Page 203 - J. C. Turner - History and Science of Knots

192 History and Science of Knots

Table 7. KNOT STRENGTH EFFICIENCY IN FISHING LINE
Monofilament nylon line, diameter not stated

Knot and Ashley number [5] 1951 [7] 1981 [22] 1983 [11]

Bends
Blood Knot (based on #295) 79% 77% 80%
Water Knot (based on #290) 79% - 95%

Loops
Blood Bight (based on #521/1047) 80% 92% 80%
Perfection Loop (#286) 60% 60%

Hitches
Half Blood (based on #300) >80% 96% 80%
Two-circle Turle (based on #305) 80% 62%

The ropes tested in Table 2 seem all to have been fairly close to 12 mm
diameter, except for the flax cord used by Wright and Magowan [36], which
was only 1/37 inch in diameter. They were using this cord as a model for
the manila climbing rope used previously [2]. Knot strength efficiencies were
higher in this cord than in any other in these tests. Wright and Magowan said
the differences `may be explained in part by the differences in pliability and
roughness, which would greatly affect the nip of the knot, and in part by the
great difference in thickness, which may well tell in favour of cord'. They go on
to say `in any case, the discrepancy must be due to some cause which affects
all knots in common; in all probability, the relative position of the knots is
unchanged'. In fact, by both the tests the Reef Knot had the lowest efficiency,
but the other knots appear in different orders. No information is given on
the size of the fishing lines in Table 7. The environmental and mechanical
conditions (temperature, humidity, rate of elongation) used in the tests in
Tables 2 to 7 are not, in general, described, so that their effects cannot be
guessed. Table 3 shows the effect of wetting the rope on knot efficiency (I am
uncertain of the identity of the knot); Day [16] stated that a Bowline was 50%
stronger after soaking the 1 ands inch diameter manila rope.

Conclusions
Day [16] said that bends on average seem to be weaker than loops and
nooses, which in turn are weaker than hitches; Chisnall [15] said that in general
hitches were stronger than loops because in a hitch the standing part passes