Pure curiosity

[BigBoB]

During the first few dives of my class we had done significant lights out work. More than 20 minutes each dive. I felt very comfortable and never really felt completely in the dark due to my hud. I guess being able to focus on the hud's constant blinking gives you something else to focus on other than the dark.

On my third day of CCR cave I experienced the worst silt out to date, lights were completely useless. Turned out one of my buddies and caves did not get along. The plan was for me to run a jump just after the peanut restriction. ..think we were going to challenge, but I can't remember exactly. About halfway across the jump, for whatever reason, I glanced back and surprisingly there was a wall of silt coming at me and I could vaguely could make out one light out of three. I then sped things up a little and tied my spool into the other line. To make matters worse for me another team had already had a spool run and all I could think about was please make it to the other line and tie in before the silt gets here. I did make it to the other line but had to tie in lights out. After tieing in I waited on the line for what seemed like 5 minutes but was probably closer to 45 seconds. After turning around I couldnt see ****, not even my hud. After some quick thinking I decided it would be prudent to figure out what I was breathing so I fiddled with the hud and positioned it up against my mask (always have it configured this way now) and followed the line to my nearest buddy and started a "bump and go". We never seemed to slow down so I assumed that my buddy that I was bumping was bumping the guy in front of him. After swimming for about 5 minutes or so we were still in the silt and I still could not make any lights other than mine and my buddies. Once coming out of the silt I could just make out two lights in front of our team and we ok'd them and the entire team exited very quickly. After surfacing, I found out that the third member of our team had gotten spooked and basically freaked out kicked up a bunch of silt, climbed over the instructor and hauled ass flutter kicking all the way out of the cave . Cave diving wasn't for him.

Question for instructors: What do you do when this happens? You have one student who is sprinting out of the cave and you have two others that are back in a huge siltout.

[BabyDuck]

phil, as for how instructors keep track...magic. i'm firmly convinced.

i think mike o'leary feels the line to 'see' what's going on, along with brief *brief* flashes of his light.

and he made me take off my vr3 for the lights-out stuff!

[Gene Powell]

... or if you dive with the people I dive with.

LOL! Sounds like my buddies been cheating on me!

[RN]

It is where I come from.

A true ZERO visibility exit? I do a lot of off the beaten path dives in small passage where exiting in reduced visibility is inevitable just because of percolation. But ZERO visibility just isn't that common for that long, especially in backmount.

[sea2summit]

... or if you dive with the people I dive with.

???? Big talk Mr. Scooter tail in the dirt and hold the trigger

FWIW I've only been in to "real" silt outs one caused by Russell that lasted all of the 3 seconds it took for JB to flush it out and the other one in the century tunnel at Maddison. Century tunnel was basically no-flow so we had to swim out and I'd say less than 75' of stuff we'd stirred up and we where clear. So yeah 38min might be long but I'd rather know I could go the distance and not have to then start freaking out after 75' of swimming.

From back in the days when I made money diving closing my eye's helped more than a few projects get done that I was making no progress on with my eye's open. If your in the situation give it a try.

[scububa]

How likely is it to lose visibility for that long and in that much of the cave? I've been in a few low to zero visibility situations and they have all cleared up enough to come off the line within a couple hundred feet. A zero visibility exit from 38 minutes in the cave isn't a realistic situation.

Yes, but to run a 10k race (pick your favorite distance/event) your training is generally longer than running 10k once. It classically takes repeated sessions of longer duration to become proficient enough to execute to standards.

[b1gcountry]

Non Cave diver question here...

How does the instructor keep an eye on you if all the lights are out. I always just assumed that they used some sort of blackout mask, and then the instructor could still have things lit up. From the sounds of what LCF posted that all the lights were just out. Is it something where you are diving in caves that the instructor knows so well, that as long as they keep close they know if you get out of sorts?

Just wondering.

Thanks
Phil

When Kathy and I did our class with Jim Wyatt, he just told us to close our eyes. Apparently, he tested us a couple times by looking into our masks, and giving us some hand signals to see if we responded, but also said that when I bumped into the same rock for the fourth time, he knew I wasn't cheating

[Gene Powell]

A true ZERO visibility exit? I do a lot of off the beaten path dives in small passage where exiting in reduced visibility is inevitable just because of percolation. But ZERO visibility just isn't that common for that long, especially in backmount.

It only takes once! You obviously have better bouyancy skills than I do.

[DA Aquamaster]

...and the other one in the century tunnel at Maddison. Century tunnel was basically no-flow so we had to swim out and I'd say less than 75' of stuff we'd stirred up and we where clear.

Marci and I have been to the end of the line in the Centruy tunnel when the cave was fairly fluffy, post flood, and even then, the viz on exit was only 6 inches or so briefly in the last man out position right after we turned, but it never went to zero.

Six inches is a lot of viz if you make use of it.

And that's probably the point of doing totally blacked out exits.

[JLH]

My last lights out drill was in the catacombs in the devils system with three divers. That was interesting. We did a lost line drill at the lips with blacked out masks. I was the first one done, after I switched masks I got to go to the top and watch the others. Then followed our line through the catacombs. As soon as we were in, we were given the lights out signal . I was leading, then the back two were told to share air of which I had no idea untill we were out.