Sudden surfacing after 30 min @ 90 feet --A dilemma...

[DC53]

I don't know if this was a near miss, just lucky, or not so much to worry about so to speak, but tonight I was diving with three other divers... It was a night dive in a quarry with 39-40 degree water. I was buddied with a very experienced diver and a pair of experienced divers were just behind us. The leader went to the bottom immediately and then slowly swam across the bottom of the quarry, mostly around 90 feet plus or minus a couple feet, except when going up a little over a boulder here and there and then back down to the bottom. 30 minuts after the start, perhaps 29 minutes bottom time around 90 feet and someone comes up from behind, gets ahold of the lead diver. From below I watch them twirling around, with the fourth diver nearby, and then all three start to go up, and not real slow at that. I still had almost 2000 psi on my steel HP 120 and 16 min NDL left on my computer with 26% nitrox (don't ask) so this was all odd. Viz was poor and even lights would disappear soon. Thinking something must be very wrong I go with them to the surface. I think about stopping at 20 feet but they don't; I think something must be REALLY wrong, and decide to blow my safety stop too, from rescue class I know how many people can be needed on the surface if something is really wrong. We're all on the surface and nobody is saying much. There's a bunch of "are you alright's?" passed around. Within a minute or two I ask if we will re-descend and return underwater and one member of the second pair says "NO!". We swim back across the quarry in the dark on the surface.

Turns out one of the two divers on air went into deco obligation, and the two went up a little bit, but then swam back down & got the lead diver, then came the confused efforts at communication, and then one or more lost bouyancy control and started to ascend (we all had tons of clothing on due to the unusual cold) and then it all went from bad to worse and they ALL went to the top, probably well faster than 30 ft/min. I had followed, perhaps somewhat slower, but still not stopping due to the above concerns. I did not lose control of my bouyancy and could have stopped at 15 feet.

My question is, in a situation like that, should I have stayed and done a safety stop alone or followed what clearly appeared to be a distressed group to the top? (Again, these are very experienced divers and I felt it unlikely that they would do a sudden unplanned mid dive surfacing, after being relatively long and deep, at night, far from shore, without safety stop, unless something was really wrong.) Thoughts, ideas?

 

[fppf]

My thought, they must not have been that experienced if one went into deco unplanned.

And the first thing they tell you in rescue is don't become the next victim. On a dive like that I would hang my stops and monitor the surface from there. If I see something really wrong its your personal choice on what to do. You where not in deco and had a fair bit of buffer before NDL so you where safe going up. I take it the guy that was in deco got lucky and is ok?

 

[idocsteve]

I would not risk my health and safety for two divers with whom I was not even buddied.

Especially since in this case it was not a certainty that there was a "life and death emergency".

 

[gcbryan]

I'm not clear as to how you could have 16 minutes before NDL with 30 minutes at 90 ffw using 26%.

Maybe you weren't down at 90 ffw for quite that long or maybe you were closer to the NDL than you think. In any event it looks like you were at least outside of the NDL.

It looks like you didn't really have a buddy since a group of 4 isn't really a buddy. I also wouldn't be relying on the experience of others now that you have over 100 dives yourself.

I would have had a buddy. If my buddy and I decided to go to the surface for the reasons you suggest then fine. I would have suggested a stop for a few minutes unless I had more to go on than experienced divers were heading for the surface.

It's not that given the circumstances going to the surface was likely to get you bent but deferring to others or thinking that other's know what they are doing is the real problem that I would suggest doing differently next time.

 

[TSandM]

Wow -- I have a hard time regarding "experienced divers" on one hand, and going into deco inadvertently and then losing buoyancy control at depth on the other.

I'm assuming you were diving solo? Unless the trio went rocketing past me, thrashing and in a mass of bubbles from anxious breathing, I would not have gone to the surface after them. I might well have ascended at what I felt was an acceptable and safe pace for me, skipped a safety stop (as they are optional, anyway) and then inquired as to whether help was needed. The first principle of rescue -- don't create another victim.

 

[Bubbletrubble]

Given the circumstances you described, I would have made a controlled ascent (33 ft/min) and skipped the optional safety stop. (That's basically what you did.) You didn't have any deco obligation, so I see no problem with going straight to the surface where you might be needed to assist with a rescue. As others have commented, I think it's strange that experienced divers would lose buoyancy control in a situation like that. Also, barely going into deco on certain computers isn't a big deal. (I'll probably get flamed for that comment, but that's how I feel about my Suunto computer.)

I realize what was going through your mind after you surfaced: "Hey, we had to cut our dive short and I still have more than half a tank of gas left. Let's do another dive!" I have to agree with the second buddy pair, though, when they emphatically denied your request to do another dive after what had happened. It's never a good idea to do a deep dive and not take a decent surface interval (1 hr.?) before doing Dive #2.

To clarify, your designated buddy was the "leader" who went up with the buddy pair, right?

When I'm diving in a large group, we agree ahead of time that if buddy teams get separated, the dive continues on. Of course, if buddies are separated within a team, then lost buddy protocols should be followed.

When buddy teams are diving different mixes or different sized tanks, it's not unusual for the leaving group to tap the leader on the shoulder and wave goodbye. Just a nice way to notify him that: "Hey, we're going to take off now."

No one got hurt ,and I think you learned a little from the experience. Have fun and dive safely.

 

[DC53]

Wow -- I have a hard time regarding "experienced divers" on one hand, and going into deco inadvertently and then losing buoyancy control at depth on the other.

I'm assuming you were diving solo? Unless the trio went rocketing past me, thrashing and in a mass of bubbles from anxious breathing, I would not have gone to the surface after them. I might well have ascended at what I felt was an acceptable and safe pace for me, skipped a safety stop (as they are optional, anyway) and then inquired as to whether help was needed. The first principle of rescue -- don't create another victim.

Yes, these were divers with 500-1000 dives (the leader / my buddy -- probably more), much in cold water. The one that was going into deco wasn't in deco much, I think. Personally I would not have gotten that concerned; he doesn't breathe much air, uses the same HP steel 120's that I do, and could have had lots of time to burn off the obligation when we eventually hit the wall on the other side and came back shallow. He and his buddy also could have followed at the limit of visibility above us.

To clarify the lead diver was my buddy; we were two pairs essentially. That was a factor in deciding to go up without stopping.

Also to clarify, I didn't want to do a "second dive" after surfacing, I was just thinking, hey, 30 seconds on the surface, no DCS symptoms, blown safety stop, lots of gas, get back under quick.

All these things came fast.... I sure would be kicking myself today if I got some DCS symptoms and possible injuries. But on the other hand if I had stayed down and somebody was on the surface with a life threatening condition and did not do well for lack of help I would be kicking myself at least as hard. Monitoring from below would have been impossible. I might have seen some lights periodically from 15 feet but nothing else. Viz was poor and it was either go with them or stay; decide right now.

 

[TheScubaBOB]

I'm going to have to second that question about how close you were to the NDL.

I just pulled-up iScuba Plan on my iPhone (which uses the formulas the PADI Tables are based on and does Nitrox using EAD) and it gives a NDL Limit of 25 minutes at 90ft with 26% Nitrox. Of course I know the tables (and therefore the formulas used to make them) are conservative so I assume you dive with a computer.

Even then we're looking at almost double the NDL (45 minutes vs 25 minutes).

Since you said the descent was pretty direct down to 90 ft I would guess you didn't take a 10 minutes gradual swim down the slope from 30 to 90 ft.

Can you please clarify this part of the dive profile you indicated?

 

[DC53]

I'm going to have to second that question about how close you were to the NDL.

I just pulled-up iScuba Plan on my iPhone (which uses the formulas the PADI Tables are based on and does Nitrox using EAD) and it gives a NDL Limit of 25 minutes at 90ft with 26% Nitrox. Of course I know the tables (and therefore the formulas used to make them) are conservative so I assume you dive with a computer.

Even then we're looking at almost double the NDL (45 minutes vs 25 minutes).

Since you said the descent was pretty direct down to 90 ft I would guess you didn't take a 10 minutes gradual swim down the slope from 30 to 90 ft.

Can you please clarify this part of the dive profile you indicated?

No the trip down is at least 45 degrees straight down, 1-2 minutes to bottom. As far as the bottom depth, the bottom was bumpy so to speak and I remember some of it in the low 90's, some in the mid 80's and maybe a 70. Median depth could very well have been in the 80's somewhere.

It is also possible that a few minutes had elapsed between my noticing the 16 min NDL time left and when the incidient happened. I was in my normal mode of turning on the computer backlight and checking things every few minutes but I wasn't watching real closely as I wasn't anticipating any problems; everything seemed to be going very smoothly, I was warm, my bouyancy was good, air consumption fairly low, etc.

When I noticed the 16 min NDL (perhaps a couple minutes before the incident?), I do remember thinking that those guys in the back on air are probably going to have some deco time, but with their experience level I didn't even give it a second thought as something they wouldn't handle smoothly.

As concerned as I was for myself, I can't imagine the two guys on air... Without symptoms, either out of NDL time or with a light deco obligation, but no symptoms, why not go back down, then come to 15 minutes and swim around at that level for a while?

That's apart from my earlier question about what I should have done.

 

[Scared Silly]

No the trip down is at least 45 degrees straight down ...

45 degrees is a slope not straight down. Are you saying you went straight down along the slope to around 70-90 feet?

As to what you did, two buddy teams one team panics about their deco obligation and thinks they need to ascend and takes your buddy with them. Like others have said you did fine ascend normally, do not put yourself in danger, skip the optional safety stop. Figure out the problem on the surface.

Next have a little chat with these "experienced" divers about their dive practices while they buy you and your buddy beers for cutting your dive short.