Model combination wire ropes with different covering materials were prepared and worked out specification for the prototype. A table model hand operated wire rope twisting machine was also developed for this. Prototype combination wire rope was twisted in collaboration with M/s South India Wire Ropes Ltd., Alwaye. Specification details, properties and field performance of the prototype studied are reported

Meenakumari, B.

Panicker, P.A.

Aquatic Commons

I Substitution of Co ation Rope" Part I" 
Production and Evaluation of a 
Combination re Ro 
B.MEENAKUMARI and P.A. PANICKER 
Central Institute of Fisheries Technology, Cochin - 682 029 
Model combination wire ropes with different covering materials were prepared and 
worked out specification for the prototype. A table modd hand operated wire rope 
twisting machine was also developed for this. Prototype combination wire rope was 
twisted in collaboration with M/s. South India Wire Ropes Ltd., Alwaye. Specification 
details, properties and field performance of the prototype studied are reported. 
In the present context of Government 
of India's effort for the exploitation of the 
:fishery resources of the middle and distant 
waters of the Exclusive Economic Zone, 
import substitution of the combination wire 
rope is of much importance. When a 
single material cannot satisfy certain spe-
cific requirement, it is a general practice to 
go in for combining materials of different 
properties to have at least the near desired 
qualities. It is in this context that com-
bination wire ropes were made and used as 
framing ropes for heavy duty trawls. 
Ropes are used either to withstand or to 
transmit force. A rope may be of high 
breaking strength and resistance to loadings 
without any appreciable extension as in the 
case of steel wire ropes or with comparatively 
low breaking strength and low resistance 
to stretch but with high degree of load 
absorption and shock resistance as in the 
case of fibre ropes (Klust, 1983). The 
former is best suited for rigging masts, 
booms, trawl winches, sweep lines, bridles etc 
and the latter is used for lines where a high 
degree of work absorption and shock 
loading is required. However, both types 
are not suitable as framing ropes of nets. 
The desired qualities for framing ropes are 
high breaking strength, very low extension 
at sustained loading, medium flexibility, 
medium mass volume ratio and roughness 
to maintain original size and shape of gear 
without being elongated under sustained 
loading and slippage. 
A steel wire rope while satisfying low 
extension and high breaking strength will 
have very low diameter,extra stiff and smooth 
and is highly susceptible to corrosion. Fibre 
ropes have comparatively low breaking 
strength, specific gravity and high extensi-
bility. A combination wire rope of .steel 
wire and natural or synthetic fibre can pro-
vide high breaking strength, low extension, 
stiffness and mass. The fibre component 
can reduce the stiffness and mass making 
the rope flexible and thicker with rough 
surface and can protect the steel component 
from accelerated corrosion in the marine 
environment. A rope thus made wiH have 
all the required qualities of a framing rope. 
Even though India is an exporter of 
different types of wire ropes and have suffi-
cient infrastructural facilities, import com-
bination wire ropes for fishing purposes 
mainly due to the present low intake and 
lack of expertise and standar4. Conse-
quent on the declaration of EEZ and the 
high priority in deep sea fishing, the intake 
of combination wire rope will be manyfold 
in the near future. Even on a very conser-
vative estimate the annual requirement will 
be about 0.5 million metres by the turn of 
the century and at the present rate the cost 
will be over Rs.15 million in foreign exchange. 
It is in this connection that Central Institute 
of Fisheries Technology took up research 
and development programme for the com-
bination wire ropes for fishing operation. 
Materials and Methods 
' 
A table model hand operated wire rope 
twisting machine (Fig. 1) was designed and 
developed for preparing combination wire 
FISHERY TECHNOLOGY 
A PROTOTYPE COMBINATION WIRE ROPE 9 
rope. The hand operated model wire rope 
twisting machine has got provision to twist 
a wire rope of six strands with central core. 
The six spools of the strands and the spool 
of central core are spring loaded to attain 
even rate of tension. The central · core 
passes through a GI pipe and the six strands 
with the core converge at a nozzle for closing 
the wire rope. The twisted rope is got 
wound in a reeling drum. The twisting 
operation is done manually with a handle 
and cycle chain arrangement. Model com-
bination wire ropes were prepared using 
0.32 mm GI wire and different types of 
covering materials like polyamide yarns, 
polyethylene tapes and monofilament 
polypropylene (PP) yarns and PP tape. 
The abrassion resitance of twisted tape 
Fig. 1. Table model hand operated wire rope twisting 
machine 
yarn was also studied by abrading selected 
samples of 1.7 mm dia twisted tape yarn 
in wet condition over oil stone upto a period 
of l 0 min of continuous abrasion with 
stages of l min interval. 1.5-2 mm dia 
PP twisted tape yarn was observed to be 
best suited and was selected as covering 
material and 3.4 mm dia 3 stranded PP tape 
yarn twisted rope as central core for the 
prototype combination wire rope. 
The steel wire component for the proto-
type was selected in consultation with M/s. 
South India Wire Ropes Ltd., Alwaye - a 
leading wire rope manufacturing firm in 
the area, and coUaborated with them in the 
production of the first prototype as per the 
specification evolved by the authors. The 
rope diameter was fixed as 16 - 18 mm 
with an approximate aggregate breaking 
Vol. 25, 1988 
CH t. CW R-1 
Rope strand 
Central core Core strand 
65 (8+ 8c +I Serl+ 6Cr S(I +6+ I Crc) 
Fig. 2. Construction details (diagramatic) of com-
bination wire rope (Cift-CWR I) 
Fig. 3. Components of the combination wire rope 
cift-CWR 1 FULL ROPE 
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F . 4 Load-elongation curve of the combination wire rope (Cift-CWR I) and its components. 1g. -. 
FISHERY TECHNOLOGY 
A PROTOTYPE COMBINATION WIRE ROPE 11 
strength of 50 - 55 KN. The first batch 
of 500 m prototype combination wire rope 
(Cift - CWR I) was prepared in April 1986 
by M/s. South India Wire Rope Ltd., 
Alwaye. 
400 iO 
., 
li\00 .. 16 .. 
0 
" 
r .. 
0 0 
..... .. 
z ,_ 
0 
"':. 
.. z 
,... 
" "' lll 
"' 
--'+ <.> 
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• ~ .. 
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"' 
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fO ;; 
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z 
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"' 
" 
--'+ ... ,_ 
x 
" 
... 
100 
I 2 3 4 6 G 7' 6 9 10_ 
l'IERIOO OF A61'!AllON IN Pli!NUTIElll 
Fig. 5. Relation between retention of strength and 
stretch with period of abrasion. 
All testings were carried out in Zw~ck 
1484 Material Testing System. Different 
components were tested for breaking strength 
and stretch and the average value of ten 
test results was taken. 
The prototype was also rigged as head 
and foot ropes of high speed demersal tra-
wls and put under extensive field trials at 
speeds upto 5 knots from the research vessel 
FORV Sagar Sampada. Samples of head 
Vol. 25, 1988 
and foot ropes were drawn at regular inter-
vals of 30 days of continuous operation 
upto 90 days and tested for strength retention. 
Results and Discussion 
The construction details are given in 
Figs. 2 and 3. The specifications and test 
results of the rope and various components 
of the combination wire rope are ,presented 
in Table 1. The lowest strength and stretch 
values of the 'full rope and :its different com-
ponents (Load - elongation curve) are 
detailed in Fig. 4. 
The abrasion resistance of the PP twisted 
yarn covering material is given in Fig. 5. 
The final strength of combination wire 
rope is lower than the aggregate strength 
of the wire components except in the 
case of rope strand stage due to the 
core component. The ranges of percentage 
reduction are: 
i) Aggregate of wire and PP component 
to final . rope 34-35 
ii) Aggregate of wire components to 
final rope 11. 0-H .20 
iii) Strand covered + Central core to final 
rope 15.5 - 16.0 
iv) Strand uncovered + Central core to 
final rope 9.0-9.5 · 
v) Aggregate of wires to central core 
6.5-7.0 
vi) Aggregate of wires + PP core to cen:-
. t'ral core 12.0 - 12.50 
vii) Aggregate of wires + PP core to rope 
strand 4.0 - 4.20 
viii) Aggregate of wires to rope strand 
2.0-2.30 
ix) Aggregate , of wires to core strand 
5.0-5.50. 
From the above it can be conduded that 
even though there is a definite reduction 
in strength at various stages from the aggre-
gate strength of wire component, the com~ 
parative low reduction at the final stage is 
mainly due to the :influence of combination 
of steel and synthetics - a hard and soft 
material rather than the influence of strength 
of the: latter. 
:=l 
tll 
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Table Details of prototype combination wire rope 
Particulars 
Specification 
Lay 
Pitch (mm) 
Diameter (mm) 
Strength (KN) 
Stretch(%) 
Weight/100 m (kg) 
Aggregate 
Strength (KN) 
Rope 
6S (8+8c+ 
1Scr)+6Crs 
(1+6+ 1 
Crc) 
Regular 
right 
hand 
125.00 
17.00 
50.80 
11.50 
38.52 
0.635 x 90 
=57.15 
Covered 
strand (S) 
8+8c+ 
lScr 
Regular 
left 
hand 
41.60 
5.50 
5.90 
4.20 
3.49 
5.9 x 6 
=35.40 
Rope strand (S) 
Uncovered Strand Strand 
strand (S) Core (Ser) cover (c) 
(Ser) 
8+ lScr 
Regular 
left 
hand 
20.80 
2.25 
5.20 
2.30 
2.56 
5.20x 6 
=31.20 
Twisted PP tape 
yarn 
Right hand 
1.60 
0.34048 0.34048 
26.43 
0.161 each 
0.34048 x 54=18.385 
Rope core 
(Cr) 
6Crs(l + 
6+Crc) 
Regular 
right 
hand 
50.00 
6.50 
24.88 
3.44 
13.09 
Rope core· (Cr) 
Core 
strand 
(Crs) 
1+6+ 
lCre 
Regular 
right 
hand 
21.40 
2.00 
4.20 
2.90 
1.86 
4.20x6 
=25.20 
Central 
core(Crc) 
PP tape 
twisted 3 
stranded 
rope 
Right hand 
12.50 
3.00 
1.73568 
38.85 
0.425 
Steel 
wire 
0.71 
0.635 
4.89 
0.293 
0.635 x 90 
=57.15 
,_ 
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A PROTOTYPE COMBINATION WIRE ROPE 
In the case of extension at break there 
is a definite increase in the extension from 
basic wire component to the finished pro-
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duct (from 4.5 - 5.0 to 11.5 - 12 %). 
However, this comparatively high extension 
rate can be attributed to the high pitch 
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Fig. 6. Load-elongation curve of used samples of combination wire rope (a,b,c used as head rope for 
30, 60 and 90 days respectively d, e, f used as foot rope for 30, 60 and 90 days respectively) 
Vol. 25, 1988 
14 
2. Strength retention of prototype 
combination wire rope after demer-
sal trawling from FORV Sagar 
Sampada as head and foot rope 
Strength retention 
Details Head rope Foot rope 
KN %KN% 
After continuous 
use for 30 days 50.18 98.78 47.75 94.0 
After continuous 
use for 60 days 47.69 93.88 36.62 72.09 
After continous 
use for 90 days 45.22 89.02 30.50 60.04 
Fig. 7. Combination wire rope after 90 days opera-
tion as foot rope. 
value (125 mm) given at the closing stage 
of rope which can be improved upon by 
adjusting the pitch at the closing stage. In 
B. MEENAKUMARI AND P.A. PANICKER 
all the other stages there is a definite redu-
ction in the extension from the basic wire 
component. Even though this increase, 
when compared to wire rope, is on the higher 
side it is negligible when compared to that 
of fibre ropes. 
The strength of PP covering material 
ranged between 0.27 and 0.34 KN mainly 
due to non-uniformity of the width of the 
PP tape yarns and the diameter of the tape 
varied from 1.5 to 1. 7 mm. The exponential 
relation of abrasion resistance indicates a 
reasonably good abrasion resistance of the 
material. 
The residual strength of the combination 
wire rope used as head and foot ropes in 
the high speed demersal trawls is given in 
Table 2. Fig. 6 indicates the load-elonga-
tion nature of the residual strength and 
stretch of the rope. Fig. 7 shows the nature 
and intensity of abrasion of foot rope after 
90 days fishing operations. Only a mar-
ginal reduction of about 11 % in the breaking 
strength of head rope and about 40 % in 
the case of foot rope is shown after 70 
hauls tried for a period of 90 days. 
The above study and the results indicate 
that there is further scope of improvements 
on prototype (Cift, CWR I) for better effi-
ciency and strength at reduced extension 
rate. Attempts are being made to improve 
upon the prototype for standardisation pur-
poses. 
The authors wish to express their thanks to Shri 
M. R. Nair, Director, Central Institute of Fisheries 
Technology, Cochin for his keen interest, encourage-
ment and approval of the paper for publication. 
They are also thankful to M/s. South India Wire 
Rope, Edathala, Alwaye for their immense help and 
co-operation in twisting the prototype. 
Reference 
Klust, G. (1983) Fibre Ropes for Fishing 
Gear. Fishing News (Books) Ltd., 
England, p. 200. 
FISHERY TECHNOLOGY 


Import substitution of combination wire rope. Part 1. Design, production and evaluation of a prototype combination wire rope

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Import substitution of combination wire rope. Part 1. Design, production and evaluation of a prototype combination wire rope

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