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

162 History and Science of Knots

is also still in occasional use [11, p. 74], [27, p. 133]. Prusik also discussed
other uses of the sling and Prusik Hitch: to safeguard a rope under load; to aid
hauling on a rope; and to attach components of several tackle systems to raise
a helpless person. All these applications are still in use. It may be of interest
to note that experts in a hurry can climb up a rope, using friction hitches and
slings only, for 30 m in a little over 1 min, and for 120 m in a little over 9 min.
These clearly described applications caught the imagination of moun-
taineers, particularly in Europe. The method of ascending a rope has become
known as `prusiking', and the slings held ready for emergency use are known
as `prusiks'. Additional applications, mainly developed since the War, include
the attachment of a middleman to a climbing rope by way of a small sling
attached to a waist length; or the attachment of a solo climber to a fixed rope,
as for a practice climb; the ascent of a fixed rope traversing difficult country
in expedition mountaineering; more elaborate tackle systems, some with au-
tomatic locking; and in caving. A few European cavers experimented with an
abseil-down, prusik-up technique in vertical caves in the 1930s [21, p. 310],
avoiding the slow and cumbersome use of ladders.
However, the idea did not catch on at that time. Meanwhile, moun-
tain rescue teams were becoming better organised, and began to investigate
techniques using rope and knots not needed for ordinary climbing or caving.
Crevasse rescue inspired the adoption of the Bowline on a Bight as a chair knot
and development of the Prusik Hitch for self-extrication, as has already been
discussed. Several ways of constructing emergency stretchers were developed
that used nothing but a single climbing rope; no special knots were used in
the construction.

Post-War Period

This might be even better called the Post-Nylon Period, because the effect of
the War most significant to climbers and cavers was the invention of nylon
ropes in 1941. The US Army has long had a mountain section. The entry
of Japan into the War abruptly terminated the supply of manila fibre, up to
that time the fibre of choice for climbing rope. Sisal proved inferior, but nylon
proved both stronger than manila and to have much greater elongation before
breakage. The shock loading on the climber at the end of a fall was much less
than when using manila. In addition, nylon was less affected by moisture,
frost or mildew; but it was more slippery and it melted at relatively low
temperatures, so that friction between two ropes could cause failure. Proper
specifications were developed for nylon climbing rope, which at that time was
all of three-strand, laid construction. After the end of the War these ropes
became the choice of climbers and cavers. Other synthetic fibres have been
tested for climbing and caving ropes, but have not removed nylon from its