Personal OOA Incident and Evaluation

[fyue]

A while back, I had an OOA incident (near miss?) and reviewed it through my head several times to try to figure out how I got there. Ultimately, I ended up writing a blog article on it. I tried to be objective and deliver the factors that lead to the incident and how I or anyone could avoid it in the future.

I believe it is important for divers to be open about personal scenarios to make themselves better divers and to teach others the lessons learned. There is no reason that one has to be so proud that they hide the fact that they make mistakes.

You can read my personal incident report at: Scuba Frank - Overconfidence Always Leads to Trouble

 

[Thiad]

Good self-analysis and a lesson about keeping attention where it's needed the most.

 

[knowone]

Confidence - Wikipedia, the free encyclopedia



Overconfidence effect - Wikipedia, the free encyclopedia



Dumb - Wikipedia, the free encyclopedia

 

[Bubbletrubble]

Frank,

Thanks for sharing your story.

You mentioned it was your first dive with a pony bottle. I didn't read any mention of a buddy. Was this your first solo dive? If not, why didn't you always carry some sort of redundant gas supply?

The reason I ask about the buddy is that having a trustworthy one at your side with adequate reserve gas would give you another option in an OOA situation (besides a CESA or buoyant ascent).

If you are solo diving, what kind of redundancy do you have in terms of depth gauge, timer, and buoyancy control device?

What mix were you breathing? At a depth of approx. 100 fsw, narcosis could have played a factor in poor decision-making during the incident.

Where I dive, most divers need to wear at least a 7mm thick hood. As such, we learn not to rely on audible alarms on our dive computers. In fact, I find them to be a nuisance and turn them off. I suppose warm water divers who don't use hoods might find the audible alarm feature more useful.

One last thing I was curious about...
Did you have a way of clipping off your goody bag to your BCD? That would have freed up your left wrist with "mission critical" info mounted to it.

BTW, your helmetcam looks pretty darn cool!

 

[daz88]

Thanks for sharing. It is a good wake up, and makes you think alittle bit. glad you made it out okay.

 

[fyue]

Frank,

Thanks for sharing your story.

You mentioned it was your first dive with a pony bottle. I didn't read any mention of a buddy. Was this your first solo dive? If not, why didn't you always carry some sort of redundant gas supply?

The reason I ask about the buddy is that having a trustworthy one at your side with adequate reserve gas would give you another option in an OOA situation (besides a CESA or buoyant ascent).

If you are solo diving, what kind of redundancy do you have in terms of depth gauge, timer, and buoyancy control device?

What mix were you breathing? At a depth of approx. 100 fsw, narcosis could have played a factor in poor decision-making during the incident.

Where I dive, most divers need to wear at least a 7mm thick hood. As such, we learn not to rely on audible alarms on our dive computers. In fact, I find them to be a nuisance and turn them off. I suppose warm water divers who don't use hoods might find the audible alarm feature more useful.

One last thing I was curious about...
Did you have a way of clipping off your goody bag to your BCD? That would have freed up your left wrist with "mission critical" info mounted to it.

BTW, your helmetcam looks pretty darn cool!

Let me see if I can answer those questions:

I had done a few dives without a proper buddy in the past, but usually dove with a buddy. It is not uncommon on this Fossil Ledge dive to be assigned a buddy, but to not stay too close together once you hit the water. The reason is that there is a lot of silt stirred up and you tend to focus on searching for fossils. Having a reel tied near the anchor offsets this a bit in terms of not getting lost. There were other divers near me, as you can see in the second video, but I did not go to them for assistance since I was able to self-assist with my pony. Attracting one of those divers' attention could certainly have been an option.

For solo diving, which I still only do rarely, I do carry two computers, both running the same algorithm, though only one is tied to my transmitter. A analog pressure gauge also has been considered.

At 95 feet, I was breathing 32% Nitrox, I believe, though that has no factor relative to narcosis (O2 is essentially just as narcotic as N2). Also, I do not tend to get narc'ed at recreational depths, so I do not believe this was a factor.

The hood was a major player. I do not wear a hood for 98% of my dives around here. The hood was new. I do rely on audible alarms. I also normally glance at my computer every minute or two. The combination of factors I wrote about prevented me from hearing the alarms and checking my computer. This was a important issue leading to the event. I have since punched earholes in my hood.

I did/do have a way of clipping my bag to my BCD. But that is impractical when there is a 10 pound 8 inch diameter vertebrae stuffed in it. It would have been flopping around and pulling awkwardly on me.

Things I should have done:

1) Test my hood in the pool and punch earholes after discovering I was deaf.
2) Add air to my BCD to make me more neutral and work less after picking up the vertebrae and then the lobster.
3) Carry everything in my right hand and/or shoot a lift bag for them.
4) Focus on what is #1 priority: My lifeline (gas supply).

Thanks on the helmetcam! I have recently modified it to use a GoPro camera which is smaller and easier to manage. I am still tweaking it, of course.

 

[Bubbletrubble]

Frank, thanks for answering all of my questions. As an instructor, you should consider sharing the story with your students. I bet it sparks a lively discussion. Along those same lines, you might want to check out the ScubaBoard threads on "What if...?" scenarios that Cave Diver and I put together (click the link in my sig). Feel free to share the scenarios with your OW students. I know I found it helpful to work through those real-life scenarios prior to certification.

It sounds to me like, if you didn't have a stay-at-your-side buddy on previous dives to this site, you were essentially solo diving without a redundant gas supply. Honestly, I think that scares me more than the actual incident you described.

For what it's worth, I think it could be argued that diving a 32% nitrox mix actually made the dive in question riskier in a sense. Had you been diving air, you would have been NDL-limited...and, assuming you were vigilant enough to check your computer (despite the lack of audible warnings), you almost certainly would have initiated your ascent before running out of back-gas (but you probably would have missed out on the lobster).

Since the helmetcam is always recording throughout the dive (right?), it kind of functions like a black box. Great for reviewing the dive in its entirety. FYI, loss of memory, perceptual narrowing, delay in response to signals, impaired judgment, and anxiety (possibly leading to increased respiration rate?) are all symptoms associated with narcosis. Food for thought.

 

[TSandM]

Also, I do not tend to get narc'ed at recreational depths, so I do not believe this was a factor.

I'll take a little issue with this. In my personal experience, this is precisely how narcosis manifests itself -- not with feelings of euphoria or drunkenness, but with dullness. I tend to fail to perceive important information, or interpret it correctly when I do.

You were at depth, working hard, and had rendered yourself unable to check your gas, and this didn't worry you. Further, when your regulator no longer delivered gas, the significance of that did not occur to you. To me, these are hallmarks of an impaired brain, maybe because I've had so many experiences of being dull and not making good decisions in precisely that depth range. Please don't discount the possibility that, in addition to the equipment considerations you've written about, your actions in this case were in part due to not being as smart at 100 feet as you are at the surface.

 

[fyue]

I'll take a little issue with this. In my personal experience, this is precisely how narcosis manifests itself -- not with feelings of euphoria or drunkenness, but with dullness. I tend to fail to perceive important information, or interpret it correctly when I do.

You were at depth, working hard, and had rendered yourself unable to check your gas, and this didn't worry you. Further, when your regulator no longer delivered gas, the significance of that did not occur to you. To me, these are hallmarks of an impaired brain, maybe because I've had so many experiences of being dull and not making good decisions in precisely that depth range. Please don't discount the possibility that, in addition to the equipment considerations you've written about, your actions in this case were in part due to not being as smart at 100 feet as you are at the surface.

Actually, I completely agree with you. Narcosis usually is seen with dullness and perceptual narrowing in my experience. It is possible/probable that I was narc'ed to a certain extent, but I do not believe it significantly affected my response. It may have contributed to the fact that I was not checking my computer enough, but I believe that the vertebrae and lobster did that job well enough by themselves. Of course, I could be wrong since I might have been narc'ed . I believe that I was not able to accept the fact that my air was low because my last check of the computer had me thinking that I had plenty of air. Even on the surface, I was surprised that my tank had run low.

A small quibble is that my regulator still delivered air, just under heavier load. I never got to where I could not draw a breath. I would guess that there were probably 2-4 more breaths available when I swapped to the pony.

It sounds to me like, if you didn't have a stay-at-your-side buddy on previous dives to this site, you were essentially solo diving without a redundant gas supply. Honestly, I think that scares me more than the actual incident you described.

For what it's worth, I think it could be argued that diving a 32% nitrox mix actually made the dive in question riskier in a sense. Had you been diving air, you would have been NDL-limited...and, assuming you were vigilant enough to check your computer (despite the lack of audible warnings), you almost certainly would have initiated your ascent before running out of back-gas (but you probably would have missed out on the lobster).

Since the helmetcam is always recording throughout the dive (right?), it kind of functions like a black box. Great for reviewing the dive in its entirety. FYI, loss of memory, perceptual narrowing, delay in response to signals, impaired judgment, and anxiety (possibly leading to increased respiration rate?) are all symptoms associated with narcosis. Food for thought. [

Yes. Not having the stay-at-side buddy without proper redundancy is certainly one of those overconfidence factors. Divers tend to think, 'This will never happen to me. I never run out of air. I always follow the rules and don't make mistakes.' Well, guess what? This could happen to you and I bet that you are making mistakes, but you just don't recognize them. If you dont believe me, I can tick off a half dozen experienced divers/experts in their field, who have died in tragic accidents that were not due to mechanical malfunction. Example: The Last Dive of David Shaw

The helmetcam was instrumental for the review my dive and determining exactly when each event occured. It is turned on before I hit the water and turned off when I am back on the boat. I can timestamp every one of my actions. I do not believe I would have been able to analyze the dive this well, without it. I recommend that every diver out there go build their own helmetcam. A zero-taskload recording device is awesome.

Another general narc comment is that I believe that I was calm and level-headed throughout the entire dive/incident. I know that I did not panic and I do not believe that my anxiety reached any critical threshhold during the dive. When I actually learned that my air was low ('pffft'), I did become nervous and the adreneline kicked in.

On a side note, it is humorous to see the potential disappointment in your comment that if I had done the dive correctly, I would not have had a lobster dinner that day (btw, it was big enough to feed 4!).