Page 177 - J. C. Turner "History and Science of Knots"

168 History and Science of Knots

accessories; the knot is thus best known as the Tape Knot (Fig. 35) [10, p.
95] [13, p. 113] [20, p. 30] [29, p. 26].

Novel Knots
The post-war knots considered so far have been only minor variations of knots
either already known in the climbing or caving worlds or at least fairly well
known in other applications. But there were some quite novel knots developed.
The first was the Tarbuck Hitch (Fig. 36), developed by Ken Tarbuck
[30] soon after the introduction of nylon climbing rope to Britain. This was
a shock-absorbing end loop, claimed to be as strong as a splice, able to hold
several times the climber's weight without slipping but, when subjected to the
shock load of a falling climber, it would slip until tight and absorb some of
the shock. The knot could be used tied round the waist if steps were taken to
limit motion when shock-loaded, but was more commonly tied into a karabiner.
Tarbuck recommended that the loop should have a diameter of around 30 cm,
so that at most about 60 cm of rope would pass through the knot to absorb
some of the shock; I have not seen any estimates of the forces involved in this
process. The knot became quite popular for a time. As kernmantle gradually
replaced laid rope in the late 1950s through to the 1970s, it was found that
when the Tarbuck Hitch held falls in the way it was designed to, the sheath
of the rope became separated from the core over some distance, making the
rope unsuitable for further use. Once climbers realised that this effect was
occurring, the Tarbuck Hitch came into disfavour and is now no longer seen
in climbing activities. A few general knotting books, however, continue to list
the knot and it seems to be finding new applications.

Fig. 36. Tarbuck Hitch Fig. 37. Mariner Hitch
The Mariner Hitch (Fig. 37), named after Wastl Mariner who developed
it [15, p. 99], allows the use of a sling to take the load off a rope for a period,
perhaps to allow knots in the rope to pass some device, using a knot that can
be readily untied and allows the load to be returned to the main rope in a
controlled smooth way, without jerks. The original version had several turns
round the karabiner and the bight tucked directly between the legs of the sling;
it is now generally agreed [14, p. 67] [29, p. 73] that it is best to share the load
between turns round the karabiner and twists round the sling. Usually there
is a full round turn on the karabiner and perhaps a couple of turns round the
sling, as shown.