Page 172 - J. C. Turner "History and Science of Knots"

A History of Life Support Knots 163
overwhelmingly dominant position.
These new properties influenced rope use and the knots tied. For example,
an early report states that `a foot of nylon will often slip through a knot
before it tightens enough'. Traditional knots had to be either abandoned and
substitutes found, or at least modified, such as by securing the running ends
to standing parts with Overhand Knots or the like.
At this time, increased mobility and affluence brought about great in-
creases in the numbers of people taking part in adventure sports, including
rock climbing and caving. All this caused a great burst of experimentation
with knots. This was increased when, beginning in the mid 1950s, kernmantle
rope (sheath and core) started to replace laid nylon rope for climbing.
Kernmantle ropes can be made with different properties for different
climbing purposes. These specialist life-support ropes are quite different from
the sheath and core ropes that have been developed for yachting and the like.
Though many have been tried, only two main designs of climbing rope are now
found: dynamic ropes for ordinary rock climbing and mountaineering, which
are normally unloaded but have good elongation under shock loads; and static
ropes used for ascending and descending on the rope, as in caving and some
rescues, with minimal stretch under a person's weight but still ample stretch
for emergency shock loads. Kernmantle ropes are even more slippery than laid
ropes, and some knots or rope usages cause separation of sheath and core.
Environmentally friendly artificial anchorages began to be developed, that
could be inserted into cracks and crevices and removed after use with much
less damage to the rock than pitons. At first, in the early 1960s, engineering
nuts with the threads reamed out were tried; then optimally shaped irregular
hexagons and other shapes were used; and more recently highly sophisticated
mechanical devices were introduced. Dynamic belays were made more con-
trollable, having all the slippage of the rope to a falling climber go past a
metal device, rather than the belayer's body; consistent friction was applied,
allowing a suital-le compromise between too large a shock loading on a falling
climber or the belay, and too long a run out of the rope, increasing the dan-
ger of hitting an obstacle or running out of rope. Nylon tape and webbing
allowed the construction of special climbing harnesses, at first improvised and
knotted, but increasingly permanent and sewn, allowing safer and more com-
fortable connection to the rope. Karabiners and other devices are now much
stronger and lighter than they were.
With these new stronger and more elastic ropes, and with new techniques
and mechanical devices, it now became possible to hold falling leaders with
minimal damage to rope and climber, so that now many climbers on routes of
the greatest difficulty almost expect to fall, perhaps several times, confident
of being held safely, to repeat the move or try elsewhere.
The greatly increased numbers of people taking part in all these sports