almost died

[MASS-Diver]

The shallower you are, the MORE risk you are at for DCI (overexpansion injuries). This is simply based on pressure differentials for a given change in depth. Ascending from 15fsw to the surface (case 1) is a .5atm pressure change, the same as ascending from 100fsw to 85fsw (case 2 - hypothetical). In case 1, the gas in your lungs expands by 50% (using the ideal gas law that you learned in your OW course), whereas in case 2, the gas expands by 12%. Which do you think is more likely to pop your lungs?

How about case 3- 100' to surface? Most run away ascents with new divers do not stop untill that person hits the surface. Being deeper puts you at more risk.

 

[Ayisha]

The shallower you are, the MORE risk you are at for DCI (overexpansion injuries).

Not exactly true. If this were a true statement, then ascending from 2 feet would be extremely risky for DCI.

Now, if you're talking about a quick ascent from 33 feet to the surface, where the pressure is being halved, then I absolutely agree with you. The first 2 ATA's represent the most risk for lung overexpansion injuries, compared to the less drastic pressure changes at greater depths.

But from 15 feet? Sorry I don't agree with you. If that were true, then all the newbies who fly to the surface after their safety stops should have DCI. Did I say that it was impossible? No. Re-read the post. I said that it:

can put you at risk of DCI, but it is unlikely from 15 feet.

 

[Scuba]

any feedback from you guys?

What you did right.

You were shallow. It is the safest depth to practice skills and gain basic dive experience. If you feel uneasy, you can easily surface at any time. If something goes wrong, you have a better chance of getting out unharmed.

You had options to deal with events, was aware of some of them, and was able to use one of them under pressure to survive unharmed. You always want at least two or more options to deal with events. Needless to say the more proficient you are at utilizing them the better the chance of success under stress.

It is safest to learn and practice under good supervision. Aside from that, think ahead to identify and mitigate the risks. Keep things simple. Progress is made one step at a time.

 

[Cacia]

Punisher, Do you feel punished yet?

I have done many sketchy things learning new hobbies....Sorry, my comment looked kinda mean to me today.

One thing I like to do is share air on a regular basis with anyone who will be a regular dive buddy. The perfect opportunity to work on this, I have found, is at the safety stop. Three minutes is a long time when you are just waiting around. This is a good place to refine buoyancy control also.

I guess you are officially initiated!

 

[mpenner]

Not exactly true. If this were a true statement, then ascending from 2 feet would be extremely risky for DCI.

Now, if you're talking about a quick ascent from 33 feet to the surface, where the pressure is being halved, then I absolutely agree with you. The first 2 ATA's represent the most risk for lung overexpansion injuries, compared to the less drastic pressure changes at greater depths.

But from 15 feet? Sorry I don't agree with you. If that were true, then all the newbies who fly to the surface after their safety stops should have DCI. Did I say that it was impossible? No. Re-read the post. I said that it:

Ayisha,
I'm glad that we mostly agree! But there are a couple of things I'd like to clear up.

Not exactly true. If this were a true statement, then ascending from 2 feet would be extremely risky for DCI.

Ascending from 2 ft (1 atm + a little bit) to the surface (1 atm) is not very much. So you are correct.
I suppose I was making a bit of a blanket statement when I said 'the shallower you are'. I was trying to illustrate that a depth change of 15 ft is much more significant when you are only AT 15 ft, compared to when you are at greater depths.

But from 15 feet? Sorry I don't agree with you. If that were true, then all the newbies who fly to the surface after their safety stops should have DCI.

I would assume that most of them are breathing or at least exhaling as they ascend (screaming, maybe? ). But the fact remains that the gas you had in your lungs at 15 ft expands by 50%. If you plan on holding that in, well, your lungs are likely not going to be that elastic. There have been cases of DCI in swimming pools. On the other hand, doing a polaris from 100 ft, IF you're exhaling, will probably NOT give you a lung overexpansion injury (but you're risking DCS).

I guess we're nitpicking. Don't hold your breath if you're breathing compressed air!

 

[Ayisha]

Ayisha,
I would assume that most of them are breathing or at least exhaling as they ascend (screaming, maybe? ). But the fact remains that the gas you had in your lungs at 15 ft expands by 50%. If you plan on holding that in, well, your lungs are likely not going to be that elastic... Don't hold your breath if you're breathing compressed air!

mpenner, I believe that you have misunderstood. Who has supported ascending while holding their breath in this thread? No one! Punisher stated from his very first post that he exhaled as he ascended, and he has asserted that repeatedly throughout this thread. It appears that you have not read this thread in its entirety before responding.

I referred to punisher's admission that he held his breath while trying to retrieve his reg, and then his rapid ascent, which he had already stated was while exhaling. I told him that DCI was not likely for his profile, but it was possible. This is KNOWING that he said he was exhaling during his ascent. Holding his breath while ascending has never been an issue on this thread.

Also, way back on page 4:

punisher wrote: Did you too read wrong and asume that I held my breath while ascending?

My answer:

Nope. I never mentioned holding your breath while ascending. I simply mentioned holding your breath when it happened and then the rapid ascent that you described.

Even if you are exhaling, it is still possible to have a lung overexpansion injury, but as we said, not likely in your situation. If the lungs are expanding faster than the air is being released, and there is nowhere for the air to go, you can have a lung overexpansion injury. So if you are having an extremely rapid ascent, and exhaling only slightly, it is possible. If you have asthma or shortness of breath, this becomes a real issue. So don't kid yourself. Exhaling during a rapid ascent greatly decreases your chances of a DCI, but it is not a guarantee.

Hmm, not only have I NEVER said that holding your breath while diving is ok at ANY time, I have said that even exhaling during a rapid ascent does not guarantee that you will not get DCI - AND if you have compromised lungs, it could potentially be more of a problem. Vastly different from your belief that I said that ascending while holding your breath is ok. ????

Your posts make no sense whatsoever.

 

[mpenner]

...vastly different from your belief that I said that ascending while holding your breath is ok.
...Your posts make no sense whatsoever.

Wow...
My apologies to anyone who took offence to or misunderstood my posts.
To rephrase my original point which was really kind of moot:
A rapid ascent (breath-hold or not) will put one at some risk of lung injury. To assume that because the ascent is taking place from a shallow depth (15 ft) the risk is small is unwise, simply because of the increased effect that small depth changes have on gas volume at shallow depths.

I'm new to this board and honestly didn't expect such an aggressive response.

 

[markfm]

mpenner -- just your lucky day, I guess
The overall lesson, for one and all, is understanding P1V1/T1 = P2V2/T2. It pertains to lung overexpansion (lung V tries to change based on the ratio of pressure change) as well as "short fill" questions if your tank has been stored in the cold or you enter cold water (pressure change based on the ratio of temp, since the tank V is inelastic).

 

[Ayisha]

Well, if it was phrased that way in the first place, then no offence would have been taken.
If I state something, I will take full responsibility for it. If I am accused of saying something I did not say, I will make that known. That is me, diplomatic or not. :11ztongue

 

[Rec Diver]

this was my first near death...it was yesterday...ft wetherill, RI. solo dive around noon. dive flag string had too much slack I would think. it came over my rt.shoulder, and in front of my face. wave pulled flag buoy up. string yanked reg out of mouth. down 15ft at this time. held breath and leaned right to regain my reg. 2 or 3 tries, gave up, and then started swimming up fast as I could...all the while trying to exhale a little air as I swam up...scared sh_tl_ss fearing DCS. reached surface and then inflated BCD. waited to die or something...nothing yet. so I took up the slack on my flag. dropped down to 6 ft and headed back to shore. 10 minutes away.

one of my mistakes was not realizing that when sweeping for the reg, don't expect to feel it in my hand. I suspect that when I swept the first time, it was right between my bicep and chest. thats where it normally ends up when I practice it. didn't remember that under distress.

another mistake was not grabbing my secondary reg which is a ps2. didn't remember that I even had a second reg. therefore am now buying a pony with reg setup. ps2 is now considered 3rd reg.

and according to some of you, most important mistake was going solo to begin with.

I think I owe it to my loved ones and to the dive comunity not to be another statistic. hurts the family real bad, and has negative impact on diving industry.

any feedback from you guys?

don't hold back by the way

You have got to be joking! A near death experience? Sounds like you just panicked.