddy teams from your boat??? If there was no other boat in sight when you went down, it means that he must have been underwater much less time than you were, however, you don't know how deep he's been. (You did say it was a boat dive, but...) If this was a shore dive did you see others swimming out toward the same general area or did you see any bubbles on your way out? Now, assuming that you went under soon after you left the shore (perhaps because of wave action) you wouldn't have any idea. 100 bar ~ 1500 psi... Rememver that NDL time is not some magic line, however, doing a reverse profile (even if it's just for a very short period of time) does increase *your* chance of DCS. Assuming you're diving with a standard AL 80 (you didn't say what size your tank was, and without that, the pressure is meaningless), you still have about 40 cu ft (half the tank) left. With this much air left I would have to say that without hesitation I would go for the other diver and bring him up with me as long as he's still breathing (you said he was breathing erratically). If it's clear he's not breathing I'd have to think a little first, but given the circumstances, I would probably still go for him. It should not be a problem to bring him up and have *plenty* of air left for the small amount of deco you will have built up, even extending it for safety. If you're on a computer, a slow ascent will most likely clear your compartments before you ever hit the 15' mark so a 3 minute saftey stop would be the "standard" precaution and I'd extend it due to the reverse profile. As long as he's breathing, I'd do a very controlled ascent attempting to minimize his risk of embolism and/or DCS and to keep his airway open. If he stopped breathing, I'd probably drop his weight belt and inflate his BC so he would head for the surface and the crew on the boat would find him. I would not, however, break my deco in this circumstance. It would most likely take the crew of the boat a few minutes to bring him into the boat anyway. I would perform any necessary decompression time and probably extend it by a few minutes to take care of the reverse profile effect. Now, deepening the dive to 122 ft (from 100) could have a signifigant impact on your required deco if you're diving the tables. I don't have my tables handy, so I can't say off the top of my head what types of times would be involved here, however, I never dive deep without my computer. If you end up with a lot of deco time, you can meet your buddy at the 15' stop and have him take the diver to the surface and lower down the spare tank to you (if required) so you can continue deco. BTW, it's always a good idea to run over several accident scenarios like this with your buddy ahead of time so you two will * know * what to do. The ideal situation would be to have your buddy start ascending so he does not go into deco, but, keep his *eyes* on you (i.e. within visible range). That way, if necessary, he could take the other diver to the surface, alert the boat crew about what happened, commmence CPR, and activate the appropriate EMS via radio while you continue your deco. Are you at increased risk for DCS on this dive - you bet. How much does it increase your risk. I don't think it would increase my risk to the point that I would be willing to let someone's life slip away, however, I am a fairly experienced deep diver and know my limits at depths well beyond what we're talking about here. If available, I would most likely breath pure O2 for a while after surfacing just to help offgas the N2 and perhaps prevent any post-dive DCS from cropping up later. This means that the O2 rig on board should have multiple connections available and should be large enough for 2 people to breath from at least as long as it takes to transfer the patients to an appropriate EMS facility. A small DAN O2 tank would most likely not be sufficient for this!!! -Carl-
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