DumpsterDiver emergency ascent from 180'

[Steve_C]

I will point out that DD is not only a very experienced diver but also an experienced free diver. He is used to being deep without much air. He also does a lot of offshore spear fishing and is aware of sharks and how dangerous they can be.

When I hike or go fishing with my brother in MT he always carries a gun. We are not hunting. But turned over boulders and other signs show we are in serious bear country (and mountain lions also). Gun is there just in case avoidance does not work.

 

[StefinSB]

@StefinSB what most people have that problem it is because the tank is set too low on the rig not because of a location issue

Will play (again) with that once I can go into the water again. Thx.

 

[bowlofpetunias]

This makes my blood boil and I will not apologize for having a rant about this.

I can't see the video nor can I get this phrase to stop echoing in my head. Normalization of deviance! A few days after a well known Dive Operation owner and IDC Instructor died while on a dive with me Sam was trying to console me when I said "I can't believe it..**** was so much more experienced and a way better diver than I will ever be". Sam said "That is ***** you were able to complete that dive **** wasn't! I've dived with both of you and I would dive with you again but I refused to dive with **** again".

You can talk all you want about gas plans, size of pony bottle,staying calm and thousands of dives of experience where complacency builds because pure blind luck kept death at bay. The best thing I can say about this situation.. at least DD was diving solo so nobody else would have to live the trauma of having him die while diving with them! Lady Luck is a fickle friend I pray that we don't wind up discussing him as the subject of an A&I thread.

"Social normalization of deviance means that people within the organization become so much accustomed to a deviant behavior that they don't consider it as deviant, despite the fact that they far exceed their own rules for the elementary safety".

The Normalization of Deviance - Situational Awareness Matters!™

 

[victorzamora]

People get hurt trying to do what they see their "betters" doing. I've seen it a hundred times among motorcycle riders. "He got his knee down going around that corner. I have the same bike and tires. Therefore, I know the bike can do it. So, I can do it too."

Lol...this right here ends in a lowside if you're lucky.

 

[CuzzA]

This makes my blood boil and I will not apologize for having a rant about this.

I can't see the video nor can I get this phrase to stop echoing in my head. Normalization of deviance! A few days after a well known Dive Operation owner and IDC Instructor died while on a dive with me Sam was trying to console me when I said "I can't believe it..**** was so much more experienced and a way better diver than I will ever be". Sam said "That is ***** you were able to complete that dive **** wasn't! I've dived with both of you and I would dive with you again but I refused to dive with **** again".

You can talk all you want about gas plans, size of pony bottle,staying calm and thousands of dives of experience where complacency builds because pure blind luck kept death at bay. The best thing I can say about this situation.. at least DD was diving solo so nobody else would have to live the trauma of having him die while diving with them! Lady Luck is a fickle friend I pray that we don't wind up discussing him as the subject of an A&I thread.



The Normalization of Deviance - Situational Awareness Matters!™

Can you explain how "Normalization of Deviance" applies to this incident?

 

[Diving Dubai]

Well, let's do a thought experiment for an open circuit, open water dive, within recreational limits.

If you had, say, an HP120 of reserve gas, you would have enough gas to deal with any emergency where having more gas would help. There would be no additional benefit of instead having, say, two HP120s of reserve gas, because there aren't any plausible accident scenarios that are survivable on two HP120s but not survivable on just one.

This would also be true comparing one HP100 of reserve gas to two HP100s of reserve gas, again, there aren't any plausible accident scenarios where the second HP100 will help.

As we work our way to smaller cylinders, we can come up with some plausible but extremely low probability scenarios, like being silted out and inadvertently ending up lost in a cave that adjoins an open water area, where having a good deal more air really does help. These situations are rare. Basic OOA emergencies caused by equipment failure are not rare, but can be resolved by making an immediate ascent. If the reserve gas supply is sufficient to allow an emergency ascent, most of the safety benefit of having a reserve is obtained. The rare situations that might benefit from an oversize reserve gas supply lead to only a marginal improvement in safety when an oversize supply is used.

The balance point is when the reserve gas supply system becomes large enough to pose additional practical difficulties of one kind or another that lead to decisions being made to dive without it. I believe that the best practice is to encourage the use of reasonably sized pony cylinders that allow a safe, immediate ascent to the surface based on actual gas planning using the intended depth and SAC rate (and a reasonable multiplier for stress). For most recreational divers this will be an AL13 or AL19. Some divers may need something larger on some dives, but a blanket recommendation of an AL40 is just plain old tech bleedover and excessive conservatism.

Of course it depends where you dive. I had an incident 2 years back that changed my thinking. I was divign a 15L (HP100?) and a AL 30, my wife a 12L and AL 30. We left the ridge (30m) on a pinnical of a site we've dived many times before well within Rock bottom and well within NDL because we would slowly come shallow to comlete a 60 min dive.

This time however we got smashed by a down current and we stopped at 55m. We litterallly had to crawl up the rock out of the current, screaming through our gas and incuring deco.

Long story short, I had between both cylinders maybe 25 - 30 bar As it happend another team on scooters saw our prdicament and met us with 80% to ensure we could really off gas.

By your statements you consider AL 40 to be too large - which is fine, everyone is entitle to their opinion.
Now however, on sites with no hard bottom at recreational depth I now sling an AL 80

I figure that after an incident no-one has everr wished they were carrying less gas

I've dived that site since, many times never had a down current since that time, but I still take the 80

 

[tbone1004]

Will play (again) with that once I can go into the water again. Thx.

the general "rule" we use is with the rig fully set up, you set the cam band height by holding the plate up by the shoulder straps *can also do this just on the hanger* and the top of the shoulder straps should be even with the valve knob. Mobility will allow you to go up or down an inch but it's a good start

 

[northernone]

Can't speak for him either but I would have been thinking 'boy am I glad I have a nice pony to ride back up to the surface'

Of course it depends where you dive. I had an incident 2 years back that changed my thinking. I was divign a 15L (HP100?) and a AL 30, my wife a 12L and AL 30. We left the ridge (30m) on a pinnical of a site we've dived many times before well within Rock bottom and well within NDL because we would slowly come shallow to comlete a 60 min dive.

This time however we got smashed by a down current and we stopped at 55m. We litterallly had to crawl up the rock out of the current, screaming through our gas and incuring deco.

Long story short, I had between both cylinders maybe 25 - 30 bar As it happend another team on scooters saw our prdicament and met us with 80% to ensure we could really off gas.

By your statements you consider AL 40 to be too large - which is fine, everyone is entitle to their opinion.
Now however, on sites with no hard bottom at recreational depth I now sling an AL 80

I figure that after an incident no-one has everr wished they were carrying less gas

I've dived that site since, many times never had a down current since that time, but I still take the 80

I think we all agree bringing suitable bail out to match the unique conditions of a particular site is wise. A one size fits all rule will leave us in a vulnerable situation eventually.

Remembering my current encounter of this winter, nearly an OOG situation from compounded issues. Rebreather, bailout deco rebreather and an al80 for a 150ft dive. When I realized my trouble I had 7hrs of breathable gasses along with me (according to the dive plan). When I reached dry land I had remnant of the al80. This was a dive site and profile I've done on a single al80 with an untouched bailout. (More factors involved in this situation, not a clear cut inadequate bailout, detailed in the incident forum)

Respect the conditions,
Cameron

 

[stuartv]

Can you explain how "Normalization of Deviance" applies to this incident?

I hope you are kidding, but I'm going to take a stab at this on the basis that it is a serious question.

There is no normalization of deviance without first having deviance.

Was there deviance in this case? What does that mean? To me it means asking the question, what standards applied in this case and did DD deviate from those standards. Standards? I can only judge his actions against the training that I have received and that I understand to be standard training for all (most?) divers. First and foremost, the training for my SDI Solo Diver certification is emphatic that you only dive solo within recreational limits, with no overhead, virtual or physical. So, by the standards of my training, his dive depth alone meant that he was very deviant from standards. Second, I suspect just about any instructor anywhere would train a diver to not dive that deep with a single cylinder and a pony that small. In my mind, that's another deviation from "standard". Third, it appears that his plan was to incur some amount of a deco obligation. Even though his good luck was to have this problem before he actually did incur deco, the plan to incur deco is still a deviation from standard, if for no other reason that that is against the training and standards for solo diving. I don't know whether DD actually has deco training, but I am going to assume so and not include that in the list of deviations from standards. Fourth, for a dive that deep OR a dive with planned deco (much less both), the standard would to be do a formal dive plan, including gas planning with calculation of reserves. Did he do that before this dive? "I've done this dive a million times and I planned it out before, 2 years ago" would not qualify as meeting "standards" per my training.

In my opinion, based solely on the info posted in this thread, it seems to be that there was clear deviation from standards.

The remaining question is, was there normalization. That seems to be an obvious "yes". Certainly for him it was. From what I gather, the dive he was doing was totally normal, for him.

So, it seems to me that this incident is a textbook example of normalization of deviance. It was bad luck to blow a HP seat. But, it was very good luck for him on the timing of that problem - and that he survived. As has been noted, there are several ways things could have gone much worse for him, even with all his skill and experience.

 

[Skeptic14]

All good points @stuartv, but how does experience as a freediver, (I have no idea how experienced/accomplished a freediver he is) factor into the situation?

If you are easily capable of sub 100ft freedives does that change things?

In my very limited experience I would imagine there would be a huge difference in an accomplished freediver doing this dive vs someone with no real free diving experience.