Uncontrolled Ascent Don't let this hapen to you!

[Jim Lapenta]

I'll set this up as quickly as possible and give my thoughts, lessons learned, then would welcome anything I have missed or do not understand, but please leave out the "get more instruction" advice as I've already signed on for further instruction since this event convinced me it is the wise course of action. I'd like to learn from those level headed rational divers with more experience than I on this forum, in addition to taking a one on one with dive instructor.

One of the lessons learned is something I haven't seen discussed here and wasn't given much attention in my open water classes, but, in my opinion, ALL beginning divers should practice frequently dumping air from their dump valves and not just dump air from the inflate/deflate hose. Not having practiced this got me in real trouble, real fast.

On my 20th dive after open water certification I experienced an uncontrolled ascent from 57 feet all the way to the surface. Yep, it scared the you know what out of me. No injury, but I was lucky.

It was near the end of the dive and I had approx 1000 psi remaining. The dive to approx 80 feet had gone well and I was near the ascent line. While practicing bouency and trying to "hover" at 60 feet in a head up position, I rose slightly.

The slight rise quickly turned into a faster rise, at which time I tried to dump air from my "inflation/deflation" hose.

The ascent, very quickly turned into an expanding air in the BC scenario and I was unable to dump air fast enough from the "inflator/deflator" hose. In the panic that followed, did I hit the wrong button? I truely have no idea. The BC exapanded so rapidly, it leads me to believe that I hit the inflate button, but am not sure. The expansion could have simply been the result of the air in the BC rapidly expanding as I ascended.

The regulator remained in my mouth, but I can tell you that when the you know what hits the fan, don't be surprised if you don't remember if you were breathing, holding your breath, or exhaling. Since I didn't suffer a lung injury, I must have been breathing. Open water training instilled in me the thought to exhale if I'm out of air, but didn't prepare me for a rapid ascent, except to avoid one. laugh

Lessons learned.

1) just when you think you are becoming a capable diver and are getting comfortable, you might need to rethink that overconfident attitude.

2) check weighting. I could have been overweight, which would have required more air in the BC for proper bouency at 60 feet, which adds fuel to the expanding air fire.

3) practice dumping air not just from inflator/ deflator hose, but from BOTH dump valves. In my case, I had never dumped air from them since the swimming pool session and couldn't find them quickly enough when I really needed them. Why do open water courses not require this to be practiced over and over?

4) get control of an ascent quickly, don't let it even get slightly out of control. I was simply amazed at how fast an ascent can get totally out of control, thinking I would just deal with the unplanned slight rise by remaining in a head up position and dumping air from the inflate/deflate hose.

5) and this is just a question from a very inexperienced diver. Why in the heck do BC's have an inflator button positioned very close to the deflator button? Am I missing something here, or is this a fairly stupid design flaw? When needed quickly it is way too easy to hit the wrong button. This issue, of course is meaningless if one regulary dumps air without using this hose.

6) I now chose to think of the inflate/deflate hose as primarily an INFLATE hose and chose to think of dumping air, at least once at depth, from the dump valves. Am I wrong on this? Come to think of it, I don't every remember any of the dive guides I followed on my 20 dives using it to dump air once they are at depth.


Your thoughts very welcome.

On number one:good point. the more I dive the more I learn that I need to always learn more.
Number two:Checking your weighting is always important. and don't just check it. record it in your log. So many people seem to forget this. All I have to do is go back and see that on such and such day I was using this suit with this tank and needed this much weight. It's also possible you were underweighted and that's why the dump had so little effect along with the big gulps of air and perhaps hitting the wrong button.
Number three: They should but most don't. Me I like to play with knobs and pulls and such.I had my own gear for my first pool session and I played with all those dumps from the get go. It's now second nature to use whatever dump I need to for the position I'm in. Mostly I use my inflator hose because my buoyancy control is such that once I'm at depth all that's required is a SMALL burp(deflate) now and then or a SMALL pinch(inflate).Once down it's all breath control and/or inertia.
Number four: well said! This is especially true with a drysuit. In the head up position if it's a too fast ascent don't just use the button. Pull on the hose. this is your rapid dump and believe me it works.
Number five: I would not have it any other way. I like everything simple and close. Forefinger on deflator, thumb on inflator. Makes perfect sense to me. Ingraine this with practice, practice, and more practice. Eliminates unnecessary task loading. If I had to use both hands for inflating and deflating I would not be able to carry my light at night, my reel on search and recovery dives, my treasure bag full of the priceless objects I've collected , and it would make uw communication a pain.
Number six: That's because the guides don't use it to dump air at depth. It is used to add a little here and there on the way down and once at depth if your control is where it should be lung volume should be enough for minor changes in buoyancy. Go up a foot or so, bigger inhale. Go down a little, bigger exhale. And you probably don't notice it but if they do use it at depth to dump air they don't dump it. You just give it a LITTLE burp.:05: You would not notice it unless you are looking for it. I do it instinctively when I hit a place like an upwelling/downwelling or a cold/warm layer. A few degrees of temp if you are really neutral can change your depth quickly. cold patch you sink. warm one you rise. First time this happened I freaked a little until I realized that for this effect to take place I must be really trimmed out and dead on neutral. Then it's like "OH YEAH, BABY!" this is what's it's about. and then to correct it with a breath even better.
Finally: Excellent post, good observations, now remember them and use em as a tool for a better dive next time. Welcome to the underwater world!

 

[Snowbear]

While practicing bouency and trying to "hover" at 60 feet in a head up position, I rose slightly.

If by "dump valve" you mean the rear ones (rather than shoulder as some BC's have), if you are in a head up position, they won't help you.

I use my rear dump almost exclusively to vent the BC.... but it only works of I'm horizontal or head down...

4) get control of an ascent quickly, don't let it even get slightly out of control.

Yep! Better yet, anticipate and vent small amounts before you even start getting positively buoyant. Once you learn to use your lungs for fine control of your buoyancy, and anticipate the need to vent your BC, rather than reacting to positive buoyancy created by expanding air in your BC, you'll have no trouble at all ... and folks will make comments about you like you did about the DM's that didn't seem to use their dump valves at all

 

[Kevfin]

You have gone through the process of realizing something went wrong and then trying to find a solution. This separates a good/great diver from a mediocre/poor diver.

Do mistakes happen? Sure. But, it's how you deal with it. You're smart enough to think it through, come up with solutions, and then ask for help too. You will do a lot better next time and if you ever teach diving you will have something to pass on to your students.

Like everyone is saying, it's minor adjustments. It takes time for the result to manifest itself, even so when using breathing. If you are truly neutrally buoyant, you should hardly have to use your BC at all. The BC is not an elevator.

Reminds me of back in the day when we used horse collars with emergency C02 cylinders. Used for emergency ascents. Sometimes people would accidentally activate them --- talk about “going ballistic!”

 

[TSandM]

I agree with you about learning the location and use of your dump valves. I had a very scary incident with an uncontrolled ascent which occurred because I got my inflator wound up in my light cord (using new gear I wasn't familiar with) and couldn't raise the inflator to dump. I kept fighting with it instead of going for the dump valve. The big lessons from that one for me were: Be very careful when using new gear, until you have become quite familiar with it. Know the locations of your dumps and practice using them. They weren't even mentioned in OW.

 

[liberato]

One thing I am very thankful I was taught as a heavily weighted cold water novice was to not remain passive when caught in an accellerating uncontrolled ascent. Instead of trying to calmly vent air in a heads up position, immediately invert and kick down vigorously. If you have dump valves all the better but getting upside down first allows you to seize control of the situation. Nor does it require any finesse, which one probably does not have much of as a beginning diver anyway...

 

[markfm]

The invert and kick might not do the trick, depending on where you're at, if a whoops occurs. Really need to combine that with knowing your dump valves.
One of my first post-cert dives, drysuit, beaucoup weight, I had an ascent problem at the end of my safety stop. No harm, quite shallow, not all that rapid, I did breathe out

My takeaways from that evolution:
1) Suit for squeeze, BCD for inflation -- I know what PADI teaches, but if you accidentally put a bit too much air in your suit, then do the invert, no way to dump. The various rolls do work, but take reaction time and thought to execute.
2) As already said, learn your dump valves, use them. I did reach down for the back valve, but on the wrong side of my BCD. You can bet I've since learned where mine are, regularly use them all.

 

[RiotNrrd]

My LDS didn't even show me how to use the dump valves. Because of this, I went and bought a Mares Airtrim BC, because I didn't feel like I could relaibly get the Scubapro BC they rented me to release air. I had several times where I was fighting with the BC to control my buoyancy, and I knew there was air in the BC, but couldn't get it out.

The Airtrim has a nifty little pneumatic valve, but you know what? It doesn't always work that great either. I have NEVER had a problem using the dump valves, and if my LDS had shown me how to use them in the first place (instead of trying to make me use the oral inflator to release), I'd probably have a "normal" BC instead of the fancy Airtrim BC.

I like my BC, but no one else has a clue how it works. Consequently, when working with people on rescue drills, people fumble and look for the power inflator hose, then freak out when they can't find it. I'm guessing if I ever have a real problem, I'm going to slowly sink to the bottom, while my rescuer frantically searches for my inflator hose.

RiotNrrd

 

[dkktsunami]

Your 6th point is the answer. I use corrigated hose as inflator only and keep hose fastened to bc with a rubber figure- 8 snorkle keeper. It can be easily pulled loose in an emergency and is always in the same position, not dangling freely. I use shoulder and rear dump valves exclusively and they work much more efficiently. Also try to lessen need to inflate/deflate by improving bouyancy. You're on the right track.

 

[CDFDiveMaster]

My advice is for what it's worth....contrary to others. Dive a slight bit heavier than normal provided your BC can handle it, maintain awareness to dump valves, exhale in the event of an acsent problem and get into the habit od dumping air as you ascend. Familiarize yourself with the location of your dump valves especially the ones that hide at the bottom rear of most BC's and the ones that hide at the top rear of some BC's. Be SAFE.

Jay

 

[jonnythan]

My opinion is that diving heavy makes buoyancy control more complicated since you have to manage a larger airspace which changes more quickly with varying depth. It doesn't make things easier.