Sewn Dyneema Sling Quad Anchor

So I have a question regarding the popular "Quad" anchor. Everyone that I've seen use it, sets it up with 6 - 8mm cordlette (which makes sense, as everyone already has it for anchor building). But my curiosity comes from the idea of using a 240cm dyneema sling. I'm curious to hear other people's thoughts on it... drawbacks vs benefits. 

I know knots weaken slings considerably, but with four strands, would it still be a significant amount of strength loss? I think durability could be an issue as well. 

But for longer multipitch climbs with both bolted and unbolted belays, I feel like it might be worth it to take a pre-tied quad out of dyneema and your cord, instead of having to tie a quad every time. For climbs with all bolted belays, it may prove to be less bulky than a quad made from cord.

Thoughts?

It works just fine. 

A knot in dyneema is of no concern.  Even if it reduced it by half it would still be stronger than almost every piece of trad gear.  (Knotting dyneema is a problem when you're doing it to tie together; say if it was cut and you wanted to turn it back into a sling.)

Edit Add: +++ for using the rope when swinging leads on multiple pitch climbs.  

In certain situations where I want a quad, I use a 240, and instead of doubling it, and getting a quad; I triple it and get a six-stranded rig. I think tripling makes it a nice, compact size, and adds a third layer of redundancy.

It works. I've seen plenty of guide's who use this set up.  It's more compact on the back of your harness than a cordalette. 

I try to use my 240 for everything, nice and compact compared to cord, add in sling or quick draw where needed if too short. Even when carrying two if on first pitch, light and do not take up much room on harness! Or use rope if swapping leads depending on the anchor. 

I prefer my 240 to cord for near everything short of rigging rappels.  If a route is well established & maintained, I often leave the cord behind in lieu of one.  This includes doubling it up to build a "quad" on bolted belays.  If I believe I'll be leaving some tat behind, I'll bring the cord or extra webbing.

John Wilder wrote:

I use my 48" dyneema/tech web slings in regular cordlette configuration, as a quad provides no advantage over the cordlette, and just takes up more material to make one.

or you can just use the rope, as a cordalette provides no advantage over the rope, and just takes up more material.....   ;)

+1 for using the rope if you're swinging leads: http://dmmclimbing.com/knowledge/slings-at-anchors/

Rope is still fast in blocks. Assuming you are on decent bolts clip a quickdraw between the two bolts, clove into one hanger direct with your locker. When your follower comes up they clove to the other bolt with their locker. Fast as can be. Yes I know, I'm gunna die.

I find the 180cm sling works very well as a quad for bolted belays

you would have to be stretching the hell out of the leads to not be able to use the rope at 2 bolts.  not sure what swapping leads has to do with anything.  just busting yer chops :)

Quad or otherwise, I use my long dyneema sling as an anchor all the time. I do tie in with the rope to add some dynamic stretch to the system and don't get above it to avoid risking a hard fall on static material. 

One trick I use to make it easier to deal with is I put a thin carabiner through the knot to reduce the friction a bit. This doesn't seem to compromise the knot but it's sure a lot easier to break down. I'm a bit curious if you all think I'm crazy for doing this as it sounds like it could make your knot slip but I've never had any issues with it as the rest of the material staying in contact cinches down on itself and the biner and grips quite hard. Having the biner there gives some leverage to undo the welded knot and you don't have to poke at it to break the knot. I suspect it also helps reduce the potential cinching/cutting effect of a tight dyneema knot getting really cranked down on and wonder if it actually increases the strength a bit due to that. 

So far the Mammut Magic 120cm sure has been working well for me.  It has the strength of Dyneema without the loss of strength or difficulty untying if you knot it.

And it makes a super nice extendo rap/lanyard on the descent. 

I would argue that for bolted anchors a sling will be faster than a rope. The weight of a double length dyneema sling is negligible.  You can keep it knotted and set up a belay in about 2 seconds. Regardless, rope anchors are good skill to have.

I don't know what routes you guys are climbing, but I've climbed very few multi-pitch routes with bolts at every belay. I've always felt a cordalette was good to have if you don't know what your getting into.

Matt, I doubt rope slippage would be an issue. The caveat in using a dyneema sling as a tether is making sure it is weighted and not loaded dynamically. But really all tethers should be weighted and not loaded dynamically. I saw someone recently clip in with a knotted dyneema sling and belay off their harness from a seated position, with plenty of slack between them and the anchor. A fall could have easily broken their sling.

Brandon.Phillips wrote:

I would argue that for bolted anchors a sling will be faster than a rope. The weight of a double length dyneema sling is negligible.  You can keep it knotted and set up a belay in about 2 seconds. Regardless, rope anchors are good skill to have.

I don't know what routes you guys are climbing, but I've climbed very few multi-pitch routes with bolts at every belay. I've always felt a cordalette was good to have if you don't know what your getting into.

Matt, I doubt rope slippage would be an issue. The caveat in using a dyneema sling as a tether is making sure it is weighted and not loaded dynamically. But really all tethers should be weighted and not loaded dynamically. I saw someone recently clip in with a knotted dyneema sling and belay off their harness from a seated position, with plenty of slack between them and the anchor. A fall could have easily broken their sling.

Excluding a situation where you climb above the anchor, wouldn't the rope itself add all dynamic stretch needed?