Challenge question III

[Jay]

BTW Cindy, Great idea for a thread. We may have to make a new forum for this!!!!!

High flow cave with a mixture of medium to large passages

2 member dive team on scooters and backmounts.

Gas on diver 1 just before incident 2500 psi (about 200 psi above thirds)

Diver 2 gas remaining unknown

Both divers diving 34% nitrox

Depth 100-110 feet. Time into dive, about 25 minutes.

Vis at start of incident 60+ feet

The two divers scootered into the cave with diver 1 leading. The mainline was still going at app 2500’ but the cave was getting very small, too small for scooters with the flow dropping rapidly.. The passage was about 10 feet wide but getting down to less then 4 feet tall quickly and diver 1 signaled to turn around. As diver 1 lost visual contact with the line during the turn around something happened that caused a significant amount of silt to develop and in a matter of a few seconds visibilty dropped to zero, a total silt out..
Diver 1 had let off the trigger to turn in the small place and was facing towards the exit, as far as he knew, when the total silt out occurred. Diver 1 had no idea what had caused the silt out and suspected some sort of natural event due to the amount of silt. Diver 1 slowly sank to the floor of the cave which was a combination of sand/silt/rock with no way to tie anything off. Diver 1 had last seen the line about four feet to his left near the wall before executing the turn around by turning to his right away from the wall and the line.
After settling to the bottom, Diver 1 could not hear his buddy’s scooter, could not see his light and could not even read his own gages as the vis was zero, nada, zilch. He remembered checking his gas supply at about 2500 psi a minute before the incident.
Diver 2 had been in a larger space and had made his turn under power. Diver 1 suspected Diver 2 was not any closer then 30-40 feet and possibly further away. The only way out was the way they had come. As Diver 1 went through his mental checks to formulate a plan, about a minute passed and the visibility did not improve one iota.

What would you do?

[aainslie]

Scary stuff. I won't ask why the team was diving thirds on scooters - that's another story. But it's what makes this scary.

Given the small size of the passage, I'd give priority to relocating the line. In a 4 ft passage one should be able to find it pretty quickly.

It'd be tempting to swim back towards the exit to find better viz but if it was some event like a rock fall you could just end up having to search for the line in an even bigger passage.

Once I'd located the line, I'd mark which way I think is out and start exiting with the scooter clipped off to me like a stage, hoping for better viz and to locate my teammate.

[aw]

As Diver 1, I'd first try to stretch my arms out and see if I could snag the line, leaving one hand and scooter at the "lost" point as a pivot. Do not lose this reference "pivot" point and get more lost. If the line's only 4 ft away, then it's within reach. If I could not reach it, I'd deploy my safety spool using a backup light as an anchor in the floor. Once the line was found, I'd mark the direction I attempted to go and start my exit. Since diver 2 should be downstream, I should feel a tieoff if he was doing a lost buddy search or bump into him. If I felt neither, I'd bang on tank and see if I got a reply. If not, I'd try going downstream a little further for clearer passage and re-evaluate if he could have gotten off the line too. If he hasn't replied to a tank bang and you can't see his light and you can't hear his breathing or his scooter running and you didn't run into him or a tieoff on the line, it would be a hard call to leave assuming he ditched you. It would be best to do a lost diver search just in case you assumed wrong.

As Diver 2, I'd wait for him a few minutes on the line for him to show. Then execute lost diver drill if he hasn't come.

In my training, we were told to always turn in the direction of the line. So you'd always be facing it. If you turn opposite the line, then you risk entanglement. Not even a bad idea to always get close to the line just before turning also, esp in small cave where silt is probable.

[Line Squirrel]

Sounds like the Little River incident from a couple years back...

[FW]

Sounds like the Little River incident from a couple years back...

Yes, it does.

Like I said in "Challange Q. II". Look for each other for 5 minutes, or so, then exit. In LR both divers found the line, but one waited too long to begin an exit.

And thirds on a scooter is a bad plan at best.

[aainslie]

Sounds like the Little River incident from a couple years back...

Like I said in "Challange Q. II". Look for each other for 5 minutes, or so, then exit.

I disagree (sorry!!). In this one I'd get the hell out quickly. in the other one I'd search for a LOOOONG time. I think they're very different scenarios.

[skip]

could you not plant something in the floor, a backup light maybe, and tie off to that? leave the scooter jammed into the bottom? although you may need it to exit.... then do the lost line drill. The passage was small, getting smaller going in, so once the mainline is found, getting out is a matter of feeling (arms extended is about 5 feet or more) if it's getting smaller or larger and thus knowing if you are proceeding right or wrong direction.

Buddy was behind, but maybe now ahead, who can tell. if both divers do lost line drill they could pass one another and never know.

By leaving a line arrow to indicate which direction you went (and if buddy did same), then you'd either run into buddies line arrow or he into yours. At some point I assume it clears and then you can figure out if enough gas/time to do lost buddy search assuming you didn't run into buddy, or his arrow, already.

-skip

[FW]

By leaving a line arrow to indicate which direction you went (and if buddy did same), then you'd either run into buddies line arrow or he into yours. At some point I assume it clears and then you can figure out if enough gas/time to do lost buddy search assuming you didn't run into buddy, or his arrow, already.

-skip

The problem with arrows is they should always point the way out, not the direction someone last went. It is also possible that they are just there as personal markers. The only thing they might tell you is that the buddy did find the line. Notes are probably better.

[Kelly Jessop]

By leaving a line arrow to indicate which direction you went (and if buddy did same), then you'd either run into buddies line arrow or he into yours. At some point I assume it clears and then you can figure out if enough gas/time to do lost buddy search assuming you didn't run into buddy, or his arrow, already.

-skip

The problem with arrows is they should always point the way out, not the direction someone last went. It is also possible that they are just there as personal markers. The only thing they might tell you is that the buddy did find the line. Notes are probably better.

I agree Forrest. We've seen this in the past where an incorrectly placed navigational marker actually facilitated the fatality. In a silt out situation and I am on the line,I use feel of a line arrow to determine direction of travel,plus if the silt out is bad enough you couldn't see initials to indicate if they belonged to a buddy. Some people will say they put special marks on their line arrow ie a notch,but in a stressful situtation most people will probably not stop long enough to grope the line arrow to find if is a "permenant" or "temporary" line arrow.

[FW]

Sounds like the Little River incident from a couple years back...

Like I said in "Challenge Q. II". Look for each other for 5 minutes, or so, then exit.

I disagree (sorry!!). In this one I'd get the hell out quickly. in the other one I'd search for a LOOOONG time. I think they're very different scenarios.

You are right, they are different. In CQ2 you would have a lot more gas to search, but that won't help if your buddy has already left. I still think in both cases, look first near the point of separation, then look along the line toward the exit.

If you get out and don't find your buddy then you can decide if you need more gas/help to search, or in the case of CQ2 you should have plenty to go back and look again. No point in searching for someone who had managed to find their way out.

If you always dive with the same buddy, you should know if they would stay, or leave. If you dive with a lot of different people, it would be good to discuss what to do in case of separation before the dive.