Uncontrolled Ascent Don't let this hapen to you!

[do it easy]

During OW classes, I'm sure I had to have been told that by pulling on the inflator hose, it also acts as a dump...

Not all BC have this feature! If you rent, be sure to check that it's there when you go over all the dump valves. I think the Scubapro's tend to have this as well as a "buddy dump" which is a little green triangle button at the top of the inflator elbow that will also dump the BC. I'm not sure if that's the name for it?

 

[jeckyll]

Glad you are ok!

I had a couple of 'unintended' ascents on my first 2 drysuit dives last weekend (non from below 33 fsw). I discussed this with my buddy for the dive (who happens to be an instructor as well) and she suggested breathing out as soon as you find yourself going up. While this didn't stop me from making another unintended ascent on the last dive, it did slow the rate. BTW, I'm using unintended because while my the computer wasn't very happy with me, the total ascent rate was somewhere around 15 seconds for 33 fsw. Much faster than desired, but not complete 'corking'.

For the person that mentioned swimming down, if you are wearing a drysuit that may not be the best approach, especially if you are using your suit as the primary method for controlling your buoyancy (I found that my biggest problem was not dumping some air from the suit early enough).

I like the idea of dumping a bit of air before starting the ascent to become slightly negative.

Bjorn

 

[Sideband]

As far as I can think of, swimming down is one of 2 options if in an uncontrolled ascent when using a drysuit for buoyancy. You can either swim down to recompress the air and try to vent once back in a bit of control, or you can get vertical and pull open the neck seal. The dry suit vents way too slowly to stop a runaway ascent.

Joe

 

[RonFrank]

The best thing to do is to go back down.

It is the same idea as going into a chamber, put the body back under pressure. The chances of DCS are going to be much less if you surface like a rocket, but then go back down to the original depth, and complete the dive with a safety stop.

I had an out of control ascent after maybe 15 dives as a result of divers below me (four of them). I was in their bubbles, at maybe 40 feet, and next thing I knew I was shooting to the surface. I just went back down to 40 feet and continued the dive.

It was not good that I had the ascent occur, but going back down immediately put my body back under pressure, allowed me to complete the dive, and do a proper safety stop at the end. I had no issues with DCS and this dive, and a 40-50 foot dive is not that deep, but certainly deep enough to get bent.

I'm not sure if this is covered in the PADI training (how soon we forget), but it is certainly a wise idea to complete a dive after an out of control ascent.

 

[jeckyll]

Quick question: Given that all dives base on the RDP are 'No-stop' dives, I guess going back down is not a necessity but instead just a safety consideration?

Thanks

Bjorn

 

[RonFrank]

Quick question: Given that all dives base on the RDP are 'No-stop' dives, I guess going back down is not a necessity but instead just a safety consideration?

Thanks

Bjorn

Just because they are *suppose* to be no stop dives, does not mean they can be Rocket ascent dives.

If you want to understand what can happen to someone who dives to 90 feet with ONLY 10 minutes of BT, and then Rockets to the surface, see the current Spiegal Grove thread where a Guy got bend doing exactly as I've described.

Safety stops may not be required in rec diving, but I don't know anyone who practices that unless diving off reefs in shallow water where the entire dive is basically at safetly stop depth.

If one get's below 30 feet for any amount of time, every model (computer) built will indicate a safety stop is necessary. IMO better conservetive vs. Bent/Hurt.l

 

[jeckyll]

Sorry, I was not advocating NOT doing a stop or 'corking'.

However, being new in a drysuit there is a distict possiblity that it will happen (talking about myself here from 30' not the original post from significantly more ).

Bjorn

 

[D_B]

You don't go back down to recompress after shooting to the surface/for possible DCI
Pretty sure It's in there too (PADI training)

DB

 

[lamont]

For recreational divers, the correct procedure is to get out of the water and to get on O2 if there is any question about DCS after an uncontrolled ascent.

If you haven't been trained in missed deco stop procedures, you shouldn't attempt them. Descending in a panic to try to do IWR after an uncontrolled ascent is a good way to increase the chance of a recreational diver suffering an injury. And if you did get a bubble lodged somewhere, you will probably be much better off trying to shrink the bubble with pure O2 than just descending down to 30 or 40 feet and trying to shrink the bubble with air or 32%. The extra atmosphere of pressure will compress the bubble, but the gas you're breathing down there is bad for trying to shrink it beyond that and the pure O2 on the surface is going to win in the long run.

 

[asaara]

IMO when one has mastered slow ascents, then one has generally very good control over buoyancy. Here's some tips from ScubaDiviing. They don't quite follow what I do, but it's a similar approach...

http://www.scubadiving.com/training/basic_skills/seven_secrets_for_safer_diving/1/

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

"Sound familiar? Instead, do it this way: When your buddy starts to make that figure 4, grab his tank valve with one hand to steady him, and at the same time check that the valve is fully open. (It's surprising how often divers forget.) With your other hand, you can grab the boat railing for support."

I do *not* like anyone, aside from myself, touching my tank valve. The only times I've nearly gone into the water with my tank off is when I've gotten everything ready, opened the valve, and someone else has come along while I wasn't looking and "helpfully" turned it off, causing me to put my gear on, give everything a test purge, and then have to contort around to get it turned back on again, or even better (thankfully, this only happened once), when I was about ready to do a back roll off the boat, some other "helpful" person decides to give that valve a twist, in the wrong direction...catching their mistake when I said "Hey, I thought I had that already open", luckily before I went in. As opposed to the approximately zero (so far) times I've forgotten to turn my tank on myself.

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.