Knots

These percentages are residual strength: the expected breaking strength of a dressed, set knot as a fraction of the unknotted rope MBS. 70% means the knot is expected to fail at about 70% of the rope’s unknotted MBS. Ranges are from published pull tests (CMC and others).

• Figure 8 follow-through

  70–80%

  Tie-in, litter bridle, terminated end on a ring or harness.

  Dress, set, long tail.

• Figure 8 on a bight

  70–80%

  Master point, clip-in loop.

• Figure 8 bend

  55–80%

  Join two ropes of similar diameter. Back up both sides with overhand knot tight against the figure 8 bend. Wide spread in tests — do not assume 80%.

• Bowline

  58–75%

  Tie-in around an object. Unties after load.

  Can capsize if not backed up (Yosemite finish or double-overhand on the tail).

• Double fisherman

  79–80%

  Join accessory cord; Prusik loops.

  Hard to untie after high load. Long tails.

• Scaffold knot

  69–81%

  Terminated eye onto a carabiner (double overhand noose).

  Cinches onto the biner.

• Water knot

  ~50%

  Join webbing. Anchor straps, bridles, wrap-2/pull-2.

  Long tails. Recheck — webbing knots creep. Never in rope.

• Overhand

  45–60%

  Stopper, backup, webbing follow-through.

  Weak as a primary knot. Fine as a backup.

• Flat overhand bend

  45–60%

  Join of two rappel ropes for snag-free pull-down. Long tails of at least 18" or 46 cm required. NOT a mainline rescue bend.

• Square knot

  45–50%

  Webbing seat or chest harness.

  Never a life-safety bend in rope. Can capsize. Back up both sides.

• Tensionless hitch

  ~100%

  Wraps around a bombproof object. No knot in the loaded rope.

  Needs diameter and friction. Several wraps; lock off.