Damage Inflicted on Climbing Ropes by Handsaws

Brian Kane; Mac Cloyes; Mollie Freilicher; H. Dennis Ryan

doi:10.48044/jauf.2009.046

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Figure 1.
Blades (left to right): used (manufacturer unknown), new standard tooth (Gilmour), IB, ZU, F1, F3, F2 (abbreviations are in Table 1).
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Figure 2.
Pendulum attached to beam; the jig that held blades (see Figure 3) is attached to the pendulum with clamps visible just below the midpoint of the pendulum.
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Figure 3.
Blade in jig attached to pendulum. “X” marks the tooth that first made contact with the rope.
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Figure 4.
Frequency distribution of percent cut, categorized by type of failure: at the knot (shaded columns) or at the cut (un-shaded columns). The value on the horizontal axis is the maximum value for each category.

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Table 1.

Different ropes and blades used in the experiment, including means (standard deviation) for measured values as well as manufacturers’ specifications. Percent strength loss (%SL) from rated tensile strength was calculated: (rated strength-knotted strength)/rated strength.

Rope (abbreviation)	Manufacturer	Mean Rated Strength^{^z} (kN)	Knotted Strength^{^y} (kN)	%SL from Rated Tensile Strength	Nominal Diameter (mm)	Diameter Under Tension^{^x} (mm)
Blaze	Yale	24.9	21.4 (2.24)	14%	11.0	10.3 (0.34)
Blue Streak (BS)	Samson	30.7	22.8 (1.19)	26%	12.7	11.9 (0.14)
Poison Ivy (PI)	Yale	28.9	25.4 (1.57)	12%	11.7	10.7 (0.26)
Safety Blue (SB)	New England	31.1	17.6 (1.84)	43%	12.7	11.7 (0.23)
Velocity (VEL)	Samson	26.7	19.5 (1.24)	27%	11.0	10.4 (0.31)
XTC	Yale	27.6	20.7 (1.55)	25%	12.7	12.0 (0.22)

Blade (abbreviation)	Manufacturer (mm)	Blade Length	Teeth per mm
FI-K1500 (F1)	Fanno	356	0.24
FI-1214 (F2)	Fanno	305	0.24
FI-1311 (F3)	Fanno	330	0.24
Ibuki (IB)	Silky	390	0.22
Zubat (ZU)	Silky	330	0.30

↵^z As published in manufacturer’s catalog.
↵^y Tied with an anchor hitch.
↵^x 41 kg (90 lbm).

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Table 2.

Means (standard deviations) for percent cut (% Cut), percent strength loss (% SL) (both in decimal form), and acceleration (m/s²) for each rope and blade (abbreviations are in Table 1). Within each classification and read down a column, means followed by the same letter are not significantly different (Tukey’s HSD, P > 0.05).

Rope	N	% Cut	% SL	% SL LS Mean^{^z}	Acceleration
BLAZE	31	0.49 (0.37)a	0.48 (0.44)a	0.29 (0.024)a	2.96 (0.38)a
BS	30	0.39 (0.34)bc	0.40 (0.37)ab	0.29 (0.024)a	3.17 (0.57)a
PI	30	0.35 (0.35)c	0.35 (0.38)b	0.26 (0.025)a	2.98 (0.52)a
SB	30	0.42 (0.34)abc	0.40 (0.37)ab	0.26 (0.024)a	3.04 (0.61)a
VEL	30	0.48 (0.34)ab	0.43 (0.42)ab	0.23 (0.024)a	2.85 (0.58)a
XTC	30	0.41 (0.34)abc	0.42 (0.39)ab	0.28 (0.024)a	2.96 (0.55)a

Blade
F1	30	0.13 (0.05)a	0.02 (0.05)a	0.15 (0.023)a	3.08 (0.33)ab
F2	30	0.47 (0.21)b	0.52 (0.23)b	0.36 (0.024)b	2.95 (0.62)a
F3	31	0.13 (0.06)a	0.03 (0.08)a	0.15 (0.023)a	3.28 (0.43)b
IB	30	0.40 (0.17)b	0.51 (0.19)b	0.41 (0.021)b	3.15 (0.54)ab
ZU^{^y}	30	1.00 (0.00)c	1.00 (0.00)c	n/a	2.50 (0.39)c

↵^z The least squares (LS) mean for % SL is the arithmetic mean adjusted for the covariate % Cut; it is followed by the standard error (in parentheses).
↵^y Zubat blades were not included in the ANOCOVA because they completely cut through every rope.