Grant Prattley

Founder and consultant at Over The Edge Rescue. Rescuer, instructor, guide, author, designer, and adventurer.

2:1 Load Release Hitch: does it work?

2:1 Load Release Hitch: does it work? 2:1 Load Release Hitch MMO Test 8mm cord

What’s in this post? We undertook testing to confirm the 2:1 Load Release Hitch rescue setup and see if it was suitable for both single and two-person loads as far as maximum force (tied off with a Munter Mule Overhand) and had enough friction for lowering during load transfer. The Load Release Hitch problem A […]

Double sheet bend; but it’s fine?

Double sheet bend; but it’s fine? Double sheet bend yosemite 10mm

In cave rescue, we had been using the Double Sheet Bend for rigging – being easy to adjust, especially in the middle of a rope or cord and easier to untie after significant loading. I was recently (2021) undertaking testing to confirm our cave rescue setup (see the post Let’s lighten the load – update), […]

Setting up your Prusiks for Lightweight Rescue

Setting up your Prusiks for Lightweight Rescue Measuring the Prusik bight

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. Pulley system setup Prusik Cord The Prusik cord we choose to […]

Why is a sling 2x the strength of a single strand?

Why is a sling 2x the strength of a single strand? single strand vs sling

What’s in this post? This post is about the theory and testing behind why making a piece of webbing into a sling is 2x the strength of a single strand. We address the specific question about tension on a single section of sling around a carabiner at the end and draw vectors to show what […]

Lightweight Jigger Testing

Lightweight Jigger Testing Lightweight Jigger Complete

What’s in this post? Testing of a lighter weight jigger (4:1CD/5:1 pre-rigged pulley system) using a 5mm Prusik and a 6mm high strength cord made with a Dyneema core with a polyester sheath. We also address the weight and volume of a jigger to compare the lighter weight version with a standard version using a 6mm Prusik […]

Webbing anchors: efficient rigging and 16mm testing

Webbing anchors: efficient rigging and 16mm testing webbing anchor header

What’s in this post? The basics for webbing anchors: So you know why you are using webbing anchors, what to use, set up and four ways of rigging. How to rig webbing anchors efficiently: Get the right (minimum) webbing length, rather than halfway through a rigging job finding out you are short and have to start […]

Testing the Figure-8 Device Block for Canyoning

Testing the Figure-8 Device Block for Canyoning

What’s in this post? Slow Pull testing the figure-8 device block variations with normal loading and incorrect loading. We also compare this to baseline methods such as the Munter mule overhand and figure-8 on a bight. Efficiency tests (speed) to find out if there is there any major differences in tying methods. Practical use comparisons […]

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