Accident analysis

[paulthenurse]

A couple of weeks ago I went on a dive where we had a near accident. Or at least that’s how it appeared at the time. The other divers and I have discussed this quite a bit over the past few weeks with the hope of determining what went wrong and how we could have prevented the anxious moments that followed. We have decided to post a description of what occurred in the hopes that others might learn something from our mistakes and hopefully avoid them. We are all fully aware that by doing so we are opening ourselves up to attack by those members of the internet diving world who build up their own egos by belittling everyone else, but we feel that what happened was such a good learning experience that we should share it.

Some background.

Diver A is a local NELD. Has about 175 dives since certification, all but a dozen of so here in the northeast. AOW, dry suit, and nitrox certified. On this day was diving in a wetsuit, using doubled aluminum 80’s filled with 32% mix. Late 40’s, pleasingly plump. (OK, fat.) Dives with regular partners. Diver A is me, Paulthenurse

Diver B (Lou) is my regular dive buddy. We have about 100 dives together. Works part time in a LDS. A bit of a whack job in a good sort of way. I know him, he knows me. We spend most of our dives with our heads stuck under rocks looking for lobster. Given the general state of visibility around here and the nature of our dives, we lose each other from time to time. Most of the time, we just keep on about our business. If we’re doing something unusual we make it a point to stick together.

Diver C (Frank) is from the left coast. Never been to New England before, wrote to NELD requesting buddies to show him around while he was here on vacation. AOW, dry suit, nitrox , DIR fundies and some cave/cavern courses. Diving dry. Using new hardware. New BP/W. New Regs. Using my other set of doubled AL 80’s filled with 32%. Been diving 8-10 years, 70 years old. Dives mostly while on vacation, used to being matched up with “buddies” on the boat and has had many experiences when ‘on the boat’ is the only time he sees his “buddy.”

The plan was to go to Halfway Rock for Dive One, then hit another site on the way home to Boston.

 

[paulthenurse]

The Dives

We arrived at HWR to find 5 boats filled with teenagers playing around. There wasn’t a whole lot of brain matter on display on these boats. (The knucklehead who dove forward off a moving boat, and was promptly run over by that boat is about par for what we witnessed.) We called over one of the boats and advised them that we would be diving here and requested that they use some care. He agreed and by the time we were ready to splash, they all left. We dropped down, followed a canyon away from the rock for a while and eventually turned and went back to the rock and enjoyed the wall. We hit about 80 feet for about 35 minutes total time, as I remember. Lou was in a single AL 80 and we used him as our controlling diver. We hung for a good safety stop at 15 feet, found a ledge at that depth and just looked around it for 4-5 minutes, than swam back to the boat.

Dive 2 was at 3 ½ Fathom Ledge. I wore a dry suit on dive 1, but on the ride to dive 2 had unwittingly knocked it to the deck where the fleece got soaked. Fortunately, I had a wetsuit in my bag and switched to that for dive 2. That started a discussion on weights and adding/subtracting weights going from wet to dry between the 3 divers and the skipper (an IANDT instructor.) Frank was unsure of his weight requirement, what with the new equipment and AL doubles. We figured out what we thought would be adequate and he used that. At the start of Dive 2 both divers wearing doubles had about 1700 PSI in their tanks. Lou had a full AL 80.

The Incident

We dropped into about 40 feet and found a bunch of bugs. We worked our way down until we stopped seeing bugs, then turned and started back up. We hit a max depth of about 65 feet and slowly started up a steep wall with a series of ledges. We were within sight of each other, visibility 10 feet at best. At around 30 feet we came over the top of one ledge. I looked over at Frank and saw him 4-5 feet above me. I had about 1000 PSI at that point. I flashed him the OK question, he responded by rolling his hand side-to-side, indicating that he was having a problem. I stopped and looked at him and he swam over to me. He was not panicked at all and was calm and in control. He seemed to have good buoyancy control, hovering next to me. I again asked if he was OK. He made the same hand gesture and grabbed at his waist belt. I gave him a sign to ‘wait right here’ and turned away and swam over the 10 feet or so to get Lou. I swam over to Lou, and got his attention and indicated that we needed to go as Frank was having some trouble. We turned and swam back to where I left Frank. He wasn’t there. We looked around in the immediate area and didn’t find him. We headed back down the wall we had just come up, looking everywhere for him or his bubbles. I was feeling very anxious, “Damn, he was telling me he was having a problem. I never should have turned my back on him and now we can’t find him. Damn. Damn. Damn.” Lou and I swam all the way down to the bottom of the wall we had just come up, searched everywhere for Frank. No bubbles, no Frank. This isn’t good. We swam back up the wall, keeping just within sight of each other, looking for Frank. When we didn’t find him we ascended to the surface to get help from the boat.

When we surfaced we found out that Frank was already on the boat.

 

[paulthenurse]

What went wrong.

Frank was indicating he was having trouble staying down. When he gestured to his belt he was indicating his weights. I didn’t get that. What I also didn’t know was that when he swam over to me he grabbed a hold of my manifold and was using that to hold himself down. When I turned away from him to go and get Lou I pulled the manifold out of his hand and he started to ascend and couldn’t stop his ascent. He eventually went head down and finned vigorously to slow his ascent. He said he had no air in his suit or his wing. He popped to surface feet first, quite close to the boat and swam to it and climbed aboard and continued to breath the 32% while sitting on the bench. The only symptom of DCS was a sudden sinus pain, which resolved after about ½ hour.

We were off in our calculations of how much weight he needed, and when he breathed down the tanks they became positively buoyant. (He also had about 1000 PSI when this happened) Coming up from depth only made matters worse.

When Lou and I got back to the spot where I had left Frank I assumed the worst. (I am an ER nurse and that’s how we do things. ~ ~Yes, the fair-skinned, fat, mid-forty year old female with sub-sternal chest pain starting 45 minutes after eating fried chicken is probably suffering from indigestion, but lets assume she’s having a heart attack and act accordingly until we prove she’s not. ~ ~ ) Worst case scenario at that moment seemed to be Lou being incapacitated and sinking down the wall we had just come up. I headed down to guard against that. I will admit that it honestly never occurred to me to look up, but given the poor visibility I doubt that we would have seen him anyways.


He said that he felt as though he rocketed to the surface but upon downloading his computer he didn’t go as fast as he initially thought. He spent 15-20 minutes breathing the remaining 32% and his sinus headache (reverse squeeze?) went away as quickly as it came on.

What should we have done differently?

1. I should never have taken my eyes off him!!!!
2. I should never have taken my eyes off him!!!
3. I should never have taken my eyes off him!!!
4. I should have grabbed him and not let go.
5. New location, new buddies, new equipment is a formula for mistakes.
6. No one had a slate or other way to communicate what the problem was.
7. We were all unfamiliar with Frank’s equipment. Including Frank.

 

[paulthenurse]

Please feel free to comment/critique. We decided to talk about this publicly as a learning experience, both for us and for others.
Paul

 

[Mako Mark]

Paul, you named this thread perfectly. No one will flame you or tell you that you are a muppet when you are trying to use past experiences to increase safety in the future.

From what I can see, you reacted correctly to the situation, there is little that you could have done to prevent this situation other than in a perfect world, had more time to do bouyancy checks with empty tanks etc etc, some people may be more critical of this than me, but I know how it can happen in the real world on a busy and bumpy boat..

I guess the only thing I would say is that touch contact is like another set of eyes. Hold onto someont untill you have acertained exactly what the problem is, especially if you are not that familiar with them, it can calm down a nervous or panicky diver and you get physical feedback of their stress levels through muscle tension etc etc.

It also allows you to take your eyes off them to look for other members of the group.

(mods, this may be better in A&I forum)

 

[victor]

Twenty twenty hindsite is always perfect.
I don't think you did anything wrong, maybe Frank could have done things slightly differently, but at 70 he is not as strong as he once was.

As soon as Frank realised he was getting light he should have grabbed some rocks. Not as good as lead but any little bit helps. If he had been carrying a boulder or 2 you might have guessed at his problems.

I think Frank had air in his dry suit, if he could swim down to you without any difficulty but a few seconds later went into an uncontrolled ascent even while swimming down.

This looks like a classic dry suit fill your feet with air situation. He reached down to grab your manifold pulling his head and body below his feet. When you turned away he was going into the handstand position with the air expanding in his ankles which had gone from 30ft to 24ft. A couple of seconds later he is at the surface.

Yes new dive gear and unfamilliar tanks he should have done a buoyancy check on empty tanks first, but then you could not have gone diving.

Just chalk it up to experience and remember to log how much lead you need with all the different tank configurations you encounter.

 

[Matsya]

Thank you for a great post and an objective analysis.
I am just about to complete 50 dives and am only a beginner. I am using your post as a learning experience and am posting this only from that point of view.
What I am able to learn from your experience is that I should never ever leave my buddy in trouble for whatever reason unless I have adequately understood the nature of the problem and am reasonably sure that if I leave her/him, he/she will remain in the same place until I return.

 

[wreckedinri]

Paul,
As the other posters have said, I also don't think anything was done "wrong". Could things have been done differently; sure. With hindsight, it's easy to see options that would have made the situation better. But, as mentioned already, this is the real world. We must make decisions in a fluid and dynamic environment, using the information that we have immediately available to us. I can’t see where anyone could have done better. Miscommunications underwater are a fact of life. Hell, it happens when people are face to face and speaking to one another and not under 50 feet of low vis water! Ya, I know some may suggest wet notes or standardized hand signals, but you did the best with what was available to you at the time. The fact that you guys step back and analyze the dive and wish to learn from past experiences illustrates the thoughtfulness and regard for safety, as well as for each other, that you bring to your scuba experience. Can’t ask for more than that from dive buddies.

Be Well,
Dennis

 

[do it easy]

Thanks for posting this. I agree that the hindsight is 20/20. You did look for Frank and you made an effort not to abandon Lou. If anything, you didn't understand what was wrong with Frank before you turned to look for Lou. It's a tough call since you said he appeared to be in control. It's important to stop problems before they spiral out of control. If you had assessed that Frank was light he could have hung onto you while you looked for Lou. Regardless, don't be too hard on yourself- use it as a learning experience.

 

[Charlie99]

That's a great post, Paul.

What it drives home to me is "PRIORITIZE. STAY WITH THE GUY IN TROUBLE".

Reviewing incidents like this makes it more likely that my decisions underwater will be the right ones.

Just last week I had a similar event (even "incident" is too strong of a word) where my buddy took off at high speed to assist a woman that had popped to the surface and decided to start swimming toward the boat a couple hundred feet away. Her buddy saw her go, and was slowly swimming in that general direction. My initial instinct was to stay with my buddy (actually kind of splitting the distance between my buddy and the guy trailing behind). Eventually, I had to decide whether to stay with my buddy, or to stay with the non-buddy (but off the same boat) diver. I abandoned my buddy and stayed with the other guy. He also had been having buoyancy problems, and his inexperience also showed in that he didn't stay with his wife when she popped to the surface and swam towards the boat.

In this case, "stay with the weak, now-unbuddied diver" trumped "stay with your buddy". But I had to think about it. Now the decision is a lot easier and a lot more automatic.

Charlie Allen