Vegetable cables used on sea vessels, according to the material from which they are made, as well as by design and classification. approved by the State All-Union Standards (GOST), are indicated on the previous pages of the site.
Behind Lately on ships practice the use kapron and nylon cables, made from synthetic fibers. Nylon cables are characterized by high tensile strength, low water absorption, high elongation in tension, good elasticity and chemical resistance. The kapron cable withstands temperatures up to +220°C.
Nylon has valuable properties of increased technical strength (for example, the tensile strength of dry nylon reaches 6300 kg/cm2). Nylon is elastic, resistant to moisture and abrasion, suitable for durable fishing tackle.
The disadvantage of kapron cables is the melting of threads (fibers) from friction on the surface of the winch drum, windlass or bollards.

General information

Most often, a three-strand cable is used on ships. A four-strand cable is weaker than a three-strand cable of the same thickness by 20-25%.
Cable work cables are used as tugs and moorings, although their strength is 25% lower than the strength of cable work cables. Their positive qualities include the best drying of a wet cable.
Cables with a thickness of 100 to 150 mm are called pearls, from 150 to 350 mm cables and over 350 mm ropes.
Hemp cable is made white (unresined) and tarred.
The pitched cable has a weight of about 12% more than the white cable, its strength is 25% lower than the strength of the white cable. Resin rope lasts longer than white rope due to better weather protection.
The dark matte color of the cable means that the cable is stale, of little use. This cable has an unpleasant odor.
The manila cable is more flexible and lighter than the hemp cable.
The manila cable gets wet a little, floats on the surface of the water, which is valuable when used as tugboats, mooring lines and rescue lines.
Coconut rope is elastic, has a strength of about four times less, and weighs half as much as hemp pitched rope of the same thickness.
The Sisal cable floats on the surface of the water, but is inferior in strength to the Manila cable.
Lyktros - a soft cable of a gentle descent, with which the edges of the sails are sheathed.
Often used for towing combined dressing cable, such as "Hercules", in which its individual strands consist of galvanized steel wires covered with sisal hemp yarn. The strands are twisted around a soft core. Rope "Hercules" is made four-strand and six-strand.
All vegetable cables must be evenly twisted along the entire length and have no defects in the strands (kinks, knots, etc.).
The new cable is pulled out without losing its strength, up to about 8-9%
its original size.
Mold weakens the rope by about 10-15%. The steeper the cable is lowered, the weaker it is. A wet rope is weaker than a dry one.

Sea hemp lines

A vegetable cable with a circumference of less than 25 mm is called line. A line with two strands (white and pitched) is called shkimushgar. A line in three threads (white and pitched) is called yuzen. Special purpose lines include: l aglin, lotlin, diplotlin, signal halyards etc. Lotlin white in 18 threads, three-strand. Diplotlin descends cable work and has 27 threads with three strands. All other lines of cable work.
Ledges for mechanical lags and signal halyards are woven and made from the best quality hemp.

Plant cable measurement

The thickness of plant cables is measured around the circumference. Typically, 10 measurements are made at different points on the cable. The arithmetic mean of these measurements will determine the cable circumference.

Caring for plant cables

Cables must be stored in dry, ventilated rooms. Plant cables are afraid of fire, heat, smoke, as well as all kinds of oils and acids. A wet cable must be dried, since an insufficiently dried cable laid in a bay will sag and prematurely lose its strength. Cables contaminated with silt during use must be thoroughly washed before drying.
Vegetable ropes that are wet in salt water are recommended to be washed with fresh water before drying; for better drying, they should be stored on wooden banquets.

Calculation of plant cables

Approximate service life (in operation) of a vegetable cable:
a) cable work - 3 years;
b) pearls - 2 years;
c) other cables - 1 year.

The cable required for work can be selected by calculating its breaking strength using the formula
R=P r (π d 2 / 4) (1)
where
d= Ö(4R / Pr * π) ,
where R - explosive strength, kg;
d - cable diameter, cm;
P r- allowable design tensile strength of the cable in tension (usually P r accept no more than 100 kg / sq. cm with cable block diameters 10d and not more than 80 kg/sq. cm for smaller diameters). Usually, when calculating cables, the load from the own weight of the cables, the acceleration force of the masses in the initial period of lifting the load, and the additional tension when bending around the pulleys of the drums are neglected.

For lifting weights, the selection of the required cable can be made according to the approximate formula
Р = nR, (2)
where P is the working strength of the cable;
n - safety factor (margin of safety);
R - breaking strength of the cable.

Example 1. Pick up a hemp cable to lift a load weighing 1500 kg. The weight Q is suspended by one free block on two cables.
Solution. The calculation is made according to the formula (2), assuming a 6-fold margin of safety. The tensile force to which the rope is subjected is equal to
R \u003d Q / 2 \u003d 1500 / 2 \u003d 750 kg.
Taking a 6-fold margin of safety, we get the working strength of the cable
P = 750 kg * 6 = 4500 kg.

To verify this calculation, from the GOST 483-41 table, we select a hemp white cable, looking for a number close to 4500 kg in the “explosive strength of the cable” column. For a high-strength cable, such a breaking strength is 4477 kg and corresponds to a cable for which d \u003d 31.8 cm. Then, denoting the allowable design tensile strength of the cable in kg / sq. see, via P r, by formula (1)
P r = R / ( π d 2 / 4) = 750 / ( π * 3,18 2 / 4)
we get the calculated tensile strength equal to 93 kg / sq. see that is perfectly acceptable.

Explosive and permissible working strength of plant cables can be approximately calculated by the formula
R = k С 2 , (3)
where R - explosive strength, kg;
k - strength factor (Table 2);
C - cable circumference, mm.

table 2

Strength factor for plant cables

Table 3

Determining the weight of a plant cable

Table 4

Ropes (ropes) lapel, cable work

(GOST 483-55)

Table 5

Cables (ropes) sisal and manila, three-strand drive, cable work

Table 6

Cables (ropes) manila ordinary three-strand cable work

(GOST 1088),

Table 7

Cables (ropes) sisal ordinary three-strand cable work

Table 8

Ropes in shipbuilding

Cables (ropes) are products twisted from steel wires or twisted from plant and artificial fibers. According to the material, the cables are divided into vegetable, steel (wire), combined and synthetic.

Plant cables are made from suitably processed plant fibers. Depending on the source material, plant cables are hemp, manila and sisal.

Hemp cables are made from hemp fibers - hemp. Hemp can be used in its pure form (white ropes) and tarred (tarred ropes). The grinding of hemp protects the cable from moisture and rapid decay, but its strength is somewhat reduced. Hemp ropes are strong and elastic, but they absorb moisture very much, so they sink in water, and in cold and wet weather become heavy and stiff.

Manila cables, made from the fibers of the stems and leaves of the banana tree, are very convenient for use on ships. The peculiarity of these cables is their low hygroscopicity, due to which they do not sink in water. These ropes are the strongest of the vegetable ropes and are flexible and highly elastic.

Sisal ropes are made from fibers from the leaves of the tropical agave plant. These cables are inferior in strength to hemp. They have a high rigidity, as a result of which they wear out quickly.

Vegetable cables are made as follows. First, the fibers are twisted into cables. Then a strand is obtained from several cables. Three or four strands twisted together form a cable, which is called a cable work cable (Fig. 16, a). Several cables (three-four) of cable work, twisted together, form a cable work cable (leash cable). The cables used for cable work are called strands (Fig. 16, b)

In order for the cable not to unwind and retain a constant shape, the constituent elements (cables, strands and cables in general) are twisted in different directions. Usually, the fibers are twisted into cables clockwise so that the coils go from left to top to the right, the cables into strands - in the opposite direction, and the strands into the cable - again clockwise. In this direction of the twist, a direct descent cable is obtained (Z-shaped different) (Fig. 16, c). In some cases, the reverse direction of the lay is used. Such cables are called reverse descent cables (S-shaped) (Fig. 16, d).

Braided cables have also been used on ships, which consist of one loosely twisted strand covered with a braid of linen threads. These cables have little stretch and do not twist, therefore they are used for signal halyards and laglins of outboard lags.

Rice. 16. Vegetable cables: a-cable work, b - cable work, c-direct descent; g-reverse descent, caboose; 2 strands, 3 strands

The thickness of plant cables is measured along the circumference. Depending on it, these cables have special names. So, cables up to 25 mm thick are called lines, from 100 to 150 mm - pearls, from 150 to 350 mm - cable and over 350 mm - ropes (cables with a circumference of 25-100 mm do not have a special name).

Steel cables are made of steel, usually galvanized, wire with a diameter of 0.2-5 mm. Depending on the number of layers, single, double and triple lay cables are distinguished (Fig. 17). The easiest way is to make a single lay steel cable. In this case, several wires are twisted directly into a cable. Such single-strand cables are called spiral. But more often in large assortment double-lay cables are made: the wire is first twisted into strands, and then several strands are twisted into a cable. If several such cables are twisted together, then a triple lay cable will be obtained.

Rice. 17. Steel cables of various lay: a - single; b - double; c - triple

Multi-strand cables are twisted around a central core (Fig. 18), which is used as steel wire or organic fibers. The core, filling the void inside the cable, prevents the strands from falling to the center, and the organic core containing anti-corrosion grease, in addition, protects the cable wire from rusting, which increases its service life. In addition to the center core, some ropes may have an organic core within each strand.

Of great practical importance is the classification of cables according to their flexibility. The most rigid are single-strand spiral cables. Cables with a wire core are rigid, and cables with a central organic core are semi-rigid. Flexible cables have multiple organic cores. Triple lay ropes have the greatest flexibility.

To designate the grades of steel cables, a digital system has been adopted, according to which each cable is marked with a product of numbers: the first of them indicates the number of strands in the cable, the second - the number of wires in each strand. When marking a triple lay cable, one more factor is added in front, which indicates the number of strands in the cable. The number of organic cores in the cable is indicated by the last digit.

For example, 6X24 +7 means a double lay cable consisting of 6 strands, each strand of 24 wires, and having 7 organic cores. A six-strand triple lay cable, each strand of which is twisted from 7 strands of 19 wires and has one organic core, will be designated: 6X7X19 + 1.

Combined cables have strands consisting of galvanized steel wires covered with vegetable yarn.

Synthetic cables are made from artificial fibers, which include kapron, nylon, curalon and the most common now polypropylene. These cables in their strength, elasticity, flexibility and durability are far superior to the best vegetable ones. They are not subject to rotting and mold, almost do not give in to the action of oil, oils, alkalis and acids. For ship work, twisted three-strand synthetic cables are most often used, and for mooring ends it is allowed to use braided eight-strand synthetic cables.

Rice. 18. Steel cables with a core: a - wire, b - synthetic, c - organic

The use of cables on ships requires knowledge of their main characteristics, of which strength is the most important. The strength of the cable is characterized by its breaking force, which is understood as the minimum load that breaks the cable. The breaking force of the rope depends on its diameter and design, the type of lay and material, the diameter of the wire, the quality of the steel, etc. The values ​​of the breaking force of the cables are given in state standards. For practical purposes, it is often sufficient to know the approximate value of the breaking force, which can be determined from various empirical formulas. The supply of ships with cables is carried out in accordance with the Rules for the Classification and Construction of Sea-Going Ships of the USSR Register.

The strength and durability of cables depends not only on their design and quality, but also on proper operation, storage and care. A good cable can quickly become unusable if elementary rules are not followed. technical operation and use it in inappropriate conditions.

Revealing the good quality of the cable depends on the correct acceptance. Upon receipt of the cable, carefully inspect it and check the basic design data and the presence of a certificate with a tag. When inspecting steel cables, they check the integrity of the galvanization, the presence of rust, the safety of the wire and the tightness of the wires in the strands. When accepting vegetable ropes, it is necessary to pay attention to their smell and color, since a musty smell indicates the presence of rot and mold.

The pitched cable should be of a uniform light brown color, free of spots, not sticky to the hands, and not crackle when unfolded. The stickiness of the cable indicates an excessive amount of resin, and dry crackling - the stale cable.

The safety of the cable is largely ensured by the correct methods of opening the coils (Fig. 19), which do not allow the formation of loops and creases (pegs), since the creases cause significant local deformation of the cables and rupture of individual wires, and also make it difficult to work with cables.

When unfolding, the plant cable bay is placed on edge, the strapping is removed and, having passed the inner end of the cable through the inner cavity of the bay, they unravel it, holding the outer hoses with their hands.

To open the steel cable coil, holding the coil by the outer hoses, roll it out on the deck and at the same time pull the running end. A thick steel cable is usually received on a ship wound on a drum. In this case, it is best to wind the cable from a rotating drum, setting it in a horizontal position on two supports.

Rice. 19. Rope unraveling: a - vegetable; b and c - steel

The cables unraveled from the bay should be stretched along the deck so that they straighten out, and then cut into pieces of the desired length. In order to prevent the cable from untwisting at the place of the cut, on both sides of this place it is pre-tied with a soft wire or cable - stamps are applied. The cut cable is wound on views or stored in small bays. From the action of moisture, the cable protects the cover, which is put on the view. In good weather, the cover must be removed to dry the cable.

Vegetation cables are usually stored in small, loose coils. The cables are laid in a coil in a twist, i.e., the direct descent cables are clockwise, and the reverse descent and cable cables are counterclockwise. To protect against the action of moisture, the bays of the plant cable are suspended or laid on gratings (banquettes). During rain or fresh weather, the bays should be covered with tarpaulins or covers. All unused cables should be stored in dry, well ventilated areas. From time to time, the cables must be carefully ventilated, for which they are. should be hung on handrails, between masts or in other convenient places.
Used cables are well dried before being laid in coils. Plant cables that are wet in sea ​​water, before drying, it is recommended to wash with fresh water. For washing large cables, you can use the ship's calls to the mouths of the rivers, where the cable can be washed overboard in river water.

Synthetic cables are not afraid of moisture, and drying them is optional, but you can’t wind a wet cable on a view. Dry the cable in the shade, as it deteriorates from the action of sunlight. When contaminated, the cable can be washed with sea water. Synthetic ropes are very sensitive to abrasion and melting, so the surfaces of the drums must be smooth.

During operation, static electricity accumulates on the surface of synthetic cables, which can cause the formation of sparks. Therefore, new synthetic cables can be used on tankers only after antistatic treatment - soaking for a day in sea water with a salinity of at least 20% or in a specially prepared saline solution (20 kg of table salt per 1 m3 of water). During operation, the cables must be rolled periodically, at least once every 2 months, on the deck with salty outboard water, which is recorded in the logbook.

Careful care is also required for combined cables with a shirt made of vegetable cables. These cables must not be laid in coils damp or wet, as the moisture remaining in the jacket can cause intense corrosion of the wire.

Steel cables should be systematically lubricated (tied). This not only protects the cable from corrosion, but by reducing friction between the wires, it helps to reduce wear. Rope grease NMZ-Z or ZZT is usually used as a lubricant. Netted cables must be lubricated with grease at least once a month. Range composition: 87% grease, 10% bitumen, 3% graphite.

The review will consider the main (most common) types of synthetic ropes. Their advantages and disadvantages. Provides basic information - difficulty level - beginner.

You can read about the types of materials used in the production of ropes in the article: Comparison of materials. Synthetic ropes: what are they made of.

1. Twisted ropes

Most common twisted three-strand ropes (Laid three-stand)
Simplified design - three individually twisted (in one direction) strands are then twisted all together (in the other direction).

Depending on the total number of twists, there may be
- soft (soft)- a small number of twists. In this case, the greatest strength of the rope and the least extensibility are structurally achieved. In this case, there will be low resistance to abrasion and a high tendency to snag and pull out strands (the formation of "tufts")
-hard- a large number of twists. Lowest strength, highest elongation and high abrasion resistance.
- medium hardness (medium)- the average number of twists. The most common of the three designs.

These ropes are made from natural fibers, metal wire, synthetic - multifilament, monofilament threads. Combined - synthetics / synthetics, synthetics / natural fibers, synthetics / metal

From the pros:
- easy to manufacture (cheap)
- convenient for splicing (interlacing - mold, fire).

Among the shortcomings can be noted:
- tendency to "unwind" (it is necessary to fix the ends of the rope)
- tendency to form loops (and knots) when the rope is unloaded, in a free state

Other types of twisted ropes will not be considered in this article due to their relatively low prevalence. A general performance comparison with other rope types can be seen in the conclusions.

2. Braided ropes

The general characteristic is the spunness of the rope, i.e. the number of strands from which it is braided. Spinning corresponds to (or a multiple of) the number of spools on the braiding machine.

Braided coreless ropes

All ropes in this group will have an internal cavity. The greater the spin, the larger the cavity diameter. For example, for 8-strand ropes, the cavity is insignificant, and it is very difficult to distinguish them by touch from a rope with a core. But a 24-strand rope without a core will already resemble a stocking (it is easy to wrinkle to a flat state).

8-strand L-type ropes. (plaited rope).

The figure shows that this rope structure is achieved by interlacing double strands. The strength and linear weight of such ropes are commensurate with twisted three-strand ropes (with matching diameters). However, they are not prone to the formation of loops and twists.

Simple hollow n-strand ropes (hollow single-braid)
They are ordinary braided ropes. Below is an 8 strand rope. This structure is achieved by simply interlacing the strands. In total, 8 bobbins of thread are used on the braiding machine, four of which move clockwise and four counter-clockwise. These ropes are easy to make and easy to use.

Ropes with diagonal weaving (twill braid)
Similar to the previous type, they have a void in the center. Visually, they are easily distinguishable from simple wicker ones.
This structure is achieved by weaving strands with an offset. For example, a machine has 12 spools of thread, six of which move clockwise and the other six move counterclockwise. However, unlike the previous view, each left strand is “covered” with two right strands. And vice versa, each right strand is “covered” with two left ones.

Diagonal braided ropes have a slightly thicker sheath than similar plain braided ropes.

Solid braid ropes
Can be separated into a separate group. Due to the special type of machines on which such ropes are produced, it is obtained inside filled with thread, i.e. without voids. Such ropes are widespread in America.

Braided core ropes

Bundles of threads, braided cores, twisted cores can be used as the core. There are also more complex designs, they are used for special purpose ropes.
The core and braid can be made from different materials This combination is used to obtain certain properties. For example, an abrasion-resistant material can be used in the braid, and a lighter or stronger material can be used in the core.

Braided core ropes (Double-braid, braid-of-braid rope)

As a rule, braided 8, 12 strand quick-draw rope is used as the core. The braid consists of a larger number of strands (usually 16 strands or more) and has a tight weave.

Ropes with parallel twisted strands (parallel stand rope)

They are ropes in which the core strands are parallel to the central axis of the rope. One of the most common examples in this group is Kermantle rope. The core consists of three-strand twisted cords, the braid is usually 24, 32 or 48 strands. Ropes of this type are very efficient (the strength of the threads is used by 80-90%, while on simple braided ropes it is only about 60%) and at the same time they do not have the disadvantages of ordinary twisted ropes.

Results
As a result, you can display a comparative table (it must be understood that this information is conditional, and the compared ropes must be of the same diameter and from the same material).

Classification and characteristics of plant cables. On ships and auxiliary vessels of the Navy, hemp, manila and sisal cables are used. Plant cables are more expensive than steel cables and less durable (non-tarred hemp cables are about 6 times weaker than flexible steel cables of the same thickness).

According to the manufacturing method, there are cables of cable work (ordinary) and cables of cable work (lapel).

Cables of cable work (Fig. 4.11, a, b) are made by twisting the fibers into cables (yarn). Several cables twisted in the opposite direction form a strand. Three or four strands twisted in the same direction as the fibers form a cable. 4-strand cables (Fig. 4.11, b) have a central core. It prevents the strands from sinking and is used in cases where special flexibility and untwisting of the cable is required. 4-strand cables are weaker than 3-strand cables of the same thickness by about 20%.

Rope work cables are usually made of right twist (straight descent). Cables of the left twist (reverse descent) are produced only by special order. Cable work cables (Fig. 4.11, b) are obtained by twisting to the left side of three or four cables of cable work of the right twist - strand-ney. The 4-strand cable has a center core for the same purpose as the 4-strand cable.

Rice. 4.11. Vegetable ropes:
a - a three-strand cable of cable work of the right twist (direct descent); b - four-strand cable of the right twist; c - three-strand cable work cable (lapel); 1 - strands; 2 - fibers; 3 - strand; 4 - cables; 5 - core

Cords - with a circumference from 8.8 to 37.7 mm;
- lines - with a circumference of up to 25 mm cable work and up to 35 mm cable work;
- cables - with a circumference of 25 to 100 mm for cable work and from 35 to 100 mm for cable work;
- pearls - cables of cable work with a circumference of 100 to 150 mm;
- cables - cables of cable work with a circumference of 150 to 350 mm;
- ropes - cables of cable work with a circumference of more than 350 mm.

Plant cables are used almost everywhere where considerable flexibility is required.

Hemp cables are made from hemp (processed hemp fibers). Cables of cable work are white (from non-tarred cables) and resinous. Cable work cables are only resin.

The squash is tarred with hot wood resin. With normal pitching, the weight of the resinous cable increases compared to the non-resined one by up to 18%. Too much resin makes the cable brittle, less flexible and heavier. Unresined cable is more susceptible to moisture and rots faster than resinous cable.

By technical indicators depending on the grade and quality of raw materials, hemp cables of cable work, both non-resined and resinous, are divided into four groups: special purpose, special, elevated and normal. Cable work cables are made only in two groups: elevated and normal.

The most common on ships are 3-strand cables of direct descent cable work, non-resined and resinous for special purposes and special ones.

Non-resined and resinous hemp cables of cable work are produced with a circumference from 30 to 350 mm. Cables with a circumference up to 275 mm are made with a length of 250 ± 10 m, and with a circumference over 275 mm - a length of 200 ± 8 m. Cable work cables are made with a circumference from 150 to 450 mm and a length of one end 100 ± 4 m.

The relative elongation of the cables without breaking the strength of 8-10%. This makes them suitable for jobs with sudden tension changes. Hemp cables are produced according to GOS T 483-55 (Table 4.11-4.13).

T a b l e 4.11

T a b l e 4.12

T a b l e 4.13

According to technical indicators, manila cables are divided into elevated and normal ones and are made in 3- and 4-strands with a circumference from 30 to 350 mm. The length of the bay (the whole end) is 250 ± 10 m. They are produced according to GOST 1088-41 (Table 4.14).

T a b l e 4.14

According to technical indicators, sisal cables are divided into elevated and normal ones and are made with a circumference from 20 to 350 mm. The length of the bay is 250 ± 10 m. They are produced according to GOST 1088-41 (Table 4.15).

T a b l e 4.15

All lines, with the exception of shkimushgar, are made from hemp good quality, sh k and m u sh g a r - from low-grade hemp. Sh k and m u sh k a - a line twisted by hand from any number of threads. Vorsa - a stump of an old cable, loosened into heels. Lines with a thickness of 18, 20, 22, 25 mm, diplotlines and laglins are made at least 200 m long, the rest - at least 100 m. Lines are produced according to G O ST 1091-41 (Table 4. 16).

T a b l e 4.16

T a b l e 4.17

T a b l e 4.18. N o t e. Large values ​​of the coefficient K correspond to smaller rope circles.

The selection of cables for a specific type of work is carried out according to the formula (4.4). According to the rules of the Maritime Register C C C R, the safety factor n for plant cables is taken in the range of 6-10; for lifting people - 14.

Rules for acceptance of plant cables. Vegetative ropes in factories are rolled into coils and pulled together in four places with bindings. In one bay of a cable with a thickness of 30 to 75 mm, from one to four separate ends of 250 m each can be assembled; cables with a thickness of 90 and 100 mm can have up to two separate ends of 250 m each; cables with a thickness of 115 mm or more are assembled at one end into a bay. Coils of ropes with a thickness of 34) to 50 mm are packed in an investment fabric or matting and sheathed.

Lines with a thickness of 18-25 mm, Lotlin, Diplotlin roll into bays 200 m long and are pulled together in four places with bindings. The remaining lines are collected in skeins 100 m long and tied in two places. The skeins are collected in packs with lines of the same size and names, the pack contains no more than 20 skeins.

The cords are wound into coils with one whole end. Several bundles are packed in a bale, tied up and sheathed with a packing cloth.

A tag with the name and characteristics of the product is attached to each packaged coil of cable, line, halyard and a certificate is given.

Upon acceptance onto the ship, the cable is carefully inspected and the main design data are compared with the tag on the coil and the certificate. The unresined cable should correspond in color to the natural color of the hemp, should not have brown spots, the smell of rot, mold and burning, should be evenly twisted along the entire length. The strands should not have knots, twists; each turn of the strand should stand out clearly. The tar rope should have a smooth surface, a uniform light brown color and a fresh tar smell. The cable should not have scuffs, knots, bulges and stick to hands. A cable that cracks when straightened (a stale cable with fibers burned out from the resin) cannot be accepted on a ship.

After an external examination, 10 measurements of the cable thickness are made in different places. The arithmetic mean of these measurements gives the circumferential thickness of the cable. Rope thickness up to 50 mm in circumference can be measured with a caliper.

Working with plant cables. To unravel the bay of a plant cable, it is placed with an edge on the deck, the strapping is removed, the inner end of the cable is threaded into the middle of the bay and it is unraveled (Fig. 4.12).

Rice. 4.12. Unraveling a bay of plant cable

Vegetable cables shrink when wet (shorten by 8-12%), and when dried, they stretch. Therefore, in rain or fog, in order to avoid breaking, the cables under tension are weakened.

The cable, which was in the water, is thoroughly dried by hanging it or stretching it to its full length above the deck. A wet and then frozen cable under tension significantly loses strength (the strength of a wet sisal cable decreases by 10-15%, untarred hemp - by 20-25%) and breaks easily, so it is recommended to use resin cables in the cold season. The cables contaminated with silt are washed in fresh water and dried.

Mats are placed at the points of contact between the cable and metal surfaces.

Cables are afraid of high temperatures, smoke, soot, soot, exposure to oils and acids (this causes the cable to decay); they are not recommended to be stretched near chimneys, kept open under the scorching rays of the sun.

The cables in operation are wound on views or laid in bays (the latter are placed in a net, on banquets or suspended). When winding the cable onto the view, the root end of it is grabbed to the view drum; cable hoses are placed on the view evenly and tightly, for which they are upholstered with a wooden mallet. A view with a cable is installed in a place protected from rain and covered with a cover. The cover is removed in good weather, the cable is ventilated. The cables are laid in coils in a twist, i.e., the direct descent cables are laid clockwise, the reverse descent and cable cables are counterclockwise.

Plant cable storage. Unused cables are stored in coils in dry ventilated storerooms; once every three months, the cables are raised to the upper deck for inspection, drying and ventilation.

It is recommended to fasten the ends of the cables by the butts, eyelets, as well as the connection of two cables with the help of steel thimbles. High-quality mold reduces the strength of the plant cable by 10-15%. Cables of large thickness, having more than two splices, cannot be used in critical work.

It is impossible to store plant cables in a packaged form, as this does not allow timely notice the beginning of their deterioration and take protective measures. Approximate service life of plant cables for cable work is 3 years, pearls - 2 years, other cables - 1 year.

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