Gas Stuck Under Undergarments/one of those days

[GCullen94]

It has taken a while for me to write this post however it was a valuable lesson learned and a dive that could have been ugly if we were deeper.

This was a sunset to night dive in southern California, we had 9 divers split up in to 3 groups.

Group One
Brandon- Single cylinder, scooter
Tom- Single cylinder, Scooter
Andrew- Single cylinder, Scooter

Group Two
Larry- Doubles
Me- Doubles
Ryan- Single

Group Three
Monica- Single (had not been in the water in a while)
Steve- Doubles
Tom- Single

I changed undergarments for this dive to a DUI Polartec Powerstreach 300. This was my 7th ever drysuit dive (I had been in aluminum doubles for my last 34 dives and that's what I felt most comfortable in.) The plan for groups one and two was to go checkout a underwater monument for about 40 minutes at 60 feet and then move back into shore. Group 1 was going to a different place however our run times were the same.

We dropped down with group 3 navigating and group 2 following. We got to the monument as expected and the dive was normal. I noticed my flexibility was reduced with the new undergarment and my breathing rate was higher than normal. It didn't help the water was about 10 degrees warmer than expected. about 3/4th the way though I noticed Monica, who was right next to me, had gone inverted and turtled. She dug a hand in the sand to hold herself there. Steve and I righted her however her fin kicked my drysuit inflater right as we righted her. This caused my drysuit valve to start free flowing. I unplugged it and vented excess gas from my wing and suit at the same time. I use my wing for buoyancy and add just enough gas to eliminate squeeze.

I stayed where I was in the water column and reconnected my inflation hose the inflation valve functioned properly after this. I felt like I had a little bit of a gas bubble in my back and when I tried to vent nothing happened. I figured I had a little squeeze going on the entire time before and that actually was what it was supposed to feel like with no squeeze. At this point Tom signaled we should turn back. We cut our plan 10 minutes short but no big deal. I was a little shaken up by what just happened as it was my first night drysuit dive and my breathing rate was still high. As we gradually moved up the sloping bottom I felt the gas bubble get bigger and bigger. At 40ft I signaled to my group something was wrong with my suit. No matter how I moved I could not vent this bubble. I tried pressing on it when it was by my valve but that did nothing except move the bubble. I though my dump valve had busted. At 35 feet I dumped some gas out of my wing and added a tiny bit to my suit and immediately tried to vent it and a few bubbles came out. The amount that came out looked right to what I had just put in, I was now throughly confused. At 30 feet I had completely emptied my wing. All my buoyancy control was done with my breathing. At 22 feet I went positive and started going to the surface. I was already diving in a skydiver position so I just flattened my legs and arms to make my ascent as slow as possible, I was exhaling all the way up. I broke the surface and signaled with my light to my group I was ok. My group was on the surface 2 minutes later we were all ok. I was a little shaken up by what had just happened.

The DUI Polartec 300 is two of their 150's sewn together. I had gotten gas trapped between the two 150's. That gas was the bubble that I was trying to vent but couldn't because it was under one of the layers. I stopped using that undergarment after that dive because it was much more restrictive than my other one and I was worried about that same problem happening at 100 feet. I have never had gas trapped again.

The other weird part of this dive was how many problems happened.
1. I had my incident
2. Monica going turtled and inverted
3. Steve had a computer failure
4. Ryan had a primary light failure
5. Tom had a drysuit dump valve issue
6. Brandon had a dry glove rip mid dive.


So questions:
1. Has anyone ever had a gas bubble like this get trapped?
2. What would you do if it happened to you?
3. Has anyone had a dive where this many issues came up?

 

[tstormdiver]

The other weird part of this dive was how many problems happened.
1. I had my incident
2. Monica going turtled and inverted
3. Steve had a computer failure
4. Ryan had a primary light failure
5. Tom had a drysuit dump valve issue
6. Brandon had a dry glove rip mid dive.

I have been taught in my technical training, "3 strikes & you're out", meaning if 3 or more things go wrong I either immediately abort the dive (ending the dive is an absolute must if any the equipment failures is a primary system) or I will not even start the dive until I am confident all equipment issues have been resolved.

1. Has anyone ever had a gas bubble like this get trapped?

Yup. Twice. 1st time was in a single cylinder coming from depth in the quarry. I was able to grab a horizontal culvert tube to slow myself momentarily at 20 ft. The went on to the surface. 2nd time was training on my rebreather. My instructor took me on a natural navigation dive on the bottom of the quarry. No one had a compass & the bottom all looked the same in 30 ft of vis. Needless to say, I went the wrong way & we did a blue water ascent from 95 ft. The gas got trapped & expanded at 40 ft. I wound up doing an uncontrolled ascent from that point. My instructor did what he could to slow me.

2. What would you do if it happened to you?

I learned to get on top of venting my drysuit very early in an ascent.

3. Has anyone had a dive where this many issues came up?

I've had dives in which a lot of things have gone wrong. I'm not shy about calling a dive, if things are too far out of hand.

 

[AfterDark]

I’ve never had a dry suit issue like that. I don’t use regular dry suit under garments . Polypro and eavy cotton sweat suits are all I can afford. I had an exhaust valve fail once and vented from the wrist seal.
Since you are still with us you apparently handled it well. Losing the undergarment was a good decision. Sounds like that one needs a little more thought and modification put into it. Did you call the manufacturer? This sounds like something they should know about.

 

[GCullen94]

I have been taught in my technical training, "3 strikes & you're out", meaning if 3 or more things go wrong I either immediately abort the dive (ending the dive is an absolute must if any the equipment failures is a primary system) or I will not even start the dive until I am confident all equipment issues have been resolved.

That is why we turned 10 early. We actually turned right after Monica had her issues and my inflator got stuck. Everything else happened in the 10 minute swim home starting with the primary light failure
Next was a liquivision depth sensor failing


Group one was at a different location however turned their dive early as well as Brandon's glove ripped at about the same time Monica had her issue. Tom and I hit the surface at about the same time with his dump valve failing mid ascent.

 

[dive_turkey]

The only thing I would have tried differently (and maybe you did?) would have been to loosen my BC straps a little and turn to one side in an attempt to move that bubble up to an arm for a wrist dump. Of course, if it's trapped in your undergarment, I'm not sure what the answer is. I suppose you could have had a buddy give you a few whacks to see if it were possible to force the air around and out. Though that would require a bit of complicated communication.

Either way, scary story, glad you're alright.

 

[undrwater]

curious G, was there still gas trapped in the undergarments when you doffed your dry suit?

 

[GCullen94]

ludwigsv- I did try a wrist dump and just wound up getting slightly wet, no gas escaped.

​

undrwater- I swam in to shore with the gas bubble still in the undergarments and a slight squeeze in the suit. When I got on shore I inflated my suit. having air around the bubble seamed to release it out of my undergarments. What we think happened is the bubble got trapped with my body on one side and the trilam on the other, giving the air no where to go but stay in the bubble. Someone's thought if I ever get the bubble feeling at depth again I should descend a little if possible and add gas to the suit where the bubble in the undergarments can release itself into the suit and then vent all excess gas out.

​

 

[Chilly_Dipper]

@Gcullen

This is actually more common then you think. Allot of undergarments (especially when they get wet) can get sucked up hard against the exhaust valve preventing air from escaping. This is especially true for underwear that has a nylon outer shell.

If you look at higher end dry suit undergarments the left arm is either made of a different high breathable material like mesh or is perforated with grommets under the common areas that dump valves are located.

Out of curiosity did you consider flooding the suit via your neck seal to prevent the uncontrolled ascent? Definitely not a desired option but better cold and wet than a chamber trip or worse dead with an embolism.

Also I question your splitting the groups into three instead of two. The three with scooters would make 1 group leaving an even number to buddy up. Groups of 3 just mean 1 person will get lost, as you friend Monica was when you found her turtled. You didn't mention her buddies helping you when you righted her so I'm going to assume they were no where in sight.

Glad you made it back to shore though and had time to write this post as it is important to discuss incidents like these to ensure they don't happen again.

 

[undrwater]

@Gcullen

This is actually more common then you think. Allot of undergarments (especially when they get wet) can get sucked up hard against the exhaust valve preventing air from escaping. This is especially true for underwear that has a nylon outer shell.

So you're saying that the bubble could have been between the undergarment and the inner surface of the dry suit, but unable to escape because the outer surface of the undergarment was blocking the escape? This could make a lot of sense since after he inflated his suit, on the surface, the higher volume of air (and less pressure on the outside) would have separated the undergarment from the exhaust.

Would moisture from sweat be sufficient to cause such a trap? Either way, I've got some mods I'm going to make on my undergarment!

 

[TSandM]

This really sounds bizarre! First off, it was an ill-fated dive -- I can't remember one with that many failures, but we've had some with more than one.

But being able to trap air IN the undergarment just sounds incredibly weird. If that's actually what happened, it's a very poor design.