ending a dive

[Thalassamania]

I'd say the sensible diver is either prepared to make a free ascent from the deepest part of their dive, or they are accepting the presence of a ceiling that they can not make it through and should be diving in a technical diving mode. Some instructors use the: "twice the depth you can free dive to," criterion.

 

[aquaregia]

I'd say the sensible diver is either prepared to make a free ascent from the deepest part of their dive, or they are accepting the presence of a ceiling that they can not make it through and should be diving in a technical diving mode.

Does this stand if you're diving with a trusted buddy with whom you've drilled air-share ascents?

 

[spectrum]

Ny the time you find your buddy or react to any given situation you could already have saved precious seconds.

In an instant you should know if your buddy is in reach. Pre-dive you should know that they have an alternate second stage (or redundancy) and even sharing a second stage is an option. I should hope that your buddy is not concurrently having a gear failure and/or be OOG as well. In other words if you are diving with a buddy your next breath is a pretty sure bet. If you are able to go the buddy route you have reset the clock and should be able to make a safe, normal direct ascent. That's hardly a loss of precious seconds

Lacking an accessible buddy you are dealing with a solo situation. Lacking a next breath a CESA and any complications that may arise from it are infinitely preferable to drowning on the bottom.

There is also something to be said for not abandoning your buddy on the bottom.

Pete

 

[DivemasterDennis]

I can second Thalasmania's response when you add both his threads together. First, a diver who uses properly maintained equipment and follows their dive plan and reads their gauges regularly will likely NEVER have a no air emergency. A diver who stay in close proximity to a buddy (and that is the whole poit of having a buddy) will always be able to acquire air from them. If for some unknowable reason, a true out of air emergency arises with no air available, every diver should train for that emergency. Things like exploiting any air in the bc, being reasonably able to slowly expel the last breath as you ascend, and so on, are skills that any diver can and should learn at some point in your training. As to the use of the term"criminal negligence," though, Thalasmania is incorrect. If there is a true out of air situation the diver alone is the negligent one in most cases, and in very rare occasions, it may be an equipment manufacturer or more likely the person who improperly serviced the gear, or the entity that rented out faulty gear. ( I've been an attorney doing civil and criminal trial work for over 33 years) Every diver needs to take responsibility for their skills, their equipment, and their activities.
DivemasterDennis
DivemasterDennis

 

[Thalassamania]

I can second Thalasmania's response when you add both his threads together. First, a diver who uses properly maintained equipment and follows their dive plan and reads their gauges regularly will likely NEVER have a no air emergency. A diver who stay in close proximity to a buddy (and that is the whole poit of having a buddy) will always be able to acquire air from them. If for some unknowable reason, a true out of air emergency arises with no air available, every diver should train for that emergency. Things like exploiting any air in the bc, being reasonably able to slowly expel the last breath as you ascend, and so on, are skills that any diver can and should learn at some point in your training. As to the use of the term"criminal negligence," though, Thalasmania is incorrect. If there is a true out of air situation the diver alone is the negligent one in most cases, and in very rare occasions, it may be an equipment manufacturer or more likely the person who improperly serviced the gear, or the entity that rented out faulty gear. ( I've been an attorney doing civil and criminal trial work for over 33 years) Every diver needs to take responsibility for their skills, their equipment, and their activities.
DivemasterDennis
DivemasterDennis

That's what makes a horse race and what a jury is for. Being out of air, for any number of reasons, is a rather predictable outcome of many things (and may be contributory negligence) but with the literature that is out that finds, for example, that to a 95% expectation of a pair of divers being able to share air successfully to the surface requires 17 repetitions of the skill in class (and, I'd argue, a similar number for free ascent training) when compared to the, "single, do it and move on to the next skill," approach that most courses offer, can be reasonably described as, "bordering on the criminally negligent."

BTW: "I've been an attorney doing civil and criminal trial work for over 33 years." That's called an "Appeal from Authority" (argumentum ad verecundiam) and is classified as a "Logical Fallacy." Be the same as me saying, "I've been an expert witness working exclusively on diver fatality and injury lawsuits for 28 years and I think that ..."

 

[aquaregia]

literature that is out that finds, for example, that to a 95% expectation of a pair of divers being able to share air successfully to the surface requires 17 repetitions of the skill in class

I tried to find something like this on Rubicon but couldn't. Can you point me towards anything?

 

[sambolino44]

I posted this idea once before. My buddy and I did some tests to see how far away we could get from each other, simulate running out of air (exhale and pretend you cannot inhale), and get to our buddy, get their attention (the buddy was expecting this), and do an air share. We were very surprised how close we had to be to each other to successfully carry this out without resorting to inhaling from our (supposedly empty) rig. Very surprised. It was a LOT closer than what we thought was a safe distance. I think most divers would also be very surprised at how close you have to be to your buddy for this to work out.

When you consider all the little things that could go wrong, like getting a "wet" reg on the share, or taking just a fraction of a second longer than expected to get your buddy's attention (or a million other things), that equates to another foot or so closer you need to be to your buddy.

We practice air sharing. We don't practice CESAs. I guess I'm just hoping I'll be able to do it if I have to.

 

[Thalassamania]

I tried to find something like this on Rubicon but couldn't. Can you point me towards anything?

Maybe Bachrach, A. and Egstrom G. "Human Performance Underwater." It might also have been one of the International Conference on Underwater Education proceedings.

 

[Thalassamania]

...

We practice air sharing. We don't practice CESAs. I guess I'm just hoping I'll be able to do it if I have to.

Hope is a hell of thing to hang your hood on.

 

[sambolino44]

Hope is a hell of thing to hang your hood on.

Are you suggesting that we should practice CESAs?