Safety stop : to do or not when panicked?

[Dhboner]

As others have said you can skip a safety stop if you don't have the gas to complete it safely but the bigger issues are a) You need to be more aware of your gas supply at all phases of the dive...getting ready to ascend and only then realizing you were at 500 psi is not good b) You signal your buddy that you are low on air and begin the ascent calmly together prepared to air share if necessary (and your buddy has enough gas in reserve) c) you need to plan the dive better including calculating your gas needs and checking in with your buddy at certain "waypoints' on the dive e.g. on the first part of the descent, when you reach bottom, when you reach the wreck, when you leave for the ascent line etc. That way you "check in" frequently and minimize the liklihood of a surprise. Coming here looking for advice suggests that have learned from this and will continue to learn so good on you

 

[Bob DBF]

If you had panicked, there would be no decision involved. If you didn't think of choice until after you got out of the water, now you have a plan that may keep panic at bay the next go round.

When deciding to make a stop or not after a dive close to NDL, I make the stop using whatever air I have left. It stops the ascent rate if I was a little excited on the way up, and a little off-gassing is better than none. As stated by others, I would use my buddy's air to my advantage if he had any extra.

Because you were caught short on air, I would suggest some workup dives starting around 80' to acclimate yourself so you look more often and understand the meaning of your air, depth, and NDL when you look. When diving deep your main focus has to be on your exit plan. I haven't been deep diving in a while and will be taking my own advice before I hit 120 again, I could probably do it without, but it only takes one mistake.



Bob
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That's my point, people, by and large, are not taught that diving can be deadly, they are taught how safe it is, and they are not equipped with the skills, taught and trained to the level required to be useful in an emergency.

 

[Storker]

It's a safety stop, not a mandatory deco stop.

So far in my diving career, I've "freaked out" exactly once, I started feeling like crap during my SS and decided I'd feel a lot better on the surface, with unlimited air, than submerged on my reg. Hence, decided I'd be better off taking the elevator to the surface. With an inflated wing and unlimited air, I felt a lot more safe than under water feeling crappy. Even if I'd passed out, I wouldn't have to rely on my reg to keep me alive.

As the old saying goes: "you can (often) cure bent, you can't cure drowned"

 

[JS1scuba]

Greetings,

This is one of those interesting posts where one clearly knows the reasons why a situation went bad yet is seeking some kind of validation from others for a minor action they chose to take. This is a common reaction professionals in my industry see more often than not. Let’s start with the simple fact that you got lucky that you did not hurt yourself or your dive partners. Give yourself a big pat on the back for that one. I suspect that your goal in exposing this dive is to learn how to get it right next time.

The initial bottom line on this one is that both you and your dive partner failed to plan a dive properly. So be it, don’t beat yourself up too much over it and use this as a learning tool for future successful dives.

Root cause analysis of accidents has shown that most accidents or incidents on dives did not happen at the time of the dive but happened long before the diver actually entered the water. Here’s where it starts:

You state:

• I didn’t feel perfectly well before starting the dive. Major headache in the morning. I had a couple drinks the night before.
• Diving with an aluminum 80s is not appropriate for a dive at 120ft
• We should have an additional tank at 15 ft.
• This dive is almost a Technical one..
• We shouldn’t dive it just as if it was a simple Saturday afternoon dive.

Other comments I read you state that when you made your ascent you had 500PSI, and that your anxiety increased as you saw that number dropping. What’s important about this statement is that it appears you are not aware of how much gas 500PSI is. What is left out of your post is the discussion of thermal protection, we have no idea what your thermal stress was.

Panic is a sudden overwhelming fear that future events will cause you harm. If one does not have a chemical imbalance that causes one to have clinical anxiety, sudden panic is often the result of one not having enough proper information to form an intelligent decision. We all experience some level of panic on occasion through everyday life, though these things are usually just inconveniences. Running low on gas in the car, overcooking the steak, under-cooking the chicken, running close to a task deadline etc. The problem with panic in diving is that in many cases it leads to serious injury or death.

The question on the safety stop is minor. The short bottom time you had may not have warranted a stop unless your ascent rate was way out of line. So let’s not spend much time on that one now. The big issue is you did not plan your dive. And I suspect It is because you were never taught how.

1. 120 foot dives are at 4.63 atmospheres. This means your gas burns 4.63 times as fast at depth as it does at the surface.

2. No stop time for a 120 foot dive is 15 minutes from time of leaving the surface to time leaving the bottom.

3. If you are an average diver you will consume about 1.00 cubic feet (cuft) of gas per minute in full gear at the surface. (+/- 15% ) Experienced active divers can drop this value to as low as .25 cuft per min but most are in the .50 -.75 cuft range.

4. A 15 minute dive at 4.63 atmospheres will consume about 69 cubic feet of gas.

5. You had 500 psi left or 13 cuft that tells me you used only 64 cubic feet of gas when you ascended meaning your actual gas usage is greater than 1 cuft per minute (you can sort that out later)

6. The 500 psi you had left (or 13 cuft) provided you enough gas to make the ascent, make a stop and get out IF you remained calm and collected.


So what went wrong, how did this dive you did go badly, it’s pretty simple and does not take a lot of guessing. Besides the hangover and improper gas supply the problem is that you did not plan the dive using the #1 tool we all use for guaranteeing a safe return. Rule of 1/3rds. (look that up) In a perfect dive you would have enough gas to get in, get down, do the dive, get up, do your stops and get out of the water with 1/3 of your gas left over. There are some mods to that in a non-overhead environment but that is for another discussion. That 1/3^rd left over … it’s for your dive partner in the event of a real emergency.

Having trained many hundreds of divers and having completed successfully many many thousands of highly challenging dives here is what I suggest for you. Go get some quality training. Spend some money, get a good TDI Intro to Technical Diving, or a GUE Fundamentals class – share your story with the instructor. Work on gas planning. If you do not have EAN cert get that as well. If you don’t have a TDI or GUE instructor around then go find the BEST instructor you can. If you don’t have one near you, then get on a plane and find one. Then you will be armed with the tools you need to plan your dives properly in the future.

I suspect there are some friends and family you have that would like to see you continue living. This is something you owe THEM.
As I mentioned earlier, you got lucky. You cheated death this time. Let's find you some training and get you back in the water.

Regards,

 

[DevonDiver]

Safety stop is optional. But it's advisable. Very advisable on deep dives, dives close to NDL or if you've pushed/violated safe ascent speeds at all.

If your level of competency (diving skills, awareness or stress management) isn't sufficient to GUARANTEE you can always complete a slow ascent and stop, then you should SERIOUSLY re-evaluate your personal depth limit.

Just because some gopher swiped your credit card and automatically handed you X, Y or Z cert cards for a few undemanding 'course dives'... doesn't mean you could, or should dive to the maximum depth limit that qualification level.

 

[RJP]

Out of curiosity, did you do a dive plan?

Before splashing did you have any idea what your NDL was? How much gas you needed to complete the dive and a safety stop?

I ask not to beat you up (well, a little) but because in a market research study I'm running currently, it seems like few, if any, recreational divers actually do any sort of dive plan before jumping in.

 

[rongoodman]

Look up minimum gas or Rock Bottom. Had your buddy come to you needing to share gas at that depth, with only 500 psi in your tank you would have run out long before you got to the surface. I wouldn't consider doing that dive without some helium in the mix and either doubles or my rebreather. You're both lucky.

 

[redacted]

Look up minimum gas or Rock Bottom. Had your buddy come to you needing to share gas at that depth, with only 500 psi in your tank you would have run out long before you got to the surface. I wouldn't consider doing that dive without some helium in the mix and either doubles or my rebreather. You're both lucky.

But that would have been 2 failures rather than one and recreational diver protocols are designed to get through one failure.

Helium, doubles, and rebreathers are tech diver chest thumping tattoos at 120 ft and really unnecessary for reasonably planned dives within recreational diving parameters. For most folks, an AL 80 will be adequate for a 120 ft dive. And 13 cu ft of gas will get you to the surface if within no deco limits. But that is the kind of recreational dive that should be turned around 1000 psi. You do need to know the consumption parameters for you and your buddy and plan accordingly. That is the kind of dive where it may be only a few minutes between "we're fine" and "oh ****" for both NDL and gas.

 

[Nuribromanski]

If ur truly panicking, u will not think about the stop u will just blow thru it for the surface. And thats ok because recreational dive = all stops are optional (theoretically). But closer u get to NDL limits, more theoretical that becomes...until finally ur "tek" diving where panic means injury/death, not less than best. So enjoy the fact that ur doing dives where panic is safer, or realize ur doing dives where panic isn't a safe option.

 

[doctormike]

When my buddy signaled for the ascent, I realized I had only 500 psi left...

This is the most important sentence in the original post.

Thanks for posting this. It seems like you are (1) able to admit your mistakes, and (2) learn from them. Those two things are very important when becoming a safe diver!