Out of air emergency at 105 feet

[DandyDon]

I think your questions/answers are more hypothetical than useful, but still...

I would have to assume that the concept of a safety stop exists because there are some rare occasions where someone who stays within the rules still has DCS-related problems upon reaching the surface.

Yes, "unexpected" hits happen. The SS is about adding additional safety to safe dive plan theory. Dr.Deco has also discussed additional steps like "hidden safety stop" of simply floating on the surface for a minute with no exertion and removing heavy gear in water before climbing the ladder as good, extra margins.

If the cure for those problems involves recompression in a tank, then would self-recompression by jumping back to 15' be as useful as the safety stop itself would have been?

Tank? "In water recompression" is a complicated procedure with risks. In this case, one agency (forget which?) used to suggest returning to around 15 ft for 5 minutes to compensate for a missed SS, but the extra risk of solo diving is greater than skipping an optional SS. Since this dive had been cut short anyway, risks for DCS were minor. Risks of a panicked DM having a Fail day of drowning, or embolism from a poorly executed CESA, were real.

Would shorter exposure to 1 atm, as compared to waiting for symptoms and transporting to a chamber, before getting recompressed limit the likelihood of complications?

Only in theory, not really in real practice.

Would it also be true that the closer your dive gets to no-deco limits, the more likely it is that your safety stop will have real value?

Yes, of course.

As a new diver, it is good to learn from mistakes of others, but don't get too involved in such while you are learning safe basics in OW.

 

[Doc Harry]

You saved someone's life, how does it feel?

 

[dktexas54]

The old saying " any landing you walk away from is a good landing" holds true here. You saved this persons life so kudo's too you. I am strong believer is emergency air systems. As a DM leading a group, he should have had one. They only cost 2-300. If you felt your safety was threatened, if you had been carrying spare air for instance, you could have stopped at 20', assessed situation, if diver was calm, given him your spare air and let him go on up to surface while you took care of yourself.

good job!!

 

[TSandM]

With regards to returning to the water to complete your stop: First off, the likelihood of any problem resulting from skipping the stop is EXTREMELY low. Second, if you happen to be one of the one hundredth of one percent of people who is going to become symptomatic, do you want to do it underwater? In water recompression is a tricky business, and the protocols for doing it (and it's only done in remote areas, where a chamber is not going to be available at all) are complicated. If you are going to develop severe pain or weakness, do you want that to happen underwater, where you are much more difficult to retrieve and assist, or on the boat?

The fact is that the stop wasn't necessary in the first place, and skipping it is extremely unlikely to result in anything untoward, and there is essentially no benefit to returning to the water to complete the omitted stop. Remember -- the Navy tables are more liberal than just about any model being used by a modern computer. The original PADI tables allowed a 60 fpm ascent rate, without a safety stop. We have added enormous conservativism to our ascent procedures, to control the tiny remaining risk of DCS in recreational diving.

Again, I would highly recommend Mark Powell's book for anybody who really wants to understand better what is going on with decompression modeling. And if you want to know about what Doppler monitoring of divers shows about rates of bubbling with various ascents and stops, you can read the papers on the DAN website, or peruse the extensive resources of the Rubicon Research Repository (link in my sig line).

 

[dumpsterDiver]

My personal hesitancy to blow off a SS is more a matter of principal than the need to enhance safety. I have zero criticism of the OP who escorted the DM to the surface (yes it was the right thing to do, I guess), but I'm not that nice and would have made him do a safety stop or do a blow-and-go from 15 feet, his choice.

I would risk my life to save someone, but as far as I'm concerned, the serious emergency that occured at 105 ft was COMPLETELY resolved by the time they made it to 15 feet.

It reminds me of the time, my buddy's (my roommate) only second stage hose exploded at 20 feet. I didn't even offer him any air, I just jumped on his back, turned his tank off and then released him and waved "good bye" as I laughed my ass off at his stupidity for not replacing the hose when it had a big anurism in it before the dive.

 

[DandyDon]

The old saying " any landing you walk away from is a good landing" holds true here. You saved this persons life so kudo's too you. I am strong believer is emergency air systems. As a DM leading a group, he should have had one. They only cost 2-300. If you felt your safety was threatened, if you had been carrying spare air for instance, you could have stopped at 20', assessed situation, if diver was calm, given him your spare air and let him go on up to surface while you took care of yourself.

good job!!

I've dived Cozumel a few times, across at PDC once, and I've never seen a Mexican DM with a Pony, and we can debate the benefits & risks of Spare Air elsewhere but none with those either. Had the donor had one and tried to pass it off to the panicked DM, I think the risks of additional problems outweigh the skipping of a SS for this brief dive, and in my personal practices - I do not pass off my Pony. It stays with me, and I'll stay with a needy diver, but I am not trusting my Pony kit to anyone else. Two of DAN's dive insurance plans cover equipment lost in an accident, but if it was not my accident - I question the coverage on a donated & dropped Pony.

 

[H2O Gal]

Two of DAN's dive insurance plans cover equipment lost in an accident, but if it was not my accident - I question the coverage on a donated & dropped Pony.

I find it hard to believe that DAN would give a rat's ass how you lost your gear if you lost it trying to aid a distressed diver! Also a pony bottle is replaceable--a human life in not......

 

[Doc Harry]

Clearly, Everyone else is not saying that.
I would be hesitant to use you as a DM or even buddy given your statement that you would prefer to hang out at an unnecessary 15' stop rather than let me share your air to surface and get to safety if I were in a similar situation.

Clueless, utterly clueless.

First order of business, do not turn one victim into two victims. For any dive to 100 feet, a safety stop is highly recommended.

If you screwed up and ran out of air, and you don't want to hang out with me at 15 feet for 3 minutes, then hasta la vista, baby! Go to the surface alone. The emergency is over once you got my regulator in your mouth. I'm going to use my 1,500 PSI to stay at 15 feet for 3 minutes after deep dive.

 

[DandyDon]

I find it hard to believe that DAN would give a rat's ass how you lost your gear if you lost it trying to aid a distressed diver! Also a pony bottle is replaceable--a human life in not......

Well, AIG is the insurance company that would consider the claim so I expect that it would have to meet their contractual requirements. Perhaps it would work, since I was involved in the other diver's accident. I'll try to remember to call and ask Monday.

As far as "a pony bottle is replaceable--a human life in not" - yep, always true, and I hope I'll do as good as N4C did next time I have an air share experience. So far, the times I have donated have always been calmer; only one was at depth and we did stop for the SS. I generally try to advise others on the boat that my Pony is turned on in the water even tho many of dive them have them turned off and to just grab the second stage without asking - I'll understand, no problem! Or my alternate second stage and we'll figure it out from there, just not the one in my mouth as I dive a Manta and it won't come out nearly as easily. Eh, if they did grab the one in my mouth, I suppose they'd make it work and I'd grab my pony, but I discourage that in advance. I see no problem with my attitude that I'll stay with the diver to the ladder but my Pony stays with me, tho.

 

[Thalassamania]

I would have to assume that the concept of a safety stop exists because there are some rare occasions where someone who stays within the rules still has DCS-related problems upon reaching the surface. If the cure for those problems involves recompression in a tank, then would self-recompression by jumping back to 15' be as useful as the safety stop itself would have been? Would shorter exposure to 1 atm, as compared to waiting for symptoms and transporting to a chamber, before getting recompressed limit the likelihood of complications? Would it also be true that the closer your dive gets to no-deco limits, the more likely it is that your safety stop will have real value?

DCS is a probalistic phenomena. The likelyhood of having an incident whilst inside the envelope of no-D limits and ascent rates is passing small. Safety stops originated as a highly effective way to "make up" for divers inability to stay within prescribed ascent rates. With today's 30 fpm ascent rates most dives are no-bubble dives to begin with.

The "cure" for DCS involves recompression to the depth at which symptoms are relieved or 60 FSW (rarely to greater depoth embolism cases) and then decompression with oxygen intervals back to the surface.

Returning to the water to undergo a "safety stop" that was actually not required in the first place, and thus have the possible added danger of pumping gas phase bubbles that are trapped on the venous side of the lung capillaries into the arterial circulation is, in my view, a highly questionable procedure. If you were to feel the need to do so I would recommend extending the safety stop time to attempt to compensate for the possibility of bubble pumping.