Knot Reference
Common rigging and rescue knots with typical strength reduction.
Reference
Knots
- Bowline Forming a fixed loop at the end of a line; rescue and rigging.Strength reduction: 30 to 40 percent of rope tensile strength.; Note: Easy to untie after loading; does not slip if dressed correctly.
- Clove hitch Securing a line to a post or anchor.Strength reduction: 40 to 50 percent of rope tensile strength.; Note: Can slip under uneven loading; back up with a half hitch.
- Figure-eight on a bight Forming a strong, easy-to-inspect loop in the middle or end of a rope.Strength reduction: 20 to 30 percent of rope tensile strength.; Note: Standard rescue knot; jams less than the figure-eight follow-through.
- Double fisherman Joining two ropes of similar diameter.Strength reduction: 20 to 30 percent of rope tensile strength.; Note: Strong and reliable; difficult to untie after heavy loading.
- Munter hitch Improvised belay or rappel device.Strength reduction: Adds friction; not a strength-reducing knot per se.; Note: Twists the rope under load; preferred in emergencies only.
Details, formula, and sources
(reference page; no compute) Common rigging and rescue knots (figure-eight, bowline, clove hitch, prusik, water knot, double fisherman) with typical strength-reduction percentages from public rope-rescue and arboriculture training materials.
NFPA 1006 / NFPA 1670 by name; National Fire Academy rope rescue training materials (U.S. government, public domain).
NFA training materials free at usfa.fema.gov. NFPA 1006 / 1670 read-only at nfpa.org/freeaccess.
Estimate. AHJ and licensed fire protection engineer govern.