Uncontrolled Ascent Don't let this hapen to you!

[asaara]

If I'm signalling OOA, check my tank valve. Otherwise, I'm sorry if this goes against your buddy check rules, but hands off! Particularly if I can't see exactly what you're doing, as in that subversive valve twist while the victim's otherwise occupied with their fins.

While we're on the topic, same goes for other equipment. Like random people that just happen to walk over and start arguing with each other over whether my tank band is too low or too high, when in my opinion, it's just right...if I say "Could you leave it alone, please? That's how I always have it.", chances are that I'm going to have a pretty good idea of exactly where it's going to ride on *my* body and whether or not it's going to hit me in the back of the head. If a whole boatload of people could all agree that it was too low, that'd be one thing and I'd consider changing, but with no two opinions matching and no good reasons given, please don't touch my gear?

 

[TheRedHead]

Really, this is as simple as keeping horizontal and using your rear dump valve while slightly heads down to dump air. I've never seen anyone in a horizontal position rocket to the surface. I'm sure it is possible, but unlikely. If you are new and unsure of your bouyancy, do not go vertical until your hand is on the upline.

When I was in OW class during our first deep pool session, I was assigned a Zeagle Ranger small BC and we were told to descend and put air into our BCs. Well, I descend and give the inflator button a good push and took off. It's amazing what half filling a 45 lb wing can do. I developed a healthy respect for expanding air.

 

[serambin]

Some may say otherwise, but if you're diving a little heavy on descent, I think it can help reduce uncontrolled assents. First, because of the increased buoyancy created by air depletion and secondly, because if you're carrying a little more air in the BCD, it is easier to vent on assent.

I know with my BCD, the upper air connection between the right and left side is narrow, without using the right upper dump valve, the right side of the BCD is slower to give up it's air. In and emergency assent situation, this delay is unacceptable. By being a little heavy, the air escapes faster and the margin for error is greater. I might mention, my BCD has three total dumps, but I have never used the right lower dump.

I do understand that in a restricted environment, such as cave diving, this over weighting might not be the correct solution.

Stan

 

[asaara]

Some may say otherwise, but if you're diving a little heavy on descent, I think it can help reduce uncontrolled assents. First, because of the increased buoyancy created by air depletion and secondly, because if you're carrying a little more air in the BCD, it is easier to vent on assent.

But if you're diving light, you've got less air in your BCD to expand to start with...of course, hit the wrong button and you're screwed. I dive light so all my pull dumps tend to get a check during each dive anyways - strangely enough, even when using AL80s, if I'm a bit lighter than even I like to be, I still have more trouble descending initially than I do with ascending too fast or hovering for safety stops with no line.

Possibly because fins are incredibly inefficient when kicking in air. Does my descent make my butt look fat?

 

[Sideband]

Heavy is not good. There is a reason it is called being overweighted. The margin for error is much smaller, not greater. More weight equates to more air in the BC and that means a greater chance of runaway ascent due to air expansion. It also means you have to dump more air to stop the runaway ascent. If you were unable to dump air fast enough when weighted correctly you will never be able to dump fast enough when overweighted.
Do a proper buoyancy check and wear just the amount of lead you need to end the dive neutral with no air in your BC at 15'.

Joe

 

[pasley]

...You may have shot some air in your BC instead of hit the defaltor button and you probably gulped great breaths of air from your regulator and moved your fins which propelled you even further up. If you were wearing a thick wetsuit, the aircells sprang to life and became very buoyant again which further contributed to your ascent.

I seldom use my rear dump valve and it doesn't work well unless I'm finning down. I think it is very important to master buoyancy control before deep diving and I'm glad that you are ok.

Ditto, I belive this to be right on the money.

 

[RonFrank]

Can't say I'm too thrilled with the first part of the article...

I do *not* like anyone, aside from myself, touching my tank valve.

I was referencing the "Practice stopping your ascent" skill as that relates to this post.

As to others touching your gear, I guess that is a personal choice every diver must make!

If you are diving with a buddy you trust, than IMO doing a buddy check including touching your gear IMO is wise. I mean if you don't trust this buddy to have the skills to check your air, can you trust them as a buddy at all?

Many DM's on charters are going to check your air. I you don't like that, then I suppose tell them so. I personally make the decision on a case by case basis. If I'm buddied up with people I don't know, I may not ask for a buddy *check* but certainly do more in discussing where my second is, where my releases are, and make sure the dive profile and plan is stated, and then repeated.

 

[asaara]

IAs to others touching your gear, I guess that is a personal choice every diver must make!

If you are diving with a buddy you trust, than IMO doing a buddy check including touching your gear IMO is wise. I mean if you don't trust this buddy to have the skills to check your air, can you trust them as a buddy at all?

Many DM's on charters are going to check your air. I you don't like that, then I suppose tell them so. I personally make the decision on a case by case basis. If I'm buddied up with people I don't know, I may not ask for a buddy *check* but certainly do more in discussing where my second is, where my releases are, and make sure the dive profile and plan is stated, and then repeated.

I'd rather, if someone wants to check my air, they look at my pressure gauge and hit the purge on one of my regs a couple times, and stay away from my tank valve. That way if I'm wearing the gear, I can *see* what they're doing.

The way I'm used to doing things is that between the time they give you the full tank and when you hand it back over to get refilled when you're done diving, *you* are the only one that touches that tank valve (aside from using it to carry the tank, if you're helping/being helped with transportation, but never turning it on or off), if someone wants you to turn it off for transport after it's all hooked up, or on to see if you're full, they ask *you* to turn it on or off.

Pardon me for being territorial, but I *am* going to be the one breathing it... *snarl* *snap* *chomp* *happy pufferfish*

 

[mm777]

Good advice.....and succinct too.
~~~~~~~~~~~~~~~~~~

"Heavy is not good. There is a reason it is called being overweighted. The margin for error is much smaller, not greater. More weight equates to more air in the BC and that means a greater chance of runaway ascent due to air expansion. It also means you have to dump more air to stop the runaway ascent. If you were unable to dump air fast enough when weighted correctly you will never be able to dump fast enough when overweighted.
Do a proper buoyancy check and wear just the amount of lead you need to end the dive neutral with no air in your BC at 15'."

 

[D_B]

Exactly
You only "overweight" yourself at the beginnig of the dive, just the amount of weight in air you are going to be lighter by at the end of the dive. Having more than that causes your buoyancy to be more touchy

DB