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Prusik Knot ?

2253 Views 11 Replies 9 Participants Last post by  GSLAM95
Does the rope that makes the Prusik knot need to be smaller diameter than the main line or does it matter? I made this set up last night with the same size rope (same stuff as the green stuff in the illustration on reply # 8 http://www.archerytalk.com/vb/showthread.php?t=771357 ) and the Prusik had the tendency to slip unless I messed with it a bunch and made sure it was super tight on the rope.

Any help would be appreciated,

Thanks
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· Bowhunter
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Yes, a rope used for the prussic know should be of smaller diameter: 2-4 mm, I think.
 

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your prussic rope should be 2 mm smaller than the main line to work correctly.

10mm=8mm
9mm=7mm
8mm=6mm
 

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I must say that it is good to see you guys doing this….

I am a Firefighter/Paramedic in N. Texas assigned to a Technical Rescue Station. With countless hours of training and certifications meeting NFPA 1670, Rope Rescue Technician, I have a few recommendations. Hope you all don’t mind me putting in my 2 cents???

First you need to make sure you are using life safety rope. You need to know that a lot of the ropes that are available at the hardware store are specifically made for utility applications and not life safety as in our case. We are trying to be safe here, right? While the numbers we use may seem to be an overkill, they are there for a reason. Hold onto your harness here while I break this down… For rope that is only going to support 1 person, as in most cases, light-use, life-safety rope is sufficient (usually 11mm). It is rated for a 1 person load with a 15:1 safety margin. For 2 people, you need rope rated to the general-use (usually 12.5mm). It is rated for a 2 person load also with a 15:1 safety margin. These numbers are important because when you fall, the forces applied to the rope will be significantly higher than what you and your gear weighs on a scale. Hence the 15:1 safety factor! The life line rope that you use for vertical attachment to the tree needs to follow the above recommendation. Finally, I would recommend it to be made of Kern-mantle construction. These are made from continuous synthetic fibers in contrast to natural fibers such as cotton or manila, which both can rot.

Second, the accessory cord used for making the prusik, needs to me smaller than the vertical rope and should be either (6 or 8mm). This allows sufficient bight when loaded. Also I would recommend tying the accessory cord together with a double fishermans knot before applying it as a prusik. Triple wrap the accessory cord and then offset the fishermans knot. Triple wrapping will provide adequate bight when loaded and the offset fishermans knot will prevent the carabineer from biting into the knot.

While all of these will make a definitive difference in your safety, using the appropriate knot to tie off the mainline is equally important. Find a solid anchor above your stand and use a “figure 8 follow-through” backed up with a safety knot. Use whatever you think is sufficient at the bottom; obviously it isn’t what holds you.

I believe someone else mentioned it, carry a 2nd piece of accessory cord to use as a prusik in case you fall and load the system. This will provide a means of escape should you need to ascend back up to unload the original prusik.

And no, I don’t repel out of the tree when I’m done! :darkbeer:
 

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as a tree climber , it is great to see everyone using a safety system. i use 10 mm climbing line and 8 mm prussik loop. i also carry a small figure 8 in my pocket just in case i need to repel down . i hope i never have to use it. be safe. kk1340
 

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ff99 Thanks for your VERY VALUABLE "2 cents" as it really is apprecaited more than you realize. :nod:
 
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