To some extent, I started something. Steph Davis posted an article regarding her favorite rope joining ‘knots’. Steph does make some compelling reasoning behind her strategies. Mammut North America picked up the blog post and shared it. I commented on it (“apply palm to forehead”). It is a great read, however I find it generally misleading, and dare I say slightly misinformed. Some of my thoughts are on nomenclature on the subject, but also regarding the security of the readers of climbing literature. A certain magazine has published a number of rappelling articles and blog posts that are factually incorrect. Gribbon at Mammut NA and I exchanged some messages regarding this topic and he inquired if I would be interested in make a statement.
I do not know Steph Davis, and I have never even met her. She is well known as an avid adventurer, well traveled first ascentionist, and exceptional climber who is sponsored by many leading equipment manufacturers. I hope to run into her someday…. I’ve secretly always been a fan of hers. She’s out there doing amazing things daily.
So now, I will kill my last horse on the subject.
I want to begin with settling a technical terminology clarification. There are differences between knots, hitches, and bends.
Knot: A knot is a compact intersection of material, using only the material itself to create a functional point.
Bend: A joint or connection made from two independent ends of material.
Hitch: A reference for when a rope attaches to an object. The object could be a carabiner or a hitch but on a host rope. (We won’t make many references to hitches in this article).
Steph’s article recommends 3 knots for tying rappel ropes together: Double Overhand Knot, Figure Eight Follow Through, and Double Figure Eight Follow Through.
First, I would say there are 3 Bends that are commonly used for joining rappel ropes or even cord ends together. This is not to say that there are no other options, simply that these are the most commonly used choices by mountain professionals, professionally trained guides, and climbing instructors like myself. In this article, I will not entertain mismatched material diameters, specialty techniques or fancy rope tricks where special techniques may need to be applied. Below, the bends are outlined in no specific order.
Beware: some of these have multiple official common names!
Grapevine Bend aka Double Fisherman Bend
Grapevine Bend aka Double Fisherman Bend
This bend is one of the most classic bends learned by climbers. It is a great choice for high security. It is very strong. According to CMC Rescue, it maintains a 68% efficiency when tied. The double fisherman’s bend is a fantastic choice for more permanent connections such as prussik cords, cordelettes, or rappel ropes when there is little chance of snags. for fancy tech cordage, follow the manufacturers recommendations for bends (some suggest a triple fisherman bend for tech cord joining). In my work, I generally use this bend to create Prussik loops, and sometimes for tying cordelettes into a loop. It is the best choice for tying ropes together for long top rope pitches. However, this can very difficult to untie after being loaded. Strive for 8-10 inches of tail once the bend is dressed and pulled tight in ropes, 3 inches in cord.
Figure Eight Bend aka Flemmish Bend
Figure Eight Bend in Use at the Gunks, NY
The figure eight bend or Flemish bend is seemingly less commonly used. I’m not really sure why. It should not be confused with the similar appearing figure eight follow through knot. This bend is a great choice for joining rappel ropes in higher load scenarios, rope rescue work, and even tying cordelettes into loops. In fact this is what I use with regular cord for my cordelettes. CMC Rescue shows a 51% efficiency. This bend is fairly easy to untie after it is loaded which makes it a great option. It is also very strong which is a bonus. Have used this bend for many years with great success. I’m also unsure what this is referenced as Flemish other than possibility that it is commonly used in Belgium. Strive for 10-12 inch tails in rope, 3 inches in cord. Be sure to dress and then pull thight before use.
Flat Overhand Bend
Flat Overhand, use with a minimum 12″ tails.
The Flat Overhand is rife with controversy. This controversy is generally related to lack of education and misinformation perpetuated by myth. This bend is flat and asymmetrical, meaning when the ropes are used for rappelling, the bend pulls smoothly across the surface. This bend is unlikely to snag. This make it a fantastic choice for rappel ropes. Stuck rappel ropes create huge challenges and increase hazards. Some climbers will tie their cordage together with the Flat Overhand. I suggest that there are better and stronger options for this task. Too, I have found in my own practice that the flat overhand seems to come loose when not in use. A disadvantage of this bend is that it appearance is quite simple misleading people to believe that it is lacking in security.
Strength: This bend is quite strong, recent informal testing at the Petzl Technical Institute during the AMGA Annual Meeting showed some fantastic results from the Flat Overhand. In fact, it is plenty strong when well dressed and pretensioned. If I had the actual numbers I would post them here, although I don’t think they have been officially published.
Tom Moyer’s testing showed minimum breaking strengths in 11mm rope with well tied bends to be 1100lbs range. Multiple tests showed failures in the range of 1200-2000 lbs. When you consider that the bend must be dressed neatly then pulled tight, you have a recipe for easy identification, and simple and fast construction.
Black Diamonds testing shows incredible strength, in excess of 3000 lbs.
Flat Overhand Key Points: 12 inch tails in rope, (for general purpose, I don’t recommend it’s use in cord), tied neatly, pre tensioned before use. Check frequently if using multiple times.
Flat Overhand Bend in use at the Gunks, NY
A Note on Backup Knots
Testing reveals that backup knots rarely add any additional strength to the load bearing knot or bend. They do not decrease the chances of a knot coming loose. Some knots namely the bowline, require a backup knot as it is easy to untie under load. Backup knots can be a waste of time and rope/material. Check your work, then partner check.
A Note on Knotting the Ends of the Rappel Ropes
Make an informed decision on wether or not to knot the ends. Weight and balance the benefits and costs. At times it makes sense too knot the ends, other times it may increase your chances of getting the rope stuck. I recently learned form a lawyer that Dogma never saved anyone.
Remember, if you have any doubt regarding the best choices for joining rope, web, or cords together, you should do your homework, and hire an AMGA Certified Guide to help you form your conclusions. Seek Qualified Instruction! Finally, recall that there is no advantage without disadvantage! Choose wisely, don’t make rash decisions because you red some online article telling you what to do!
Be careful out there.
Tom Moyer https://user.xmission.com/~tmoyer/testing/EDK.html
CMC Rescue Knot Efficiency Calculator (app available in the iPhone App Store)
Black Diamond Testing http://blackdiamondequipment.com/en/qc-lab-what-is-the-best-rappel-knot.html
Disclaimer: Climbing and activities at height are very dangerous. You are solely responsible for your own actions and failures. Period. Don’t blame someone else for your mistakes.