Perth incident

[KeithG]

The article mentions an ascent from 30 m and a dive of 30 minutes. That makes me think this was probably a dive requiring deco stops that they missed.

CESA can get you bent, nut the alternative of death by drowning is usually not the preferred choice.

I had not considered a deco dive as I thought the first OOA action would be to swap to your pony.

I did a little googling and many of the CESA articles I found did mention risk of DCS. I had forgotten thos. None (so far) provided any additional info except that "it might happen".

 

[Dan]

The guys mentioned tingling sensation on skin & pain in the bone, which means DCS.

 

[Dan]

Once your buddy is in panic situation, he won’t listen to you. Any attempt to calm him down may just futile effort & wasting precious air left in your tank. I say this because it just happened to me last Sunday.

Here is what happened to us. I went wreck diving to 90’ deep with a newbie who rented his gears. We discussed about how we were going to dive the wreck (going down along the anchor line). I showed him my hand signal for half tank (1500 psig) and empty (500 psig). Since I’m the more experienced diver, he offered me to lead & he’d follow. He’d tap my shoulder when he reached 1000 psig, so we could begin to ascend.

We went down to the wreck uneventful (visibility was about 40’, water temperature was about 73F). Once we reached the wreck, his rented reg started to make funny whistling sound and he tapped me on my back. I turned around and look at his SPG and noticed some bubbles streaming out of the fitting, not bad enough to be alarmed, and his pressure was still about 2000 psig. Mine was still about 2600 psig. I look straight to his big round eyes and gestured an OK & an up/down waving hand signal to calm him down & point my finger to his SPG that he still have plenty of air, sticking 2-finger up to sign for 2000 psig. Then trying to tell him when his SPG reached 1000 psig, then we could go up by pointing to his SPG & sticking my index finger & thumb up. But his was in shear panic & just started to fin his way to the anchor line. All I could do was to follow him back up & to make sure that we did a 3-min safety stop at the bar hung by the boat at 15’ depth.

 

[Seaweed Doc]

I had not considered a deco dive as I thought the first OOA action would be to swap to your pony.

I did a little googling and many of the CESA articles I found did mention risk of DCS. I had forgotten thos. None (so far) provided any additional info except that "it might happen".

People sometimes don't follow the protocols. Given my initial training was way back when, if I was following the stuff I learned in Openwater I'd do a deco dive on a single tank using Navy tables without a second thought.

(I also wouldn't have an octopus. I would wonder why new divers kept insisting they couldn't go past 60 feet, when I "knew" oxygen toxicity didn't kick in until about 200' and as long as you were aware of narcosis you were good to that depth. Ah, the good old days. Of course, people were more likely to die diving back then.....)

 

[Bob DBF]

I did a little googling and many of the CESA articles I found did mention risk of DCS. I had forgotten thos. None (so far) provided any additional info except that "it might happen".

It's like doing NDL dives, the tables give the parameters to stay within NDL, one of which is your ascent rate, and staying within the parameters does not guarantee no DCS, but the risk is very low. During a CSEA it would be easy to violate the ascent rate, this gives a greater risk of DCS, it is still low but might be enough for DCS to rear its ugly head. As one goes closer to, and into deco, this would become more of an issue.


Bob

 

[wgw04024]

Agreed, once had the reg in his mouth, panic should be over. If you are using one of those full face masks, would someone normally carry an extra mask? 10-15 minutes to make an ascent (dialogue in the video). Not at rec limits.

 

[Kevrumbo]

That was roughly a 36m/min air-share ascent (twice the max recommended emergency ascent rate of 18m/min), non-stop straight up to the surface. Rule Out panic inducing CO2 Retention/Hypercapnia as precipitating cause.

10-15 minutes to make an ascent (dialogue in the video). Not at rec limits.

Nominal ascent rate of 10m/min to surface from 30msw should take 3min; optionally add a 5min safety stop at 4.5msw assuming NDL and that's approx 8min Time-to-Surface.

(Or more conservatively, two minutes to ascend from 30msw to 15msw at 10m/min; five minutes to ascend to surface at 3m/min assuming NDL, and adding an optional five minutes safety stop at 4.5msw yields approx 12 minutes TTS).

 

[clownfishsydney]

They mention air pouring out of his gauge, none that I could see, did not appear to be a leak. My guess is that he really ran out of air and was not watching his gauge. Thirty minutes at 30 metres would go close to emptying my tank and I have a very low air consumption. No real indication of what the problem actually was.

 

[Steve_C]

I do not see any indication of a pony.

The diver who was aiding his buddy may not have had a lot o air left. Sounds like this happened around the time they would be going up. Plus the diver with problems is probably sucking air once on the other reg.

Still I do not understand the emergency ascent unless buddy was in near panic and barely controllable. If buddy was in a full face mask prio, now during the ascent he is maskless which adds to his stress..

 

[KeithG]

[QUOvvv

I do not see any indication of a pony.

The diver who was aiding his buddy may not have had a lot o air left. Sounds like this happened around the time they would be going up. Plus the diver with problems is probably sucking air once on the other reg.

Still I do not understand the emergency ascent unless buddy was in near panic and barely controllable. If buddy was in a full face mask prio, now during the ascent he is maskless which adds to his stress..

What's the protocol for learning how to use a FFM? Not that there is a PADI course, but I would assume that part of being prepared would be drills swapping to an alternate without a mask. Should you also be carrying a spare mask so that you can restore proper vision?