Preferred single anchor setup

[ibarro]

Quick question for you all - when you have a single anchor, e.g. a tree, what's the preferred rigging setup?

Is it a single loop, as described here >> http://dyeclan.com/outdoors101/canyoneering101/?page=webbing-single-loop (and here >> http://www.canyoneeringusa.com/techtips/water-knot-webbing-anchor/ ), i.e. basically loop webbing around the anchor, tie a water knot to form a sling, attach the quick link and away you go?

Or is it preferable to tie the webbing into a sling first, and then use that to make a girth hitch to the anchor?

Is one stronger than the other?

90008

[ibarro]

I'm going to take a punt and guess that the girth hitch is NOT preferred - adds no redundancy and presumably decreases strength...?

[ratagonia]

Interesting question, perhaps.

For this kind of question, there are many good ways to rig it, and even more bad ways. Both the ways you show are just fine.

There are times when a girth hitch (or a wrap 3 pull 1) is preferred to hold the webbing in the place you put it on the tree. For instance on the first rap in Engelstead, in order to hold the webbing high on the tree some kind of hitch to the tree is preferred. (High webbing on THIS tree makes both the start of the rappel and the pull easier).

If you are worried about strength, then you are already in trouble. Or at least the strength of the webbing. How strong do you think the webbing is?

Tom

[ratagonia]

In a sense, if the run of webbing is long, it is "better' to run a single strand rather than a double strand. Though this is somewhat like counting the angels that can dance on the head of a pin...

Every human artifact we leave in the wilderness is litter. By using a single strand, you minimize how much litter you leave, with no change in utility.

Additionally, you only brought so much webbing. You might need more further on... a single strand uses up as little of your supply of webbing as necessary.

There are many considerations to take into account when rigging anchors.

Tom

[kiwi_outdoors]

the is less to check in the single loop and there is less to go wrong; the old maxim "less is more" is a good one for your question

[ibarro]

Very happy to keep it simple if that works effectively...

Tom - when you say double strand, is this what you mean (see pic below)? i.e. just a double wrap? With the increased litter being the twice the length of webbing needed (if its intended to reach as far as the single loop would have reached)? As I understand it, the double wrap decreases the force on each strand (but obviously adds no redundancy) - but presumably this is only a mildly incremental benefit if the forces generated on rappel are unlikely to be an issue anyway...?

90010

[ratagonia]

Very happy to keep it simple if that works effectively...

Tom - when you say double strand, is this what you mean (see pic below)? i.e. just a double wrap? With the increased litter being the twice the length of webbing needed (if its intended to reach as far as the single loop would have reached)? As I understand it, the double wrap decreases the force on each strand (but obviously adds no redundancy) - but presumably this is only a mildly incremental benefit if the forces generated on rappel are unlikely to be an issue anyway...?



That would be quadruple strand.

[ibarro]

Thanks Tom. At the risk of sounding daft - what do you mean by double strand? If my first pic in this thread is single strand (ignoring the girth hitch pic) and the last pic with two loops round the anchor is quadruple strand, I'm not quite sure what would be inbetween those and therefore a double strand? Thanks!!

[ratagonia]

Thanks Tom. At the risk of sounding daft - what do you mean by double strand? If my first pic in this thread is single strand (ignoring the girth hitch pic) and the last pic with two loops round the anchor is quadruple strand, I'm not quite sure what would be inbetween those and therefore a double strand? Thanks!!

Your initial pictures: There are two strands of webbing between the anchor and the ring = double strand.

This page has examples of rigging anchors single strand: http://www.canyoneeringusa.com/techtips/webbingknotsparttwo/

[ibarro]

Thanks Tom! Haven't ever actually done it that way before...