safety question

[JAMIE MCG]

Say after a 30 min dive at 60 ft. you are heading up to your safety stop and you see another diver go up and not stop and possible having trouble at the surface, can you go up and check on him and if not an emergency go back down within a minute and continue your safty stop without any problems.

Thanks Jamie

[DiveMaven]

A safety stop is just that, for safety. It's not a deco stop, so you technically have no obligation to do it. With that profile as long as you ascend slowly, you don't need to do a safety stop and could simply go straight to the surface.

I'm one of those folks that always does a safety stop if my dive goes deeper than 30' or so, and usually pushes the stop to 5 minutes instead of the "standard" 3. But in an emergency, as long as I were within the NDLs and my ascent was slow, I'd blow by the safety stop without a second thought.

[HappyFunBoater]

I agree with DiveMaven about long safety stops. I find it very relaxing to just float around, look at the fishes, play with my equipment, test my backup reg, practice skills, etc. It gives everyone else a chance to get back on the boat and I can stay out of their way.

[BIGG_BUDD]

What she said...

[ScubaCatgirl]

Yep! I agree with all of the above!

[Matsya]

While I agree with the first part, that it will probably will not affect you if you go directly to the surface without a stop, I am not very certain about the second part - whether once having ascended to the surface descending again to continue the safety stop has any beneficial effect.

Probably more knowledgeable Boarders can answer this?

On the whole I make it a point to do a safety stop regardless of the depth that I have gone to and regardless of the bottom time. To me it is a matter of cultivating a safety habit and as others have said I find it relaxing to just stay at 5metres looking around and practicing various skills.
I should think that in THE SPECIFIC SITUATION that you have hypothesised it is not an issue but what would apply for dives to the recommended maximum recreational depth of 30 metres or dives where a safety stop is considered REQUIRED?

[Louma]

I know I’m going to put a damper on the above replies, but here it goes: Though a safety stop is not mandatory why do you think every accrediting agency recommends it? My guess is that it has been proven to work. Don’t forget that the largest physiological changes are from 33’ to the surface. Also, remember your Instructor saying something along the lines that “even if you do everything right, you can still get bent.” Making this safety stop is helping to do everything right.

Now, let’s look at a segment of the Rescue Divers class. One of the statements drilled into a RD students head is don’t do anything that will lead to 2 fatalities. Meaning that you, as a Rescue Diver, should not do anything that could put yourself in a position of harm. Not that I think that you would die doing the described profile but who knows? At 60’ for 30 min. you have built up a significant portion on N2 in your system. Also, are you sure you are making a slow assent? It may seem it, but now the adrenaline is kicked-up a notch. I’ll give you a real life example that I experienced: I was responsible for 4 Advanced Open Water students. Paired them up 2 and 2. I had a Dive Master to assist. We were at 70’ doing the deep dive portion of the class and we were going to shoot a lift bag also. About 25 min into the dive one of my students gets out of his BC and shoots to the surface (the reason he did this is another story). I signaled his buddy to stay down. I got the Dive Masters attention to stay with the students and I went up. At 15’ I hung for my safety stop. I was able to look up and signal the diver to see if he was OK. I got the OK signal back. I did my 3 minutes.

Now, if I didn’t get the OK and I did see that he was in trouble would I have surfaced? Probably – but then again I would be putting myself at risk which you are not supposed to do. I’ll tell you this though; if it were a family member you bet I would surface and face the consequences later.

And last, but not least, once you surfaced don’t go back for a safety stop. It could do more harm than good. Stay up and if you start showing signs of DCS get O2 and medical assistance.

[miketsp]

Say after a 30 min dive at 60 ft. you are heading up to your safety stop and you see another diver go up and not stop and possible having trouble at the surface, can you go up and check on him and if not an emergency go back down within a minute and continue your safty stop without any problems.

Thanks Jamie

Short answer - Yes.

You said safety stop so OK.

..snip..
And last, but not least, once you surfaced don’t go back for a safety stop. It could do more harm than good. Stay up and if you start showing signs of DCS get O2 and medical assistance.

Have to disagree.

No problem to go and check on the surfaced diver and then go straight back down to your safety stop level.
Bubble formation is not instantaneous and you will still gain some benefit from the improved offgassing rate at the safety stop level.

And of course since it was a safety stop, no problem if you have to stay at the surface to help.

[Matsya]

Short answer - Yes.

You said safety stop so OK.



Have to disagree.

No problem to go and check on the surfaced diver and then go straight back down to your safety stop level.
Bubble formation is not instantaneous and you will still gain some benefit from the improved offgassing rate at the safety stop level.

And of course since it was a safety stop, no problem if you have to stay at the surface to help.

And last, but not least, once you surfaced don’t go back for a safety stop. It could do more harm than good. Stay up and if you start showing signs of DCS get O2 and medical assistance.

Two totally divergent views one from an instructor and one from a person with 201-500 dives. This is how new divers like us get slightly confused.

Edit:

I think I could have rephrased this post slightly. What I had in mind is that if two probably very equally experienced divers have totally divergent opinions on such an important aspect of diving as a safety stop, it only becomes very clear that there do not seem to be any standards for such cases. When I meant new divers get confused I did not mean by you the posters, but by the non-existence of precise guidelines for even such critical questions as this.

[Louma]

I am first appologizing that my answers are long but I feel that this is an important subject.

Miketsp, now I’m going to disagree. I’m approaching this question from the point of view that every certifying agency concedes that “every dive you make puts you at risk, even when everything is done right.” Quite frankly, not enough is known about diving, and why complicate things with possible problems. Going back under the water starts to complicate things. Can it be done, sure? Should it be done? Let’s look at a few things:

Since I am a NAUI Instructor I’ll use NAUI text and information (this is what I am most familiar with). In Chapter 4 on Diving Science in the O/W book it states three steps to help in preventing DCS. 1) Staying within the time limits of the tables, 2) always ascend at a rate no faster than 30’/min. and 3) the third step in preventing DCS is to always perform a precautionary decompression stop at 15’ for 3 to 5 minutes.

I realize that uploading of N2 takes time and certain compartments (tissues) take in N2 at different rates. If the pressure is constant ingassing occurs rapidly at first and then slows down until your body reaches equilibrium many hours later. It then takes many hours to outgas completly. We control this ingassing by regulating our pressure and time. “Don’t stay down too deep, too long and come up too fast.” Besides pressure and time some other things to consider to help avoid suffering DCS – dehydration, temperature, fatigue, injuries, hard work before, during or after the dive, drugs, alcohol, obesity, age, going to altitude after diving, etc.

From the NAUI Master Diver certification book Chapter 4: Diving Physiology-

“If you stay too long and ascend too quickly at depth, inert gas (mostly N2) that you absorb can come out of solution and form small bubbles in your body.” “It is not likely to be the case that every dive makes bubbles in your body.” But, later on in this paragraph it is stated “susceptibility to DCS varies with individuals.” So, more potential problems putting a diver at risk?

Using the NAUI dive tables and assuming this is the first dive of the day a 60’ dive for 30 min. translates to an “F” diver. PADI you’re an “L”, SSI and Navy you’re also an “F”, others you’ll have to do the conversions. You’ll have N2 in your body. How much? I guess it varies by individual, but it warrants a SIT time.

Let’s get back to the original question about the diver shooting to the surface that may or may not be in trouble. You go to the surface, and there is a problem with this diver, is he your dive buddy? If not, where is your buddy? – I would think everyone would see this as a potential problem.

Let’s say that the diver in trouble was your buddy. You now do a tank tow and bring your buddy to the boat; you assist the crew with getting him back onto the boat. You now jump back in the water to do your safety stop (because you think you have too much nitrogen in your system - maybe not much – but, how much is too much? And if you don’t think you have too much N2, then why are you going back into the water?). Hopefully, you told the crew what you are doing.

You now are the last one in the water. Let’s say something did happen to you. We don’t know for sure that something could happen, but we have to concede that it is possible why? because all individuals are different and not enough is known about diving. You now black out and sink to the bottom why? because you ran 5 miles before the dive, went in the hot tub to relax your throbbing muscles and forgot your water bottle back in the car. In your excitement and haste you forgot to put any air in your BC and you always dive a little over weighted to stay down.

The boat crew was so preoccupied with the rescue of your dive buddy with giving O2, first aid, collecting statements, securing gear, calling the Coast Guard, filling out forms, their stress levels going through the roof, they forgot about you. After about 15 or 20 minutes someone remembers that there was this other diver. Where did he go?

So, not all of the problems with going back underwater have to do with the formation and alleviation of bubbles, whether instantaneous or not or what size they become a problem, or wether they even developed. Different people will react differently. There are no assurances in diving. No one can say for sure that it is safe for you to go back into the water. Me, I’ll take my chances on the surface. And, I’ll instruct my students to do the same.