Question silt out communication

[lermontov]

wondering what comms system do people use in a silt out - had a recent trip where one diver went through a silty restriction and was waiting for the second diver to come through - second diver didn't want to follow so both waited for each other to make a move -both fearing if they both went at the same time they would meet head to head in a tight unturnable restriction

I have an idea of a plan but wanting to hear others systems

eg a signal for :
i need help
I are you coming?
yes im coming
no im not coming

 

[elmo]

What @oya said. Do not pull on the cave line ever.
Every cave line should be tight, loose line, especially in a silt out is a disaster.

I definitely agree with respect to permanent line (or temporary line when you’re not beyond the last tie off). Where a tug can work, without risk of damaging the cave, dislodging tie offs, or snapping the line, is when the lead diver is running line and the second diver is between the last tie off and the lead (as they should be). When holding a reel it’s quite easy to tell if someone is signalling on the line. Most Australian caves have little or no permanent line, so we’re using our primary reels frequently (Tank cave, where the OP was is a very nice exception, with kilometres of well-marked permanent line). Most of our caves are also silty and one diver needs to go ahead through restrictions, out of touch reach of the second. The communication technique has limited application, and of course is absurd where touch or light communication is possible. But it can be used in some situations.
Regardless, if I were ahead and the second diver didn’t follow through a restriction, of course I would return whether or not I felt anything on the line. And I would expect the same of my teammates.

 

[rddvet]

Line signals I was taught as part of CDAA (Cave Divers Association of Australia) were:
1 tug of line: stop
2 tugs: ok (question and response, equivalent to ok hand signal)
Continuous tugs: not ok / I need assistance / distress
I assumed that was universal but perhaps not.
It doesn’t work very well with tight permanent line, or with thick gloves. But it’s quite well if someone is running out line (primarily or spool). There’s one cave in Mt Gambier where there’s a loose permanent line/rope through a restriction precisely for this purpose.

Oh f—k no. If that was discussed as part of the pre dive plan I’m out.
Besides being just a stupidly dangerous idea, what happens in a place like France where you may encounter metal line, not the classic white
line.
Edit: just saw you meant the line coming off the reel. That’s somewhat better, but still a no for me. Seems like a good way to pull off a loop and get it entangled on your buddy. Still a hell no for me

 

[mr_v]

Your best bet is to turn around and review the situation on the surface.

 

[boulderjohn]

Situations like this can indeed happen, and they can be fatal. About 5 years ago there was a thread about some sort of short range radio-type device, and people scoffed that it wouldn't ever be needed. I disagreed.

I was a part of a team that had a pair of advanced divers exploring a very tight and challenging cave. One went through a tight restriction with the understanding that the other would await his return. For whatever reason, the one who was supposed to wait did not, and so the two met head to head in a complete siltout in a very tight section. Why did he not wait? Maybe he thought the forward diver was taking too long and might need help. We will never know, though, because he never made it out alive. Some kind of short range communication device would have been nice.

 

[NW Dive Dawg]

I am admittedly not a caver so my suggestions for this scenario are not well founded. But it seems that if two "disconnected" divers are still within reasonable sound range that you could easily have some pre-agreed tapping signals.

 

[Rilelen]

As several people have said, this is easier to discuss on the surface ahead of time or with a regular dive buddy. In general, touch contact works okay in zero vis if you’re close enough, and nobody is panicked.

For a situation where one buddy has gone through a silted out restriction and the other is waiting, my regular buddy and I have a fairly good sense of how long the other *should* take to come through if they aren’t stuck or having problems. If more than that time goes by, we will cautiously head back into the restriction making sure we can back out if/when we meet our buddy coming the other way.

If we do run into each other, we make touch contact to check everyone is okay -if so, the diver coming to check backs up to give them space to keep slowly working their way out. If it’s not a full true zero vis situation, lights can also be helpful communication albeit at very short range and only in some situations (eg at the ceiling, or near the end of the siltout).

 

[kensuf]

FWIW, just because you thoroughly discuss a plan on the surface, that does not mean everyone will fully remember a complex plan when you get to depth. Hopefully they do, but I've seen people forget what they were supposed to do (and not to throw stones from within glass houses, I've been that guy before myself).

"If it doesn't make sense on the surface, it sure won't make sense at 100'."

 

[boulderjohn]

"If it doesn't make sense on the surface, it sure won't make sense at 100'."

Most of my cave training came at about 100 feet. I am sure I was experiencing some degree of narcosis, because I felt even more stupid than normal on pretty much every one of those dives.

 

[lermontov]

Situations like this can indeed happen, and they can be fatal. About 5 years ago there was a thread about some sort of short range radio-type device, and people scoffed that it wouldn't ever be needed. I disagreed.

I was a part of a team that had a pair of advanced divers exploring a very tight and challenging cave. One went through a tight restriction with the understanding that the other would await his return. For whatever reason, the one who was supposed to wait did not, and so the two met head to head in a complete siltout in a very tight section. Why did he not wait? Maybe he thought the forward diver was taking too long and might need help. We will never know, though, because he never made it out alive. Some kind of short range communication device would have been nice.

what happened to the diver in the lead - did they exit somewhere?

 

[lermontov]

some sort of signalling was discussed after the first 2 divers got back and debriefed - i teamed up with one of them on the second day and went back to have another go - the plan was indeed after 10 min head back solo regardless of which side of the restriction we were on, (that takes a bit more planning to ensure the way back on both sides is lined at jumps etc) added to that if a diver needs assistance -rapid taps with a double ender on the tanks was the simplest signal we could devise

The big difference is if its a new lead and theres unknowns on the route and may not go

you could of course elaborate on an audio signal but ill leave it simple for now