DumpsterDiver emergency ascent from 180'

[Schwob]

Not about what occurred with dumpsterdiver because I do not know if he could still draw air from his reg after the failure while bubbles still "blew", but curious:

If you have any such (at the point in detail unknown) major failure (single tank plus pony) and concluded it is bailout time, but can still draw air from the failed stage, which (in coarse distinction) is the more appropriate reaction and why and to keep it simple, lets say it's a solo dive, no buddy involved (leaning towards b myself to keep it simple, but curious):

a.) Switch to pony and shut down back gas to preserve in case it still might come in handy, start ascend and manage it such that it takes advantage of pony's air supply (e.g. slow enough and with stop if you can afford to (if the pony was sized appropriately, you can)

b.) Dont bother shutting down, but start ascend, draw backgas for as long as it comes and prepare to switch to pony only for when backgas stops...

 

[northernone]

It helps when you do a lot of apnea and you kind of learn you have about five to seven minutes before you black out from being hypoxic and about another 15-30 minutes after that where your epiglottis is locked down tighter than Fort Knox. Helps with the not panicking when you know youll probably be fine and worst case just do an uba and hope you end up face up at the surface.

UBA and coming to face up on the surface is why I'm still alive... However, it's worth noting in a public forum it's fairly easy to get in a situation where you can blackout in 2 minutes under reasonable circumstances. The quoted 5-7 minutes is quite ideal. Worse case is dead. Floating up with an uncompromised airway is a rather rare outcome. While avoiding panic is key and I agree with the point you're making I'm putting some caution on the likelihood of survival if you're counting on 5-7 minutes before blackout.

Regards,
Cameron

 

[blac86]

UBA and coming to face up on the surface is why I'm still alive... However, it's worth noting in a public forum it's fairly easy to get in a situation where you can blackout in 2 minutes under reasonable circumstances. The quoted 5-7 minutes is quite ideal. Worse case is dead. Floating up with an uncompromised airway is a rather rare outcome. While avoiding panic is key and I agree with the point you're making I'm putting some caution on the likelihood of survival if you're counting on 5-7 minutes before blackout.

Regards,
Cameron

Very true, especially in an emergency situation if your heart rate stays high and doesn't go into bradycardia you'll burn up available O2 rather quickly. I think the mantra for this thread is surviving emergencies requires calm thinking under pressure.

 

[northernone]

Very true, especially in an emergency situation if your heart rate stays high and doesn't go into bradycardia you'll burn up available O2 rather quickly. I think the mantra for this thread is surviving emergencies requires calm thinking under pressure.

I'm with you 100%. Panic is deadly.

Dive safe,
Cameron

 

[tbone1004]

@Schwob your pony has sufficient gas for your full ascent based on your gas planning strategy. In the event of a failure like that, you switch to the pony, shut down the offending valve, and make your ascent. If for whatever reason it really goes sideways you can open or feather the offending valve and finish it out, but better off to shut down and protect the tank because you did proper gas planning and have sufficient gas to get up from that depth.

 

[uncfnp]

Not about what occurred with dumpsterdiver because I do not know if he could still draw air from his reg after the failure while bubbles still "blew", but curious:

If you have any such (at the point in detail unknown) major failure (single tank plus pony) and concluded it is bailout time, but can still draw air from the failed stage, which (in coarse distinction) is the more appropriate reaction and why and to keep it simple, lets say it's a solo dive, no buddy involved (leaning towards b myself to keep it simple, but curious):

a.) Switch to pony and shut down back gas to preserve in case it still might come in handy, start ascend and manage it such that it takes advantage of pony's air supply (e.g. slow enough and with stop if you can afford to (if the pony was sized appropriately, you can)

b.) Dont bother shutting down, but start ascend, draw backgas for as long as it comes and prepare to switch to pony only for when backgas stops...

I would start my ascent and switch when needed. And the biggest reason for this choice is that I can not reasonably reach my valve for a shutdown. No reason to waste time and effort trying.

 

[tbone1004]

I would start my ascent and switch when needed. And the biggest reason for this choice is that I can not reasonably reach my valve for a shutdown. No reason to waste time and effort trying.

that arguably requires adjustment of your gear. The risk here is that depending on how bad the first stage failure is, water ingress can and will eventually fill the tank which will make it as heavy in the water as it is on land and that's a real bad day. No different than doing everything you can to prevent a CCR from flooding completely since it turns into a brick

 

[uncfnp]

Hmmm. Interesting dilemma. There is no gear configuration that will allow me to do a valve shutdown except sidemount. Tech and doubles divers tend to forget that it is not uncommon for single tank recreational divers to be unable to do a valve shutdown. I understand that even for BM doubles this can be a difficult (but required) skill. This is why I choose SM rather than backmount for doubles.

So tbone1004 what type of first stage failure would allow the tank to fill before a recreational diver could make a safe ascent? How often has this happened?

 

[TONY CHANEY]

well there are a few takeaway points here. One] don't plane a dive to 180', single tank with an al 13 pony, spearfishing and solo. two] if something happens then stay on the reg until it is depleted (which he did as you can tell by the time line at 4:19). three] ditch any equipment that is not needed for life support. Too many divers have been recovered with their catch, porthole, speargun, etc still attached to them.

 

[tbone1004]

@uncfnp I had the diaphragm come out of a first stage which would allow water ingress into the tank. Once the tank has completely emptied itself, the valve is also free to move and may get unscrewed.
Time it takes is a while, and I am unaware of any instances on OC where it has caused a problem because they usually get to the surface in time, but there are quite a few instances of a good amount of water being inside of a tank that was breathed down.

Why are you unable to do a valve shutdown? We require all of our students to perform this in the pool and use their ability to reach the tank valve as the height requirement for their rig. No exceptions. It is easier than reaching the isolator in doubles