Cord size for building prusik anchors?

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Cord size for building prusik anchors?

Postby OpenTrackRacer » Sep 10, 2012 7:30 pm

We exploring with some new (to me) people last week and was exposed to prusik based anchors for the first time. I can see these being handy for some situations where slings just don't cut it. I want to make some up but I'm not sure what size cord to use. Any suggestions?

Thanks!

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Re: Cord size for building prusik anchors?

Postby Tim White » Sep 10, 2012 8:40 pm

"prusik based anchors" :shrug: Are you referring to a cordelette anchor? If so, 7mm and 8mm prusik cord is common.
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Re: Cord size for building prusik anchors?

Postby OpenTrackRacer » Sep 10, 2012 9:46 pm

Nope. I'm talking about making a prusik to go around things like fixed pipes or rails where a sling won't work due to slipage.

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Re: Cord size for building prusik anchors?

Postby Scott McCrea » Sep 11, 2012 10:40 am

I guess, like most things, it depends on the situation. One of the great things about Prusik knots is that when loaded enough, they will slip. Sounds like you don't want these to slip. There could be better knots/hitches for rigging to pipes or rails. Usually, my first choice is to rig straight to it, not adding any "links to the chain." A Prusik might work fine. You could also put the "Dog and Tails" hitch in your knowledge toolbox. Here's a thread at the International Guild of Knot Tyers Forum about hitches around a pipe: LINK
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Re: Cord size for building prusik anchors?

Postby Anonymous_Coward » Sep 11, 2012 11:22 am

Clove Hitch.

Requires no webbing or prusik cord.
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Re: Cord size for building prusik anchors?

Postby OpenTrackRacer » Sep 11, 2012 11:24 am

Thanks for the link Scott. There's a lot of interesting information there. From what I've seen there and elsewhere, it sounds like 7mm cord is a good size for this purpose.

Thanks for all feedback!

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Re: Cord size for building prusik anchors?

Postby NZcaver » Sep 11, 2012 1:03 pm

Anonymous_Coward wrote:Clove Hitch.

Requires no webbing or prusik cord.

That's what I'd do.
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Re: Cord size for building prusik anchors?

Postby OpenTrackRacer » Sep 11, 2012 3:33 pm

Wouldn't sliding down the anchor be a concern with a clove hitch?

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Re: Cord size for building prusik anchors?

Postby snoboy » Sep 11, 2012 7:28 pm

Mike:

Your query is very relevant to what I am doing at work this week. We are removing an old sprinkler system from the ceiling of an industrial building. As we cut each piece away we have to lower it to the ground. We are attaching to it with 8mm - 6 wrap prusiks on 6 & 8" pipe, then lowering them. The pipe is hanging vertically from one end, and we are getting no slippage.

So... I would say there is one data point for you - 8mm works well on 6-8"pipe. I would probably stick to that or 7mm, just for the anchor strength. a loop of that is equally matched in strength to a knotted 11mm rope (+ or - of course).

Another product on my radar, but with no personal experience of it yet, that I suspect might work well for what you want to do is Sterling's Hollow Block. Possible cons are limited length, and being aramid (kevlar) it may not be super durable.

If you want to load something along it's long axis I would avoid the Clove Hitch, and look at something like a Rolling Hitch.

I'm sure you are on this, but don't forget to verify the structural integrity of the metal you are considering for an anchor! Also relevant to this week's work! ;)
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