What causes one to drown while doing SCUBA?

[MXGratefulDiver]

Bob, I am not joking. I was told to always inflate my bc to ascend. I'm SSI certified and it was pounded into me to do that. When I'd ascend too quickly, per my dive computer, I'd dump air a bit to slow down.
But, by inflating the bc, you could avoid the surface drowning situation like havnmonkey described, right? Can't sink with an inflated bc.
Angela

Angela, you need to discuss this with your instructor again ... I am fairly certain you misunderstood what he or she was telling you.

... Bob (Grateful Diver)

 

[CoyKoi]

If the buddy runs out of air and you can't inflate his/her BC to ascend and your system alone won't get you both up quickly enough... can you manually inflate the buddy's BC underwater? If so, do you use a half breath then pull of your reg, use another half breath to continue to try to inflate their BC?
Angela

If all else fails, drop your buddy's weights.

 

[CoyKoi]

I am not joking. I was told to always inflate my bc to ascend. I'm SSI certified and it was pounded into me to do that. When I'd ascend too quickly, per my dive computer, I'd dump air a bit to slow down.
But, by inflating the bc, you could avoid the surface drowning situation like havnmonkey described, right? Can't sink with an inflated bc.
Angela

NCSCUBADOOBA, if you are overweighted it might take a bit of prodding to get you started on an ascent. Try losing some of that lead. On your next dive, before you ascend, get neutrally bouyant. Take a deep, slow breath and pause for a moment (with your diaphram only, of course). You should start to ascend naturally. Kick slightly and prepare to dump air from your BC because you will be ascending at that point. Please, NEVER, NEVER inflate your BC to ascend. Inflate only when you're at the surface. We want you to be a safe, long-lived diver.

 

[NCSCUBADOOBA]

I thought more about this today. I distinctly remember being taught to hold one arm up above my head to check for obstruction and do a 360 on the way up and the other arm is also raised holding the bc inflator hose. I remember this b/c I wanted a dive computer and my instructor and I decided on a wrist mounted computer so I could see my ascent rate as I ascended. Now... in Belize, I never used my BC in ascend b/c it was a shallow dive and i just ended up surfacing and inflated on the surface.
I can see why it's a bad idea to inflate on ascent (coming up too quickly) but I also see how you can monitor your ascent rate with your computer. I will definitely attempt a non inflated BC ascent next time though!!!!!
Angela

 

[boulderjohn]

I thought more about this today. I distinctly remember being taught to hold one arm up above my head to check for obstruction and do a 360 on the way up and the other arm is also raised holding the bc inflator hose.

Angela, that is perfectly correct.

Remember, though, that there are two buttons on that hose: inflate and deflate. The reason you hold the hose up in the air is so you can DEFLATE the BCD as you go up. Air wants to rise, and if your hose is not up in the air, it won't vent properly. If you were supposed to INFLATE, you would not need to hold it up in the air.

 

[Charlie99]

.....) but I also see how you can monitor your ascent rate with your computer. I will definitely attempt a non inflated BC ascent next time though!!!!!

Actually, you will probably find it easier to control your ascent, at least over periods of 10 seconds or so, by looking at the little specks of junk in the water to control your instantaneous ascent rate. Come a complete halt for a while in the 30' range to get everything under control, and then using either the junk in the water or by looking at the surface, do your ascent to around 15'.

If you start off neutrally buoyant, you will find it easier to do the ascent while still in a horizontal position ---- this add to the drag in the up/down direction and makes controlling the ascent easier. Same thing for holding a constant depth for a 15' safety stop.

Just hanging at a 15' safety stop without finning or moving hands is really good practice in buoyancy control. Once you get the "hang" of that, then doing a slow ascent is pretty much automatic.

 

[Surf & Sky]

Yeah, I wish they would list "drowing due to______________________" you know? I feel like knowledge is power, and the more reading/research I do about diving and things that can be avoidable and how to handle a crisis the more questions that I have.

I think this would be great as well, but usually this is impossible. A coroner’s job is to determine the medical cause of death, not to investigate an accident. Accident investigation is considerably more difficult. Also, coroners don't necessarily know a regulator from a propeller.

Imagine an airplane accident. The coroner's job is relatively easy; the cause of death is generally "massive trauma," or something equally obvious. The only real medical question is whether or not drugs or medication where involved. The accident investigation team, on the other hand, has to try to reconstruct the events and determine what went wrong.

In the case of scuba accidents, there is no agency like the FAA to ensure that an accident investigation is done. Sometimes the scuba community can figure out what happened, sometimes we can't.

 

[Surf & Sky]

I see most students in pool sessions nailed to the bottom for their skills. When it comes time to do ascents, they are fighting negative buoyancy. Prior to doing ascents, I have them get neutral by adding air to their BC. Is it possible that this is what you were instructed to do?

This is a great point. As a beginning scuba student, I can attest to the truth of this. I just finished certification with a NAUI instructor, and this is how it went.

In class, we were taught the principles of buoyancy control and told to ascend/descend and do everything else with neutral buoyancy.

Next, I was given 20 lbs of weight as a starting point. Now, I am an athletic 170 lbs, and I am naturally a sinker. Plus, I am only wearing a 3 mil shorty. I did my pool session weighted this way. On the bottom (6'), the instructor deflated my BC. I'm sure this makes it easier to keep a large class corralled in one place to practice skills. To go up, we just pumped up the BCs "like an elevator."

A lot of beginning dives go that way. Deflate regulator, sink to bottom, work on skills, inflate regulator, ascend.

Fortunately, my instructor showed me how to do a real buoyancy check. It's not difficult, but it takes some time and attention. Turns out, I only need about 7 lbs with a steel tank. Also, during the later open water dives, we did a lot of buoyancy practice and swimming near the bottom emphasizing being neutral and ascending that way.

I can see how a careless instructor or a hurried program might give the wrong impression about BC use. For most people, if they are told one thing, and then practice something else, they are much more likely to remember the practice.

 

[LeFlaneur]

I believe that PADI teaches divers to squirt a little air in their BC to begin their ascent, and then vent as they go (not that I agree with this. Just saying...). Some new divers incorrectly interpret that as meaning to inflate their BC to ascend.

No, PADI does not teach this and made it very clear in my OW to vent on ascent.