Analysis of a bad dive

[Spectre]

All these threads about bad dive experiences got me to make time to finish writing up the experience I had a few weeks back...
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I’ve chosen to change the names of everyone involved in this dive, as the point of this posting isn’t to single out anyone, make anyone look bad, or otherwise insult anyone. It’s meant as a story for everyone [most especially those involved] to learn from. The fact of the matter is everyone involved made mistakes, and we dove as a team. The mistakes in the dive were made as a team, and the whole team is involved. Feel free to rip on us as a group, but please don’t single out any diver involved.

Three divers, Jim, Mike and Steve, went on a fairly deep [90 fsw] wreck dive, on a boat, at night. The surface conditions weren’t bad, but they also weren’t ideal. There was a slight current as well as 3-4 foot chop on the water. Jim was in the water first, and headed for the current line to grab on and wait for Mike and Steve. Steve entered second, swam back to Jim and proceeded to get himself situated. Mike entered last and started getting himself situated as well. Jim mentioned to Mike to grab the current line so he didn’t have to worry about drifting while he prepared. Jim then looked back at Steve and noticed him about 10 ft beyond the buoy, and still drifting.

Steve was busy getting his gear all situated, adjusting his weight belt and getting ready to dive. When Jim called to him, he assumed it was a call for descent and said to hold on. Jim called again and Steve realized there was something up, looked up, and Jim mentioned coming over and grabbing the line, which Steve did.

Steve continued to get his gear situated, Jim was waiting, and Mike signaled for decent, and went. Jim fumbled for his regulator, got it, started dumping his BC and tried to descend. After doing his best impression of a basking shark, all the while kicking Steve in the face, Jim finally dumped the rest of his BC, relaxed, and started along the current line. Steve followed, and Mike was way ahead. After getting to the mooring line Mike started the vertical decent down to the float and mooring chain at about 55 ft. At this point Mike looked back and realized Jim and Steve weren’t behind him anymore. Mike waited for Jim and Steve to catch up. All three got together, and continued the rest of the way down to the deck of the wreck at 88 fsw.

They all grouped together there, got everything set and headed out on a counter-clockwise pattern. The group separated slightly, but the visibility was excellent and they all were within 15 feet of each other. About 10 minutes into the dive, Steve signaled for Mike, who didn’t notice. Steve then signaled for Jim, who finally noticed and came over to see what’s up. Steve, pointed to his pressure gauge and signaled low on air. Jim, glanced at the gauge, saw it reading 1200 psi, signaled to Mike and headed for the mooring chain with Steve. Reaching the mooring chain, Jim looked back to wait for Mike, so all three could group up and begin the ascent. Mike swam by, and headed up the chain as Steve had already begun his ascent.

Mike was stuck in a precarious position. He had Steve ascending the line, and Jim still at the bottom. Making a judgement call based on the information he had available, he decided to head up after Steve, leaving Jim at the bottom of the mooring line. Not seeing Steve’s SPG, and knowing that Steve had turned the dive because of being low on air, Mike make the call to stick with Steve, since it was possible Steve could be very low on air.

Jim looked up and saw that both Mike and Steve were gone, and began his ascent. Watching his computer ascent rate, he decided to not go at his usual very slow pace, and pushed it at the 30 fsw/min limit. Mike and Steve got to the end of the chain, looked back for Jim, and finally seeing Jim’s light, Steve continued to head up, with Mike following.

The three grouped up where the current line meets the mooring line. Since the tide was high, that point was 20 fsw. Mike was up about 18 fsw deciding were to do the safety stop, when Jim suggested we move down the current line to 15 fsw for the stop.

Steve was having trim issues, and was holding the line to get a little help with his buoyancy. As a result the line was pulled, and Jim noticed the group was at 8 fsw. Signaling to descend back to 15 fsw for the safety stop, Jim started to descend, with Mike following. Mike accidentally let to much air out of his BC, and was trying to get some more air in, while trying to recharge the glow on his depth gauge with his light. Jim began to flash his light down on Mike wildly, as Jim was at 20 fsw with Steve fighting positive buoyancy at 8 fsw and Mike down at 35 fsw. Mike ascended, Steve descended, and Jim looked at the current line which was flowing in all different directions, and made a judgement call. Due to the dive turned well below NDL limits, no alarms showing on his computer, and serious buoyancy issues, Jim decided to abort the dive at this point without the safety stop, as problems were snowballing. All three exited the water safely.

Now what did we learn. First and foremost 99% of the issues could have been handled with dive planning. We thought we had a plan. Turn pressure and turn times were discussed, group up, descend, group up, dive, turn, ascend. What did we miss?

Well… what we missed and the lessons we learned are:

• “Meet you at the buoy” wasn’t proper planning for where to group up prior to descent.
• “Wait until everyone agrees to descend before descending” was assumed, but not verbally communicated.
• “If separated on descent, wait for the others” assumed, not communicated.
• “Group up at the ascent line before ascending” was assumed, not communicated.
• “Let the guy with the ascent rate indicator lead the ascent” and “Let the guy with the computer signal the safety stop location”. Not discussed.
• Make sure everyone is comfortable with neutral buoyancy in mid-water at night, and everyone understands to use lines as guides, not buoyancy corrections. Also make sure there is an alternate plan in case there are buoyancy problems. What we should have done is continue up the mooring line to 15 fsw, do our safety stop, and then swim along above the current line to the back of the boat [option #1], or ascend the mooring line to the bow of the boat, then swim on the surface to the back of the boat for exit [option #2].
• Deep warm-water boat dives shouldn’t be considered much experience for a cold water deep night dive. The effect on your ascent buoyancy when dealing with the squeeze in a two piece 7 mm suit is a hell of a lot different than a 3 mm suit.
• When doing something new, limit the task load. If you’re not comfortable with a night dive, then leave the camera behind.
• Check your air levels before you’ve completely geared up. Steve’s tank was a little skimped on the fill. His second tank as it turns out, was definitely topped off and would have been a much better choice.

Thankfully, we are all safe, and able to look at this dive and learn from it, so that hopefully these mistakes don't happen again. "That which doesn't kill us only makes us stronger".

 

[SubMariner]

Great story on "lesson learned", Jeff. Posting it here took a lot of courage; no one likes to admit that they had a "bad dive".

Thanks for sharing it with us. The analysis at the end was especially good.

Take care, eh?!

~SubMariner~

 

[art.chick]

Yeah, no need to rip on 3 guys who learned a lot of stuff the hard way. Communication really is the biggest deficit in diving. So many problems come about because everyone thinks the others should be clear on his plans. Sometimes I think I am playing an underwaer "Simon-says" with some of my buddies.

 

[ScubaCRNA]

The post and the comments that followed are what makes this site. No flaming or blaming, just good information that I know I can use. Thanks for the lessons learned. They will go in my "lesson bank"

 

[ckharlan66]

Thank you for posting this so we all can learn from the experience without anyone else having to go throught it.

We all can and have either learned something or at least had the point driven home.

Chad

 

[FredT]

It did however qualify as a good "learning experiece" or "interesting dive" that could have turned into a "bad dive".

Do you remember the old Chinese curse "May you live in interesting times?"

Lets put this dive in perspective.

A "good dive" is one where everybody comes home breathing on the same boat they went out on, and nobody bleeds.

A "bad dive" requires chopper support to keep somone breathing or calling the recovery folks. If you are ever involved in a truely bad dive situation the differences are obvious.

Spectre,

We all learn from mistakes. You made a few. You recognized them even if you recognized them a bit late. Nobody got hurt. Good dive.

OTOH
It's always best to learn from other people's mistakes. It's less painful and fewer people die. The Cavers understand that down in their bones. Dozens of people died to learn the lessons necessary to make today's cave divers "safe". OSHA inspects "near miss" reports as well as accidents to learn the slight differences between the two, and what made the "accident" an accident instead of a near miss. You also understand this because you posted the report so others could learn from it. You also asked for input in case you missed something else that could be learned from your experience. Both are "Good Things"!

I am much more likely to post an "interesting dive" than one that went 100% according to plan. There is generally more to be learned from an "oops" dive.

The only things I see you possibly could have missed are:

1. 3 person buddy teams are bad news at night unless all agree on SIMPLE rules. "Meet at the ascent line." is NOT a simple rule that will encompass all possible events in a 3 man buddy team dive. A "better" plan we have used where a 3 man team is necesary is the low air man is to be escorted to the upline by at least one buddy (preferably both). The man on the upline is now in less danger than the man sucking air at depth so the remaining diver remains with deeper diver. Unless otherwise agreed the diver who dropped the LOA diver hurries the odd man up to the one hanging! The exception is if all three are experienced enough to "solo" the existing conditions. In that case the LOA diver will know he will turn his dive early relative to the others while still onthe boat, and the team will plan the dive to "drop him at the upline" with more than enough gas to surface safely a couple of times before continuing their dive.

I've done MANY 3-man night dives and hundreds of 2 man night dives. IME those 3 man dives are the ones where problems are more probable. I avoid them if practical. I can't recall a serious problem on a 2 man night dive, but I can give you an entire handfull of problematic 3 man night dives including a couple of near drownings and a "lost diver" that was eventually recoverd breathing.

2. Hang a submersible strobe or other light source at stop depth(s) on a shot line under the boat from the same cleat the descent or mooring line is made fast to. If you are shallower than the appropriate strobe go deeper, if deeper, come up. A strobe will be visible as a point source about 4X the "normal" vis while a chemlight is only good for about 2X. It avoids all that "recharging the gauge" distraction.


Good post!

FT

 

[Manogr]

This is the kind of posts we need !!

Excellent...educational !


Manogr

 

[MikeS]

Jeff,

Great post, there’s no better teacher than experience, even if it’s someone else’s. Your post highlights the complication of the decision-making process resulting from diving with a three-some. It’s a lot easier and less stressful to have to worry about a single buddy, than having to make the decisions that Mike was faced with of deciding which diver to stay close to.

Mike