Forced descent in Blue Hole

[Christi]

...the clock is running very fast down there and with the combination of lack of traning and CO2 narcosis, i expect that most of the divers doing that dive are very overconfident....

Don't you mean N2 narcosis?

 

[Chaseh]

I've posted my Blue Hole experience elsewhere on this board so it won't be news to some of you...

I dove with Amigos Del Mar and we had 2 DMs for 12 divers. The group included myself and my then husband with our whopping 7 post-cert dives, a guy doing his VERY FIRST post-cert dive (with a camera) and a bunch of other people. The group made it to 147' with at least one guy below that.

The only person who was not allowed to do the dive was the new certs girlfriend because she only got her Scuba Diver card, not a full OW card. She was allowed to do the other 2 dives that day that both maxed in the 80-100' range.

There are so many things wrong with this scenario that it still gives me chills. I take responsibility for doing the dive to some extent, but when you're being told that "sure, it's an advanced dive, but you guys are fine" it's easy to want to believe that. With that few dives I really had no concept what "advanced" meant when applied to a dive site. We were just diving!

Turns out that ADM had lost a diver in the hole the week before. I don't actually know if the body was ever recovered or what happened in that incident.

I'm not really sure what I want anyone to do about it, but I'm still horrified that anyone let me do that dive. If one person had said, "look, by 'advanced' we mean more that you've got" I'd have stayed home and been happy. I wasn't just allowed to do the dive, I was encouraged to do the dive, that's where I get a little angry.

Rachel

Ok, so I am the guy that was below 150' on that dive. It was a great dive for us, but as I've posted on the subect on SB before, new divers should take precautions to protect themselves down their, because the dive opps may not.

As Rachel said, we dove with ADM on that trip, and it was a bounce. The guys that were actually doing it as their first certified dive were a mess all day, and one actually bled out from a burst capillary (sp?) into his mask.

No one here has mentioned the shark portion of the dive, so maybe ADM has changed their opperation a bit, including keeping it a bit shallower. On our dive, we made a manditory stop in the sand in about 30' from what I remember. At that point, the ADM boat started tossing a bunch of fish bits into the water to draw in the sharks for our entertainment. It was awesome, and yet a pretty irresponsible undertaking at the same time.

Have they stopped doing this?

They also hung a tank for the stop, but it was dangling in the middle of the feeding sharks. The bloody noob is lucky he did need to make a move for that tank.

 

[vondo]

No one here has mentioned the shark portion of the dive, so maybe ADM has changed their opperation a bit, including keeping it a bit shallower. On our dive, we made a manditory stop in the sand in about 30' from what I remember. At that point, the ADM boat started tossing a bunch of fish bits into the water to draw in the sharks for our entertainment. It was awesome, and yet a pretty irresponsible undertaking at the same time.

Have they stopped doing this?

They also hung a tank for the stop, but it was dangling in the middle of the feeding sharks. The bloody noob is lucky he did need to make a move for that tank.

When I did it a year ago, I was with an op out of Caye Caulker (Paradise Down). We moored 50' maybe from ADM. We went in first and during our SS, ADM was feeding the sharks. But, I think ADM's divers were all on the boat. I think this may have been before their dive. We kept just ahead of ADM the whole day, which was nice.

 

[lamont]

Don't you mean N2 narcosis?

nope, i meant a CO2 hit. particularly if the regs aren't good, the air is thicker and you've got another 60 psi that the IP in your LP hose has to push against, which all makes for higher work of breathing. combine that with some excitement and you can get rapid, shallow breathing and CO2 buildup -- which is much more narcotic than N2 and which can lead to feelings of suffocation and panic. good, well-maintained regulators can help prevent against this, along with breathing some helium (the lower gas density / viscosity results in less work of breathing in addition to removing the nitrogen). experience and fitness will also help.

so, what can plausably happen is everyone is down at 130 and fine. then someone's regulator free-flows and everyone gets exited. that stresses the ability of everyone's regulators to deliver air and you can start seeing divers (particularly the guy with the free flow who is in a jacuzzi of bubbles) overbreathing what their regs can deliver at that depth. then the CO2 builds up and starts impairing people severely and causing feelings of panic. now you've got a fairly serious snowball occuring from just a small and fairly common equipment problem. having an experienced diver along who can get the valve shutoff and the victim onto an octo and get everyone promptly ascending will really help in this situation, but if the divers are without a DM, or the DM has little experience themselves, this situation could really get out of control.

 

[DandyDon]

Makes sense, except I've never heard CO2 hits called narcosis?

I try to make it clear to all on any boat I'm on: "If you need air, don't ask - just grab either of the second stages on my BC. The pony will be on, I'll take that cue, and we'll start ascending. Just don't try the one in my mouth, as it's stuck on a Manta mouthpiece."

When I see a diver who looks like he may be in distress, I'm quick to offer a spare second stage, purging a few bubbles to get their attention in case s/he might be in a panic. I've done a few ascents holding the other diver's BC.

A smartass friend of my local dive buddy came with us to Coz when the local was just starting to learn, always running low on air (until he got a Sea Cure mouthpiece), and after seeing me take the local up a couple of times, the smartone said: "I've always got plenty, share mine." He did, but neither grabbed the other's BC. The smartone took off swimming, the hose did a rubber band jump in the water, and this is the one time I didn't react well - laughing too hard thru my reg at my local bud waving arms. The DM jumped him until I could control myself.

I've tried to become a better diver in the 2 years since...

 

[Christi]

That explanation makes sense. I thought you were referring to nitrogen narcosis...my bad!

nope, i meant a CO2 hit. particularly if the regs aren't good, the air is thicker and you've got another 60 psi that the IP in your LP hose has to push against, which all makes for higher work of breathing. combine that with some excitement and you can get rapid, shallow breathing and CO2 buildup -- which is much more narcotic than N2 and which can lead to feelings of suffocation and panic. good, well-maintained regulators can help prevent against this, along with breathing some helium (the lower gas density / viscosity results in less work of breathing in addition to removing the nitrogen). experience and fitness will also help.

so, what can plausably happen is everyone is down at 130 and fine. then someone's regulator free-flows and everyone gets exited. that stresses the ability of everyone's regulators to deliver air and you can start seeing divers (particularly the guy with the free flow who is in a jacuzzi of bubbles) overbreathing what their regs can deliver at that depth. then the CO2 builds up and starts impairing people severely and causing feelings of panic. now you've got a fairly serious snowball occuring from just a small and fairly common equipment problem. having an experienced diver along who can get the valve shutoff and the victim onto an octo and get everyone promptly ascending will really help in this situation, but if the divers are without a DM, or the DM has little experience themselves, this situation could really get out of control.

 

[lamont]

more than anyone needs to know about CO2:

http://www.gue.com/Research/Exercise/q2_2e.htm

 

[DandyDon]

more than anyone needs to know about CO2:

http://www.gue.com/Research/Exercise/q2_2e.htm

Thanks! Excerpting from it...

Carbon dioxide is a narcotic gas capable of depressing awareness to the degree of total loss of consciousness.

Learn things here all the time, but then - they is a lot more to learn in that article.

 

[occrider]

No one here has mentioned the shark portion of the dive, so maybe ADM has changed their opperation a bit, including keeping it a bit shallower. On our dive, we made a manditory stop in the sand in about 30' from what I remember. At that point, the ADM boat started tossing a bunch of fish bits into the water to draw in the sharks for our entertainment. It was awesome, and yet a pretty irresponsible undertaking at the same time.

Have they stopped doing this?

They didn't chum the water when I did the blue hole, but they did do that for our local dives. For one of the dives they tossed some fish overboard to draw in the nurse sharks and grouper, in another dive the DM deployed an upside down clorox bottle, using a string, about 10-15ft above us. Whatever was in it, it was shark catnip as a lot of them came over to investigate. They didn't go into a frenzy, they didn't even bite the bottle ... they just kind of nuzzled it. Anyway, I know responsible divers aren't supposed to do that, but I can't say that I didn't guiltily enjoy it.

 

[wreckchick]

Actually, Chase, I forgot that you were one of the deeper guys. I was talking about the dude that "didn't need a buddy" who was a good 10-15' below us all day trailing the pack. You remember, the "nuclear physicist"?

R