March 29, 2022

Introduction to the Biner Block Rappel Technique

by Bernice

The biner block rappel technique is used primarily by climbers who make lengthier rappels. The technique allows them to use a climbing rope on descents then retrieve it by pulling on a much lighter rope. The biner block is made by attaching a clove hitch to the carabiner’s spine.

Assuming the spine of the biner is flat, the clove hitch is tightened tightly, and the biner is locked.

The mechanism involved here is that one side of the rope is tied on the biner, which will be blocked by a braking device such as a GriGri.

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While one end of the rope is rigged so that it does not slide through the biner, the other side is allowed to slide through. Once down, the other rigged rope can be pulled to retrieve the entire rope

This technique might be needed when rappelling on a damaged rope, though that should not do that unless it’s your last option to get off the cliff.

It’s another safe option if you are rappelling off from long distances and the rope isn’t enough to get you to the bottom.

In that case, the rope will be retrieved, attached to the bolts at the interval’s anchors, locked in the biner block mechanism, and used again. 

Table of Contents
Biner Block Rappel
Watch the entire video on how to use the biner block rappelling technique.

Related Article: GriGri vs. ATC

How to Perform the Biner Block Rappel Technique?

The biner block rappel technique is a technique for descending from a rappel point. It is an alternative to the figure-8 rappel technique and the Munter hitch rappel technique.

The biner block rappel technique is a descent technique used with two ropes.

The biner block rappel technique may be used in situations where the Munter hitch or figure-8 rappels are not possible or desired.

The biner block rappel technique may also be used when only two climbers are on the rope, as it does not require a third person to set up and anchor the system at the top of the climb.

The main difference between this and other techniques is that this one uses two carabiners attached to each side of the rappelling rope.

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There are two main scenarios where you can perform the biner block rappel technique.

  • How to Make a Biner Block for a Half-Rope Length Rappel
  • How to Make a Biner Block for More than a Half-Rope Length Rappel

How to Make a Biner Block for a Half-Rope Length Rappel? 

A single rope will suffice when you are going down for only a length half your rope or any values below the half length. And it’s as simple as stealing candy from a toddler. Follow the four steps listed below.

Step 1 

Now at the clip, thread the line through the rappelling equipment. That is either the maillon or rappelling ring though specifically, you should use a locking carabiner biner.

Last update on 2023-09-28 // Source: Amazon Affiliates

After threading, both ends of the ropes should get to the ground or the bottom of the climb. So, you are left with two sides on a different phase of the locking carabiner.

If you’re not descending to the bottom, use a biner with the overhand on a bight to secure both sides of your body. 

Step 2 

Weave a figure eight on the bight. This should be done on the other phase of the rope that will be clipped to another strand and secured to the carabiner. You may also weave the figure-eight knot on the side of the damaged rope. 

Figure-eight knots are aimed at hooking on the anchor’s rappelling gear. That’s the thread that you’ll be pulling.

Make sure the weaving is big enough, or the carabiner isn’t too big. Unfortunately, big HMS biners, like the Petzl William, can force a figure eight on relatively thin ropes of about 8mm to slide past when heavily strained.

Step 3

Now clip the rappelling device or a biner on this rope such that when it’s weighted, the figure-eight knot prevents it from passing through the biner or the ring. 

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Step 4

Slide down on this end until you reach the base of the next rappel or the ground. Attach the draw strand’s tip to your body or the anchor.

After hitting the ground or the base, give the draw strand a vigorous downward push to remove the stuck knot, then pull the rope off steadily.

The steps above can be done repeatedly until you get to the ground. 

Related Article: Ways to Set up a Top Rope Anchors

How to Make a Biner Block for More than a Half-Rope Length Rappel? 

Whenever you want to rappel using a rope length that exceeds the half-length, you will be required to use a second rope. You may use a dynamic climbing rope or a designated pull cord. 

Still, if you may, use a damaged rope on this end. But don’t mistake it for the rope you use for the descent unless you are in a mood for having a pounded potato head and a few cracked ribs! Ooh no! Have we scared you? Hang on and follow these set steps below.

Step 1

Thread either rope’s ending into the anchor’s rappelling gear. Your rappelling rope will be the part of the line you slide through. Ensure you slide through the rope’s end that’s not damaged. 

Step 2

Link up the ends of ropes A and B in a flat overhand twist. You can back this up with a secondary stack flat on the overhand twist.

The flattened overhand bends are aimed to grip the anchor’s rappelling gear. The draw rope is the strand that does not slip past the anchor. 

It is essential to ensure that the knot is big enough or that the maillon/ring/carabiner is small enough. With sufficient force, extremely large HMS carabiners, such as Petzl William, will pass figure eights on skinny ropes (*8mm).

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So, if there are any uncertainties, a bigger knot, such as a double fisherman’s knot, can be used. If you’re not descending to the bottom, use a biner and a blighted overhand to secure both sides of your body.

Step 3 

A locking carabiner should be attached to your rappel strand with a figure-eight tied on a bight.

Step 4

Fasten your rappelling devices on the other end of the rappelling biner rope. Afterward, ensure the biner blocks the flat overhand jams as you descend on the rope.

Step 5

Descend to the bottom of the next rappel point by rappelling the entirety of this rope. Attach the draw strand’s tip to you or push it to the base.

Dislodge the jammed knot by giving it a vigorous downward tug, gradually dragging the strands down.

What are the Advantages of Using Biner Block Rappel?

  • With a biner block, you can rappel down rocks that are twice or even more the size of your rope. 
  • They allow you to rappel using only one rope, and you can set the ropes for swim disconnects. 
  • Biner blocks are less prone to be pulled through the rapid.

What are the Disadvantages of Using Biner Block Rappel?

  • You will need two carabiners for the biner block. 
  • Under pressure, a clove knot made with a tight or strong rope can slide.

The Best Practices of Using the Biner Block Rappelling Technique

The best practices for using the biner block rappelling technique can be found in climbing and rappelling textbooks.

Last update on 2023-09-28 // Source: Amazon Affiliates

  • The basic idea is to use a biner block as a safety device when rappelling.
  • The biner block is an anchor point placed at the top of the rappel rope.
  • Rappellers clip their carabiners to the biner block and then descend by moving down their length of rope.
  • The carabiner should always be clipped to both strands of rope, not just one strand.

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Last Updated on February 8, 2023 by Roger

About the author


Bernice often jokes that she is better at climbing than walking. With avid parents of climbing, her first encounter with the high vertical rock walls was at the age of one. Her favorite style of climbing is bouldering.

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