Setting up your Prusiks for Lightweight Rescue
This article will go over setting up 8mm Prusiks (with flexible cord) for 10mm rescue rope. These are long and short Prusiks used as a progress capture and rope grab in a pulley system.
The Prusik cord we chose to use was an 8mm 15kN Kordas Accessory cord. This cord is very flexible and grips well onto the 10mm rope.
Why this cord?
From experience, over extended use, the cord doesn’t easily work-harden, i.e. become stiff. It continues to work even when full of mud and can be cleaned and reused. All other accessory cord we have tried do not work as well. Also, the Prusik cord doesn’t last forever, so monitor and replace it regularly.
So why such a high rating on the cord?
The idea behind this was to match the rope to the Prusiks we are using. The 10mm rescue ropes without knots have a break strength of around 27kN, which is about the same as the 8mm cord as a loop – 15×2=30kN.
- Short = 120cm (with 3.5cm tails and tensioning the finished loop is around 36cm)
- Long = 150cm (with 3.5cm tails and tensioning the finished loop is around 51cm)
- Short and long Prusiks need to be different colours for easy ID.
- The short length is used with a small Prusik minding pulley such as the SMC 50mm PMP (shown below) or the Petzl Mini.
- The long length is based on having around 5-6cm (or the width of 3-4 fingers) between the long and short Prusik when tied and being able to tie an overhand – a method for separating single pulleys when hauling.
Tying and tensioning the Prusiks
- Tie with a double fisherman’s bend. Check out how to tie below.
- Tails are 3.5cm long.
- Tension with one foot in the loop, with the bend in one side, pull up on that side or use a pulley system for tensioning.
Note: We prefer using the double fisherman’s bend as, in testing, the loop was on average over 20kN.
Measure the bight
- The Prusik bight is 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 Prusiks together with an overhand on the other end to the bends.
- Clip the Prusiks onto a carabiner and clip the long Prusik back to the carabiner again to make it short.
- Clip to your harness with a carabiner.
Tie the Prusiks together
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