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5.5 kn for prusik

Original Post
edennis · · Unknown Hometown · Joined Apr 2013 · Points: 0

Is it safe to use 5mm accessory cord that has a strength rating of 5kn for a prusik?

Jay Eggleston · · Denver · Joined Feb 2003 · Points: 21,326

Sure, that's 1120 lbs.

K R · · CA · Joined Jan 2014 · Points: 50

The downside being potentially less friction in thinner cord and less abrasion resistant. Just stating the obvious though. I haven't tried it.

mountainhick · · Black Hawk, CO · Joined Mar 2009 · Points: 120

In actual use, you don't get more effective "friction" from thicker cord. Thinner (within reason) and softer cord tends to lock up more.

With the rope I use most often, 6mm as a third hand is better all around in actual use. 5mm locks too easily.

FrankPS · · Atascadero, CA · Joined Nov 2009 · Points: 276
Pontoon wrote:The downside being potentially less friction in thinner cord and less abrasion resistant. Just stating the obvious though. I haven't tried it.
I think the "obvious" would be more friction, not less.
K R · · CA · Joined Jan 2014 · Points: 50

I guess what's obvious to me isn't necessarily correct. ;)

To me more material would seem obvious to cause more friction, but apparently not.

I did use a very thin cord for an auto block once, and it didn't work super well. It took too many wraps and didn't hold its shape as well as other options.

BigFeet · · Texas · Joined May 2014 · Points: 385

Yes, this should work for a prusik.

It depends on the rope and prusik diameter combination along with what prusik wrap you use as to what the effectiveness of the hold you achieve is. Along with other variables, such as, the types of materials (sling with rope compared to rope with cord) used.

I would try out different combinations on the ropes you will use before you trust your life on it while 100' off the ground. Better to know how the gear you use will react when called on.

J. Serpico · · Saratoga County, NY · Joined Dec 2009 · Points: 140

A greater difference in diameter usually locks better. So 5mm cord on a 10mm rope should work better than 8mm cord on a 9mm rope. At least that has always been my experience. 5kn should be plenty, the loads should be static.

20 kN · · Unknown Hometown · Joined Feb 2009 · Points: 1,346
FrankPS wrote: more friction, not less.
I agree. Considering extremes, 1mm cord would grab extremely well as a prusik, whereas 13mm wouldent probably grab at all, tat is unless you are using it on a 2" mooring line.
Guideline #1: Don't be a jerk.

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