Your climbing rope is the lifeline that keeps you and your partner safely connected to the rock. Over the last century, these super strong lengths of braided nylon have been refined into a perfectly engineered combination of versatility and shock absorption power.
There is one EXTREMELY important difference between static and dynamic ropes-- the ability to stretch under a load. In most climbing situations, a dynamic rope must be used or you risk severe consequences such as shock-loading, personal injury, and/or anchor systems failure.
Dynamic elongation is the term used to describe the amount of stretch capable in a rope when fallen upon. Dynamic ropes range upwards of 40% in dynamic elongation. That means if you fall 100 feet and generate enough force, the rope could stretch another 40 feet to absorb the forces of the fall. The ability to absorb such a high amount of force helps to make falls feel "softer" and minimizes the forces applied to the anchors.
Static, or working, elongation refers to the amount of rope stretch when 176 pounds is applied to the rope. In dynamic ropes this figure is 5% or more. In static ropes it is less than 5%. In some situations, such as rescue, big-wall, rappelling and canyoneering, a rope that has low static elongation is ideal. This is because stretchy ropes will rub over any edges creating undo wear, or dangerous situations.
So, if you are top-roping, sport, trad, alpine, or mountaineering choose a dynamic rope. If you are canyoneering, rappelling, big-wall hauling, or working rescues then choose a static rope. But never use a static rope where a dynamic rope should be used.
Static ropes have four main uses: rappels, rescues, hauls, and anchors. Because their working elongation is so low, they minimize any rubbing against sharp edges. This keeps a rope healthy longer and creates more efficient haul systems and smoother rappels.
