Time to meat Human Anchors A temporary human (meat) anchor is used in sports such as caving and canyoning, to get the first or all but the last person down, using a person (or people) that is suitably positioned in a stance where they can use the friction of rope on the rock, their own […]
Forces on an inclined plane and Tippy the tip truck How do you figure out the forces is a common question I get when teaching a particular subject. None more so than those on an inclined plane (or slope). Rather than getting onto the whiteboard to explain, from time to time, I bring out Tippy the […]
A pulley system progression means stepping up from a smaller mechanical advantage — say a 3:1 simple — to a larger one, like a 5:1 or 9:1 compound, as a haul gets harder. This post tests whether that progression is actually worth it in practice, using load cells to compare the predicted force reduction at 90% pulley efficiency against what haulers really felt, and checks whether some systems in the progression turn out more efficient than others.
Vlad to help – a replacement for the master carabiner Back in November 2018, I decided to purchase a Grivel Vlad and put it on my harness to see if it was going to be a useful addition. The Vlad could be helpful as a master carabiner for anchor station organisation for multiple clip-ins. There are […]
Jigger Setup: Troubleshooting As we head around various rescue groups, we find many jiggers (aka a set of fours) rigged incorrectly or operating inefficiently. Despite leaving everything in good working order, we often come back at a later time and see the jigger fairies have come in and made a mess. To illustrate my point, […]
Progress capture testing for a jigger I was about to post an article about the jigger (aka a set of fours) – how to build (and troubleshoot) using a couple of small double pulleys and cord (coming soon). I tried to remember if I had ever tested the progress capture Prusik as this would be […]
Lightweight systems – testing to the next level Once you start testing you is realise there is more testing to do. The testing aimed to push the limits of the belay for the lightweight rescue system. We decided on a 1.5m drop on 3m of rope with a 200kg load. Back in 2017, we did […]
The American Death Triangle in the real world Recently (Feb 2018) I wrote a blog on the forces involved in the American Death Triangle. I questioned if there were some occasions we can use this style of rigging. Note: I would recommend reading this first article before diving into this one: American Death Triangle and […]
Mechanical rescue belay for 10mm rope? Putting two belay devices with assisted braking through their paces We tested rescue belays (belay devices with assisted braking) as they would function as part of a two-rope system for lightweight back-country rescue. Out in the real world of the backcountry, you often don’t have dry clean conditions. So […]
Have you ever been told never to use the American Death Triangle for 2-point anchor rigging as it has a pulley effect on the anchors and is considered ‘bad’ or is ‘dreaded’? In this article, we will consider the American Death Triangle in more detail and see what’s going on. What sparked my interest was […]
