DIR and SPG

[Jason B]

The line should never be outside of arms reach anyway.

If you dive the devils system in High Springs (high flow), and stay within arms reach of the line, you aren't going to get very far at all (maybe make it to the lips which is 270ft).
If you are reading the cave, at times you'll be 20ft from the line in there.

 

[rjack321]

Never been there, can't really comment. But it seems like the line might be in the wrong place or is the consensus that its vitually impossible to lose vis in that high a flow anyway (?) Or that if you did lose track of it you'd end up back in the basin in OW. Presumably this is a spring not a siphon

Assuming you were trained down there, did your Cave1 instructor recommend being more than arms length from the line?

 

[Kendall Raine]

top 3 causes of death in trained cave divers
excessive depth - from narcosis and/or exceeding MOD
failure to maintain guideline
failure to reserve 2/3rds gas for exit

In that order from accident analysis. There's a slightly different list for OW divers. None of which has much to do with scooters, spgs, or air shares.

Scooters blowing out the vis is not a high risk event. If it happened it woud be high risk, it just doesn't happen very much. Scootering in a cave is at a vastly different level than "do I check my spg after an s-drill or not" kinda question/issue.

If I dove in kelp forests all the time the concept of the SPG check would have more merit IMO.

Glad to see "Blueprint" is still required reading in intro.

As for scooters blowing out viz, it certainly doesn't happen unless you're scootering, true. Eagles Nest ring a bell?

 

[Meng_Tze]

Never been there, can't really comment. But it seems like the line might be in the wrong place or is the consensus that its vitually impossible to lose vis in that high a flow anyway (?) Or that if you did lose track of it you'd end up back in the basin in OW. Presumably this is a spring not a siphon

Assuming you were trained down there, did your Cave1 instructor recommend being more than arms length from the line?

In medium/high flow the risk of silt staying there is minimal to non-existent. All the silt is already blown out and sand/larger particles are left. These sink almost immediately when stirred up. Even when doing training dives there, you can be at times a bit far from the line. As long as you know where it is at all times you should be fine. I had training scenarios where my lights went off and I was all the way up in the gallerie (near the ceiling). Lights go off, you deflate (in high flow this is the only thing that will get you down almost vertically, other wise just deeply exhale)) and go down as quickly as possible. If you know where the line is, you can find it in the dark and follow out. But it is something you need to work at. reading the cave, remembering what you just passed (look back when you passed a significant feature to remember what it looks like and would feel like). My cave instructor was not too obvious about where I needed to be in relation to the line, as long as I could find it in the dark. Of course I started out swimming close to it ( ), but as time progressed, comfort with ones abilities gets you further away to enjoy more and be higher up out of the main flow.

 

[DIR-Atlanta]

Never been there, can't really comment. But it seems like the line might be in the wrong place or is the consensus that its vitually impossible to lose vis in that high a flow anyway (?)

Probably more the latter than the former. Devil's is a high flow system and a lot of people scooter in there, so the line tends to be run in such a way that it won't interfere with that.

In the Gallery (which is the area of the system from the main opening to the Lips), the line is run along the right-hand wall as you are going in. If you try to swim where the line is however, then you will blow through your gas right quick-like, because you will be swimming in the main part of the flow. For a swimming diver, the "trick" is to get up close to the ceiling - the top part of the passage has a few more twists and turns, which provides places where you can swim more easily out of the flow. You are mostly in sight of the line at that point, but definitely not arm's length.

Once you get to the Main Junction at about 450 feet of penetration, the cave passage begins to split and the flow is greatly reduced. It's a lot easier to swim closer to the line at that point.

There are still definitely parts of the cave where you can silt things out though, even with the flow. I remember on my first dive to Double Lines, I was nervous and trying to follow the permanent line really close, and wound up practically crawling through some really low stuff (and stirring things up pretty good in the process). The good news is that if that happens, you can usually just wait a couple of minutes and things will clear out enough to return the visibility to "reasonable".

All my cave instructors emphasized staying close to the line and referencing it often, but Jason B is right - there are just some situations where it's not practical to be arm's length all the time.

 

[rjack321]

In MX the recommendation is to stay within arms reach for 2 reasons.

1) its safer, in MX it would be really easy to get on the wrong line (oh s**t time)

2) its a "trail"
Chris LM had a nice analogy... Its like hiking. Would you take a machete and chainsaw to the forest because you wanted to go "over there"? Your bubbles and percolation do damage the features, so stay on the trail and minimize the impacts of your passage.

I understand FL may differ.

Yes the blueprint and some other reading is still required. Although that list isn't in there as I recall (its been awhile)

I still think the whole SPG check question is a misprioritization of what's important - at least in a cave. OW gives a heck of alot more options so you need more data to make a decision.

 

[SparticleBrane]

Keep all these hints coming, I'll need all of them when I take my cave course.

 

[Meng_Tze]

Keep all these hints coming, I'll need all of them when I take my cave course.

Another hint. they don't throw drills and scenarios at you on the way in............. on the way out; anything goes....

 

[Kevrumbo]

Kev:

Did they cover what you do if the total light failure happens first and then a diver goes OOG in a three man team? Let's say a scooter sticks on in a restriction. Total instantaneous silt-out. Hopefully you have enough time to find the line. You sure won't have time for much else before you're blind. What happens to the donor switch, SPG monitoring, etc then? If you're in flow in a spring, the stuck scooter will blow silt down your route of exit until you get it shut off.

As for being unlikely, the simultaneous light failure mode really simulates silt-out conditions. Not so unlikely. (Agreed actually assuming nine simultaneous light failures is silly.) Silt-outs in cave can be so bad you literally can't read your gauges no matter how many lights are burning. Seems to me your procedure better contemplate donor switch/gas management in a three way without being able to check the SPG or read your watch at all. Hint: They did teach you how to tell time without a timer, right? If you can estimate elapsed time you can estimate consumption and switch point.

We had this drill roughly similar to the above during my latest Wreck Class: a 3-man team laying line suddenly "losing all their masks" (including backup masks:11: ); after re-grouping on the line for egress, one of my teammates presumably was "declared OOG" and promptly ripped my Primary out of my mouth. I positioned him in the middle, put my other teammate in the lead per protocol, and we made our way out using touch contact. . .

The method I used in desperation to estimate elapsed time (I'm gonna really get flamed for this one! ): Play the Final Jeopardy Tune in your head --it's about 30 seconds long-- and try to keep a running tally. . .

 

[rjack321]

Another hint. they don't throw drills and scenarios at you on the way in............. on the way out; anything goes....

There are always exceptions though... E.g. If they think you've gone far enough for the upcoming scenario and want to save some gas for the next dive. My primary failed on the way in once and I gave Chris LM some grief about it, told him that was cheatin'