How deep?

[spector39]

Hello. I'm sure these have been asked before, but couldn't find an answer with search.

#1 Assuming you run out of gas, what is the max depth one could be at to safely make it to the surface before losing consciousness? I realize it can depend on the person's lung capacity and other factors so I'm looking for more of a "ballpark" answer based on the average diver.

#2 Similarly, if you have to get to the surface quick, what is the max depth one can be at to make it to the surface without getting severely bent (as in requiring prompt medical treatment?)

Thanks!

 

[Stujiro]

20 feet? These questions are sort of like how fast can I drive while drunk and still make it home from the bar. Sure maybe you make it but geez let's not try it okay?

I'm saying 20 based on entry level cork depth. You see a lot of this during check out dives.

 

[DCBC]

Hello. I'm sure these have been asked before, but couldn't find an answer with search.

#1 Assuming you run out of gas, what is the max depth one could be at to safely make it to the surface before losing consciousness? I realize it can depend on the person's lung capacity and other factors so I'm looking for more of a "ballpark" answer based on the average diver.

#2 Similarly, if you have to get to the surface quick, what is the max depth one can be at to make it to the surface without getting severely bent (as in requiring prompt medical treatment?)

#1 This depends largely upon the diver's state of mind and amount of gas in their lungs at the time of the emergency ascent, their fitness, etc. I believe that I have been capable of 200' free ascents in my time and believe most people can do a 200 foot positive buoyant ascent successfully if a decompression chamber is readily available. The surface is King. Without the surface, you die. If you make the surface you may live, so the surface should always be your goal...

I train my basic students to do a swimming ascent from 50 feet and Advanced Divers 100 feet. The diver needs to maintain his or her capabilities.

#2 It depends upon gas absorption; time at depth. As this depends on the time and mixture, your question cannot accurately be answered with the information available.

 

[spectrum]

Some where around 50-60 feet is where people find that a successful CESA becomes very difficult.

As for getting bent It depends on a slew of factors including how deep you are and the dive profile up to the moment. "In the day" 60 FPM and no stops was the standard for dives with no deco obligation. Faster than that and you are on your own.

Not venting effectively and getting an embolism is a very possible consequence in an incident such as you describe. It could also be the most likely to be fatal.

The best management of these situations is avoidance.

Pete

 

[MaxBottomtime]

Escape from submarines have been successfully made at depths of 300 feet.
AmericanHeritage.com / Why the Best Technology for Escaping from a Submarine Is No Technology
You have to remember to exhale all the way to the surface, but it can be done.

 

[knotical]

In the (hopefully unlikely) event that you do run out of air at depth, you will be able to get some more air from your cylinder as you ascend because the ambient pressure is decreasing. So keep that regulator in your mouth.

 

[Superlyte27]

I posted an article about a submarine that went down in like 270' of water. 71 passengers, including people who were not mariners made it to the surface from 270'. No fatalities.

 

[LeadTurn_SD]

Hello. I'm sure these have been asked before, but couldn't find an answer with search.

#1 Assuming you run out of gas, what is the max depth one could be at to safely make it to the surface before losing consciousness? I realize it can depend on the person's lung capacity and other factors so I'm looking for more of a "ballpark" answer based on the average diver.

#2 Similarly, if you have to get to the surface quick, what is the max depth one can be at to make it to the surface without getting severely bent (as in requiring prompt medical treatment?)

Thanks!

I think it is more important to understand and remember that very deep CESA's have been accomplished without injury in emergency situations.

That knowledge alone goes a long way... Knowing it can be done may be enough to keep you from giving up and allow you to stay calm and in control enough to reach the surface.

My deepest CESA (swimming ascent in basic OW training) was 60'. I felt I could have gone quite a bit deeper; a 100' swimming ascent would have been harder but possible for most of those in my OW class.

Best wishes.

 

[berk]

I train my basic students to do a swimming ascent from 50 feet and Advanced Divers 100 feet. The diver needs to maintain his or her capabilities.

Amen. If you can't make it up from there you shouldn't be diving there. Another reason to stay within NDL's.

If you're at a depth deeper than you can swim or start to push past a trivial amount of deco, an ESA is no longer an option at all. Then you are in an overhead environment and better have the gear and training for that. (or a chamber on deck)

Good reasons to keep in shape and go back to the surface for a snack, an interval and a fresh tank. Two dives can be better than one for a recreational diver.

-matt

 

[Stujiro]

I think i might have read this a little wrong. I was thinking buoyant ascent, and not CESA.

If you read the shark attack story by Bret Gilliam i think he did a nearly 400 foot free ascent. Though he was severely bent he did survive.

A great story but not for the faint at heart.

Shark Attack! | Divers' Blogs