Are siltouts inevitable?

[phillip1]

I think what most of us are saying is this statement isn't true. A more accurate statement would be "any acute, severe stress is going to atleast slightly raise the probability of a diver taking actions that might have a tendency to reduce the visibility in the cave."

Precisely

[LiteHedded]

a siltout while shutting down a valve shouldn't be inevitable. if it is you should be practicing this more often IMO
could it happen? sure. SHOULD it happen? no. not unless you're in a really tight spot anyway

[DA Aquamaster]

i didn't get the feeling that my instructor thought 'why bother doing the drills in trim since you'll silt it out anyway', but more 'if there's a big enough emergency that you're doing emergency things, there's a big enough emergency to get on the line'. he *did* say that in a real lost line, arm sweep that cave all you need to!

so, yeah to most op's - plan for the worst, hope for the best.

I had the same instructor and had a similar impression.

Certainly the goal was to clearly avoid silting a cave while shutting down a post and/or initiating a gas share, but there was recognition that if this occurs, you're in a far better position if you are on or very near the line and getting there while dealing with the situation should be high on the priority list.

For example, in debriefing one drill the point was made that once the diver with the failure had the long hose - the donating diver needed to use that length and get on the line, even if the OOA diver was distracted and/or pre-occupied and was apparently content to hang out in mid passage dealing with the failure. The team as a whole is far better off if someone is on the line and properly oriented for the exit before the viz goes south as it greatly speeds the transition from immediate action with the failure to actiually exiting the cave.

[SuPrBuGmAn]

a siltout while shutting down a valve shouldn't be inevitable. if it is you should be practicing this more often IMO
could it happen? sure. SHOULD it happen? no. not unless you're in a really tight spot anyway

Damn right, I mean comon, the valves are right there in front of me :P LOL

[LiteHedded]

Damn right, I mean comon, the valves are right there in front of me :P LOL

is your manifold broken? you should really get that looked at

[SuPrBuGmAn]

Let me know if you see it anywhere, I seem to have lost it.

[netmage]

I was reading another thread where someone said that, in an out of air situation, you were going to silt the cave out, anyway. I dove with somebody last year who maintained that one of his instructors had told him not to worry about trim during valve drills, because in the event of having to do a valve shutdown, "You were going to silt the cave out, anyway." (It's unclear if anybody actually said this to him, but he had come away with it, anyway.)

My cave instructors, all five of them, would not have been happy with me, had I responded to ANY drill, simple or cascading, by disturbing the viz. Some probably would have strangled me with my own long hose if I had Now, I know those are drills, and real problems are much more stressful. Since the worst problem I have had so far is a dead light (and I didn't silt the cave out getting out my backup) I don't know what I would do in the event of a real emergency.

So I'm asking . . . for any of you who have had to do a shutdown or share gas with somebody, did you silt out the cave?

'not to worry'... that instructor should have their card yanked... Pls post, or PM me the thread involved...

In this day and age where people yell, gripe and ***** at an organization for trying to raise the bar, then someone goes forward and so blatantly lowers the bar is unacceptable....

[carrielsal]

Interesting question. I wonder if the original OP mixed up what the instructor was saying. I read a post here yesterday that supposedly an instructor recommended having the long hose on the left post. Turned out that the student was confused, and what the instructor had actually said was the exact opposite of what the student understood.

Carrie

[Webmaster]

Try not to.

But if you do, it shouldn't be a big deal. i.e. You should always be mentally prepared to handle that.

[lamont]

A valve shutting down could be in response to a free-flowing second stage, and most of the cave that I've been in so far has actually been percolation-free -- so i can't see how a siltout would be "inevitable" in that case. If the normal bubbles from 3+ divers isn't causing a siltout, I don't see how a brief free-flow is going to inherently cause a silt-out. If I couldn't do a valve shutdown while neutral and trimmed and generated a needless silt out in the process by crashing into the bottom then I'm just causing myself more stress than I need.

If the cave is already silting out due to percolation just because of your passage, and you have an additional gas loss issue, then simple math suggests that you're going to have less viz than you would have otherwise. At some point it might be so silted out that it doesn't make any difference otherwise (particularly while exploring in passages that are just going to be zero viz exits due to percolation anyway), but it seems _obvious_ that you should use skill to attempt to minimize any stressors. You shouldn't optimize for silting out the cave.