Question about ascent incident

[Leejnd]

I just became certified a couple weeks ago, and this past weekend I went out for my first post-certification dives on a dive boat to Catalina Island (SoCal). There were a number of very experienced divers and DM's on board, who were all wonderful in helping me remember and improve my skills. Everything went fantabulous, until the third dive.

As a noob, naturally I'm still trying to get a handle on bouyancy. On our first two dives we were at 76' and 71', and I had very little trouble with it, managing to comfortably hover and change depth with my breathing. On my third dive we'd been down at 45' for about 25 minutes, and had ascended to 25' and poked around in the kelp there for about 10 minutes. But here I found bouyancy to be a bit more challenging. In addition to this, my fins are more bouyant than I was expecting, and at 25' they kept raising up on me when I wasn't moving forward.

After we'd been at 25' for about 10 minutes, I found that my fins were floating above me and I was having some trouble maintaining depth. I tried to vent my BCD, but I guess I didn't realize how inverted I was...I realize now I should have used the vent on the back, but I didn't. I thought I'd raised the deflation hose high enough and then pressed the vent button, and all of a sudden there were a bazillion bubbles around me, as if the earth had opened up beneath me and was burping out gas! I immediately started ascending and I couldn't stop. It all happened so fast, and the next thing I knew I was at the surface (with my buddy, an experienced diver, about 3 fin-kicks behind me). He immediately took me back down to 15', and checked me out to ensure I wasn't panicking or feeling ill (I was fine). We stayed there for about ten minutes, and then returned to the boat and surfaced.

Now, first allow me to request that no one bash me for whatever I did wrong. (I've seen a lot of that around this board.) Please remember I've only just been certified and this was my first dive trip since certification. My first two dives were with a DM as a buddy, and I was told I did everything perfectly. On my third dive I went with someone else who isn't a DM, but is very experienced. If I did something stupid, I'm sure I'm not the first new diver who has, and I'm hoping to learn from this.

So, here are my questions. First and foremost I'd like to know if I was truly in danger of DCS by having an uncontrolled ascent from 25'. I can tell you that I didn't hold my breath -- I was breathing normally, maybe a little rapidly from slight stress. But I never felt panic. I knew almost instantly what was happening and tried to spread out my limbs to slow me down, but it happened so fast. Could I have been harmed seriously from this ascent from that depth?

Second, was it of value to immediately descend to 15'? There were some differences of opinion on this -- some on the boat said that it would have made no difference, as any bubbles in my tissues would have already been formed; others said that if we did it quick enough it might have slowed down the development of bubbles.

Third, where did all those bubbles all around me come from?? Okay, so the air in my BCD must have been higher than the vent valve so it couldn't vent from there...I get that. But it was as if my BCD suddenly started free-flowing...from where? The moment I broke the surface it stopped and I was immediately able to vent, empty my lungs and descend, but I still have no clue where all those bubbles came from in the first place.

One thing I will say that I already learned from this incident is that I didn't panic...I knew something was going very wrong, but rather than feel fear (which I recall thinking would be useless!) my mind immediately went to my training, and tried to scroll through what I'd learned. I do hope that's an indication that I'll behave the same way if I encounter an emergency again.

I'd appreciate any input, so I can learn from this. Naturally I know better now than to try to vent my BCD from the deflation hose when I'm upside down!

Thanks,

LeeAnne

 

[Charlie99]

So, here are my questions. First and foremost I'd like to know if I was truly in danger of DCS by having an uncontrolled ascent from 25'. I can tell you that I didn't hold my breath -- I was breathing normally, maybe a little rapidly from slight stress. But I never felt panic. I knew almost instantly what was happening and tried to spread out my limbs to slow me down, but it happened so fast. Could I have been harmed seriously from this ascent from that depth?

Yes.

Second, was it of value to immediately descend to 15'? There were some differences of opinion on this -- some on the boat said that it would have made no difference, as any bubbles in my tissues would have already been formed; others said that if we did it quick enough it might have slowed down the development of bubbles.

If you were asymptomatic -- in other words, you felt normal, then it was a good thing to do. Particularly since you had a buddy with you, and you were only on the surface for a short while.

OTOH, if the situation is out of control, or you don't have a buddy, or you don't have sufficient air, the stay on the surface, get on the boat, notify the crew, and carefully monitor yourself. Perhaps go onto O2. If you have any symptoms you should also get on the boat, and start O2.

There is a procedure called "surface deco" in commercial diving. This is where divers that have a mandatory deco obligation are hauled to the surface, stripped of their gear, and then quickly shoved into a chamber sitting on the deck of the ship, which is then pressurized back down to depth. They must do this within 5 minutes of leaving their mandatory stop depth and heading for the surface. Your short pop to the surface and then back down is kind of like the same thing, but without nearly as high of loading, and probably much less than 5 minutes on the surface.

Third, where did all those bubbles all around me come from?? Okay, so the air in my BCD must have been higher than the vent valve so it couldn't vent from there...I get that. But it was as if my BCD suddenly started free-flowing...from where?

No offense, but my bet is that you were pushing the INFLATE button, not the deflate and the bubbles you saw were from the overpressure dump valve opening up. The only other way to get bubbles out like that would be if you were so grossly overweighted that you had your BCD more than half full and going up expanded the air enough to pop the dump valve. Note likely.

 

[Leejnd]

No offense, but my bet is that you were pushing the INFLATE button, not the deflate and the bubbles you saw were from the overpressure dump valve opening up. The only other way to get bubbles out like that would be if you were so grossly overweighted that you had your BCD more than half full.

Someone else suggested that, but I SWEAR I knew the difference! I'd been inflating and deflating it without trouble up until then...I agree that it would seem the most likely explanation, but I shudder to think I would have made such a boneheaded error!

LeeAnne

 

[cummings66]

Yup, you had to hit the inflate button and the bubbles came out the valve near the back bottom most likely if you were fins up.

You could have been hurt since you had been down deeper and you didn't say how long you were at this depth, but since you've reported no symptoms you're probably fine and I'd say be careful next time. If you don't notice something happening when it should stop and check it out, in this case you probably had your finger on the button for a short time and not the quick press.

 

[TheRedHead]

I think she hit both the inflatorr and purge - the old breathing off the power inflator trick. You are in more danger of having an embolism from a fast ascent than DCS after spending 10 minutes at 25 feet. Next time, dump from the rear, pulling the string towards your butt.

 

[Leejnd]

Yup, you had to hit the inflate button and the bubbles came out the valve near the back bottom most likely if you were fins up.

You could have been hurt since you had been down deeper and you didn't say how long you were at this depth, but since you've reported no symptoms you're probably fine and I'd say be careful next time. If you don't notice something happening when it should stop and check it out, in this case you probably had your finger on the button for a short time and not the quick press.

Yeah I did say how long -- 45' for about 25 min, then 25' for about 10 min. One thing I'm considering is, did I inadvertantly press both buttons...y'know, perhaps I was squeezing it too tight with my hand while trying to press the deflate button? That's something to think about -- I'll spend some time in the pool really practicing inflating and deflating.

LeeAnne

 

[Leejnd]

I think she hit both the inflatorr and purge - the old breathing off the power inflator trick. You are in more danger of having an embolism from a fast ascent than DCS after spending 10 minutes at 25 feet. Next time, dump from the rear, pulling the string towards your butt.

I'm starting to think you're right...that must be what I did. Honestly, I didn't even KNOW about the dump vent on the rear -- that wasn't covered in my class. (Yeah, it was PADI.) I do know about it now!

 

[TheRedHead]

One thing I'm considering is, did I inadvertantly press both buttons...y'know, perhaps I was squeezing it too tight with my hand while trying to press the deflate button? That's something to think about -- I'll spend some time in the pool really practicing inflating and deflating.

I think that's exactly what you did. And I don't think you were in any danger of DCS. It is just a matter of getting familiar with your equipment and you have the right idea about practicing. We all make silly newb mistakes.

 

[cummings66]

I missed the times and you're pretty much fine based on the times you gave, IMO you don't need to practice those buttons in the pool when you can do that in front of TV. You'll get that at the surface anyhow and the suggestion to use the string and pull is a good one. In fact I normally descend horizontally by pulling on my string. The inflate valve is the only one I use until I surface then I'll blow some air into it instead of using tank air for the BC. I try to avoid wasting Nitrox for my BC if I can.

To be honest I've made that mistake at the surface myself when I first started diving and it's not something I'd care to do at depth. After a few dives you'll have it solid especially if you stick to pulling the string to dump air.

 

[Bismark]

Glad to here you were okay. One quick question re: your floating fins. I could be wrong but I believe most fins would not be buoyant enough to cause your legs to float up. My guess, from the location of your dive, is that you were wearing a fairly thick wetsuit (7mm?) and it is not uncommon for relatively inexperienced divers wearing such suits to experience this problem. Moreover, as you ascended, your buoyancy increased, further making matters worse. Some people wear ankle weights (2lbs) and this can help however the majority don't so you can learn to keep your body position such that they should prove uneccesary. You will find that honing your diving skills in colder water, where you have to deal with more relative changes in buoyancy caused by thick neoprene, drysuits, and the like, will make diving in tropical waters a piece of cake. Keep this in mind as you keep diving and know that you are developing your skills in more adverse conditions than where most people dive. I guarantee that when you step off the dive boat in 85 degree weather, after doing 50 dives in cold waters that you will feel like you are Jacque Cousteau.