In a static kernmantle rope, the maximum allowed stretch is what percent?

In a static kernmantle rope, the maximum allowed stretch is what percent?

• A. 10%
• B. 20%
• C. 15%
• D. 25%

Answer: (B)

Static kernmantle rope is meant to behave predictably with minimal length change when loaded, so rescue and rigging systems stay stable and anchors aren’t surprised by a line that grows or shrinks during use. The standard for static rope sets a maximum elongation of about 20% of its length under the specified working load. Keeping elongation within this bound provides enough give to absorb small shocks without letting the rope drift so much that the rigging geometry changes or forces on anchors increase. Dynamic ropes are designed to stretch far more to absorb falls, which is why their numbers are not relevant here. The other values either would be too restrictive for practical use or allow too much stretch, risking instability in the setup; 20% is the commonly accepted limit for static kernmantle rope.

Static kernmantle rope is meant to behave predictably with minimal length change when loaded, so rescue and rigging systems stay stable and anchors aren’t surprised by a line that grows or shrinks during use. The standard for static rope sets a maximum elongation of about 20% of its length under the specified working load. Keeping elongation within this bound provides enough give to absorb small shocks without letting the rope drift so much that the rigging geometry changes or forces on anchors increase. Dynamic ropes are designed to stretch far more to absorb falls, which is why their numbers are not relevant here. The other values either would be too restrictive for practical use or allow too much stretch, risking instability in the setup; 20% is the commonly accepted limit for static kernmantle rope.