Monday, June 17, 2013

Saturday Night Live Clinic: Recap - Knots for Joining Rope and Webbing

Six people attended the clinic I gave Saturday night in the Uberfall. The main discussion topic was "knots for joining rope and webbing". We also discussed friction hitches, rappelling and a bit of toprope anchor management, but a large portion of the time was spent covering different knots for joining rope ends.

Knots for Joining Rope Ends During Rappels and When Tying Cordalettes

Flat Overhand

Perhaps the most common knot for joining rope ends during a rappel scenario is the flat overhand (euro-death knot). Honestly, this knot is a bit of a crapshoot. If it's tied neatly (dressed and pretensioned) and with long tails it behaves more-or-less predictably, beginning to roll somewhere around 1000 lbs. However, if it's not tied and pretensioned properly it will begin to roll in the 200 lb range. If the tails aren't long enough the ends might roll through the knot. As a result of unpredictable inversion or "rolling", this knot is only appropriate for low-load scenarios like rappelling. One of the reasons it's a popular knot when rappelling is because it's easy to untie and it allegedly does not snag. Here's a basic list of where it's good and bad to use:
  • Good for joining rope ends, even of different diameters, for rappelling
  • Bad for joining ropes in belay/climbing scenarios
  • Bad for tying webbing together
  • Bad for tying cord/webbing when replacing material on cams and hexes
  • Hard to maintain proper dressing and pretension for joining ends of cordalette, use with extreme caution
The flat figure eight - a BAD knot to use - it
inverts easily and eats up it's tails as it inverts
The flat figure eight, which is similar to a flat overhand, but uses a figure eight, is less desirable and more unpredictable. It really should not be used at all. It rolls more easily, uses more tail as it rolls, and it's a bit harder to dress properly. Many rappel accidents or rappel anchor failures have been recorded while using this knot. It's unstable and it rolls easily.

Flemish Bend

The flemish bend - good for rappels, belays, and tying
cordalette together
The flemish bend, a retraced figure eight with the ropes entering the knot from either side, is a good strong knot with predictable behavior. It's easy to tie, easy to recognize visually, and relatively easy to untie afterward. This is a good knot to use for joining ropes while rappelling or while belaying. Here's a general list of good's/bad's for the flemish bend:
  • Good for joining rope ends, even of different diameters, for rappelling
  • Good for joining ropes in belay/climbing scenarios
  • Good for joining ends of cordalette, can be untied so cordalette can be cut or used as a single strand

Double Fisherman's Knot

The double fisherman's knot - stable, strong
and hard to untie
The double fisherman's knot, is another good all-around option for joining rope ends together in any scenario. Even the sloppiest dfk's stay tied properly and don't fail prematurely or unpredictably. It is hard to untie, making it a good choice when you want the knot to be permanent.
  • Good for joining rope ends, even of different diameters, for rappelling
  • Good for joining ropes in belay/climbing scenarios
  • Good for joining ends of cordalette, canmot be untied easily. You'll need to cut the cordalette to leave some behind.
  • Good for tying webbing on rappel anchors (permanent)
  • Good for reslinging cams and hexes

Knots for Joining Webbing Ends

Water Knot

The water knot, is a good choice for webbing when you want to untie the webbing afterward. As I've mentioned in past posts, the water knot slips through cyclic loading, making it a bad choice for webbing on rappel anchors in the Gunks that see hundreds of rappellers each weekend.
  • Good for tying webbing together for toprope anchors, it will untie with relative ease
  • Bad for tying webbing on rappel anchors, where the webbing will become permanent, because of slippage during "cyclic loading"
Water knot - good for tying webbing together if you need
to untie it afterward

Double Fisherman's Knot

This knot is good to use when tying webbing together. It's strong, it's permanent, and it will nearly always hold despite the fact that it looks sloppy.
  • Good for joining webbing ends for permanent use, like rappel anchors.
  • Good for reslinging cams if you're going to do that by hand.
The double fisherman's knot - rarely seen using webbing, this
is THE knot to use when equipping rappel anchors, even when
using webbing

For great information regarding pull testing of water knots and flat overhands check out this webpage:

Ryan Stefiuk is an AMGA Certified Rock Guide. If you like what you see here consider hiring an AMGA trained and certified Rock, Alpine, or Ski Guide.

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