SINKING MATERIALS
∎ Metals
Density |
Multiplication factor* | ||
Type |
(g/cc) |
freshwater | sea water |
aluminium | 2.5 | 0.60 + |
0.59 + |
brass | 8.6 | 0.88 + |
0.88 + |
bronze | 7.4 | 0.86 + |
0.86 + |
to 8.9 |
0.89 + |
to 0.88 + |
|
cast iron | 7.2 |
0.86 + |
0.86 + |
to 7.8 |
0.87 + |
0.87 + |
|
copper | 8.9 |
0.89 + |
0.88 + |
lead | 11.4 |
0.91 + |
0.91 + |
steel | 7.8 |
0.87 + |
0.87 + |
tin | 7.2 | 0.86 + | 0.86 + |
zinc | 6.9 | 0.86 + |
0.85 + |
∎ Textiles
Density |
Multiplication factor* | ||
Type |
(g/cc) |
freshwater | sea water |
aramide (kevlar) | 1.20 | 0.17 + | 0.15 + |
cotton | 1.54 | 0.35 + | 0.33 + |
hemp | 1.48 | 0.32 + | 0.31 + |
linen | 1.50 | 0.33 + | 0.32 + |
manilla | 1.48 | 0.32 + | 0.32 + |
polyamide (PA) | 1.14 | 0.12 + | 0.10 + |
polyester (PES) | 1.38 | 0.28 + | 0.26 + |
polyvinyl alcohol (PVA) | 1.30 | 0.23 + | 0.21 + |
polyvinyl chloride (PVC) | 1.37 | 0.27 + | 0.25 + |
polyvinylidene(PVD) | 1.70 | 0.41 + | 0.40 + |
ramie | 1.51 | 0.34 + | 0.32 + |
sisal | 1.49 | 0.33 + | 0.31 + |
∎ Other Materials
Density |
Multiplication factor* | ||
Type |
(g/cc) |
freshwater | sea water |
brick | 1.9 | 0.47 + |
0.46 + |
chalk | 2.4 | 0.58 + | 0.57 + |
concrete | 1.8 | 0.44 + |
0.43 + |
to 3.1 | 0.68 + |
0.67 + |
|
earthenware | 2.2 | 0.55 + | 0.53 + |
glass | 2.5 | 0.60 + | 0.59 + |
rubber | 1.0 | 0.00 | 0.03 - |
to 1.5 | 0.33 + | 0.32 + | |
sandstone | 2.2 | 0.55 + | 0.53 + |
stone | 2.5 | 0.60 + | 0.59 + |
ebony | 1.25 | 0.20 + | 0.18 + |
* Multiplication factor used to calculate the 'weight in water' of differnt materials, as shown on page 4.
FLOATING MATERIALS
∎ Wood
Density |
Multiplication factor* | ||
Type |
(g/cc) |
freshwater | sea water |
bamboo | 0.50 | 1.00 - | 1.05 - |
cedar, red |
0.38 |
1.63 - | 1.70 - |
cedar, white | 0.32 | 2.13 - | 2.21 - |
cork | 0.25 | 3.00 - | 3.10 - |
cypress | 0.48 | 1.08 - | 1.14 - |
fir |
0.51 |
0.96 - | 1.01 - |
oak, dry | 0.65 | 0.54 - | 0.58 - |
oak, green |
0.95 |
0.05 - | 0.08 - |
pine | 0.65 |
0.54 - |
0.58 - |
pine, Oregon | 0.51 | 0.96 - | 1.01 - |
pine, poplar | 0.41 | 1.44 - | 1.50 - |
oplar | 0.48 | 1.08 - | 1.14 - |
spruce | 0.40 | 1.50 - | 1.57 - |
teak |
0.82 |
0.22 - | 0.25 - |
walnut | 0.61 | 0.64 - | 0.68 - |
∎ Fuel
Density |
Multiplication factor* | ||
Type |
(g/cc) |
freshwater | sea water |
petrol (normal or super) | 0.72 | 0.39 - |
0.43 - |
petrol for lamps | 0.79 | 0.27 - |
0.30 - |
diesel fuel | 0.84 | 0.19 - |
0.22 - |
crude oil, heavy | 0.86 | 0.16 - | 0.19 - |
crude oil, light | 0.79 | 0.27 - | 0.30 - |
fuel oil, heavy | 0.99 | 0.01 - | 0.04 - |
fuel oil, | |||
Intermediate (merchant vessels) | 0.94 | 0.06- | 0.09 - |
∎ Textiles
Density |
Multiplication factor* | ||
Type |
(g/cc) |
freshwater | sea water |
Polyethylene(PE) | 0.95 | 0.05 - | 0.08 - |
Polypropylene(PP) | 0.90 | 0.11 - | 0.14 - |
Polystyrene, expanded | 0.10 | 9.00 - | 9.26 - |
∎ Others
ice | 0.95 |
0.11- |
0.14- |
Oil | 0.90-0.95 |
Examples of loss of buoyancy as a function of duration of immersion:
after |
0 days | 10 days | 15 days |
cork | 4.5 kgf | 4.0 | |
wood | 2.0 kgf | 1.0 | 0 |
where :
Ρ = weight (kg) in water
A = weight (kg) in air
DW = density (g/cc) of water (freshwater 1.00; sea water 1.026)
DM = density (g/cc) of material
* The term in brackets, the multiplication factor, has been calculated for the materials most commonly used in fisheries, with the results given in the tables on pages 2-3. The factor followed by a + sign indicates a sinking force. The factor followed by a - sign indicates a buoyant or floating force. To obtain the weight in water of a certain quantity of material, simply multiply its weight in air by the factor.
Example
a:
1.5 kg of
cork in air The table on page 3 gives the multiplication factor for cork:
so,
1.5 x 3.00(-) = 4.5 kg flotation in freshwater
1.5 x 3.10H = 4.65 kg flotation in sea water
Example
b :
24.6 kg of polyamide (nylon) in air The table on page 3 gives
the multiplication factor for polyamide:
so,
24.6 χ 0.12( + ) = 2.95 kg flotation in freshwater
24.6 χ 0.10( + ) = 2.46 kg flotation in sea water
∎ Example c: Calculating the weight in water of a bottom gillnet
component | weight(kg) | weight(kg) |
in air | in sea water | |
ropes: 2 x 90 m PP Ø 6 mm | 3.060 | -0.430 - |
netting: 900 x 11 meshes 140 mm stretched mesh PAR 450 tex with bolchlines | 1.360 | + 0.136 + |
floats: 46 corks x 21 g (in air) (or 50 floats of 60 gf each) | 0.970 |
- 3.000 - |
sinkers: 180 lead sinkers, 80 g each (in air) (1) | 14.400 | + 13.100 + |
or 111 stones, avg. weight 200 g (2) | 22.200 | |
TOTAL | (1) 19.790 | |
(2) 27.590 | 9.806 + |
The weight of α gillnet in water is calculated by adding the weights of the different components, taking into account the sign of the factor. The sign of the total indicates the type of net we have made; thus, this gillnet with a + sign would be a bottom net with a sinking force of 9.806 kg.
∎ Definitions
— Safe working load (SWL), is the maximum load that an item is certified to lift in service. Another equivalent term in use is Working load limit.
— Breaking load (BL) is the maximum load that an item can hold with a static load before it breaks. Another equivalent term in use is Breaking strength.
— Safety factor
Very important : The loads used in these calculations are static loads. Dynamic or shock loads increase the stress considerably, and thus increase the possibility of breakage.
∎ Values of the safety factor
(a) For ropes
Diameter (mm) | 3-18 | 20-28 | 30-38 | 40-44 | 48-100 |
Safety factor | 25 (est) | 20 | 15 | 10 | 8 |
(b) For wire ropes and metal hardware : safety factor about 5-6.
∎ Safe working load
∎ Polyamide (PA)
Amilan (Jap)
Anid (USSR)
Anzalon (Neth)
Caprolan (USA)
Denderon (E. Ger)
Enkalon (Neth, UK)
Forlion (Itd)
Kapron (USSR)
Kenlon (UK)
Knoxlock
(UK)
Lilion (Ital)
Nailon (Ital)
Nailonsix (Braz)
Nylon (many coun.)
Perlon (Ger)
Platil (Ger)
Relon (Roum)
Roblon (Den)
Silon (Czec)
∎ Polyethylene (PE)
Akvaflex (Nor)
Cerfil (Port)
Corfiplaste (Port)
Courlene
(UK)
Drylene 3 (UK)
Etylon
(Jap)
Flotten (Fran)
Hiralon (Jap)
Hi-Zex (Jap)
Hostalen G (W. Ger)
Laveten (Swed)
Levilene (Ital)
Marlin PE (Ice)
Norfil (UK)
Northylen (Ger)
Nymplex (Neth)
Rigidex (UK)
Sainthene (Fran)
Trofil (Ger)
Velon PS (LP) (USA)
Vestolen A (Ger)
∎ Polypropylene (PP)
Akvaflex PP (Nor)
Courlene PY
(UK)
Danaflex (Den)
Drylene 6
(UK)
Hostalen PP (Ger)
Meraklon (Ital)
Multiflex
(Den)
Nufil (UK)
Prolene (Arg)
Ribofil (UK)
Trofil P (Ger)
Ulstron (UK)
Velon P (USA)
Vestolen P (Ger)
∎ Copolymers (PVD)
Clorene
(Fran)
Dynel (USA)
Kurehalon
(Jap)
Saran (Jap, USA)
Tiviron (Jap)
Velon (USA)
Wynene (Can)
∎ Polyester (PES)
Dacron (USA)
Diolen (Ger)
Grisuten (E. Ger)
Tergal (Fran)
Terital (Ital)
Terlenka (Neth, UK)
Tetoron (Jap)
Terylene (UK)
Trevira (W. Ger)
∎ Polyvinyl alcohol (PVA)
Cremona (Jap)
Kanebian
(Jap)
Kuralon (Jap)
Kuremona (Jap)
Manryo (Jap)
Mewlon (Jap)
Trawlon (Jap)
Vinylon (Jap)
∎ Commercial names of combined twines for netting
Kyokurin | Cont. fil PA + Saran |
Livlon | Cont. fil PA + Saran |
Marlon A | Cont. fil PA + St. PVA |
Marlon B | Cont. fil PA + Saran |
Marlon C | Cont. fil PA + Cont. fil PVC |
Marlon D | Cont. fil PA + Saran |
Marlon E | St. PA + St. PVA (or PVC) |
Marumoron | Cont. fil. PA + St. PVA |
Polex | PE + Saran |
Polysara | PE + Saran |
Polytex | PE + cont. fil. PVC |
Ryolon | Cont. fil. PES + Cont. fil. PVC |
Saran-N | Cont. fil. PA + Saran |
Tailon (Tylon P) | Cont. fil. PA + St. PA |
Temimew | St. PVA + St. PVC |
Cont. fil. | = | continuous fibres |
St. | = | staple fibre |
∎ Nylon, polyamide (PA) | Sinks
(density = 1.14) Good breaking strength and resistance to abrasion Very good elongation and elasticity |
∎ Polyester (PES) | Sinks
(density = 1.38) Very good breaking strength Good elasticity Poor elongation (does not stretch) |
∎ Polyethylene (PE) | Floats (density = 0.94-0.96) Good resistance to abrasion Good elasticity |
∎ Polypropylene (PP) | Floats (density = 0.91-0.92) Good breaking strength Good resistance to abrasion |
∎ Polyvinyl alcohol (PVA) | Sinks
(density = 1.30-1.32) Good resistance to abrasion Good elongation |
Properties |
PA | PES | PE | PP | |
Floats | No | No | Yes | Yes | |
- | Appearance | ||||
- | Continuous fibres | X | X | - | X |
- | Short (staple) fibres | (X) | (X) | - | (X) |
- | Monofilament | (X) | (X) | X | (X) |
- | Sheets | - | - | (X) | X |
Combustion | Melts following short duration of heatingforms molten droplets | Melts and burns slowly with bright yellow flame | Melts and burns slowly with pale blue flame | Melts and burns slowly with pale blue flame | |
Smoke | White | Black with soot | White | White | |
Smell | Celery-like fishy odour | Hot oil faintly sweet | Snuffed out candle | Hot wax/burning asphalt | |
Residue | Solid yellowish round droplets | Solid blackish droplets | Solid droplets | Solid brown droplets |
X | = | Commonly available |
(X). | = | Material exists but is less common |
- | = | Not available |
∎ Simple fibres
Titre (denier) : Td = weight (g) of 9000 m of fibre
Metric
number : Nm = length (m) of 1 kg of
fibre
English
number for cotton : Nec = length (in
multiples of 840 yd) per lb
International system:
tex = weight (g) of 1000
m
of fibre
∎ Finished twine
Runnage,
metres/kg : m/kg = length (m) of 1 kg of finished twine
Resultant tex : Rtex = weight (g) of 1000 m of finished twine
∎ Equivalents and conversions
textile/system | PA | PP | PE | PES | PVA |
Titre/denier | 210 | 190 | 400 | 250 | 267 |
International tex system | 23 | 21 | 44 | 28 | 30 |
∎ Estimating the diameter of twine
In addition to precise measurements from instruments such as micrometer, magnifying glass and microscope, there exists a quick method of estimation. Roll 20 turns of the twine to be measured around a pencil and measure the total length of the turns.
Example :
If 20 turns of the twine measure 6 cm, then the diameter of the twine = 60 mm/20 turns = 3 mm
Note : The strength of twine or rope depends not only on its thickness, but also on the method ond degree of twisting or braiding its yarns.
∎ Calculation of Resultant tex (Rtex) of twine
Case 1 : When the structure of the twine is known
Example
:
Netting twine made
of nylon (polyamide), with 210
denier single yarns, 2 single yarns in each of the 3 folded yarns (strands)
which make up the twine.
To find the Resultant tex (Rtex) we have to apply a correction to the calculated value, taking into account the structure of the finished twine (twisted, braided, hard lay, degree of twist, etc.). A rough estimation of Rtex can be found by adding 10% to the value calculated above:
138 tex + 10% = R 152 tex (estimate)
Note : In view of the complex structure of braided twines, it is the general practice in fisheries for the gear designer to use the Rtex value without going into detail.
Case 2: A sample of twine is available for evaluation
Example
:
5 m of twine, placed on a percision scale, weigh 11.25 g.
We know that twine of R 1 tex weighs 1 g per 1000 m, and the weight per meter of the
sample twine is 11.25/5 = 2.25 g/m. So, 1000 m of the sample would weigh 1000 x 2.25 = 2250g, or R 2250 tex
Note : The strength of twine or rope depends not only on its thickness, but also on the method and degree of twisting or braiding its yarns.
Eg.: twisted nylon (polyamide) twine
m/kg | Rtex g/1000m |
yds/lb ā/ |
20 000 | 50 | 9 921 |
13 500 | 75 | 6 696 |
10 000 | 100 |
4 960 |
6 450 | 155 | 3 199 |
4 250 | 235 | 2 180 |
3 150 | 317 |
1 562 |
2 500 | 450 |
1 240 |
2 100 | 476 |
1 041 |
1 800 | 556 |
893 |
1 600 | 625 |
794 |
1 420 | 704 | 704 |
1 250 | 800 | 620 |
1 150 | 870 | 570 |
1 060 | 943 | 526 |
980 | 1 020 | 486 |
910 | 1 099 | 451 |
850 | 1 176 | 422 |
790 | 1 266 | 392 |
630 | 1 587 | 313 |
530 | 1 887 | 263 |
400 | 2 500 | 198 |
360 | 2 778 | 179 |
310 | 3 226 | 154 |
260 | 3 846 | 129 |
238 | 4 202 | 118 |
225 | 4 444 | 112 |
200 | 5 000 | 99 |
180 | 5 556 | 89 |
155 | 6 452 | 77 |
130 | 7 692 | 64 |
100 | 10 000 | 50 |
a/ yds/lb | = | approx. (m/kg)/2 |
– m/kg | = | approx. (yds/lb) x 2 |
No of yarns denier |
No. of denier Td |
Tex |
210 x 2 | 420 | 47 |
3 | 630 | 70 |
4 | 840 | 93 |
6 | 1 260 | 140 |
9 | 1 890 | 210 |
12 | 2 520 | 280 |
15 | 3 150 | 350 |
18 | 3 780 | 420 |
21 | 4 410 | 490 |
24 | 5 040 | 559 |
27 | 5 670 | 629 |
30 | 6 300 | 699 |
33 | 6 930 | 769 |
36 | 7 560 | 839 |
39 | 8 190 | 909 |
42 | 8 820 | 979 |
45 | 9 450 | 1 049 |
48 | 10 080 | 1 119 |
60 | 12 600 | 1 399 |
72 | 15 120 | 1 678 |
96 | 20 160 | 2 238 |
108 | 22 680 | 2 517 |
120 | 25 200 | 2 797 |
144 | 30 240 | 3 357 |
156 | 32 760 | 3 636 |
168 | 35 280 | 3 916 |
192 | 40 320 | 4 476 |
216 | 45 360 | 5 035 |
240 | 50 440 | 5 594 |
264 | 55 440 | 6 154 |
360 | 75 600 | 8 392 |
Note : 210 denier = 23 Tex
A = breaking load, dry without knots (single twine)
B = breaking load, wet, knotted (single twine)
∎ Twisted, continuous filament
m/kg | Rtex | Diam. mm |
A kgf |
B kgf |
20 000 | 50 | 0.24 | 3.1 |
1.8 |
13 300 | 75 | 0.24 | 4.6 |
2.7 |
10 000 | 100 | 0.33 | 6.2 |
3.6 |
6 400 | 155 | 0.40 | 9 |
6 |
4 350 | 230 | 0.50 | 14 |
9 |
3 230 | 310 | 0.60 | 18 |
11 |
2 560 | 390 | 0.65 | 22 |
14 |
2 130 |
470 |
0.73 | 26 |
16 |
1 850 | 540 | 0.80 | 30 |
18 |
1 620 | 620 | 0.85 | 34 |
21 |
1 430 | 700 | 0.92 | 39 |
22 |
1 280 | 780 | 1.05 | 43 |
24 |
1 160 | 860 | 1.13 | 47 |
26 |
1 050 | 950 | 1.16 | 51 |
28 |
970 | 1 030 | 1.20 | 55 |
29 |
830 | 1 200 | 1.33 | 64 |
34 |
780 | 1 280 | 1.37 | 67 |
35 |
700 | 1 430 | 1.40 | 75 |
40 |
640 | 1 570 | 1.43 | 82 |
43 |
590 | 1 690 | 1.5 | 91 |
47 |
500 | 2 000 | 1.6 | 110 |
56 |
385 | 2 600 | 1.9 | 138 | 73 |
315 | 3 180 | 2.0 | 165 | 84 |
294 | 3 400 | 2.2 | 178 | 90 |
250 | 4 000 | 2.4 | 210 | 104 |
200 | 5 000 | 2.75 | 260 | 125 |
175 | 6 000 | 2.85 | 320 | 150 |
125 | 8 000 | 3.35 | 420 | 190 |
91 | 11 000 | 3.8 |
560 |
250 |
∎ Braided, continuous filament
m/kg | Rtex | Diam. approx. mm |
A kgf |
B kgf |
740 | 1 350 | 1.50 | 82 | 44 |
645 | 1 550 | 1.65 | 92 | 49 |
590 | 1 700 | 1.80 | 95 | 52 |
515 | 1 950 | 1.95 | 110 | 60 |
410 | 2 450 | 2.30 | 138 | 74 |
360 | 2 800 | 2.47 | 154 | 81 |
280 | 3 550 | 2.87 | 195 | 99 |
250 | 4 000 | 3.10 | 220 | 112 |
233 | 4 300 | 3.25 | 235 | 117 |
200 | 5 000 | 3.60 | 270 | 135 |
167 | 6 000 | 4.05 | 320 | 155 |
139 | 7 200 | 4.50 | 360 | 178 |
115 | 8 700 | 4.95 | 435 | 215 |
108 | 9 300 | 6.13 | 460 | 225 |
95 | 10 500 | 5.40 | 520 | 245 |
81 | 12 300 | 5.74 | 600 | 275 |
71 | 14 000 | 5.93 | 680 | 315 |
57 | 17 500 | 6.08 | 840 | 390 |
A = breaking load, dry without knots (single twine)
B = breaking load, wet, knotted (single twine)
Diam. mm |
m/kg | Tex* | A kgf |
B kgf |
0.10 | 90 900 | 11 | 0.65 | 0.4 |
0.12 | 62 500 | 16 | 0.9 | 0.55 |
0.15 | 43 500 | 23 | 1.3 | 0.75 |
0.18 | 33 300 | 30 | 1.6 | 1.0 |
0.20 | 22 700 | 44 | 2.3 | 1.4 |
0.25 | 17 200 | 58 | 3.1 | 1.8 |
0.30 | 11 100 | 90 | 4.7 | 2.7 |
0.35 | 8 330 | 120 | 6.3 | 3.6 |
0.40 | 6 450 | 155 | 7.7 | 4.4 |
0.45 | 5 400 | 185 | 9.5 | 5.5 |
0.50 | 4 170 | 240 | 12 | 6.5 |
0.55 | 3 570 | 280 | 14 | 7.5 |
0.60 | 3 030 | 330 | 17 | 8.8 |
0.70 | 2 080 | 480 | 24 | 12.5 |
0.80 | 1 670 | 600 | 29 | 15 |
0.90 | 1 320 | 755 | 36 | 19 |
1.00 | 1 090 | 920 | 42 | 22 |
1.10 | 900 | 1 110 | 47 | 25 |
1.20 | 760 | 1 320 | 55 | 30 |
1.30 | 650 | 1 540 | 65 | 35 |
1.40 | 560 | 1 790 | 75 | 40 |
1.50 | 490 | 2 060 | 86 | 46 |
1.60 | 430 | 2 330 | 98 | 52 |
1.70 | 380 | 2 630 | 110 | 58 |
1.80 | 340 | 2 960 | 120 | 65 |
1.90 | 300 | 3 290 | 132 | 72 |
2.00 | 270 | 3 640 | 145 | 75 |
2.50 | 180 | 5 630 | 220 | 113 |
Japanese numbering system for Monofilament
N° Japan |
Diam. (mm) |
N° Japan | diam. (mm) |
0.20 | 0.55 | ||
2 | - | 12 | - |
0.25 | 0.60 | ||
3 | 14 | - | |
0.30 | 0.70 | ||
4 | - | 18 | - |
0.35 | 0.80 | ||
5 | - | 24 | - |
0.40 | 30 | 0.90 | |
6 | - | ||
7 | 0.45 | ||
8 | - | ||
0.50 | |||
10 | - |
∎ Multimonofilament
Diameter* |
x | number of filaments | m/kg | A kgf |
0.20 | x | 4 | 6 250 | 9 |
0.20 | x | 6 | 4 255 | 14 |
0.20 | x | 8 | 3 125 | 18 |
0.20 | x | 10 | 2 630 | 24 |
0.20 | x | 12 | 2120 | 26 |
* for monofilament, tex and Rtex are the same.
A = breaking load, dry without knots (single twine)
B = breaking load, wet, knotted (single twine)
POLYESTER (PES)
∎ twisted, continuous filaments
m/kg | Rtex | Diam. mm |
A kgf |
B kgf |
11 100 | 90 |
5.3 |
2.8 | |
5 550 | 180 | 0.40 | 10.5 | 5 |
3 640 | 275 | 0.50 | 16 | 7.3 |
2 700 | 370 | 0.60 | 21 | 9.3 |
2 180 | 460 | 0.70 | 27 | 12 |
1 800 | 555 | 0.75 | 32 | 14 |
1 500 | 670 | 0.80 | 37 | 16 |
1 330 | 750 | 0.85 | 42 | 18 |
1 200 | 830 | 0.90 | 46 | 20 |
1 080 | 925 | 0.95 | 50 | 22 |
1 020 | 980 | 1.00 | 54 | 24 |
900 | 1 110 | 1.05 | 60 | 26 |
830 | 1 200 | 1.10 | 63 | 28 |
775 | 1 290 | 1.15 | 68 | 29 |
725 | 1 380 | 1.20 | 73 | 30 |
665 | 1 500 | 1.25 | 78 | 32 |
540 | 1 850 | 1.35 | 96 | 40 |
270 | 3 700 | 1.95 | 180 | 78 |
POLYETHYLENE (PE)
∎ twisted or braided thick filaments
m/kg | Rtex | Diam. approx. mm |
A kgf |
B kgf |
5 260 | 190 | 0.50 | 7.5 | 5.5 |
2 700 | 370 | 0.78 | 10 | 7 |
1 430 | 700 | 1.12 | 27 | 19 |
950 | 1 050 | 1.42 | 36 | 24 |
710 | 1 410 | 1.64 | 49 | 35 |
570 | 1 760 | 1.83 | 60 | 84 |
460 | 2 170 | 2.04 | 75 | 54 |
360 | 2 800 | 2.33 | 93 | 67 |
294 | 3 400 | 2.56 | 116 | 83 |
225 | 4 440 | 2.92 | 135 | 97 |
190 | 5 300 | 3.19 | 170 | 125 |
130 | 7 680 | 3.68 | 218 | 160 |
100 | 10100 | 3.96 | 290 | 210 |
POLYPROPYLENE (PP)
∎ twisted, continuous filaments
m/kg | Rtex | Diam. approx. mm |
A kgf |
B kgf |
4 760 | 210 | 0.60 | 13 | 8 |
3 470 | 290 | 0.72 | 15 | 9 |
2 780 | 360 | 0.81 | 19 | 11 |
2 330 | 430 | 0.90 | 25 | 14 |
1 820 | 550 | 1.02 | 28 | 15 |
1 560 | 640 | 1.10 | 38 | 19 |
1 090 | 920 | 1.34 | 44 | 23 |
840 | 1 190 | 1.54 | 58 | 30 |
690 | 1 440 | 1.70 | 71 | 36 |
520 | 1 920 | 1.95 | 92 | 47 |
440 | 2 290 | 2.12 | 112 | 59 |
350 | 2 820 | 2.32 |
132 | 70 |
300 | 3 300 | 2.52 | 152 | 80 |
210 | 4 700 |
2.94 |
190 | 100 |
177 | 5 640 | 3.18 | 254 | 130 |
∎
m/kg | Rtex | Diam. approx. mm |
A kgf |
B kgf |
4 760 | 210 | 0.60 | 9 | 6 |
3 330 | 300 | 0.73 | 13 | 9 |
2 560 | 390 | 0.85 | 18 | 12 |
1 250 | 800 | 1.22 | 32 | 22 |
1 010 | 990 | 1.36 | 38 | 24 |
720 | 1 390 | 1.62 | 57 | 36 |
530 | 1 900 | 1.94 | 73 | 46 |
420 | 2 360 | 2.18 | 86 | 54 |
325 | 3 070 | 2.48 | 100 | 59 |
240 | 4 100 | 2.90 | 150 | 88 |
185 | 5 400 | 3.38 | 215 | 120 |
150 | 6 660 | 3.82 | 300 | 170 |
Tarred Cotton | ||
Diameter mm | kg/100 m | R kgf |
3.0 | 1.056 | 45 |
3.5 | 1.188 | 55 |
4.0 | 1.320 | 66 |
4.5 | 1.585 | 77 |
5.0 | 1.915 | 88 |
5.5 | 2.448 | 100 |
6.0 | 2.905 | 113 |
6.5 | 3.300 | 127 |
Sisal | ||||
Diameter |
Standard |
Extra |
||
kg/ 100 m |
R kgf |
kg/ 100 m |
R kgf |
|
6 | 2.3 | 192 | 3.3 | 336 |
8 | 3.5 | 290 | 4.7 | 505 |
10 | 6.4 | 487 | 6.4 | 619 |
11 | 8.4 | 598 | 9.0 | 924 |
13 | 10.9 | 800 | 11.0 | 1 027 |
14 | 12.5 | 915 | 14.0 | 1 285 |
16 | 17.0 | 1 100 | 17.2 | 1 550 |
19 | 24.5 | 1 630 | 25.3 | 2 230 |
21 | 28.1 | 1 760 | 29.0 | 2 390 |
24 | 38.3 | 2 720 | 39.5 | 3 425 |
29 | 54.5 | 3 370 | 56.0 | 4 640 |
32 | 68.0 | 4 0501 | 70.0 | 5 510 |
37 | 90.0 | 5 220 | 92.0 | 7 480 |
40 | ||||
48 |
** In English-speaking countries the size of a rope is sometimes measured by its circumference in inches (in.) or by its diameter in inches Diameter of rope 0 (mm) = approx. 8 x c (inch)
Example: 0 (mm) of a rope of 2.25 inch circumference 0 (mm) = 2.25x8 = 18 mm (approximate)
Hemp |
||||
Diameter mm** |
Standard | Extra | ||
kg/ 100 m |
R kgf |
kg/ 100 m |
R kgf |
|
10 | 6.6 |
631 |
7.8 |
600 |
11 | 8.5 |
745 |
10.0 |
708 |
13 | 11.3 |
994 |
13.3 |
944 |
14 | 14.3 |
1 228 |
17.0 |
1 167 |
16 | 17.2 | 1 449 |
20.3 |
1 376 |
19 | 25.3 | 2017 |
29.8 |
1 916 |
21 | 30.0 | 2318 |
35.4 |
2 202 |
24 | 40.2 | 3 091 |
47.4 |
2 936 |
29 | 59.0 | 4 250 |
70.0 |
4 037 |
32 | 72.8 | 5 175 |
86.0 |
4 916 |
37 | 94.8 | 6 456 |
112.0 |
6 133 |
40 | 112.0 | 7 536 |
132.0 |
7 159 |
48 | 161.0 | 10 632 | 190.0 | 10 100 |
Manilla | ||||
Diameter |
Standard | Extra | ||
kg/ 100 m |
R kgf |
kg/ 100 m |
R kgf |
|
10 | 6.2 | 619 | 6.2 | 776 |
11 | 9.15 | 924 | 9.25 | 1 159 |
13 | 11.2 | 1 027 | 12.4 | 1 470 |
14 | 14.2 | 1 285 | 15.0 | 1 795 |
16 | 17.5 | 1 550 | 18.5 | 2 125 |
19 | 25.5 | 2 230 | 26.65 | 2 970 |
21 | 29.7 | 2 520 | 30.5 | 3 330 |
24 | 40.5 | 3 425 | 41.6 | 4 780 |
29 | 58.4 | 4 800 | 59.9 | 6 380 |
32 | 72.0 | 5 670 | 74.0 | 7 450 |
37 | 95.3 | 7 670 | 98.0 | 9 770 |
40 | 112.5 | 8 600 | 115.8 | 11 120 |
48 |
Diameter |
Polyamide |
(PA) |
Polyethyene |
(PE) |
Polyester |
(PES) |
Polypropyene |
(PP) |
4 | 1.1 | 320 | 1.4 | 295 | - | - | ||
6 | 2.4 | 750 | 1.7 | 400 | 3 | 565 | 1.7 | 550 |
8 | 4.2 | 1 350 | 3 | 685 | 5.1 | 1 020 | 3 | 960 |
10 | 6.5 | 2 080 | 4.7 | 1 010 | 8.1 | 1 590 | 4.5 | 1 425 |
12 | 9.4 | 3 000 | 6.7 | 1 450 | 11.6 | 2 270 | 6.5 | 2 030 |
14 | 12.8 | 4 100 | 9.1 | 1 950 | 15.7 | 3 180 | 9 | 2 790 |
16 | 16.6 | 5 300 | 12 | 2 520 | 20.5 | 4 060 | 11.5 | 3 500 |
18 | 21 | 6 700 | 15 | 3 020 | 26 | 5 080 | 14.8 | 4 450 |
20 | 26 | 8 300 | 18.6 | 3 720 | 32 | 6 350 | 18 | 5 370 |
22 | 31.5 | 10 000 | 22.5 | 4 500 | 38.4 | 7 620 | 22 | 6 500 |
24 | 37.5 | 12 000 | 27 | 5 250 | 46 | 9 140 | 26 | 7 600 |
26 | 44 | 14 000 | 31.5 | 6 130 | 53.7 | 10 700 | 30.5 | 8 900 |
28 | 51 | 15 800 | 36.5 | 7 080 | 63 | 12 200 | 35.5 | 10 100 |
30 | 58.5 | 17 800 | 42 | 8 050 | 71.9 | 13 700 | 40.5 | 11 500 |
32 | 66.5 | 20 000 | 47.6 | 9 150 | 82 | 15 700 | 46 | 12 800 |
36 | 84 | 24 800 | 60 | 11 400 | 104 | 19 300 | 58.5 | 1 6100 |
40 | 104 | 30 000 | 74.5 | 14 000 | 128 | 23 900 | 72 | 19 400 |
R = breaking strength, dry
Direction of twist of twines, ropes and cables
* Safe working bad, see
page 5
**Conversion inch-mm, seepage 15
Some knots are used more than others. In selecting which knot to use the following points should be considered : — the use of the knot — the type of rope — whether the knot will slip — whether the knot is permanent.
∎ Joining two cords
Two cords of the same diameter, multifilament
Two cords of same diameter, monofilament
Two cords of different diameters or different types
Sheet bends are also useful for joining two identical cords
∎ Loops
Fixed loop
Running loop
Some knots are used more than others. In selecting which knot to use the following points should be considered : — the use of the knot — the type of rope — whether the knot will slip — whether the knot is permanent.
∎ For stopping a rope from running through a narrow space (i.e. sheave)
∎ Knots for mooring
∎ To close the codend of a trawl
(codend knot)
∎ To shorten a rope
Some knots are used more than others. In selecting which knot to use the following points should be considered : — the use of the knot — the type of rope — whether the knot will slip — whether the knot is permanent.
∎ Steel - Sisal 3 strands
Untreated | Tarred | |||
Diameter (mm) |
kg/m | Rkgf | kg/m | Rkgf |
10 | 0.094 | 1 010 | 0.103 |
910 |
12 | 0.135 | 1 420 | 0.147 |
1 285 |
14 | 0.183 | 1 900 | 0.200 |
1 750 |
16 | 0.235 | 2 400 | 0.255 |
2 200 |
18 | 0.300 | 3 100 | 0.325 |
2 800 |
20 | 0.370 | 3 800 | 0.405 | 3 500 |
22 | 0.445 | 4 600 | 0.485 |
4 200 |
25 | 0.565 | 5 700 | 0.615 |
5 300 |
28 | 0.700 | 7 500 | 0.760 |
6 700 |
30 | 0.820 | 8 400 | 0.885 |
7 600 |
∎ Steel - Sisal 4 strands
Untreated | Tarred | |||
Diameter (mm) |
kg/m | Rkgf | kg/m | Rkgf |
12 | 0.135 | 1 420 | 0.147 | 1 285 |
14 | 0.183 | 1 900 | 0.200 | 1 750 |
16 | 0.235 | 2 400 | 0.255 | 2 200 |
18 | 0.300 | 3 100 | 0.325 | 2 800 |
20 | 0.370 | 3 800 | 0.405 | 3 500 |
22 | 0.445 | 4 600 | 0.485 | 4 200 |
25 | 0.565 | 5 700 | 0.615 | 5 300 |
28 | 0.700 | 7 200 | 0.760 | 6 400 |
30 | 0.775 | 8 400 | 0.840 | 7 600 |
R = Breaking strength dry
* Safe working loads, see page 5
∎ Steel -Manilla B, 4 strands
Untreated | Tarred | |||
Diameter (mm) |
kg/m | Rkgf | kg/m | Rkgf |
12 | 0.138 | 1 500 | 0.150 | 1 370 |
14 | 0.185 | 2 000 | 0.205 | 1 850 |
16 | 0.240 | 2 500 | 0.260 | 2 350 |
18 | 0.305 | 3 300 | 0.335 | 3 000 |
20 | 0.380 | 4 000 | 0.410 | 3 800 |
22 | 0.455 | 5 000 | 0.495 | 4 600 |
25 | 0.575 | 6 200 | 0.630 | 5 700 |
28 | 0.710 | 7 600 | 0.775 | 6 900 |
30 | 0.790 | 8 900 | 0.860 | 8 200 |
32 | 0.890 | 9 500 | 0.970 |
8 750 |
34 | 1.010 | 11 200 | 1.100 | 10 200 |
36 | 1.140 | 12 000 | 1.235 | 11 000 |
40 | 1.380 | 15 000 | 1.495 | 14 000 |
45 | 1.706 | 18 500 | 1.860 | 17 500 |
50 | 2.045 | 22 500 | 2.220 | 20 000 |
∎ Steel - Polypropylene
Diameter (mm) |
Number of strands | kg/m |
Rkgf |
10 | 3 | 0.105 | 1 230 |
12 | 3 | 0.120 | 1 345 |
14 | 3 | 0.140 | 1 540 |
16 | 3 | 0.165 | 2 070 |
18 | 3 | 0.240 | 3 000 |
14 | 6 | 0.250 | 4 000 |
16 | 6 | 0.275 | 4 400 |
18 | 6 | 0.350 | 5 300 |
20 | 6 | 0.430 | 6 400 |
22 | 6 | 0.480 | 7 200 |
24 | 6 | 0.520 | 7 800 |
26 | 6 | 0.640 | 9 700 |
R = Breaking strength dry
* Safe working loads, see page 5
∎ Floatline (with floats inside)
Principal advantages (1) and disadvantages (2)
Floatline (with floats inside)
Interval between |
Flotation |
52 | 480 |
47 | 500 |
35 | 570 |
20 | 840 |
35 | 2 850 |
20 | 3 000 |
∎ Leadline (with leads inside)
Principal advantages (1) and disadvantages (2)
Braided with a centre core of lead
Diameter (mm) |
kg/100 m |
Rkgf |
2 | 2.3 - 3.5 | 73 |
2.5 | 4.6 | |
3 | 6.5 - 7.1 | 100 |
3.5 | 9.1 | |
4 | 11.1 - 12.3 | 200 |
4.5 | 14.5 | |
5 | 15.2 - 18.1 | 300 |
Diameter (mm) |
kg/100 m |
Rkgf |
7.2 | 7.5 | 360 |
8 | 12.5 | 360 |
8 | 18.8 | 360 |
9.5 | 21.3 | 360 |
9.5 | 23.8 | 360 |
9.5 | 27.5 | 360 |
11.1 | 30.0 | 360 |
12.7 | 37.5 | 675 |
Rope with a lead core in three strands
Diameter | kg/100 m |
Rkgf |
6 | 8.7 | 495 |
7 | 11.2 | 675 |
8 | 13.3 | 865 |
10 | 21.6 | 1 280 |
12 | 26.6 | 1 825 |
14 | 33.0 | 2 510 |
R = breaking strength
there are also leadlines of 0.75; 0.90; 1.2; 1.5; 1.8 kg/100m
Examples of common marine wire rope
Type |
Structure and diameter |
Example of Use |
S |
7 x 7 (6/1) central heart: steel Ø 12 to 28 mm |
Standing rigging | + | |
6 x 7 (6/1) Central heart: textileØ 8 to 16 mm |
Standing rigging Warps for small trawlers Small coastal vessels |
+ | |
6 x 12 (12/fibre) Central heart, strand cores, fibre Ø 8 to 16 mm |
Bridles and warps for small trawlers moorings and running rigging |
++ | |
6 x 19 (9/9/1) Central heart of steel or textileØ16 to 30 mm |
Trawler warps | + | |
6 x 19 (12/6/1) Central heart of textile Ø 8 to 30 mm |
Trawler's sweeps
and warps running rigging |
+ | |
6 x 24 (15/9/fibre) Central heart and strand cores of textile Ø 8 ta 40 mm |
Purse wire bridles and otter board strops, running rigging moorings and towing | ++ | |
6 x 37
(18/12/6/1) Central heart of textile Ø 20 to 72 mm |
Purse wire moorings and running rigging mooring | ++ |
S = flexibility
+ = poor or average
++ = good
As a general rule, the greater the number of strancs, and the greater the number of filaments per strand, the greater the flexibility of the cable.
(for structure, see page 24) examples
6 x 7 (6/1) | ||
diam. mm |
kg/ 100 m |
R kgf |
8 | 22.2 | 3 080 |
9 | 28.1 | 3 900 |
10 | 34.7 | 4 820 |
11 | 42.0 | 5 830 |
12 | 50.0 | 6 940 |
13 | 58.6 | 8 140 |
14 | 68.0 | 9 440 |
15 | 78.1 | 10 800 |
16 | 88.8 | 12 300 |
6 x 19 (9/9/1) | ||
diam. mm |
kg/ 100 m |
R kgf |
16 | 92.6 | 12 300 |
17 | 105 | 13 900 |
18 | 117 | 15 500 |
19 | 131 | 17 300 |
20 | 145 | 19 200 |
21 | 160 | 21 200 |
22 | 175 | 23 200 |
23 |
191 |
25 400 |
24 | 208 | 27 600 |
25 | 226 | 30 000 |
26 | 245 | 32 400 |
6 x 24 (15/9/fibre) | ||
diam. mm |
kg/ 100 m |
R kgf |
8 | 19.8 | 2 600 |
10 | 30.9 | 4 060 |
12 | 44.5 | 5 850 |
14 | 60.6 | 7 960 |
16 | 79.1 | 10 400 |
18 | 100 | 13 200 |
20 | 124 | 16 200 |
21 | 136 | 17 900 |
22 | 150 | 19 700 |
24 | 178 | 23 400 |
26 | 209 | 27 500 |
6 x 12 (12/fibre) | ||
diam. mm |
kg/ 100 m |
R kgf |
6 | 9.9 | 1 100 |
8 | 15.6 | 1 940 |
9 | 19.7 | 2 450 |
10 | 24.3 | 3 020 |
12 | 35.0 | 4 350 |
14 | 47.7 | 5 930 |
16 | 62.3 | 7 740 |
6 x 19 (12/6/1) | ||
diam. mm |
kg/ 100 m |
R kgf |
8 | 21.5 | 2 850 |
10 | 33.6 | 4 460 |
12 | 48.4 | 6 420 |
14 | 65.8 | 8 730 |
16 | 86.0 | 11 400 |
18 | 109 | 14 400 |
20 | 134 | 17 800 |
22 | 163 | 21 600 |
24 | 193 | 25 700 |
6 x 37 (18/12/6/1) | ||
diam. mm |
kg/ 100 m |
R kgf |
20 | 134 | 17 100 |
22 | 163 | 20 700 |
24 | 193 | 24 600 |
26 | 227 | 28 900 |
R = Breaking strength
(steel 145 kgf/mm2)
*Safe Working Loads, see page 5
NO | YES |
∎ Winding onto a drum depending on the direction of lay in a wire.
∎ Drums: |
the diameter of a drum (D) relative to the
diameter of the wire rope (Ø) to be held on the drum — D/Ø depends on the
structure of the wire rope, and depending on the particular situation, D should range from 20Ø to 48Ø. In practical
use on board fishing vessels, depending on the space available, the following
values are common :
D = 14Ø or more |
∎ Sheaves : |
The diameter of a sheave (D) relative to
the diameter of the wire rope (Ø) to be used with the sheave — D/Ø depends on the
structure of the wire rope, and depending on the particular situation, D should range from 20Ø to 48Ø. In practical use on board fishing vessels,
depending on the space available, the following values are common:
D = 9Ø or more |
Width of sheave relative to the diameter of the wire rope
∎ Location of sheave relative to drum
Maximum fleet angle of a steel wire between a fixed sheave and a drum with manual or automatic spooling gear:
L = C x 5 (or more); C x 11 is recommended
(In order to let a sheave shift with changing wire angles, it is often better to use a flexibly attached block rather than a fixed sheave.)
∎ Cable clamps should be fastened with nuts on the standing part of the wire
∎ Stainless steel, heat treated and painted (examples)
Construction |
diam. mm |
R kgf |
1.00 | 75 | |
0.91 | 60 | |
0.82 | 50 | |
0.75 | 45 | |
0.69 | 40 | |
0.64 | 34 | |
0.58 | 28 | |
1.5 | 210 | |
1.4 | 170 | |
1.3 | 155 | |
1.3 | 140 | |
1.2 | 120 | |
1.1 | 100 | |
1.0 | 90 | |
0.9 | 75 | |
0.8 | 65 | |
0.7 | 50 | |
0.6 | 40 | |
0.6 | 30 | 2.2 | 290 |
2.0 | 245 | |
1.8 | 200 | |
1.6 | 175 | |
1.5 | 155 | |
2.2 | 220 | |
2.0 | 180 | |
1.8 | 155 | |
1.6 | 130 | |
1.5 | 115 | |
1.4 | 100 | |
1.3 | 85 | |
2.4 | 290 | |
2.2 | 245 | |
2.0 | 200 | |
1.8 | 175 | |
1.6 | 155 | |
1.5 | 130 | |
1.4 | 110 | |
1.9 | 290 | |
1.8 | 245 | |
1.6 | 200 | |
1.5 | 175 | |
1.3 | 155 | |
1.2 | 135 | |
1.1 | 110 |
∎ Galvanised steel, not lubricated
Diameter |
Number of |
Diameter
of wires |
kg/m |
R kgf |
|
Strands | Wires | ||||
2 | 5 | 1 plus 6 | 0.25 | 0.016 | 125 |
3 | 6 | 1 plus 6 | 0.30 | 0.028 | 215 |
4 | 6 | 1 plus 6 | 0.40 | 0.049 | 380 |
5 | 6 | 7 | 0.50 | 0.081 | 600 |
6 | 6 | 9 | 0.50 | 0.110 | 775 |
R = breaking strength
∎ Types of mesh nets
b - bar length
∎ Dimension of mesh, stretched mesh (a), and mesh opening (OM)
Meshes of metallic
or plastic netting
see page 107
SYSTEM | PLACES USED | TYPE OF MEASURE | |
a | stretched mesh | international | distance (N direction) between the centres of the 2 opposite knots of a stretched mesh * |
OM | mesh opening | international | maximum inside measure (N direction) between the 2 opposite knots of a stretched mesh * |
b | bar length | some European countries | length of one bar of mesh |
P | pasada | Spain, Portugal | number of meshes per 200 mm |
On | omfar | Norway, Iceland | half the number of meshes per Alen (1 Alen = 628 mm) |
Os | omfar | Sweden | half the number of meshes per Alen (1 Alen = 594 mm) |
R | rows | Netherlands, UK | number of rows of knots per yard (1 yard = 910 mm) |
N | knots | Spain, Portugal | number of knots per metre |
F | Fushi or Setsu | Japan | number of knots per 6 inches (6 inches = 152 mm) |
Conversions |
* Note that stretched meshsize is not the same as mesh opening, which is considered in many fisheries regulations.
A simple method of measuring stretched meshsize is as follows: extend a panel of twine fully in the N direction (see page 32 for N direction), and measure the distance between the entres of 2 Knots (or connexions) separated by 10 meshes. Then divide this measure by 10.
∎ Knots
The height of the single knot is approximately equal to three times the diameter of the twine.
∎ Edges and selvedges
∎ Cutting rate
∎ Values of the parts of a cut
Bars | Sideknots | Meshes | 1T2B | 4N3B | |
B |
N |
T |
|||
Decrease in meshes D | 0.5 | 0 | 1 | 1 +2x0.5 | 4x0 + 3x0.5 |
Height in meshes H | 0.5 | 1 | 0 | 0 + 2x0.5 | 4x1 + 3x0.5 |
Value D/H | 0.5/0.5 | 0/1 | 1/0 | 2/1 | 1.5/5.5=3/11 |
Number of meshes decreasing (or increasing) in width
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | |
1 | AB | 1Τ2Β | 1T1B | 3T2B | 2T1B | 5T2B | 3T1B | 7T2B | 4T1B | 9T2B |
2 | 1Ν2Β | AB | 1T4B | 12B | 3T4B | 1T1B | 5T4B | 3T2B | 7T4B | 2T1B |
3 | 1MB | 1N4B | AB | 1T6B | 1T3B | 1T2B | 2T3B | 5T6B | 1T1B | 7T6B |
4 | 3Ν2Β | 1N2B | 1N6B | AB | 1T8B | 1T4B | 3T8B | 1T2B | 5T8B | 3T4B |
5 | 2MB | 3N4B | 1N3B | 1N8B | AB | 1T10B | 1T5B | 3T10B | 2T5B | 1T2B |
6 | 5Ν2Β | 1MB | 1N2B | 1N4B | 1N10B | AB | 1T12B | 1T6B | 1T4B | 1T3B |
7 | 3Ν1Β | 5N4B | 2N3B | 3N8B | 1N5B | 1N12B | AB | 1T14B | 1T7B | 3T14B |
8 | 7N2Β | 3N2B | 5N6B | 1N2B | 3N10B | 1N6B | 1M4B | AB | 1T16B | 1T8B |
9 | 4Ν1Β | 7N4B | 1N1B | 5N8B | 2N5B | 1N4B | 1N7B | 1M6B | AB | 1T18B |
10 | 9Ν2Β | 2MB | 7N6B | 3N4B | 1N2B | 1N3B | 3N14B | 1N8B | 1N18B | AB |
11 | 5Ν1Β | 9N4B | 4N3B | 7N8B | 3N5B | 5N12B | 2N7B | 3N16B | 1N9B | 1N20B |
12 | 11Ν2Β | 5N2B | 3N2B | 1MB | 7N10B | 1N2B | 5N14B | 1N4B | 1N6B | 1N10B |
13 | 6Ν1Β | 11N4B | 5N3B | 9N8B | 4N5B | 7N12B | 3N7B | 5N16B | 2N9B | 3N20B |
14 | 13Ν2Β | 3N1B | 11N6B | 5N4B | 9N10B | 2N3B | 1N2B | 3N8B | 5N18B | 1N53 |
15 | 7MB | 13N4B | 2MB | -1N8B | 1MB | 3N4B | 4N7B | 7N16B | 1N3B | 1N4B |
16 | 15Ν2Β | 7N2B | 13N6B | 3M2B | 11N10B | 5N6B | 9N14B | 1N2B | 7N18B | 3NB10B |
17 | ΒΝ1Β | 15N4B | 7N3B | 13N8B | 6N5B | 11N12B | 5N7B | 9N16B | 4N9B | 7N20B |
18 | 17Ν2Β | 4N1B | 5N2B | 7N4B | 13N10B | 1N1B | 11M4B | 5N8B | 1N2B | 2N5B |
19 | 9Ν1Β | 17N4B | 8N3B | 15N8B | 7N5B | 13N12B | 6N7B | 11N16B | 5N9B | 9N20B |
N = Sideknots
T = Meshes
B = Bars
∎ Knotless netting
∎ Knotted netting
Where
W = estimated weight lg) of netting
H =
number of rows of knots in the height of the netting 2 x number of meshes
L = Stretched length
(m) of netting
Rtex and m/kg — the size of twine in the netting
K = knot correction factor to take into account the weignt of the knots (single knot); see table below
K = (knot correction factor) for different netting panels
Stretched meshsize (mm) |
Twine diameter (d) in mm | |||||||
0.25 | 0.50 | 0.75 | 1.00 | 1.50 | 2.00 | 3.00 | 4.00 | |
20 | 1.20 | 1.40 | 1.60 | 1.80 | - | - | - | - |
30 | 1.13 | 1.27 | 1.40 | 1.53 | 1.80 | 2.07 | - | - |
40 | 1.10 | 1.20 | 1.30 | 1.40 | 1.60 | 1.80 | - | - |
50 | 1.08 | 1.16 | 1.24 | 1.32 | 1.48 | 1.64 | 1.96 | - |
60 | 1.07 | 1.13 | 1.20 | 1.27 | 1.40 | 1.53 | 1.80 | 2.07 |
80 | 1.05 | 1.10 | 1.15 | 1.20 | 1.30 | 1.40 | 1.60 | 1.80 |
100 | 1.04 | 1.08 | 1.12 | 1.16 | 1.24 | 1.32 | 1.48 | 1.64 |
120 | 1.03 | 1.07 | 1.10 | 1.13 | 1.20 | 1.27 | 1.40 | 1.53 |
140 | 1.03 | 1.06 | 1.09 | 1.11 | 1.17 | 1.23 | 1.34 | 1.46 |
160 | 1.02 | 1.05 | 1.07 | 1.10 | 1.15 | 1.20 | 1.30 | 1.40 |
200 | 1.02 | 1.04 | 1.06 | 1.08 | 1.12 | 1.16 | 1.24 | 1.32 |
400 | - | 1.02 | 1.03 | 1.04 | 1.06 | 1.08 | 1.12 | 1.16 |
800 | - | - | - | 1.02 | 1.03 | 1.04 | 1.06 | 1.08 |
1600 | - | - | - | - | - | 1.02 | 1.03 | 1.04 |
Example : Knotted netting of twisted nylon twine, R1690 tex (590 m/kg), 100 mm bar length (200 mm stretched mesh length), height 50 meshes, length 100 meshes
50 meshes = 100 rows of knots in height
Stretched length = 100 meshes x 0.200 m = 20 m
Diameter of twisted polyamide twine 1690 Rtex = 1.5 mm (see page 12)
K in the table above = 1.12 (stretched mesh 200 mm; diameter 1.5 mm)
W = 100 x 20 x (1690/1000; x 1.12 = 3785 g = about 3.8 kg
The drag of a net is proportional to the number and type of meshes in the netting, and to the orientation of the net panel(s) in the water.
Where
S |
= |
twine surface area (square metres) |
N |
= |
number of meshes at the top of the panel |
n |
= |
number of meshes at the bottom of the panel |
H |
= |
number of meshes in the height of the panel |
a |
= |
stretched mesh (mm) |
= | diameter of twine (mm) |
Example : In the piece of netting shown above on the right, if N = 16; n = 6; H = 6; a = 80 mm; = 1.5 mm
∎ NET WEBBING: CALCULATING TWINE SURFACE AREA OF A TRAWL
PANEL Surface | No of Panels | N+n/2 | H | N+n/2xH | a (mm) | (mm) | 2(a x Ø) | Twine Area |
A | 4 | 21 | 24 | 504 | 80 | 1.13 | 181 | 0.36 |
B | 2 | 61 | 90 | 5490 | 80 | 1.13 | 181 | 1.99 |
C | 1 | 279 | 30 | 8370 | 60 | 0.83 | 100 | 0.84 |
D | 2 | 194 | 140 | 27160 | 60 | 0.83 | 100 | 5.43 |
E | 2 | 136 | 100 | 13600 | 40 | 0.83 | 66 | 1.80 |
F | 2 | 54 | 90 | 4860 | 80 | 1.13 | 181 | 1.76 |
G | 2 | 97 | 30 | 2910 | 60 | 0.83 | 100 | 0.58 |
J | 2 | 86 | 150 | 12900 | 40 | 1.13 | 90 | 2.32 |
Twine surface area without knots |
TOTAL S = 15.08 m2 |
In order to compare the twine surface areas of two trawls, the trawls should be as nearly the same shape as possible. In the case of such comparisons the surfaces of the lengthening pieces and the codend (parts without oblique orientation), will cause no significant drag, and can be disregarded.
∎ Hanging ratio (E) is commonly defined as :
Example : 200 meshes of 50 mm stretchea mesh size hung on a rope of 8 m
∎ Other expressions used for hanging ratio :
E=L/Lo | Lo/L | (Lo-L)/Lox100 | (Lo-L)/Rx100 |
Estimate of the height as mounted % of stretched height |
|
(hanging ratio) |
(1) | (2) | (3) | ||
0.10 | 10 % | 10 | 90 % | 900 % | 99 % |
0.20 | 20 % | 5 | 80 % | 400 % | 98 % |
0.30 | 30 % | 3.33 | 70 % | 233 % | 95 % |
0.40 | 40 % | 2.5 | 60 % | 150 % | 92 % |
0.45 | 45 % | 2.22 | 55 % | 122 % | 89 % |
0.50 | 50 % | 2.00 | 50 % | 100 % | 87 % |
0.55 | 55 % | 1.82 | 45 % | 82 % | 84 % |
0.60 | 60 % | 1.56 | 40 % | 67 % | 80 % |
0.65 | 65 % | 1.54 | 35 % | 54 % | 76 % |
0.71 | 71 % | 1.41 | 29 % | 41 % | 71 % |
0.75 | 75 % | 1.33 | 25 % | 33 % | 66 % |
0.80 | 80 % | 1.25 | 20 % | 25 % | 60 % |
0.85 | 85 % | 1.18 | 15 % | 18 % | 53 % |
0.90 | 90 % | 1.11 | 10 % | 11 % | 44 % |
0.95 | 95 % | 1.05 | 5 % | 5 % | 31 % |
0.98 | 98 % | 1.02 | 2 % | 2 % | 20 % |
Note : It is recommended that only the hanging ratio E be used
∎ Examples of common horizontal hanging ratios
∎ Calculation of the surface covered by a piece of netting
Where
S | = | surface covered by netting (in square metres) |
E | = | hanging ratio (horizontal) |
L | = | number of meshes in lengtn |
H | = | number of meshes in height |
a2 | = | (stretched mesh size in metres) squared |
Example :
Note : The surface covered ¡s at a maximum when E = 0.71, that is when each mesh forms a square
∎ Calculation of mounted height
The actual height of a mounted (rigged or hung) net depends on the stretched height and the hanging ratio.
The general formula permitting estimation in all cases is :
where E2 = horizontal hanging ratio multiplied by itself
Example : Given the piece of netting described on the preceding page with hanging ratio of 0.90 :
∎ Table for estimating mounted height
Example
:
Given the
piece of netting described on the preceding page, mounted with the horizontal
hanging ratio 0.90, we can deduce from the table above (E to A to H) that its
mounted height is 44% of the stretched height.
Stretched height = 500 meshes of 30 mm = 500 x 30 mm = 15 m
Mounted height = 44% of 15 m = 6.6 m
∎ Netting with straight edges (i.e. AB, AT, and AN)
Netting having the same number of meshes, and meshes of the same size, or approximately the same size.
Netting having a different number of meshes or meshes of a different size
∎ Netting cut obliquely with a combination of cuts B and N or Τ Pieces having a different number of meshes and different cuts
Examples
∎ - Examples of fish hook characteristics
Regular hooks | ||
Number |
gap (mm) |
Shank diam. (mm) |
12 |
9.5 |
1 |
11 |
10 |
1 |
10 |
11 |
1 |
9 |
12.5 |
1.5 |
8 |
14 |
1.5 |
7 |
15 |
2 |
6 |
16 |
2 |
5 |
18 |
2.5 |
4 |
20 |
3 |
3 |
23 |
3 |
2 |
26.5 |
3.5 |
1 |
31 |
4 |
1/0 |
35 |
4.5 |
Forged hooks | ||
Number |
gap (mm) |
Shank diam. (mm) |
2 | 10 | 1 |
1 | 11 | 1 |
1/0 | 12 | 1 |
2/0 | 13 | 1.5 |
3/0 | 14.5 | 1.5 |
4/0 | 16.5 | 2 |
5/0 | 10 | 2.5 |
6/0 | 27 | 3 |
8/0 | 29 | 3.5 |
10/0 | 31 | 4 |
12/0 | 39 | 5 |
14/0 | 50 | 6 |
∎ Straight hooks 'J' shape, ring eye
∎ Kirbed (offset) hooks
∎ Reversed hooks
∎ Double and treble hooks
∎ Specialised hooks for particular species or fishing methods
Trolling
Longlines
Pole and line
∎ Lures
∎ Knots for ring-eyed hooks
∎ Knots for flatted shank hooks
∎ Swivels
∎ Three-way swivels
∎ Snaps
∎ Knots for joining branditine or snood to mainline
∎ Knots for joining branditine to snood
There are a great variety of seine floats, with L ranging from 100 to 400 mm; Ø from 75 to 300 mm; and buoyancy from 300 to 22000 gf.
Durability is a most important characteristic of a seine float.
Examples : In expanded PVC, two types of manufacture
L | Ø | Ø | Wt. (g) in air | buoyancy kgf |
195 | 150 | 28 | 350 | 2.2 |
203 | 152 | 28 | 412 | 2.2 |
203 | 175 | 28 | 515 | 3.0 |
L | Ø | Ø | Wt. (g) in air | buoyancy kgf |
192 | 146 | 26 | 326 | 2.4 |
198 | 151 | 28 | 322 | 2.5 |
198 | 174 | 33 | 490 | 3.5 |
For the dimensions given, the buoyancy varies depending on the material.
Rough estimation of the buoyancy-may be found by measuring the float.
Estimation of the number of floats necessary for a seine :
Examples
Dimensions (mm) |
Buoyancy (gf) |
|
Ø x L | Ø | |
30 x 50 | 6 | 30 |
50 x 30 | 8 | 50 |
50 x 40 | 8 | 67 |
65 x 20 | 8 | 55 |
65 x 40 | 8 | 110 |
70 x 20 | 12 | 63 |
70 x 30 | 12 | 95 |
80 x 20 | 12 | 88 |
80 x 30 | 12 | 131 |
80 x 40 | 12 | 175 |
80 x 75 |
12 | 330 |
85 x 140 | 12 | 720 |
100 x 40 | 14 | 275 |
100 x 50 | 14 | 355 |
100 x 75 | 14 | 530 |
100 x 90 | 14 | 614 |
100 x 100 | 14 | 690 |
125 x 100 | 19 | 1 060 |
150 x 100 | 25 | 1 523 |
Estimating the buoyancy from the size of the float :
buoyancy (in gf) = 0.67 x L (cm) x 2 =(cm)2
Dimensions (mm) |
Buoyancy (gf) |
|
Ø x L | Ø | |
76 x 44 | 8 | 70 |
88 x 51 | 8 | 100 |
101 x 57 | 10 | 160 |
140 x 89 | 16 | 560 |
Dimensions (mm) |
Buoyancy (gf) |
|
Ø x L | Ø | |
76 x 45 | 8 | 70 |
89 x 51 | 8 | 100 |
102 x 57 | 10 | 160 |
140 x 89 | 16 | 560 |
158 x 46 | 8 | 180 |
Estimation of the buoyancy from the size of a float
buoyancy (in gf) = 0.5 x L (cm) x Ø2 (cm)2 Ø2 = external diameter multiplied by itself
Examples
L (mm) |
Ø (mm) |
Ø (mm ) |
Buoyancy (gf) |
25 | 32 | 6 | 20 |
32 | 58 | 10 | 60 |
42 | 75 | 12 | 110 |
58 | 66 | 12 | 175 |
60 | 70 | 12 | 200 |
65 | 75 | 12 | 220 |
65 | 80 | 12 | 250 |
58 | 23 | 8 | |
60 | 25 | 10 | |
72 | 35 | 25 | |
80 | 40 | 35 | |
100 | 50 | 100 |
Ø (mm) |
Ø (mm ) |
Buoyancy (gf) |
146 | 100 | 110 |
146 | 88 | 200 |
146 | 82 | 240 |
184 | 120 | 310 |
184 | 106 | 450 |
200 | 116 | 590 |
200 | 112 | 550 |
Examples from suppliers' catalogues
Diameter (mm) |
Volume (litres) |
Buoyancy kgf |
Maximum depth (m) |
|
200 | 4 | 2.9 | 1 500 | |
200 | 4 | 3.5 | 350 | |
280 | 11 | 8.5 | 600 | |
75 | 0.2 | 0.1 | 400 | |
100 | 0.5 | 0.3 | 500 | |
125 | 1 | 0.8 | 400-500 | |
160 | 2 | 1.4 | 400-500 | |
200 | 4 | 3.6 | 400-500 | |
203 | 4.4 | 2.8 | 1 800 | |
200 | 4 | 3.5 | 400 | |
280 | 11-11.5 | 9 | 500-600 | |
152 | 1.8 | 1.3 | 1 190 | |
191 | 3.6 | 2.7 | 820 | |
203 | 4.4 | 2.8 | 1 000 | |
254 | 8.6 | 6.4 | 1 000 |
The table below shows that, for floats of equal diameter (200 mm in this case), the volume and buoyancy may vary a great deal, depending on the material and placement of holes or lugs.
Ø 200 mm | Plastic, center hole | Plastic, side hole | Plastic, with screw lug |
Aluminium, with lugs |
|
Volume | 4 | 4 | 4 | 4 | 4.4 |
Buoyancy (kgf) | 2.9 | 3.5 | 3.6 | 3.5 | 2.8 |
* Note : The maximum effective depth of a float depends on the manufacture, and should be specified by the supplier. It cannot be deduced from the appearance, shape or colour
Examples:
1/ Solid floats (PVC)
Ø (mm) |
L (mm) | Ø (mm) |
B (mm) | C (mm) |
Buoyancy (kgf) |
125 | 300 | 25 | 200 | 90 | 2.9 |
150 | 530 | 25 | 380 | 100 | 7.8 |
150 | 600 | 25 | 450 | 100 | 9.2 |
150 | 680 | 25 | 530 | 100 | 10.4 |
150 | 760 | 25 | 580 | 100 | 11.5 |
200 | 430 | 45 | 290 | 110 | 10.5 |
L (mm) |
I (mm) |
H (mm) |
Ø (mm) |
Buoyancy (kgf) |
300 | 300 | 200 | 35 | 12 - 15 |
180 | 180 | 180 | 25 | 4 |
2/ Inflatable floats
Ø (mm) |
Ø (mm) |
Ø (mm ) |
L (mm) |
L' (mm) |
Buoyancy (kgf) |
510 | 160 | 11 | 185 | 18 | 2 |
760 | 240 | 30 | 350 | 43 | 8 |
1 015 | 320 | 30 | 440 | 43 | 17 |
1 270 | 405 | 30 | 585 | 43 | 34 |
1 525 | 480 | 30 | 670 | 43 | 60 |
1 905 | 610 | 30 | 785 | 48 | 110 |
2 540 | 810 | 30 | 1 000 | 48 | 310 |
Ø |
Ø (mm) |
Ø (mm ) |
L (mm) |
Buoyancy |
760 | 240 | 38 | 340 | 7.5 |
1 015 | 320 | 38 | 400 | 17 |
1 270 | 405 | 51 | 520 | 33.5 |
1 525 | 480 | 51 | 570 | 59 |
Examples
∎ Leads for ropes
L (mm) | 25 | 38 | 38 | 32 | 32 | 32 | 25 | 45 | 45 | 45 |
Ø (mm) | 16 | 16 | 13 | 10 | 8 | 6 | 6 | 5 | 5 | 6 |
G (g) | 113 | 90 | 64 | 56 | 50 | 41 | 28 | 28 | 28 | 16 |
∎ Leads for lines, examples of shapes
∎ Example of mould for leads
∎ Example of groundrope rings for a gillnet
Ex:
Ø (mm) | Ø (mm) | Pg |
210 | 5 | 105 |
220 | 6 | 128 |
∎ Chains
Ø (mm) |
Approximate Weight kg/m | Ø mm |
Approximate weight kg/m | |
5 | 0.5 | 11 | 2.70 | |
6 | 0.75 | 13 | 3.80 | |
7 | 1.00 | 14 | 4.40 | |
8 | 1.35 | 16 | 5.80 | |
9 | 1.90 | 18 | 7.30 | |
10 | 2.25 | 20 | 9.00 |
High tensile steel
Ø mm |
LxE (mm) |
S.W.L. Ton.f |
Breaking strength Ton.F | Weight kg/m |
7 | 21 x 10.5 | 1.232 | 6.158 | 1.090 |
10 | 40 x 15 | 2.514 | 12.570 | 2.207 |
13 | 52 x 19.5 | 4.250 | 21.240 | 3.720 |
16 | 64 x 24 | 6.435 | 32.175 | 5.640 |
19 | 76 x 28.5 | 9.000 | 45.370 | 7.140 |
∎ Thimbles
∎ Clips for wire rope
* Safe Working Load see page 5
∎ Shackles
Ø mm |
C (mm) |
O (mm) |
S.W.L. Ton.f |
B.S. Ton.f |
6 | 12 | 18 | 0.220 | 1.350 |
8 | 16 | 24 | 0.375 | 2.250 |
10 | 20 | 30 | 0.565 | 3.400 |
12 | 24 | 36 | 0.750 | 4.500 |
14 | 28 | 42 | 1.200 | 7.250 |
16 | 32 | 48 | 1.830 | 11.000 |
18 | 36 | 54 | 2.200 | 13.200 |
20 | 40 | 65 | 2.600 | 16.000 |
24 | 40 | 75 | 3.600 |
22.000 |
30 | 45 | 100 | 5.830 |
35.000 |
∎ Links and Clips
* Safe Working Load see page 5
∎ Swivel, forged steel
Ø mm |
E (mm) |
Ø mm |
S.W.L.* Ton.f |
B.S.** Ton.f |
8 | 17 | 14 | 0.320 | 1.920 |
10 | 25 | 15 | 0.500 | 3.000 |
12 | 28 | 18 | 0.800 | 4.800 |
14 | 35 | 20 | 1.100 | 6.600 |
16 | 35 | 20 | 1.600 | 9.600 |
18 | 38 | 25 | 2.000 | 12.000 |
20 | 43 | 26 | 2.500 | 15.000 |
25 | 50 | 33 | 4.000 | 24.000 |
30 | 60 | 40 | 6.000 | 36.000 |
∎ Swivel, tempered steel and hot galvanized
Ø mm |
S.W.L.* Ton.f |
Weight kg |
8 | 0.570 | 0.17 |
16 | 2.360 | 1.12 |
22 | 4.540 | 2.61 |
32 | 8.170 | 7.14 |
∎ Swivel, high tensile stainless steel
A (mm) |
B (mm) |
C (mm) |
S.W.L.* Ton.f |
B.S.** Ton.f |
Weight kg |
146 | 48 | 20 | 3 | 15 | 1.3 |
174 | 55 | 27 | 5 | 25 | 2.1 |
200 | 62 | 34 | 6 | 30 | 2.8 |
* Safe working load see page 5
** Breaking strength, see page 5
"G" link High tensile steel | ||
F mm |
S.W.L.* Ton.f |
B.S.* Ton.f |
25 | 1.1 | 8 |
30 | 3.6 | 15 |
34 | 5.0 | 25 |
38 | 7.0 | 35 |
* Sale working load and breaking strength see page 5
∎ For trawl
∎ For seine : Opening purse clips or rings
Interior Diam. mm |
Exterior Width mm |
Exterior Length mm |
Thickness mm |
Opening mm |
Breaking strength Ton.f | Weight kg |
A | B | C | D | E | ||
86 | 128 | 180 | 22 | 34 | 0.400 | 1.3 |
107 | 172 | 244 | 32 | 47 | 3.800 | 4.0 |
107 | 187 | 262 | 32 | 52 | 5.400 | 5.0 |
110 | 187 | 262 | 37 | 53 | 6.500 | 6.0 |
75 | 128 | 200 | 19 | 40 | 1.800 | 2.0 |
94 | 150 | 231 | 25 | 47 | 2.200 | 3.0 |
103 | 169 | 253 | 28 | 50 | 3.000 | 4.0 |
103 | 169 | 262 | 35 | 53 | 3.500 | 5.0 |
106 | 175 | 264 | 38 | 53 | 3.600 | 6.0 |
25 | 65 | 111 | 17 | 17 | 5.000 | 0.5 |
38 | 80 | 140 | 15 | 25 | 6.000 | 0.65 |
36 | 90 | 153 | 19 | 29 | 12.000 | 1.1 |
Examples
Ø | L | A | B |
mm | mm | Weight in air kg | Weight in air kg |
200 | 165 | 7.5 | 9.5 |
250 | 215 | 10 | 12.5 |
300 | 260 | 18 | 22 |
350 | 310 | 29 | 24 |
400 | 360 | 35 | 40 |
Ø | L | Ø | A | B |
mm | mm | mm | Weight in air kg | Weight in air kg |
200 | 380 | 30 | 12 | 14 |
250 | 570 | 32 | 15 | 17.5 |
300 | 610 | 35 | 25 | 29 |
350 | 660 | 60 | 42 | 46 |
400 | 715 | 60 | 51 | 56 |
Examples
∎ BuntsØ (mm) | 229 | 305 | 356 | 406 |
Wt. in air (kg) per piece | 4.40 | 9.10 | 11.80 | 19.50 |
Wt. in water (kg) per piece | 0.98 | 2.10 | 2.85 | 4.4 |
Ø (mm) | 305 | 356 | 406 |
Wt. in air (kg) per piece | 5.10 | 8.00 | 11.50 |
Wt. in water (kg) per piece | 1.65 | 2.20 | 3.50 |
∎ Spacers
L(mm) | 178 | 178 |
Ø (mm) | 121 | 165 |
Ø (mm) | 44 | 66 |
Wt. in air (kg) per piece | 1.63 | 2.30 |
Wt. in water (kg) per piece | 0.36 | 0.57 |
∎ Rings or "cookies" (made from old tyres)
diameter ext. Ø (mm) | 60 | 80 | 110 |
diameter int. Ø (mm) | 25 | 30 | 30 |
Weight* (kg/m) | 2.3 | 3.0 | 7.5 |
diameter ext. Ø (mm) | 200 | 240 | 280 |
diameter int. Ø (mm) | 45 | 45 | 45 |
Weight* per piece (kg) | 5.0 | 7.0 | 10.5 |
* Weight in air