How Deep Can You Do An "Out Of Air Emergency Ascent" From?

[Hawk]

Uncle Pug, If you read the initial question I stated that planning is what some say is the best meathod, I agree to a point. IF we lived in a perfect world and humans were not what we are, proned to making mistakes, this would be the best method. This should be the method that is the first and most relied on method. However, in my opinion people, no matter how competant they may be, make mistakes and I for one feel that some kind of emergency backup should be at least considered. I know of nobody that I will trust to never make a mistake. Once again opinions are, well you know the rest of the phrase. I am really surprised that it took you so long to chime in.



Later, Hawk.

 

[Se7en]

Uncle Pug

Your approach with ponys is correct, as long as you always follow rule number #1

I sometimes have carried a pony bottle, when diving from cattle boats, with divers who I'm not too sure of


I'm not worried about myself or MY buddy running out of air (I'm not DIR, but I'm not stupid), but I often end up in a situation where I become a defacto divemaster to a larger group following us around.

In these circumstances, I think there is some place for a pony you can hand off completely to a panicing diver. It has happened to a buddy of mine while we were diving (I was luckily head down a hole) that another diver ripped reg from his mouth, mask dislodged, and started towing him to the surface. (Strangely, the paniced diver was not out of air - just thought he was...)

I'd prefer to be able to hand over a pony and keep away

Mike

 

[Uncle Pug]

Originally posted by Hawk
I am really surprised that it took you so long to chime in.

I held it in as long as I could and this is certainly not a slap at you Hawk as the originator of the thread

The following is just Pug's opinion and nothing more:

Here's the deal, see...
You have to deal with this from a planning perspective instead of Just saying... "well we're bound to screw up sometime so lets all concentrate on that."

I'm saying "let's all concentrate on how not to screw up."

Gas planning 101... every dive....
First figure your Rock Bottom!

Rock Bottom = the amount of gas you will need to get back up from your deepest depth to your first gas switch (technical) or the surface (recreational) using normal ascent rate with any necessary stops X two (for your buddy's share - should he be OOA you can both make it.)

Subtract the Rock Bottom from your gas supply and then figure your gas plan, turn pressure/ascent pressure ect. Now subtract that from your total pressure. Never even think of going past your Rock Bottom. It does not exist until you need it. Hopefully you never will.

In a worst case senario of total gas loss you or your buddy will still have your Rock Bottom and you both can make a controlled ascent.

Don't know how to figure your Rock Bottom?
Spend time learning how to do this....
Ask questions about this....

Don't want to bother with figuring your Rock Bottom and gas planning?
Spend time worrying about running OOA....
Ask questions about this....

Now this is all just my opinion and while it ought to be everyones I respect your right to disagree.... no problem there... this is just my take on how to prepare for emergencies and what questions are the right ones to be asking.

My buddy's Rock Bottom is my emergency back up... totally inedependant, redundant and immeadiately accessible.

 

[Uncle Pug]

Originally posted by Se7en
I sometimes have carried a pony bottle, when diving from cattle boats, with divers who I'm not too sure of


I'm not worried about myself or MY buddy running out of air (I'm not DIR, but I'm not stupid), but I often end up in a situation where I become a defacto divemaster to a larger group following us around.

Lotus Man....
I agree with you....
And while I eschew clusters and cattle boats....
I think that a stage rigged *pony* is what I would carry if I were thrust into that situation....


BTW: where do I find pictures of a car like yours.... I am intrigued!

 

[budgy]

Hi Uncle Pug,
I dive generally with a single twelve and no pony.
I have seen an O ring blow it happened to another diver just starting his descent. It isn't common, and it happened with a yoke fitting not a din. I suppose it could happen to me or you at any time during a dive.
I have had a reg free flow, though I could still breath from it. I have seen a high pressure hose burst. I have seen the valves on stab jackets and dry suits jam on inflate and connecting hoses that free flow when disconnected. Nothing to do with air management, old equipment and poor maintainance. There was an occasion a buddy diver got alarmed and suddenly more than doubled their previous monitored consumption rate we were not that deep 15 m and very far from the shore, we finished the dive on my octopus, and I still had a 100bar on exit. I think the independant twin or redundant air supply pony is a safer system, though I have no practical experience in their use.

 

[SpyderTek]

I'm sorry I don't think the "Rock botom" idea is practical until you get much further along in your certifications. A basic OW diver using AL80 with normal air would calculate a rock bottom using those parameters at 15-20 minutes at 20' dive. (estimated)

Its a nice idea and one that makes alot of sense when you have mixed gasses, larger gas volume, long term experience with low SAC rates etc. But if we actually followed these no one would want to keep diving.

Why bother diving? Just snorkel.

I'm sorry but any field, be it bussiness, marketing, sales, meicine, etc will always tell you that the bst policy is to plan your best but expect your best not to be good enough and carry an out. We all make mistakes all the time. To think otherwise is denial and / or arrogance

What is interesting to observe subjectively is that 9 out of 10 deaths in scuba arent the newbies with BOW on their AL80's its the advanced Tech divers. Now is this because the advanced people are taking their scuba for granted because they have so much experience and / or the newbies just being so affraid of anything happening that they bring along extra "unneeded" saftey equipment I couldnt say.

Liberally,

SpyderTek

 

[Uncle Pug]

Originally posted by budgy
Hi Uncle Pug,

Hi Budgy,
In your analysis of the cause of the failures you list you state that it was due to old equipment and poor maintainance.

Also I gathered from the description of the failures that none resulted in a true OOA but allow the diver experiencing the failure to continue to use the equipment in a controlled ascent with the exception of the OOA buddy sucking on your octopus.)

What do you think is the best solution to these problems that have experienced in the past?

 

[Uncle Pug]

Originally posted by SpyderTek

What is interesting to observe subjectively is that 9 out of 10 deaths in scuba arent the newbies with BOW on their AL80's its the advanced Tech divers.

Where did you get this statistic SpyderTek????

Oh... and the idea of Rock Bottom is taught to every OW diver...
They just aren't told what it is and that is why they grow bold and ignore it....
Better to teach it for what it is - an inviolable prinicple - from the beginning....

You know it as the old *always back on the boat with 500 psi* now changed to the new *always back on the boat with 700 psi* and duely noted on SPGs with a Red shaded area.

 

[solodiver]

I dive high pressure tanks 3500psi
gas management for my tanks are. 500 psi rock bottom leaving 3000 psi to be divided into thirds. OK it's not quite thirds as you have to figure out your buddies sac, so that no matter where you are in your dive you well always have enough gas for both of you to return safely to the exit point. so if your buddy uses 200psi more then you every 20 minutes in 40 minutes thats 400 psi more then you for my tanks thats 13.8 cu ft of gas

My gas plan looks like this . strat 3500psi - 500psi = 3000psi.
turn around point 2200psi exit 1400psi +500 =1900psi So if all went well i'm out of the water with 1900pst or 110 cu ft of gas

I dive twined 120 cu tanks

 

[budgy]

Hi Uncle Pug,
The training plan was that if I run out air for any reason, I could buddy breath or more recently use my buddy's octopus. However I find in practice I am often diving with people that are novice or though qualified, appear oblivious to my presense and lead me to believe, that though they may also be in the water, I am often diving solo.
The situation where I breath out and when I breath in the reg locks and there's no air, is probably never going to happen. I think if I was trying to keep up with a speedy oblivious, and had difficulty, he would be out sight before I could catch him and never know I was gone. I like the convenience of a small tank which I can swing over my head to put on, I have considered getting small independant twins, or the other option the pony. Maybe its just a desire to buy another unnecessary gadget.