large air bubble on a deep dive

[tech_diver]

I can look at the question as a kind of 'thought experiment.' It did remind me of a real life scenario.

My buddy and I were on a dive along a rock wall and swam up under a ledge that went back to an air pocket 60 feet down. It was large enough for us to poke our heads up into it. Seems innocent enough...

My buddy was about to take his reg out of his mouth and talk....
STOP!
Do not breath from air pockets! You have no idea what CO2 or fart gas has collected from previous divers. One good breath could be trouble.

Then...

My buddy is about lift his console into the air so he could look at his computer.
STOP!
A dive computer can sense air pressure just like water pressure but if the transducer goes between ambient air pressure and ambient water pressure, the transducer could possibly get damaged. I've never actually seen it happen but not going to test it with my computer.





Respect air pockets at depth.

 

[Powertrip]

I appreciate everyone’s comments. For those that haven’t seen my post in the military subforum, in addition to a deep interest in diving that I’ve had since at least high school back in 2000 or so I’m also an amateur writer (nothing published mostly just because I enjoy writing and I sometimes share what I’ve written with friends).

I’ve been soaking up everything I can about diving during the initial excitement now that I’m finally in a place in life where I can afford the time and money investment to jump right in (pun intended) which means re-reading my favorite Clancy book of all time, Without Remorse and re-watching The Abyss for the first time since childhood.

I had an idea for a story that involved divers going deeper than I ever would or would want to and while it’s fiction and a fantasy I didn’t want it to be something the enthusiasts I was considering sharing with to go ‘that’s not how that works!’ With the technical things because if I could get that right… it would keep the immersion and fantasy aspect of it from taking you guys out of the enjoyment. It’s what John wick got right and movies like the 80s action flicks the expendable was inspired by didn’t. And why those other movies would never be taken serious by gun enthusiasts.

The crazy events in The Abyss were MORE Believable, as crazy as they were could be swallowed BECAUSE Cameron put so much work into getting the details right, and it’s why that movie still holds up today.

I’ve been a firearms instructor since 2007. Another hobby that like diving has a smaller interest base, especially here in New Jersey where if I’d have responded to a question, even a silly one like mine was looking back on it I would have likely made someone feel self conscious the way I felt. No one wants to feel like the guy the instructor has to babysit, especially knowing they’re in a class for something that if you get it wrong (eg firearms or diving) someone could die

And regarding the ones saying if you think this was bad you should see the responses you’d have gotten on Facebook… there’s a reason I came to SB and not there

 

[Vicko]

Water "transfers" pressure, so a diving bell or a hypothetical air pocket are at the same pressure as the water enclosing them, well not dive bells because they are isolated from the ambient pressure but that is a whole other explanation. It does nothing to your tissue saturation that the water was not already doing.

 

[Marie13]

I appreciate everyone’s comments. For those that haven’t seen my post in the military subforum, in addition to a deep interest in diving that I’ve had since at least high school back in 2000 or so I’m also an amateur writer (nothing published mostly just because I enjoy writing and I sometimes share what I’ve written with friends).

I’ve been soaking up everything I can about diving during the initial excitement now that I’m finally in a place in life where I can afford the time and money investment to jump right in (pun intended) which means re-reading my favorite Clancy book of all time, Without Remorse and re-watching The Abyss for the first time since childhood.

I had an idea for a story that involved divers going deeper than I ever would or would want to and while it’s fiction and a fantasy I didn’t want it to be something the enthusiasts I was considering sharing with to go ‘that’s not how that works!’ With the technical things because if I could get that right… it would keep the immersion and fantasy aspect of it from taking you guys out of the enjoyment. It’s what John wick got right and movies like the 80s action flicks the expendable was inspired by didn’t. And why those other movies would never be taken serious by gun enthusiasts.

The crazy events in The Abyss were MORE Believable, as crazy as they were could be swallowed BECAUSE Cameron put so much work into getting the details right, and it’s why that movie still holds up today.

I’ve been a firearms instructor since 2007. Another hobby that like diving has a smaller interest base, especially here in New Jersey where if I’d have responded to a question, even a silly one like mine was looking back on it I would have likely made someone feel self conscious the way I felt. No one wants to feel like the guy the instructor has to babysit, especially knowing they’re in a class for something that if you get it wrong (eg firearms or diving) someone could die

And regarding the ones saying if you think this was bad you should see the responses you’d have gotten on Facebook… there’s a reason I came to SB and not there

I’m a fellow shooter (in IL, no less). Both diving and shooting have rules to follow.

 

[Dody]

Curiosity? It's a good thing for experienced people to see other's opinions.

I actually believe that the OP question is valid apart from the depths involved. From what I understand, he wanted to know if there is a pressure difference in a submerged cave and in an air pocket just above. The answer as he now knows is that there is none. It is pretty normal to ask such a question.

 

[rongoodman]

My buddy is about lift his console into the air so he could look at his computer.
STOP!
A dive computer can sense air pressure just like water pressure but if the transducer goes between ambient air pressure and ambient water pressure, the transducer could possibly get damaged. I've never actually seen it happen but not going to test it with my computer.

This makes no sense at all. You take your computer out of the water after every dive and re-pressurize it the next time you jump in.

 

[Robert H. Diver]

.

 

[tech_diver]

The concern about the computer is that the air pocket is pressurized beyond sea level. It's going from a pressurized water environment to a pressurized air environment.

Like I said, I never saw it happen, but didn't want to try it. I think the first time I heard it was from one of the computer manufacturers.

 

[tech_diver]

The concern about the computer is that the air pocket is pressurized beyond sea level. The transducer is going from a pressurized water environment to a pressurized air environment.

Like I said, I never saw it happen, but didn't want to try it. I think the first time I heard it was from one of the computer manufacturers.

accidental double post

 

[Powertrip]

I’m a fellow shooter (in IL, no less). Both diving and shooting have rules to follow.

Never felt like I implied they didn’t. I spent the first thirty years of my life living in Champaign Illinois btw.

It’s hard to know exactly where you were going via text but your comment sounds like you’re saying in addition to my actual comment, that I asked for the responses I got… if I’d said something like ‘hey getting my OW soon then I’m gonna go do some solo cave diving. But if I dip my head up into an air bubble will my head explode?’ I’d say yes I asked for some ribbing and a handful of ‘guess we will be reading about this guy in the obits’

But I didn’t say that. I asked a hypothetical question because I’m ignorant of the science and was honestly shocked by how some responded

As a fellow shooter, I’m sure you’ve had friends with absolutely zero knowledge of firearms beyond movies and the news ask some questions that made you roll your eyes and go ‘oh my god…’ I know I have. But say one of your girlfriends went to the range and made the mistake of saying clip instead of magazine got a response similar to what I first got here and that turned her off from guns, I think you and I would both agree that who said it did a disservice to her and the gun culture as a whole. For some people, the first time they interact with the gun community determines how deep they pursue it. And I’d hate for someone to turn away from something that could one day save their life

I will say, I got my answer. And if I’d just gotten the science part of it I would’ve realized I knew the answer. Because it was exactly like the scenes in Deep Blue Sea where when pressure was lost the room filled. And that after sleeping on it I was less put off by the comments but not every person who comes here and asks a question like that is gonna stick around after that which is a shame