Impact Force
The impact force is the force
exerted on the lead climber in a fall, all of the force must be
countered by the belayer. The magnitude of the force depends on
four things; rope elongation, body weight, fall factor and belay
method. The dynamic belay, which is where the belayer lets some
of the rope slip through the tube or plate belay device as the fall is
arrested, this decreases the impact force greatly. There are a
few other tricks such as having the belayer jump as the force of the
fall comes on them, it gives the same affect as the dynamic
belay. The fall factor = Vertical distance fallen ,
Length of rope out
the higher the fall factor the
larger the impact force on the climber. The most important aspect
of the fall factor is to recognize that the closer the
climber is to the belayer, the stronger the impact force will be; this
is due to less rope available to absorb some of the force.
Obviously a heavier climber is going to create a larger impact force
and should therfore think about using thicker ropes and placing extra
protection.