Water in regulator at depth causing panic

[tursiops]

for a ppo2 of 0.2 at 4atm it's not air.

Silly. What's the point?

 

[Wibble]

Of course for a ppo2 of 0.2 at 4atm it's not air. So i's ether a hypoxic mix, or one breath, where oxygen is already used up.

Please sir, sir….

At 1ATA it’ll be 20% / 4 = 5% oxygen

5% oxygen is the gas used down to a PPO2 of 1.4**. Over to you Mr Dalton..
Pressure = Dose / Mix = 1.4 / 0.05 = 28ATA = 270m = 885.826772 feet!


** PPO2 of 1.4 at that depth is a little high…

 

[Raphus]

Please sir, sir….

At 1ATA it’ll be 20% / 4 = 5% oxygen

5% oxygen is the gas used down to a PPO2 of 1.4**. Over to you Mr Dalton..
Pressure = Dose / Mix = 1.4 / 0.05 = 28ATA = 270m = 885.826772 feet!


** PPO2 of 1.4 at that depth is a little high…

C'mon.. it was an example to show, that going shallower doesn't increase the oxygen, as someone said before. And that a mix perfectly fine at depth is not very fine, when going shallower. Exactly what happens when free diver get shallow water blackout.

Don't know what's the problem..

 

[boulderjohn]

The deepest real life submarine escapee that survived a free ascent with no equipment that I am aware of was from 200 ft and he was bleeding from the mouth and nose at the surface.

If I recall correctly, an escape hood is used by the US Navy for depths less than 300 feet and there is a newer encapsulating suit designed for 600 ft.

Look for US Navy videos from the 1950s, when they were first doing it, and you will see people doing it with absolutely nothing but what amounts to a snorkel vest. One of them references British Navy successful attempts from 300 feet.

Today they do use more specialized equipment. The point is that they were successful from deep depths with no special equipment and after having fully exhaled before ascending.

 

[L13]

Look for US Navy videos from the 1950s, when they were first doing it, and you will see people doing it with absolutely nothing but what amounts to a snorkel vest. One of them references British Navy successful attempts from 300 feet.

Today they do use more specialized equipment. The point is that they were successful from deep depths with no special equipment and after having fully exhaled before ascending.

I was in the US Navy, on submarines. We were trained to fully exhale before starting the ascent. We were trained that there was no danger of running out of air (or oxygen in that air), the primary danger was the rapid expansion of inadequately vented gas bubbles (lungs, sinuses, ear, etc). The second greatest danger was the rapid compression of inadequately vented gas bubbles during the rapid compression as the escape trunk was flooded (normal air pressure in the submarine was usually slightly less than 1 ATA). Lung over-pressure was the most fatal risk specifically mentioned in the training.

 

[GJC]

Look for US Navy videos from the 1950s, when they were first doing it, and you will see people doing it with absolutely nothing but what amounts to a snorkel vest. One of them references British Navy successful attempts from 300 feet.

Today they do use more specialized equipment. The point is that they were successful from deep depths with no special equipment and after having fully exhaled before ascending.

Watched a couple on YouTube. Very impressive. I saw the one with the inflatable horse collar Mae West type.

From 60 ft it took just over 10 sec. to ascend. From 90 ft it was about 15 or 20 sec. That would be a fun ride to try if they built one at Universal or Disneyland, but I know that regardless of how carefully I prepped, my ears and sinuses would never survive that.

I can see that the likelihood of them getting bent is pretty low because they are exiting from a 1 ATM environment and had very little nitrogen accumulation time at depth. Therefore they can ascend fast with almost no nitrogen tissue load to cause bubbles. But the risk of barotrauma to lungs, ears and sinuses is way up there at those ascent rates. I think I'll keep carrying my pony bottle around with me in case my primary set up craps out at depth and just take my time ascending.

 

[kissonerga.ccr]

But the risk of barotrauma to lungs, ears and sinuses is way up there at those ascent rates. I think I'll keep carrying my pony bottle around with me in case my primary set up craps out at depth and just take my time ascending.

…and that’s the line of reasoning that had me start tec diving – doubles first, then ccr. Slippery slope, this

 

[kissonerga.ccr]

C'mon.. it was an example to show, that going shallower doesn't increase the oxygen, as someone said before. And that a mix perfectly fine at depth is not very fine, when going shallower. Exactly what happens when free diver get shallow water blackout.

Don't know what's the problem..

We were just messing with you, and also feeling a bit pedantic

I agree with your overall logic though

 

[Salt]

A simple layman’s experiment: Breathe normally. After your next exhale hold your breath and see how long you last.

My results:
0-10 seconds - no problem
10-15 - getting uncomfortable
15-25 - holding on
25-30 - gotta take a breath

So I would estimate you have about 10-15 seconds to think through and resolve an out of air situation underwater. Things go downhill from there.

Whether or not you can successfully ascend while exhaling from depth (will the expanding air be sufficient), I’ll leave for others to debate.

 

[Salt]

Two other items:

1) Is it feasible to inflate your BC to accelerate an ascent while exhaling?
- can the BC burst or will it vent itself
- and then there is the issue of DCS

2) Someone on another thread mentioned deliberately swallowing the water in your regulator (assuming you couldn’t or chose not to purge it); then you are able to breathe. That thought never crossed my mind before. Seems like a simple solution.