Two Points of Contact Rule

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Re: Two Points of Contact Rule

Postby Scott McCrea » Nov 7, 2013 8:40 pm

PeterFJohnson wrote:When I went through my training on the industrial/professional side they viewed ascenders as 1/2 a point of contact and descenders and other devices as a full point of contact.

So, would a cowstail with a non-locking biner be one point or a half?
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Re: Two Points of Contact Rule

Postby PeterFJohnson » Nov 8, 2013 6:48 pm

Scott McCrea wrote:
PeterFJohnson wrote:When I went through my training on the industrial/professional side they viewed ascenders as 1/2 a point of contact and descenders and other devices as a full point of contact.

So, would a cowstail with a non-locking biner be one point or a half?


Non-locking biners are a no-no for life connections in the professional/industrial world so it would be considered zero points of acceptable contact. I guess I should clarify that nowhere is the 1/2 point of contact actually codified in OSHA or ANSI standards. It was just how it was taught to me when I went through SPRAT training, and I thought it was a helpful way to view it. But maybe the whole 1/2 point confuses things more than it helps when it comes to caving. I can already think of a few caving centric exceptions that complicate it.
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Re: Two Points of Contact Rule

Postby NZcaver » Nov 8, 2013 7:19 pm

I have seen a pair of cowstails with non-locking carabiners clipped into a single ascender described as 2 points of contact. I thought that was stretching the rules a bit, but we are talking a stationary ascender on the rope. Like most caving rules, I guess "it depends."
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Re: Two Points of Contact Rule

Postby caver.adam » Nov 10, 2013 9:40 am

Not sure about the last post...you only count the items that touch the rope. It sounds like you are having two biners and lines on one ascender. Since there is only one ascender touching the rope that only counts as one point.
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Re: Two Points of Contact Rule

Postby caver.adam » Nov 10, 2013 9:41 am

Although, I've seen some people use two non-locking facing opposite directions instead of a locking biner. The rational being that if you accidentally unclip one the other will still be clipped.
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Re: Two Points of Contact Rule

Postby NZcaver » Nov 10, 2013 1:25 pm

caver.adam wrote:Not sure about the last post...you only count the items that touch the rope. It sounds like you are having two biners and lines on one ascender. Since there is only one ascender touching the rope that only counts as one point.

The logic, as explained to me, was the ascender is a stationary point during a changeover and the user is physically clipping into and out of it with 2 devices and 2 separate actions. In this context the ascender is effectively being equated with a hard tie-in (a knot), or a descender - either of which is generally considered an acceptable single point of contact with a rope. This was coming from a very experienced instructor of vertical techniques and cave rescue so I felt it was worth mentioning for added perspective.
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Re: Two Points of Contact Rule

Postby chh » Nov 10, 2013 2:59 pm

It's funny, I don't think that 2 points refer to a time past when knots were the primary point of contact. If anything, I'm MORE confident in my knots than I am in a mechanical ascender given the appropriate interface, of course.
That being said, I hang off 1 ascender during changeovers, with two carabiners. I don't know if this is 0, 0.5, 1, or 2 points, nor do I care for punditry. I am a rope professional and I'll say this, OSHA, ANSI, SPRAT, or whomever, doesn't care what we do underground because none of us are earning money while we do it. Do what doesn't get you killed in the simplest fashion possible.
Your words of caution are no match for my disaster style!
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Re: Two Points of Contact Rule

Postby Extremeophile » Nov 10, 2013 7:22 pm

Scott McCrea wrote:
PeterFJohnson wrote:When I went through my training on the industrial/professional side they viewed ascenders as 1/2 a point of contact and descenders and other devices as a full point of contact.

So, would a cowstail with a non-locking biner be one point or a half?

I did the math, and it counts as 0.71 points of contact (with rounding).

Given how critical cows tails are in vertical caving, I've never been comfortable with non-locking biners. They need to be quick to clip and unclip, and I've found that key lock auto-lockers with a simple twist and open mechanism are a better alternative to non-lockers. These can be quickly manipulated with a single hand and I particularly like the Mammut Element.
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Re: Two Points of Contact Rule

Postby Chads93GT » Nov 11, 2013 11:33 am

If I am not mistaken Alpine Caving Techniques shows 2 non lockers on the cowstails with a locker holding the foot loops to the hand ascender. The non locker is then clipped into the locker.

Do folks deem that bad since the cows tails arent locking?

I have mine set up this way.
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Re: Two Points of Contact Rule

Postby NZcaver » Nov 11, 2013 2:19 pm

Chads93GT wrote:If I am not mistaken Alpine Caving Techniques shows 2 non lockers on the cowstails with a locker holding the foot loops to the hand ascender. The non locker is then clipped into the locker.

Do folks deem that bad since the cows tails arent locking?

I have mine set up this way.

Not bad, just personal preference. I had non locking carabiners on my cowstails for years. Then the idea of using compact screwgate lockers was presented to me and I modified my system. My long cowstail is clipped into the small oval stainless maillon joining my upper ascender to my footloop, and the carabiner is usually locked. My short cowstail carabiner is usually left unlocked for clipping in and out of things, but can easily be locked when needed. Best of both worlds.
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Re: Two Points of Contact Rule

Postby PeterFJohnson » Nov 11, 2013 2:21 pm

ACT does indeed recommend non-lockers. This was how I was taught, and it seems to be standard practice.

But I too have found that with the smaller autolocking carabiners on the market now I would prefer the extra safety. Some people argue that locking carabiners(especially autolockers) have the potential to fail in a cave because they might get dirt or mud in the mechanism. But even in very muddy caves I haven't had critical problems with them - although they do get sticky.

Your call I guess. Not sure the quantitative points of attachment gain between lockers/non-lcokers... :tonguecheek:
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Re: Two Points of Contact Rule

Postby Stan Allison » Nov 15, 2013 5:29 pm

I use a non-locker on my short cowstail and a locker on my long cowstail. The disadavantage of a locker is that a traditional non-autolocking locker can become partially wedged open by the locking mechanism if the locker isn't fully locked. Since I typically use my short cowstail on rebelay bolts where I don't lock it, I find that a non-locker is preferable for ease of use. If I ever have my non-locker fail, I will officially become SPLAT qualified!

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Re: Two Points of Contact Rule

Postby snoboy » Nov 15, 2013 5:46 pm

Stan Allison wrote:I use a non-locker on my short cowstail and a locker on my long cowstail.


That's how my frog is setup. I like having a locker on the ascender, since it moves a lot. Since I am typically hanging on the weighted short cowstail, I feel OK with the non locker there. That said, the caves I tend to frequent don't have a lot of traversing. I might switch out for a locker on the short if they did.
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Re: Two Points of Contact Rule

Postby ian mckenzie » Nov 17, 2013 12:36 am

On the original question: some thoughts.

You ascend with two ascenders, but descend with one descender. In either mode, you ought to emply a cowstail when passing an obstacle. So the rule is not 'two points' or 'one point', it is 'use the cowstail'. Same rule in either direction.

If you didn't use a cowstail on an ascending maneuver, that 'micro-second' of single-device contact usually means you are standing in your footloop while swapping your chest croll (assuming a Frog). Should something go amiss, you risk a small fall-factor onto the sfety cord of your foot jammer which, as it is a toothed instrument, is not so great. Hence the desirability of a second contact-point. No such risk is involved with a descender during a similar maneuver as it is not a toothed instrument.

Also, an ascender can slip as we all know, so if you are only attached to the rope with one that's not so good. Descenders, on the other hand, are supposed to slip, so a slip downwards is not really catastrophic. Hence the need for redundancy on an ascending maneuver that is not necessary on a descending maneuver.
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Re: Two Points of Contact Rule

Postby cavedoc » Nov 18, 2013 5:49 pm

I like Ian's reasoning above. It makes sense to me.

Just to be a PITA, for those that use lockers, do you lock them? Sure, if they're autolocks,but for a standard one? I have a locker on both cowstails, but it's mostly so I don't have to think about which is which and I know I have one around if I needed to switch it out. I don't routinely lock it. (putting on flame proof cave suit)
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