Section
7 Fibre ropes
7.1 General
7.1.1 Natural and
man-made fibre ropes are to comply with the requirements of an International
or recognised National Standard and are to be suitable for the use
for which they are proposed.
7.1.2 Ropes may
be manufactured from one of the following materials:
| Natural fibre
|
Man-Made fibre
|
| Hemp
|
Polyester
|
| Manila
|
Polyamide (nylon)
|
| Sisal
|
Polypropylene
|
|
|
Polyethylene
|
|
|
Aramid
|
|
|
HMWPE or UHMWPE
|
Proposals to use other materials will
be specially considered.
7.1.3 In general,
each length of rope is to be manufactured from only one type of natural
or man-made fibre. The fibre is to be a long staple or continuous
multi-filament, unadulterated and free from defects. Proposals to
use a combination of materials or other types of fibre will be specially
considered.
7.1.4 Weighting
and loading matter is not to be added and any added lubricant is to
be kept to the minimum. Any rot-proofing or water repellancy treatment
is not to degrade the fibre nor is it to add to the weight or reduce
the strength of the rope.
7.1.5 Where resin
products, or other treatments, are used to improve the grip at terminations
of synthetic ropes with very low coefficients of friction, they are
not to degrade the fibre nor to add to the weight or reduce the strength
of the rope.
7.1.6 Man-made fibres
are to be adequately stabilised against degradation by ultraviolet
light.
7.2 Application
7.2.1 Typical minimum
breaking loads of natural fibre ropes are shown in Table 8.7.1 Breaking loads of natural fibre
ropes (3 strand) and man-made fibre ropes in Table 8.7.2 Breaking loads of man-made fibre
ropes (3 strand). However, attention is drawn
to the fact that the strength of man-made fibre ropes may vary appreciably
between different manufacturers.
Table 8.7.1 Breaking loads of natural fibre
ropes (3 strand)
| Size of rope
|
Sisal
|
Manilla Grade 1
|
Hemp
|
Diameter,
mm
|
Approximate
circumference,
mm
|
kN
|
kN
|
kN
|
| 16
|
51
|
18,0
|
20,3
|
17,0
|
| 18
|
57
|
21,4
|
24,4
|
22,5
|
| 20
|
63
|
28,5
|
32,5
|
26,5
|
| 22
|
69
|
34,0
|
38,6
|
31,5
|
| 24
|
76
|
40,7
|
45,7
|
37,5
|
| 28
|
88
|
53,3
|
61,0
|
50,5
|
| 32
|
101
|
68,8
|
79,0
|
65,0
|
| 36
|
113
|
87,0
|
96,5
|
81,5
|
| 40
|
126
|
104,2
|
119,4
|
100,0
|
Table 8.7.2 Breaking loads of man-made fibre
ropes (3 strand)
| Size of rope
|
|
Man-made fibre
|
| Diameter, mm
|
Approximate
circumference,
mm
|
Sisal
kN
|
Polyamide (nylon)
kN
|
Polyester
kN
|
Polyethylene
kN
|
| 16
|
51
|
35,0
|
53,0
|
41,0
|
28,0
|
| 18
|
57
|
44,5
|
67,0
|
51,0
|
35,0
|
| 20
|
63
|
53,7
|
83,0
|
63,0
|
43,0
|
| 22
|
69
|
65,0
|
100,0
|
76,0
|
51,0
|
| 24
|
76
|
76,0
|
120,0
|
91,0
|
61,0
|
| 28
|
88
|
101,0
|
158,0
|
122,0
|
80,0
|
| 32
|
101
|
128,0
|
200,0
|
157,0
|
104,0
|
| 36
|
113
|
161,0
|
248,0
|
193,0
|
130,0
|
| 40
|
126
|
194,0
|
300,0
|
239,0
|
156,0
|
7.2.2 Fibre ropes
are not generally acceptable in the lifting appliance systems covered
by this Code except for the following applications:
| •
|
Derrick systems:
|
|
|
Slewing guy tackles (but not
pendants) where the SWL of
the guy does not exceed 4,0 t.
Boom head guys in union purchase rigs.
|
| •
|
Launch and recovery systems for diving
operations:
|
|
|
Proposals for the use of synthetic
fibre ropes for lifting purposes will be considered.
|
| •
|
Deep water exploration and ROV
handling.
|
| •
|
Falls on the LSA or tender craft
handling systems of large commercial yachts, where permitted by National
Administrations.
|
7.2.3 The safety
factor to be applied to fibre ropes is, generally, to be 25 per cent
higher than the equivalent safety factor for a steel wire rope.
7.3 Splicing and terminal connections
7.3.1 The lengthening
of fibre ropes by splicing is not permitted.
7.3.2 Eye splices
are to consist of not less than:
-
Natural fibre ropes:
- Three full tucks and two tucks in which half the fibres in each strand
have been cut away.
-
Man-made fibre ropes:
-
Four full tucks and
two tucks in which half the fibres in each strand have been cut away.
The ends of the strands are to be fused.
-
For synthetic ropes
with low coefficients of friction, the manufacturer’s advice
for making an efficient termination is to be followed.
|