Dynamic kernmantle rope stretches up to what percentage at failure?

• A. No stretch
• B. As much as 60%
• C. Up to 10%
• D. Up to 30%

Answer: (B)

Dynamic ropes are built to absorb energy by stretching when they’re loaded. As a rope takes a fall or is pulled toward its breaking point, the fibers elongate and the sheath slides over the core, allowing the rope to extend a lot before it finally fails. Under standard testing, the maximum elongation observed at the point of failure can be as high as about 60% of the rope’s original length. That upper limit varies with rope diameter, construction, age, and conditions, but it explains why a dynamic rope can feel noticeably longer under load and why it’s used to soften falls. It isn’t just minimal stretch, and it isn’t limited to a small percentage like 10% or 30% as the final stretch—those figures underestimate what can happen when the rope reaches its breaking point.