What’s in this post?
We review how to set up 8mm Prusik loops for 10mm rescue rope.
Context
Prusik Loops are tied with 3-wraps (3-on-3) onto the rescue rope to form a progress capture or rope grab in a pulley system for rope rescue.
Prusik Cord
The Prusik cord we choose to use was an 8mm 16kN Kordas Accessory Cord.
This cord is flexible and grips well onto the 10mm rope. By flexible cord I mean you can bend in half easily when pressed between your thumb and fore (index) finger.
Why this cord?
From actual field experience, the cord doesn’t easily work harden over extended use, i.e. become stiff. It works even when full of mud and can be cleaned and reused. Other accessory cords may not work as well.
Remember, the Prusik cord doesn’t last forever, so monitor and replace it regularly.
So why such a high rating on the cord?
The idea was to match the Prusik breaking strength and rescue rope we use.
- The 10mm rescue ropes without knots have a breaking strength of around 27kN
- The 8mm as a loop without bends have a breaking strength of around 16kN x 2 = 32kN
Cutting Lengths
- 120cm (with 3.5cm tails and tensioning, the finished loop is around 37cm)
Notes
- Try to use a different coloured cord compared to your rope.
- The loop is sized to use with a small Prusik minding pulley, such as the Rock Exotica Mini and the Petzl Mini (shown below).
- The length is based on having a gap of around the width of 4-5 fingers (or 8-9cm) between the top of a 3-Wrap Prusik when tied and the base of the Prusik minding pulley. This length allows the Progress Capture Prusik to be released after loading – you need more length than you think.
Tying and tensioning the Prusiks
- Tie with a double fisherman’s bend. Check out how to tie it below.
- Tails are 3.5cm long.
- Tension with one foot in the loop, with the bend in one side, and pull up on that side (or use a pulley system).
Note: We prefer to use the double fisherman’s bend as, in testing, the loop was, on average, over 20kN.
See the test report for more information Let’s Lighten The Load
Measure the bight
- The Prusik bight is around 4cm.
Capture the carabiner
- Capture the carabiner to prevent cross-loading.
- Use a couple of rubber rings. The ones we use are from a farm supply shop.
Note: This type of carabiner capture takes less time and uses less space than heat shrink
When you are done
- Tie the Prusik with an overhand halfway along.
- Clip the Prusik onto a carabiner and clip it back again to make it short.
- Clip to your harness.
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Grant
Over the Edge Rescue
Author’s Note: This post was originally published in February 2018 and has been completely revamped and updated for accuracy and comprehensiveness.
Disclaimer
SUMMARY: This post is not an instructional guide. Use at your own risk. We assume no responsibility or liability for any errors or omissions. Testing was under controlled conditions with a limited set of equipment. The views, information, or opinions expressed in the post are solely those of the author.
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