Rookie Diver mistake: uncontrolled ascent

[By9468840]

hi everyone. just wanted to share my experience.
I currently have about 27 dives under my belt. At my 6th dive, I was in calm waters with minimal current and good visibility with my dive buddy (my wife with +80 dives).
I must say I was pretty excited to hit -18m for the first time and wanted to ascend a few meters back up to level off with my buddy, at around 15m depth. Unfortunately the only way I could think of (the laziest way) was to add a tiny bit of air in my bcd. next thing I remember is my wife looking at me with " wtf are you doing?" kind of look and she was around 5m BELOW me. Before I realized what was going on, I surfaced. The entire dive group was ahead of us and no one except my wife realized that I surfaced from 18m up like a rocket. I did not panic, looked underwater and saw my wife signalling if I was ok. I was fine but I lost all my confidence and joy to continue the dive. Luckily i close to the boat so did a nice comfy surface swim to the boat with my wife.

Lessons Learned:
- never inflate the BCD before ascend. I later talked to the DM about this. Now got it figured out .DUmping tiny bit of air off bcd and kicking upwards seem to work perfectly fine. Obviously my OW instructor never talked to me about how BCD air inflates with ascend if you dont dump a bit.
- remember to use the quick air dump valves on the BCD in such cases. I was desperately trying to use the inflator hose to dump air but it didnt seem to work efficiently in certain positions. I totaly forgot that i could pull the strings on the dump valves.

 

[Mudd]

You're also not giving yourself enough credit here: You did something very smart - played it safe and went back to the boat rather than go back down and continue the dive.

You'd be surprised how many people would go back down and potentially risk their own health.

 

[meagicano]

When I got back in the water after a long absence I started ascending quickly on my first dive out. It wasn't from as far down as you - more like 20ft (versus 18m) - but I just flipped myself upside down and finned as hard as I could while trying to find the dump valve.

I should have tested all my dumps with myself in different positions after being out of the water for so long because my muscle memory wasn't really there.

After we got out, my buddy said he was really impressed I started swimming head down to try and stay under water because he usually dives with his wife and she just kind of panics when she starts to float up.

Anyway! Good call on not going back down. It's better to be safe than sorry, especially if things went as fast as it sounds.

 

[spectrum]

By9468840,

I agree staying topside (for the day) was the thing to do.

The fact that air rises to the highpoint in the BC bladder and that it is the dump valve at that highpoint you must use needs to be come intuitive. This isn't something you will do right just by remembering that there are multiple dump points. The inflater must be held high to vent effectively. Think Statue of Liberty, not chicken wing.

With a few more dives you will come to sense that "getting positive" state and it will be natural to activate the correct dump based on your position.

The expansion of gasses on ascent is an effect of Boyle's Law, was that not mentioned in your training? Another result had you held your breath would have been potentially fatal lung over expansion.

Pete

 

[Mudd]

When I got back in the water after a long absence I started ascending quickly on my first dive out. It wasn't from as far down as you - more like 20ft (versus 18m) - but I just flipped myself upside down and finned as hard as I could while trying to find the dump valve.

I should have tested all my dumps with myself in different positions after being out of the water for so long because my muscle memory wasn't really there.

With you on this one: this season I was making conscious decisions to look for my dumps all throughout the dives from different angles. I want to be Quickdraw McGraw if/when the necessary time comes.

 

[tstormdiver]

It can be OK to add a tiny bit of air to the BC to get yourself neutral (if you are not already, though you should be). At that point, you should have to kick a little to get your ascent started. The expansion on air in air spaces (including the BC & the body) upon ascent, is critical & should have been addressed in your OW class. You can use the quick dumps it certainly helps, but you can also empty your lungs to help. As you gain experience, you will learn to more effectively get rid of excess air, before it becomes a problem. Generally, if you are getting into a run away ascent,.. it may be too late (can't hurt to try, though). I'm lucky, I have very sensitive ears that equalize very easily. I can tell when I change depth even .3 m up or down... That clues me in to when to let air or add air to the BC. Big thing is,... unless it is an emergency (& the only true emergency is running out of air- which should never happen if you plan your gases properly), take your time ascending & don't get into a hurry.

 

[openmindOW]

just wanted to share my experience.

Thank you for doing so, 9468840.

You have nothing to be embarrassed about. You made a mistake, as we all have. And you learned from it.

Keep diving.

 

[dumpsterDiver]

It can be OK to add a tiny bit of air to the BC to get yourself neutral (if you are not already, though you should be). At that point, you should have to kick a little to get your ascent started. The expansion on air in air spaces (including the BC & the body) upon ascent, is critical & should have been addressed in your OW class. You can use the quick dumps it certainly helps, but you can also empty your lungs to help. As you gain experience, you will learn to more effectively get rid of excess air, before it becomes a problem. Generally, if you are getting into a run away ascent,.. it may be too late (can't hurt to try, though). I'm lucky, I have very sensitive ears that equalize very easily. I can tell when I change depth even .3 m up or down... That clues me in to when to let air or add air to the BC. Big thing is,... unless it is an emergency (& the only true emergency is running out of air- which should never happen if you plan your gases properly), take your time ascending & don't get into a hurry.

LOL.. I have had MUCH bigger emergencies underwater than having nothing to breathe!! Where do you come up with this stuff?

 

[openmindOW]

The expansion of gasses on ascent is an effect of Boyle's Law, was that not mentioned in your training?

Pete, i regret to say that Boyle's Law is not emphasized in OW classes by some agencies.

Even worse, Divemaster Programs are watering down their physics requirements.

 

[LakerPride]

I made the same mistake in my first year of diving I was in Seychelles, my original OW course was taught over two days by a retired Brit living in a small hut on the beach in Phuket, and I was a young (18 y/o) cocky Marine. So either he failed to mention Boyle's or I didn't care enough to listen, I knew it all at that point obviously! I was using my BC like an elevator, took a few mistakes to figure out that wasn't the proper way to do things. Not to mention I didn't dive for a long time and retook the OW and AOW as a 27 y/o and picked up a lot I had missed the first time around. Glad you learned and nothing adverse came of it.