a hypothetical for discussion

[jcr]

Let me emphasise this - if I had dived with only double the gas theoretically needed to exit, I would have run out somewhere around the Henkel, and drowned. If I had dived with triple the reserves, I would have barely made it. I NEEDED a 4x reserve.

First, let me say that I agree thirds is unlikely to be sufficient in a catasrophic gas loss at maximum penetration. Divers should be able to calculate theoretical minimum reserves and add to them based on various factors.

However, your dive seems to be a prime example of why conventional gas planning does not translate to closed circuit rather than why conventional gas planning is insufficient. Without knowing the details of the dive, it seems like several exacerbating factors should be considered that would cause a diver to add reserves whether planning an OC or CC dive. You mentioned complex navigation, difficult restrictions, solo (?) etc. You obviously recognized those difficulties and planned accordingly.

My point is that an OC dive team planning a relatively simple dive in Peacock would not require the same reserves. The real art to dive planning is recognizing the exacerbating factors and planning accordingly.

[Sludge]

I have been specifically taught not to use the two different signals.

I can guess. The problem with using two different hand signals for two different situations would be...

[alias]

Glad to find more finger twirlers amongst cavers. I was starting to think cave community was mainly thumbers because so adamant has been the resistance if not ridicule when bringing this up pre-dive. I am always sure to ask what people use for turning, especially because my first cave instructor was a thumber. I have always been a turner not a thumber but I’ve found that a lot of cavers prefer the unequivocal thumb. I will do what is agreed but I can’t help it that I always associate thumb with ‘out NOW’, and get slightly irritated if there are delays without explanations after it is presented.

[DA Aquamaster]

I will do what is agreed but I can’t help it that I always associate thumb with ‘out NOW’, and get slightly irritated if there are delays without explanations after it is presented.

It's even more annoying the other way - when you thumb a dive to exit NOW and team members start dicking around and delay the exit.

[Sludge]

If anyone insists on a thumb, they're going to have a hard time catching me exiting.

[bletso]

To me it is important to use the two different signals as they are meant to be. One dive a while back I was with a dive buddy and he turn the dive (twirled finger), so I answered and we started out. I made a couple of stops and he became a little antsy and gave the thumbs up signal which changed the tone of the dive. Nothing serious but a he had become very anxious being a newbe cave diver and wanted the hell out of Dodge.

I have thumbed very few dives over the years and reserve the thumb for what it was intended for.

Dale

[fghray1]

Easy, Get your butt out of the cave at the nearest exit, If you did what your suppose to an studied the map you should know where that is even if it's the first time in the cave. There is only one real emergancy in a cave. That's No gas. The rest are just things to deal with.

[sskasser]

If anyone insists on a thumb, they're going to have a hard time catching me exiting.

I'd think it'd be the opposite. If someone gives me the thumb, I'm going to be on them like the proverbial "white on rice" to ensure I'm available to help with whatever prompted thumb, should it get worse.

And yep, I go over the twirl vs thumb before a dive with a new buddy. If I have any doubt as to a possible problem when I get the thumb, I return the thumb and as I'm turning (not wasting any time!), I also get beside the buddy and point at them, followed by the OK...as in "you ok, bud?"

[Sludge]

Okay, Shirley, I guess I didn't make myself clear. This would be for someone who insists that a finger twirl is an unacceptable signal, and a thumb is the only way to signal turning on thirds.

I would make sure things were indeed fine, then make a beeline for the exit.

(That was me being a DB. Get it?)

[Gary]

I'm a finger twirler. If someone gives me the thumb I'm going to be pretty concerned about identifying the problem that lead to the emergency so I can account for it on the exit. (Do I put them in front to light the way for them and find/communicate with them? Do I need to worry that their one remaining regulator could go and I should be extra handy? Are they cold/confused/gonna pass out? Or a emphatic turn on gas remaining?)

Yes, thumbs-up means "EXIT" no question on that - but if they don't say what is wrong (and I can't see "it" for myself) I will probably ask.