Extend the Anchor Tie-In

[rcwild]

Most canyoneers have already figured out that daisy chains are inappropriate for use as safety tethers, yet people continue to use them. Their primary argument has to do with length adjustment.

Sometimes two tether lengths – one short and one long – can be beneficial, like when doing transitions (changeovers for you cavers). This one is simple. Use a Petzl Spelegyca or an Imlay Clipster (long) with a canyon quickdraw (short).

Sometimes it's nice to have the ability to clip in long or short to the anchor. This one is simple, too. Use a daisy chain to extend the anchor. Using one as a safety tether can create a very dangerous situation. Their bulk makes them tend to snag on sticks, rocks, etc. Just an annoyance unless you happen to get snagged while under water.

The photo below illustrates a Metolius PAS (Personal Anchor System) girth hitched to a rope bag and clipped to the anchor. It could be clipped to the anchor using any of the loops and multiple people can clip their safety tethers to any of the loops.

NOTE: The PAS is among the most inappropriate daisy chains for use as a safety tether. The large loops are even more prone to snagging than a regular daisy. But the full-strength loops make it ideal for use in this application. Keep in mind that it is made with Spectra, which has significant tensile strength but is prone to catastrophic failure when shock loaded. Shock loading can be avoided by remaining below the anchor once you clip in.

In response to the shock loading issue, Sterling Rope came out with a nylon version of the PAS. Unfortunately, they are marketing it as a safety tether. Poor choice for that, but it will work well for extending the anchor as shown.

[tj_wetherell]

Rich,
I have several questions regarding this post - can you (or others) clarify?


<... Use a daisy chain to extend the anchor....>
Isn't this a poor choice also? Most Daisy's are intended for bodyweight only (in the pockets) (right?), and many are made of spectra. I'm not sure I agree with using a pocket rated at 500lbs as part of an anchor. If you just use the full 'sling' then you basically get a large spectra runner. Attach your personal tether to it, fall above the anchor, and I see no difference between it and a Metolius PAS except some energy absorption due to a more elastic material (nylon).

On the shock load issue, as long as the load generated in the fall does not exceed some "safe" level of the tether the shock should not be an issue - err. right?. Your rule of thumb (don't climb above the anchor) is a good way to keep the fall factor lower.

So. What do you recommend for an adjustable length tether? Onmisling might seem like a good choice given its full strength pockets, and nylon construction - although I have always wondered about the strength of the pockets at the very ends.

If you have any data on shock loading of Spectra I'd love to see it - Especially if it indicates failure below the rated tensile strength.

-tom (w)

[rcwild]

There is another thread in the forums titled Safety Tethers (http://www.canyoneering.net/forums/showthread.php?t=700&highlight=ITRS) with information about shock loading issues.


Isn't this a poor choice also? Most Daisy's are intended for bodyweight only (in the pockets) (right?), and many are made of spectra. I'm not sure I agree with using a pocket rated at 500lbs as part of an anchor.

Not sure if the pockets are even rated to 500. Quite a bit lower me thinks. I lumped daisy chains together in my warning about safety tethers, but for extending the anchor I'm specifically recommending something like the PAS.

I just measured the set-up in the photo. If I clip into the end loop of the PAS with the long end of my Spelegyca, it measures 54 inches from the rapide on my harness to the end of the carabiner that is clipped to the anchor. That's as long as the longest daisy chains I've seen used as safety tethers. PAS is Spectra and nylon. Spelegyca is nylon. Petzl may not advertise this, but the Spelegyca (formerly Energyca) will absorb more impact than a simple nylon sling. Not true of the Imlay Clipster, but it is nylon.

If you're using Spectra in your system, you should pay attention and try to avoid getting above your anchor. I think the same advice should be given when using nylon, even though it is better able to absorb impact. I'll let the engineers explain the ramifications of having a mix of Spectra and nylon in the system


Onmisling might seem like a good choice given its full strength pockets, and nylon construction - although I have always wondered about the strength of the pockets at the very ends.

I'm not really an OmniSling fan, but it would work in the same way I illustrated using the PAS. Most people make it a habit to avoid the pockets on either end. You can also buy OmniSling that is tacked at the ends so even those pockets are full-strength.

[tj_wetherell]

Thanks for the clarification Rich.

I was honing in on the statement in your first post:
"Use a daisy chain to extend the anchor. Using one as a safety tether can create a very dangerous situation".

Metolius rates their daisy pockets at 300lbs, BD's dynex at 674lbs (from their websites).

Thanks for the link to the tethers discussion!

-tom (w)

[MIQ_WRX]

Sterling is showing their version of the PAS daisy chain. http://www.sterlingrope.com/2005/climbing_products3.asp?pmid=14

Scroll down to accessories.

They say it can absorb 3 fall factor 2 drop tests.:)

They also mention, "Allows for a clear disconnect in deep pools of water" :confused:

<O:pI'm not sure what that means. Does anyone know what they are getting at?
<O:p
I like setting the rope length so there is no "disconnect" in water other than the end of the rope passing through my descender before, or just as, I enter the water. Are there situations where this is not possible and this extention would be useful?

-MIQ

[mtngoat59102]

They also mention, "Allows for a clear disconnect in deep pools of water" :confused:<O:p I'm not sure what that means. Does anyone know what they are getting at?

-MIQ

Since my first marriage I have given up mind reading but I will take a stab @ what I think this means. It would make sense that that they are refering to extending your belay device and that having the belay device away from your harness would make for an easier disconnect in water. You gotta love the climbers perspective on canyoneering! Anyway, that is what makes sense to me since they clearly note the advantages of their product for extending your belay device.

[rcwild]

Sounds like Neil and I had similar experiences with our practice wives. I'm no mind reader either, but I have reason to believe Neil's perception is correct.

If you are treading water and doing a wet disconnect, the extension might keep your rappel device out of the water where you can see it while disconnecting. I'm not convinced that is a real benefit. Of course it is a totally moot point if you are setting your rope length.

I contacted Sterling a few weeks ago and provided them a link to this thread so they can track canyoneer's experiences and perceptions. They are aware of some of the concerns about snagging, etc.

[rcwild]

Split off the Purcell Prusik discussion to its own thread at:

http://www.canyoneering.net/forums/showthread.php?t=700