What did I just read?

[wyandottecaver]

"Maybe a better option than relying on a single ascender would be finding ways to stay out of waterfalls while on rope."

True enough :)

[Anonymous_Coward]

. If your hanging in a waterfall and not going anywhere, it's time to get out of there any way you can.

Not sure how being in a waterfall would make a one-point changeover easier than a two-point one.

[Extremeophile]

But, I have to agree. If you get into that 1 out of a 100 situation and you can't do a "proper" changeover (here to mean always having two points of attachment), don't necessary try to adopt reality ("2 points is impossible for some reason") with your idea of reality ("I must have to points of attachment"). Go with reality, change your concept of what things SHOULD be and do what it takes to save your life.

Okay, so if you're being chased by Chuds then maybe jumping across pits with an ice axe is necessary, or if your trapped by flood water and the cave is filling up then maybe free diving sumps to reach the ocean is necessary, or if you're in an out-of-control rappel then maybe you need to jam some unfortunate body part into your rack. I don't think that's what's being debated, and I think we would all agree improvisation is sometimes needed. Rather, it seems like some are saying that going to a one ascender attachment is okay under certain circumstances that might be anticipated. I'm arguing otherwise.

[Cody JW]

I just think common sense and the most basic math tells you that two is better than one if there is any kind of choice. Maybe if the one ascender like a croll on a frog is weighted it is not going anywhere, but if the second one makes you feel better it certainly will not hurt anything and an extra Petzl type does not weigh much. I think if your life is hanging on the line a second attach upper safety in some situations like removing the upper on a frog to cross a difficult lip ( I have had to do this many times) is just common sense. Odds are , you will never need it, but you already own it . Like the old saying goes -"It is better to have it and not need it than to need it and not have it " especially in the vertical caving business.

[Mike Hopley]

Can anyone even imagine a scenario where hanging from a single ascender, under static tension, causes an accident? Before you call something unsafe (or "less safe"), you should be able to explain why it is unsafe. If you can't do that, it's just superstition or woolly thinking.

Efficiency is a form of safety. You may one day hear the drum beats of a flash flood above you, and have only seconds to changeover and get off the rope (this is not theoretical; people have died because they couldn't get off the rope fast enough). My changeover technique is very simple and very fast. It works much better for me than the more complicated alternatives I have tried.

I'm genuinely interested in people's thoughts about why hanging from a single ascender is dangerous. Please, don't just scold me; educate me! Maybe you'll end up saving my life by sharing your reasons.

I just think common sense and the most basic math tells you that two is better than one if there is any kind of choice.

Two descenders? Two ropes (enjoy the tangle)? Two harnesses?

These are all choices you could make. For that matter, why stop at two?

[driggs]

I'm genuinely interested in people's thoughts about why hanging from a single ascender is dangerous. Please, don't just scold me; educate me! Maybe you'll end up saving my life by sharing your reasons.

Ascenders don't spontaneously explode, nobody is proposing redundancy for the static case. It is when we make dynamic, complex movements on rope, however, that connection points may fail. It is these situations that we need to avoid, and redundancy is there to catch failures of these sorts. Examples:

When you cross a rebelay in the down direction, you are completely detaching your sole connection point (your rappel device on the up-rope), switching to an intermediate connection point (the rebelay anchor), then switching again to a single connection point (your rappel device on the down-rope). Any failure during any of those dynamic connection changes will cause you to drop like a rock.

Clipped your non-locker cowstail to the hanger but the bolt is bad? Your cowstail 'biner gate didn't fully close? Your cowstail 'biner accidentally threaded through the rubber keeper but not the actual knot? Cowstail knot worn to the point of failure? We attach a second, redundant connection point always, with "muscle memory", so we don't accidentally miss one of these connection failures when exhausted.

Thread your rack back on under the rebelay but threaded in a death rig? Accidentally cross-load the descender attachment 'biner across the gate so it'll snap when you load it with your body weight? Thread your rack onto the loose end of the rebelay rope rather than the down-rope? Only thread 4 bars when you thought you threaded 6? Redundant connection point is there to protect you during this dynamic connection change. In the case of a lip or rebelay, this means having an ascender or cowstail clipped to something else until you're certain beyond any doubt that switching to a single connection point has succeeded.

This is what Scott McCrea calls the Rappel Test. We do it every time, with muscle memory, because we never know when to expect an accident.

A changeover from ascent to descent is a change of connection points. Your upper ascender is already on rope, and already works, or else you'd already be cratered. But during a changeover, you are moving dynamically, and in the case of some cavers fighting with a full-size rack, may be literally thrashing on rope. If the changeover fails (you still wind up with your ascender loaded rather than your descender), you're thrashing again, removing the descender, throwing a second ascender back on, repositioning yourself to try again. This is the safer of the two changeover scenarios because you already know that upper ascender is successfully attached from the start, but you're in a situation where you will potentially be flailing about; given the choice, do you choose no redundancy because it's marginally easier/quicker/simpler?

A changeover from descent to ascent, however, should you choose to do it with only a single ascender on rope during the changeover, is a connection change from single point (descender) to single point (upper ascender). When you unthread that rack, there must be no possibility of connection failure in that upper ascender. OK, it's clipped onto the rope, is the footloop you're about to stand up in going to fail? The attachment between your ascender and you lanyard? Have you used it today, is it threaded into your gear loop rather than your half-moon? Given the choice, how much harder is it to stand up tall and put the Croll above your descender, for two points of attachment, before unthreading the only point that you have 100% confidence in?

[PeterFJohnson]

Can anyone even imagine a scenario where hanging from a single ascender, under static tension, causes an accident? Before you call something unsafe (or "less safe"), you should be able to explain why it is unsafe. If you can't do that, it's just superstition or woolly thinking.

I raised the issue of ascenders slipping while holding a static, human sized load in a previous thread. The take away, at least for me, was that while theoretically a cam should hold under load, in practice it does slip when situational factors change. A number of people listed cases where their ascenders slipped under load(as opposed to the far more common occurrence of an ascender slipping while being loaded). I won't rehash that thread, but there are reasons to believe that the friction engaging the cam can easily change causing the ascender to slip.

Two descenders? Two ropes (enjoy the tangle)? Two harnesses?

These are all choices you could make. For that matter, why stop at two?

This is a good point. There is a line to be drawn with redundancy. However, in this case I see a mode of failure for one single ascender. Can I tell you for sure that one ascender is going to slip under certain circumstances? No. But do I see enough evidence to suggest I shouldn't try it? Yes. And furthermore I have no real good reason to go down to one ascender.

[Extremeophile]

nobody is proposing redundancy for the static case.

Actually I am. Although you make a number of good arguments, and one might conclude from this that there really aren't any truly static moments when on rope. Part of my argument is that an ascender rated for 4kN is not enough of a safety factor even in a purely static situation. This is roughly 1/6 the strength of a typical carabiner. If this was enough of a safety factor, then we would all be using 5mm cord to rappel (same 4kN rating).

I'm a little surprised there's so much debate over this. I'm all for reviewing and challenging the status quo, but I thought this was a well established standard in all roped vertical work. If ascenders are developed that are rated to 22kN, can never come off the rope when cross-loaded, and won't cut the rope with a fall impact, then perhaps relying on a single ascender will become the new standard practice.

The way I do a changeover from ascent to descent requires the descender to get threaded onto the rope and both ascenders to come off. I simply don't remove either ascender until the descender is already locked-off. This takes exactly the same amount of time as removing one ascender first, but provides a greater safety margin. About the only time saving, single ascender trusting, move I can think of would be moving past a rebelay during ascent without clipping a cowstail into the anchor. I've never been in such a hurry that I felt the need to skip this step.

[Extremeophile]

Before you call something unsafe (or "less safe"), you should be able to explain why it is unsafe. If you can't do that, it's just superstition or woolly thinking.

woolly thinking?

Efficiency is a form of safety.

I agree completely, but of course some balance is needed.

Two descenders? Two ropes (enjoy the tangle)? Two harnesses?

These are all choices you could make. For that matter, why stop at two?

Too much or too little of just about anything might be bad. I'll take two bolts over one for a main anchor, even though one is more efficient. Sometimes I'll even go for two beers after a good cave trip.

[Carl Amundson]

Two descenders? Two ropes (enjoy the tangle)? Two harnesses?

These are all choices you could make. For that matter, why stop at two?

Too much or too little of just about anything might be bad. I'll take two bolts over one for a main anchor, even though one is more efficient. Sometimes I'll even go for two beers after a good cave trip.

Bolts & beer; I'm good with a little redundancy here.

[Cody JW]

Mike H and anyone else who does not understand- I do not remember mentioning rappel devices in my previous post. I was referring to the use of ( in certain situations where the upper comes off during a climb )a QAS in addition to the upper foot loop ascender on a frog. I am also assuming one has a safety line from the upper foot loop Jumar or Petzl to the seat harness.I was also mentioning that one may already have a QAS attached to their harness for use to get on rope on certain lips. Also I am not advocating more than the QAS. It is just common sense ( I guess not so common anymore) to attach a Jumar that one may already have on their seat in certain lip situations when the upper foot loop Jumar may need to come off to negotiate a lip. Also , I am using the term Jumar generically like saying Coke if one is drinking Coke, Pepsi, Dr. Pepper ect.

[Anonymous_Coward]

I'm a little surprised there's so much debate over this. I'm all for reviewing and challenging the status quo, but I thought this was a well established standard in all roped vertical work.

Derek, I was surprised about this too when I brought it up a few years ago. Check out "Hanging From One Piece", from 23 Sept. 2009 to see how I got schooled on the subject. At the time I thought that two points of attachment was an inviolable rule (or should at least be treated as such most of the time). Turns out many cavers will hang from one ascender, either in special cases or as part of their established changeover routine.

[Jeff Bartlett]

What the hell happened to this thread? I thought we were talking about this retarded article in the News. Can't we start a new thread titled "Discussion about changeovers and ascender safety protocol, version 376?"

[driggs]

What the hell happened to this thread? I thought we were talking about this retarded article in the News.

It was decided that we'd all rather argue senselessly about anything than think any further about sunguramy attempting to weigh her butt.

Of course, now that I've gone back on topic, I wonder if she could use the Archimedes bathtub method to determine the displacement of her butt, then weigh the same volume of lard?

Gah, another horrible mental image!!

Quick, someone try to convince me that I shouldn't use a spectra cowstail!

[Extremeophile]

Quick, someone try to convince me that I shouldn't use a spectra cowstail!

A Spectra cowstail is fine as long as you have a lard butt to absorb the impact.