BLOG ARCHIVE — IDEAS THAT HOLD UNDER LOAD

Rope. Rigging. Reason

Where field craft meets first principles — every technique stress-tested by maths, every system shaped by research, every team lifted by clear leadership.
Rope Rescue
Grant Prattley

Progress Capture Testing for a jigger

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 good to go into the post. There was a memory of testing over ten years ago and but couldn’t find anything recently. What I am

Grant Prattley 16/07/2018
Rope Rescue
Grant Prattley

Lightweight systems – testing to the next level

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 some initial testing for tandem Prusiks and Grigri+ for a 1m drop on 3m of rope – Let’s lighten the load Our baseline numbers for

Grant Prattley 12/06/2018
Abseiling
Grant Prattley

The American Death Triangle in the real world

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 driving on the wrong side of the road My conclusions for side-by-side ring bolts: threading the rope through the rings and abseiling on double ropes

Grant Prattley 23/04/2018
Rope Rescue
Grant Prattley

Mechanical rescue belay for 10mm rope?

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 not only did we undertake drop testing with a brand new dry rope we also field tested inside a muddy, wet cave with 40 lowers

Grant Prattley 24/03/2018
Canyoning
Grant Prattley

Deploying the rope for a big canyon pitch

Deploying the rope for a big canyon pitch Using rethrow and out of the bag techniques Over the past few years, we have been descending some bigger canyons. By this I mean the pitch is longer than half the length of your rope, e.g., 30m for a 60m rope. On these big pitches, it can be difficult for deploying your rope due to obstructions or weather conditions. The standard way we have dealt with bigger pitches is to: Thread and pull

Grant Prattley 28/02/2018
Abseiling
Grant Prattley

The American Death Triangle and driving on the wrong side of the road

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 a recent comment on a Facebook discussion about the subject. A valid question about a double-bolt anchor placed for a horizontal handline: ‘If it is

Grant Prattley 11/02/2018
Guiding
Grant Prattley

Ice Anchor Testing Fox Glacier

Ice Anchor Testing Fox Glacier Every year, Fox Glacier Guiding takes thousands of people onto the Fox Glacier. As part of their operation, they guide people on hikes around the glacier where they use ice screws for hand lines (safety lines) and for top rope ice climbing where they use a mixture of ice screws and V-threads. We teamed up with Fox Glacier Guiding to undertake ice anchor testing. This testing was phase 1 to get a winter baseline to

Grant Prattley 30/01/2018
Rope Rescue
Grant Prattley

Baseline testing for lightweight rope rescue

Baseline testing for lightweight rope rescue Making sure we have sufficient safety factor for 10mm rope and 7mm cord This article is about getting some hard data to back up a change in practice – using lightweight rope rescue systems. That is going from 11mm to 10mm rope for backcountry rescue and the associated change in Prusik cord size from 8mm to 7mm. Who would want to carry more gear that’s heavier when lightweight may well do the job. Check out

Grant Prattley 23/01/2018
Rope Rescue
Grant Prattley

Let’s lighten the load

Let’s lighten the load After a particularly arduous 24hrs underground and 1000m of hauling on a deep cave SAREX(Search And Rescue EXercise) we started our journey towards asking the right questions about lightweight rope rescue. Could we lighten up the backcountry rope rescue gear we use while keeping acceptable safety margins? We knew we had to start with a change in philosophy. The realisation that changed my thinking was that every rope rescue I had done was a single-person load.

Grant Prattley 16/01/2018
Abseiling
Grant Prattley

Double Fisherman’s vs Overhand Rethread

Double fisherman’s vs. overhand rethread Tying Prusik loops with a bend for your Prusik Minding Pulley For tying Prusik loops I have always used the double fisherman’s bend. However, the double fisherman’s is bulky and as a result, never sits quite right on the body of the Prusik Minding Pulley (PMP). I decided to try the overhand rethread as an alternative. There were a few questions I had; would an overhand rethread sit better against the PMP, allow for easier

Grant Prattley 20/10/2017
Abseiling
Grant Prattley

Sheet Bend vs Bowline Knot

A knot that drives you around the bend! On a cave excursion through Bulmer cave system (New Zealand) I noticed, on two occasions, a single sheet bend rigged at the top of a fixed handline but being used as if it was a bowline knot. I suspect the person rigging these handlines meant to tie a bowline knot but got it wrong. The way to tell at a glance if you have a sheet bend is the bight is on

Grant Prattley 05/10/2017
Set of fours load capture
Lightweight Rescue
Grant Prattley

Build a 9:1 pulley system with a Jigger

Build a 9:1 pulley system with a Jigger Something I am always looking to do is find new ways to make gear more useful. For rescue one of the great tools in the toolkit is the jigger (aka set-of-fours). This is a pre-constructed pulley system made, in this instance, with two double pulleys. It has a set mechanical advantage of 4:1 simple(s) with a change of direction (CD) or a 5:1s. A 4:1sCD (left) or 5:1s (right) can be useful

Grant Prattley 28/02/2017
Canyoning
Grant Prattley

Rig a big canyon pitch

Rig a big canyon pitch Over the past few years, we have been descending some bigger canyon pitches. By this I mean the pitch is longer than half the length of your rope where you need to join another. You may get away with doubling your rope until the day you need to do a rescue, and then you’ve created yourself a very large headache. You know the type of headache I mean. The ‘I never thought that would happen to me’

Grant Prattley 13/12/2016
Anchor acronyms
Anchors
Grant Prattley

When anchor acronyms go bad

When anchor acronyms go bad There are a lot of anchor acronyms out there in the rigging, rope and rescue world. A few examples include: SERENE: Solid (or strong), Equalized, Redundant, Efficient, No, Extension ERNEST(A): Equalized, Redundant, No, Extension, Solid (or strong), Timely, (Angles) STRADS: Solid, Timely, Redundant, Angles, Distribution, Shockload They are all basically variations on the same theme. Issues with anchor acronyms They are usually considered rules that you must follow. The acronyms do not take into account the

Grant Prattley 08/12/2016
Abseiling
Grant Prattley

Get more friction with a double Munter

Get more friction with a double Munter A number of organisations (e.g.ski patrols and glacier guiding) use a 6mm Spectra or Dyneema line for escape or access. The upside of using this type of system is it is lightweight and easily carried all day. One of the downsides is that you need to use a Munter/Italian Hitch in a carabiner as other friction devices don’t work in such a small line. Recently I have heard of a person losing control

Grant Prattley 05/12/2016

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