Balmoral marine equipment handbook

This set of documentation, aimed to be of some practical assistance for the ship crew members directly involved in day-to-day operation, routine maintenance, periodical testing and also repair works of the SSHST1 cargo deck cranes, consists of five separate files representing the instruction manuals for machinery parts, hydraulic parts, and electric parts, spare parts and tools list, and finally test result. This operation and maintenance manual was specifically compiled by INP Heavy Industries specialists and it is a really must-have book for all personnel of the ships having such cranes installed as it will be of great technical help.

Balmoral Marine are very pleased to release the present updated version of the Marine Equipment Handbook. Inside this comprehensive guide book the user will find everything he or she is willing to know about different marine and all associated equipment, anchoring and mooring equipment.

There are also basic conversion tables provided in this publication. You will definitely find all technical info you're looking for in this book - anchors, chasers and grapnels, chains and fittings, wire ropes and fittings, synthetic ropes, spooling machines, buoys, various lifting equipment, fenders, mooring systems, load testing, chain inspection, service and supply info requirements.

Chain strengths are expressed as grades followed by a number. The letter used varies with countries but the strength of the chain remains the same. The number relates to the type and hence the strength of the steel.

U1 grade is mild steel, U2 is a high tensile steel and U3 is a special heat treated steel. These grades are normally only used within the shipping industry as the oil industry demands even greater strengths for the chain used.

Although this chain is still in use it has been superseded by new grades such as Rig Quality 3 and Rig Quality 4. These grades were introduced by the classification societies in order to standardise quality. The same grades also apply to the joining links that may be used with the chain. Tables showing the various strengths of chain are shown overleaf. The offshore industry dictates that chain must be periodically inspected for wear and defects. The level of inspection and the intervals of these surveys are laid down by the classification authorities.

Balmoral carries out such inspections in line with relevant classification society requirements. Balmoral Marine is the exclusive worldwide agent for BEL Grapnel, supplying J chasers; permanent chain chasers; J lock chain chasers; permanent wire chasers and detachable permanent chain chasers. Grapnels, used for recovering chain and wire from the sea bed, are also provided. Upgraded designs for deep water have been included.

All models have been verified by the University of Newcastle. The operational sequence of chasing is shown below. Stage 1. GRAPNELS The grapnel was designed as a fishing tool primarily for the purpose of recovering an anchor and chain which has become detached and has fallen to the sea bed. The operational sequence is as follows: Stage 1. Lifting eye dimensions shown are standard for each type. Specials can be made to suit customer requirements.

A simple procedure of heaving on the chaser while simultaneously hauling in the anchor line with the rig winch surfaces the anchor easily, ready for retrieval.

Independent wire rope core IWRC ropes are the stronger of the two and offer the greater resistance to crushing and high temperatures. Fibre core FC wire ropes while weaker, offer advantages in terms of flexibility, weight and of course price. Along with the diameter, two numbers are normally used to define the construction of a wire rope.

The first refers to the number of strands in the rope and the second to the number of wires per strand. In general, the greater the number of wires, the greater the flexibility of the rope. As the number of strands increase, so the section of the rope tends towards an even circle which is essential for the wear characteristics of ropes which pass over sheaves. While it is impossible to include a comprehensive list of all wire ropes in a publication of this size, this section should be a useful reference guide for those constructions in common use.

When selecting a wire rope for a particular service in addition to. Resistance to bending fatigue and resistance to abrasion require two different types of rope. Maximum resistance to bending fatigue is obtained from a flexible rope with small outer wires whereas to obtain maximum resistance to abrasion a less flexible rope with larger outer wires is required.

The correct selection of a wire rope involves a compromise between these two characteristics, the following diagram gives an indication of the relative abilities of various constructions to withstand wear and abrasion.

In addition to physical protection due to the complete envelopment of steel wire, zinc provides sacrificial protection as corrosion of the steel is prevented until the zinc is removed from comparatively large areas.

In extreme cases corrosion can be combated by the use of stainless steel wire rope. Further guidance to rope selection is given in BS Code of Practice for The selection, care, and maintenance of steel wire ropes. In addition to providing internal lubrication for free movement of the component wires, the lubricant also gives protection against corrosion. Due to the internal pressures set up as the rope flexes, and other outside influences met during its work, the original lubricant may soon be reduced and to ensure maximum rope life supplementary lubricant should be applied periodically during service.

How rigorous the duty or corrosive the conditions will dictate the frequency of these applications. All steel wire ropes, including galvanised and stainless, will derive benefits from lubrication. Fibre cores are generally used, as, when impregnated with grease, they help to provide internal lubrication as well as contributing to flexibility. Where high resistance to crushing or to heat is needed and where additional strength or low stretch is required steel wire cores are used.

Variations in length of lay alter the elastic properties of the rope, e. Both ordinary lay and Langs lay ropes are normally laid up in a right hand direction, but left hand lay can be supplied on request. Ordinary lay ropes are suitable for all general engineering purposes. A Langs lay rope offers a greater wearing surface and can be expected to last longer than an ordinary lay rope on an installation where resistance to wear is important, but it has less resistance to unlaying than an ordinary lay and its application must be limited to installations in which both ends of the rope are secured against rotation.

It follows that the contact between all wires in the strand is linear. Ropes of this construction are not subject to failure by the bending of wires over the wires of the underlying layer. It follows that the wires in successive layers make point contact.

Where ropes are operating over pulleys, nicking of wires and secondary bending at these points of contact occur, and failure of the wires by early fatigue may result. It is seldom that fewer strands are used but, for special applications, more than six are employed. During the process the strands and wires are given the helical shape they will assume in the finished rope. In a preformed rope broken wires do not protrude and greater care is required when inspecting for broken wires.

Preformed rope offers certain advantages over non-preformed rope, eg: 1. It does not tend to unravel and is less liable to form itself into loops or kinks and is thus more easily installed. Due to the reduction in internal stresses it has greater resistance to bending fatigue. A 9 Compacted construction with a double parallel steel core: - Extra High breaking load. Available with plastic full impregnation - Ideal for corrosive environments - Additional resistance to fatigue - High resistance to fleet angles - High resistance to dynamic loads and shock loading.

Suitable for use on: hoist, auxiliary hoist, main hoist. The construction designed to achieve the lowest rotation: - Extra high breaking load - Ideal for hoists applications with one part line - the best rotation resistance properties - Very flexible construction - High resistance to contact pressures thanks to Langs Lay.

Excellent performance on equipment with multi-layer reeving system and high demand of flexibility. Available with plastic protected core, achieving all the benefits of core protection and construction stability recommended for subsea operations.

For larger diameters, the more flexible 6 x 37 rope is recommended. The construction is normally a 6 x 19 9. Even with Preformed rope, it is recommended that one serving be applied at each side of the cutting point to prevent distortion of the rope ends by the pressure applied during cutting.

Soft annealed single wire or marlin should be used. Where wire is used the table below is given as a guide to size of wire, length and number of servings recommended, for Stranded Ropes. At least two servings each of a length six times the diameter of the rope should be employed. The bridge of the grip should invariably be fitted on the working part of the rope, and the U-bolt on the rope tail or dead end of the rope. Grips should not alternate in position on the rope.

As a safety measure and to secure best results it is important to re-tighten all grips after a short period in operation, for, due to the compression of the rope under load, there will be a tendency for the grips to loosen. Refer to the manufacturers instructions for quantity of grips recommended. The measurements are taken at two points at least 1 metre apart and at each point the two diameters at right angles are measured.

The average of these four measurements is the actual diameter of the rope. The bottom of the grooves should be arcs of circles equal in length to one-third of the circumference of the rope. The depth of a groove in a pully should be at least equal to one and a half times the rope diameter and the groove in a drum should not be less than one-third of the rope diameter.

The angle of flare between the sides of the sheaves should be approximately 52 but should be greater if the fleet angle exceeds 1. The clearance between neighbouring turns of rope on a drum should not be less than:. Too great a radial pressure between sheave and rope will cause excess wear of the sheave grooves and will result in reduced rope life.

The radial pressure may be determined from P. Permanent constructional stretch is due to the settling of the wires in the strand and the compression of the central core.

This stretch is irrecoverable and most of it occurs during the early part of the ropes life. The following figures of percentage constructional stretch will give results within acceptable practical limits.

Elastic stretch is the capacity of the individual wires to elongate, under load, due to their elastic properties. Providing the rope is not loaded beyond its elastic limit, it will return to its original length after removal of the load. A uniform factor of safety cannot be given for all engineering applications. Where a rope is used on equipment, the factor of safety of which is not specified, the minimum factor of safety shall not be less than 5 to 1.

The load due to shock is dependant upon the magnitude of the static load and the speed of load application. Every effort should be made to avoid slack rope when load is applied. The undernoted formula may be used in computing the rope capacity of any size of drum or reel. While it will give results that are very nearly correct for wire rope evenly spooled, when the rope is not spooled evenly the drum capacity is slightly reduced.

Remember to take account of large end terminations which could hamper spooling. Formula: A d. The dimension A should be taken to the outside of the rope only, and not to the outside of the flange. The sketch shown below may be used to determine the proper direction of rope lay for spooling or winding on flat or smooth face drums. When a rope is wound on to a drum any tendency of the rope to twist when tension is released will be in a direction which would untwist the rope at the free end.

The advantage of spooling in the correct directions is that when any load is slackened off the laps on the drum will hug together and maintain an even layer. With incorrect spooling the laps will move apart on removal of load and when the load is reapplied the rope may criss-cross and overlap, and flattening and crushing of the rope will result.

The correct spooling direction for right and left hand lay ropes is shown in the sketch below. This applies to both ordinary and Langs lay ropes.

Pass a shaft through the centre of the reel and jack it up to allow the reel to revolve freely. Pull the rope straight ahead keeping it taut to prevent it from loosening up on the reel. Heavy coils should be placed on a turntable and two crosspieces placed on top of the coil to prevent laps springing out of place and kinking. Light Flexible Ropes may be rolled along the ground so that the rope lies straight.

The technical characteristics of a wire rope can be easily determined of the beginning of its life cycle whilst monitoring high contact areas can also be effectively managed. Operator skills, however, are more difficult to monitor. Typical reasons for a wire rope to be withdrawn from service are listed below: a. In examination, if possible, all the records should be analysed and inappropriate points should be eliminated. Some of the hints to help in finding possible cause for these failings are given below.

If the groove is too narrow, the rope gets wedged in it, the strands and wires cannot move as is required for bending, and this condition is detrimental to the life cycle of the rope. On the other hand, too wide a groove also has an adverse effect on rope life due to the high surface pressure between rope and sheave.

For traction sheaves the radius of the groove is usually adapted as closely as possible to the radius of the rope to obtain maximum traction. The rope is supported in the best possible manner if the arc of contact with the groove contour can be deg.

This corresponds to a throat angle of 30 degrees. However, with a large fleet angle or with oscillating loads, the throat angle should be larger up to 60 degrees to avoid undue wear of the rope and sheave flanges. The height of the flanges should be at least 1. The rope and groove are inevitably subject to wear during operation. Since the diameter of a rope becomes smaller due to abrasion and stretch, it will wear out the groove to the smaller diameter of the worn rope. If a new rope is laid in such a worn groove, it will get wedged in the narrow groove and this will have a very adverse effect on its life.

It is also possible that the rope cuts its profile into the groove. Therefore the grooves should be inspected before installing a new rope and if necessary they must be remachined, preferably with a profile cutting tool. If a groove shows excessive wear, this may be an indication that the sheave material is too soft. In this case a sheave of a harder grade steel must be used which better resists the abrasive effect of the rope, or a larger diameter sheave should be taken.

When ropes are wound on drums, attention must be paid to the fleet angle, that is the included angle between the rope running to or from the extreme left or right of the drum and an imaginary line drawn from the centre of the sheave normal to the axis of the drum.

When this angle is too large, the rope in this extreme position will be pressed with great force against the flange of the sheave which causes undue friction and wear of both the rope and the sheave.

With a plain faced drum a large fleet angle will, in addition, cause the rope to travel too fast from the side to the centre of the drum thereby leaving gaps between the wraps. When winding a second layer, the rope is forced into these gaps which results in serious deterioration.

When, on the other hand, the rope is wound past the centre of the drum, a too large fleet angle will cause the next wrap to scrub against the preceding wrap as the rope runs more towards the side of the drum.

If the fleet angle is too small, the rope does not travel fast enough towards the centre of the drum and, apart from scrubbing, at a certain moment the wraps will pile up ie the next wrap is laid on top of the preceding one and is then pressed to the side of the preceding wrap with great force.

This has a detrimental effect on the rope and the equipment on which it is used shock loads. Piled up. The starting position should be at the correct drum flange so. See illustration on p 4. Here too, close supervision should be maintained throughout installation. This will help ensure: 1 the rope is properly attached to the drum 2 appropriate tension on the rope is maintained as it is wound on the drum 3 each wrap is guided as close to the preceding wrap as possible, so that there are no gaps between turns 4 there are at least two dead wraps on the drum when the rope is fully unwound during normal operating cycles Loose and uneven winding on a plain smooth faced drum, can and usually does create excessive wear, crushing and distortion of the rope.

The results of such abuse are lower operating performance and a reduction in the ropes effective strength. Also, for an operation that is sensitive in terms of moving and spotting a load, the operator will encounter control difficulties as the rope will pile up, pull into the pile and fall from the pile to the drum surface. The ensuing shock can break or otherwise damage the rope. Rock Very poor anchoring. B C 50 Soft Mud Bottom. Anchor A B C D E F G H J Weight mm mm mm mm mm mm mm mm mm lbs 42 53 61 67 72 77 81 85 10, 91 15, 20, 30, 40, 45, Anchor A B C D E F Weight mm mm mm mm mm mm Shackle Ibs mm 80 90 10, 12, 14, 15, 16, 20, 25, 30, 33, 40, 45, 50, 60, 70, Anchor A B C D E K L S Weight mm mm mm mm mm mm mm mm Kg 60 65 80 80 90 Anchor A B C D E F G H J K N P S Weight mm mm mm mm mm mm mm mm mm mm mm mm mm Kg 70 70 80 75 70 90 95 95 The sizes quoted are for the most commonly used sizes but Balmoral will gladly supply concrete sinkers to any size required by a client.

Mass of Proof Mass of Proof Mass of Proof Anchor Test Load Anchor Test Load Anchor Test Load Kg Kg Kg Kg Kg Kg Introduction There are currently two types of chain in common use within the marine industry. Studlink chain which is the most popular is used by the shipping and the oil Industry. Open link, which has no studs, is generally used in special mooring applications such as permanent moorings for FPSOs for the larger diameter chains and buoy and marine moorings for the small diameters.

Chain is normally supplied in Long lengths of chain mean no joining links, which may be the weakest links, but shipping and handling can be a problem.

Chain size is generally expressed as the diameter of the steel at the bending area. This can mean that steel bars of mm may be used to manufacture chain of 76mm diameter.

Chain can be fitted with open end links to enable shackle connections to be made. These end links are normally forged to the chain using an intermediate link also known as an enlarged link. These links are larger than the diameter of the chain to take into account the differing radii and the reduced strength of the links due the end link being studless. Chain strengths are expressed as grades followed by a number. The letter used varies with countries but the strength of the chain remains the same.

The number relates to the type and hence the strength of the steel. U1 grade is mild steel, U2 is a high tensile steel and U3 is a special heat treated steel. These grades are normally only used within the shipping industry as the oil industry demands even greater strengths for the chain used. Although this chain is still in use it has been superseded by new grades such as Rig Quality 3 and Rig Quality 4. These grades were introduced by the classification societies in order to standardise quality.

The same grades also apply to the joining links that may be used with the chain. Tables showing the various strengths of chain are shown overleaf. Offshore Industry dictates that chain must be periodically inspected for wear and defects. The level of inspection and the intervals of these surveys are laid down by the classification authorities. Balmoral can carry out such inspections in line with relevant classification society requirements.

Size Weight mm kg 19 1. Size Weight mm kg 19 2. Size Inside Length. Gap Outside Pin Dia of Eye. Inside Size Length. Outside Gap of Eye Pin Dia. GREEN PIN Inside Weight SWL Size Pin Dia Gap Length Safety Tonnes mm mm mm mm kg 89 95 Size Weight mm kg 19 6 25 12 32 24 38 40 44 63 51 98 57 64 70 76 83 89 95 Weight mm mm mm mm mm mm Tonnes kg 90 35 38 30 10 24 32 40 45 35 15 35 45 55 42 25 50 50 60 50 35 70 60 75 60 50 98 70 86 70 60 80 90 80 75 Size Weight mm kg 19 4.

The operational sequence of chasing is shown below. GRAPNELS The grapnel was designed as a fishing tool primarily for the purpose of recovering an anchor and chain which has become detached and has fallen to the sea bed. The operational sequence is as follows: Stage 1 Stage 2. Recovery Wire Rope. Proof Type S. Lifting eye dimensions shown are standard for each type. Specials can be made to suit customer requirements. Proof S. Introduction Wire ropes can be grouped into two broad categories by the type of central core used.

Independent wire rope core IWRC ropes are the stronger of the two and offer the greater resistance to crushing and high temperatures. Fibre core FC wire ropes while weaker, do offer advantages in terms of flexibility, weight and of course price. Along with the diameter, two numbers are normally used to define the construction of a wire rope. The first refers to the number of strands in the rope and the second to the number of wires per strand.

In general, the greater the number of wires, the greater the flexibility of the rope. As the number of strands increase, so the section of the rope tends towards an even circle which is essential for the wear characteristics of ropes which pass over sheaves.

While it is impossible to include a comprehensive list of all wire ropes in a publication of this size, this section should be a useful reference guide for those constructions in common use. When selecting a wire rope for a particular service in addition to the minimum breaking load, the required resistance to abrasion and to bending fatigue must be considered. Resistance to bending fatigue and resistance to abrasion require two different types of rope.

Maximum resistance to bending fatigue is obtained from a flexible rope with small outer wires whereas to obtain maximum resistance to abrasion a less flexible rope with larger outer wires is required. The correct selection of a wire rope involves a compromise between these two characteristics, the following diagram gives an indication of the relative abilities of various constructions to withstand wear and abrasion.

In addition to physical protection due to the complete envelopment of steel wire, zinc provides sacrificial protection as corrosion of the steel is prevented until the zinc is removed from comparatively large areas. In extreme cases corrosion can be combated by the use of stainless steel wire rope. Further guidance to rope selection is given in BS Code of Practice for The selection, care, and maintenance of steel wire ropes.

In addition to providing internal lubrication for free movement of the component wires, the lubricant also gives protection against corrosion. Due to the internal pressures set up as the rope flexes, and other outside influences met during its work, the original lubricant may soon be reduced and to ensure maximum rope life supplementary lubricant should be applied periodically during service.

How rigorous the duty or corrosive the conditions will dictate the frequency of these applications. All steel wire ropes, including galvanised and stainless, will derive benefits from lubrication. Fibre cores are generally used, as, when impregnated with grease, they help to provide internal lubrication as well as contributing to flexibility. Where high resistance to crushing or to heat is needed and where additional strength or low stretch is required steel wire cores are used.

Variations in length of lay alter the elastic properties of the rope, e. Both ordinary lay and Langs lay ropes are normally laid up in a right hand direction, but left hand lay can be supplied on request. Ordinary lay ropes are suitable for all general engineering purposes. A Langs lay rope offers a greater wearing surface and can be expected to last longer than an ordinary lay rope on an installation where resistance to wear is important, but it has less resistance to unlaying than an ordinary lay and its application must be limited to installations in which both ends of the rope are secured against rotation.

It follows that the contact between all wires in the strand is linear. Ropes of this construction are not subject to failure by the bending of wires over the wires of the underlying layer. It follows that the wires in successive layers make point contact. Where ropes are operating over pulleys, nicking of wires and secondary bending at these points of contact occur, and failure of the wires by early fatigue may result.

It is seldom that fewer strands are used but, for special applications, more than six are employed. Where there are seven wires in a strand, they can be arranged in only one way, i. Where there are more than seven wires in a strand, they can sometimes be arranged in different ways and it is because of this that in this catalogue the arrangement of the wires in the strand is invariably shown in brackets following the total number of wires per strand, e.

During the process the strands and wires are given the helical shape they will assume in the finished rope. In a preformed rope broken wires do not protrude and greater care is required when inspecting for broken wires.

Preformed rope offers certain advantages over non-preformed rope, e. Unless otherwise requested all ropes are supplied preformed. High resistance to the corrosive effect of salt water is accomplished by the use of specially galvanised steel wires and by impregnating the fibre core with special lubricant.

Ropes used as running rigging require to be flexible, and 6 x 12 fibre cores or 6 x 19 in the small sizes is usually preferred.

For larger sizes, the more flexible 6 x 37 rope is recommended. We recommend 6 x 36 construction, but in large sizes where greater flexibility is desirable, 6 x 41 construction is recommended. Rotary drilling lines are used for controlling the position of the drill string.

Balmorals rotary drill lines are extensively used throughout the world and meet the highest standard requirements.

The construction is normally a 6 x 19 9. The high concentration of bending stresses combined with heavy abrasive wear on the outer surface of the rope can cause premature failure of the rope unless the correct rope is chosen. However with the change to deepwater locations we would recommend the use of a turboplast rope manufactured by Casar which is an 8 strand rope offering a longer lifetime and greater breaking loads a lifetime application can be calculated against the intended rope specification, the sheaving arrangement and working cycles.

These auxiliary ropes are used to lower tools into the well for either cleaning purposes or for coring. Balmorals experience in the design and specification of wire rope for mooring systems has enabled Balmoral to supply some of the largest anchor lines currently used in the offshore market.

Anchor lines are supplied in Right Hand Ordinary Lay in drawn galvanised finish with independent wire rope core in either 6 x 36, 6 x 41 OR 6 x 49 construction dependent upon the diameter. When cutting non-preformed rope, adequate servings should first be applied to both sides of the point where the cut is to be made, to prevent the rope from untwisting.

Even with Preformed rope, it is recommended that one serving be applied at each side of the cutting point to prevent distortion of the rope ends by the pressure applied during cutting. Soft annealed single wire or marlin should be used.

Where wire is used the table below is given as a guide to size of wire, length and number of servings recommended, for Stranded Ropes. Less than 22mm 1. At least two servings each of a length six times the diameter of the rope should be employed. The bulldog grip should be fitted to wire rope as shown in Fig 1, and not as shown in Fig 2.

The bridge of the grip should invariably be fitted on the working part of the rope, and the U-bolt on the rope tail or dead end of the rope. Grips should not alternate in position on the rope.

As a safety measure and to secure best results it is important to re- tighten all grips after a short period in operation, for, due to the compression of the rope under load, there will be a tendency for the grips to loosen. Refer to the manufacturers instructions for quantity of grips recommended. The actual diameter is measured with a suitable caliper fitted with jaws broad enough to cover not less than two adjacent strands. The measurements are taken at two points at least 1 metre apart and at each point the two diameters at right angles are measured.

The average of these four measurements is the actual diameter of the rope. The diameter of a drum or pulley should not be less than times the diameter of the outside wire of the rope.

The bottom of the grooves should be arcs of circles equal in length to one-third of the circumference of the rope. The depth of groove in a pully should be at least equal to one and a half times the rope diameter and the groove in a drum should not be less than one- third of the rope diameter.

The angle of flare between the sides of the sheaves should be approximately 52 but should be greater if the fleet angle exceeds 1. The clearance between neighbouring turns of rope on a drum should not be less than Too great a radial pressure between sheave and rope will cause excess wear of the sheave grooves and will result in reduced rope life. When a rope leads from a drum to a fixed position Centre Line of Sheave Shaft sheave, abrasion is present that reduces rope life as a result of chafing on the drum, sides of sheave groove, or neighbouring turns of rope.

Fleet Angle. The Fleet Angle is the included angle between the Centre rope in its position of greatest travel across the Line of Centre Line Sheave of Rope drum, and a line drawn through the sheave at right angles to the drum axis. For good rope service the Fleet Angle for a plain faced drum should not exceed 1. The stretch of a wire rope under load consists of Permanent Constructional Stretch and Elastic Stretch.

Permanent Constructional Stretch is due to the settling of the wires in the strand and the compression of the central core. This stretch is irrecoverable and most of it occurs during the early part of the ropes life. The following figures of percentage constructional stretch will give results within acceptable practical limits. Light Heavy Loads Loads. Elastic Stretch is the capacity of the individual wires to elongate, under load, due to their elastic properties.

Providing the rope is not loaded beyond its elastic limit, it will return to its original length after removal of the load. The approximate diameter of the outer wires of a six stranded round strand rope may be found from the formulae A uniform factor of safety cannot be given for all engineering applications.

Where a rope is used on equipment, the factor of safety of which is not specified, the minimum factor of safety shall not be less than 5 to 1. The load to which a rope is subjected in service includes forces due to acceleration, bending and shock in addition to static force.

The average of these four measurements is the actual diameter of the rope. The bottom of the grooves should be arcs of circles equal in length to one-third of the circumference of the rope. The depth of a groove in a pully should be at least equal to one and a half times the rope diameter and the groove in a drum should not be less than one-third of the rope diameter. Permanent constructional stretch is due to the settling of the wires in the strand and the compression of the central core.

The following figures of percentage constructional stretch will give results within acceptable practical limits. Providing the rope is not loaded beyond its elastic limit, it will return to its original length after removal of the load. Where a rope is used on equipment, the factor of safety of which is not specified, the minimum factor of safety shall not be less than 5 to 1. The load due to shock is dependant upon the magnitude of the static load and the speed of load application.

While it will give results that are very nearly correct for wire rope evenly spooled, when the rope is not spooled evenly the drum capacity is slightly reduced. Remember to take account of large end terminations which could hamper spooling. The dimension A should be taken to the outside of the rope only, and not to the outside of the flange. When a rope is wound on to a drum any tendency of the rope to twist when tension is released will be in a direction which would untwist the rope at the free end.

The advantage of spooling in the correct directions is that when any load is slackened off the laps on the drum will hug together and maintain an even layer. With incorrect spooling the laps will move apart on removal of load and when the load is reapplied the rope may criss-cross and overlap, and flattening and crushing of the rope will result.

The correct spooling direction for right and left hand lay ropes is shown in the sketch below. Pull the rope straight ahead keeping it taut to prevent it from loosening up on the reel.

Heavy coils should be placed on a turntable and two crosspieces placed on top of the coil to prevent laps springing out of place and kinking. Light Flexible Ropes may be rolled along the ground so that the rope lies straight. Operator skills, however, are more difficult to monitor. Some of the hints to help in finding possible cause for these failings are given below. Possible causes of rope damage Failure Symptoms Possible causes Fatigue Traversal wire breaks on strands a bends on small dimensioned reels b Vibration and shock loads c Unsuitable rope compositions d Corrosion e Unsuitable joints at terminals Breaking under excessive load Conical and plastic type of breaks at rope wires a Excessive load b Wrong rope diameter and construction c Unsuitable joints at terminals Wear Wear on external wires a Changes in rope or reel diameters b Changes on load c Big fleet angle d Unsuitable reels e Abrasives in the rope f Unsuitable groove dimensions Corrosion Pittings on wire surfaces and breaks on wires caused by corrosion a Insufficient lubrication b Unsuitable storing conditions c Corrosive atmospheric effects If the groove is too narrow, the rope gets wedged in it, the strands and wires cannot move as is required for bending, and this condition is detrimental to the life cycle of the rope.

On the other hand, too wide a groove also has an adverse effect on rope life due to the high surface pressure between rope and sheave. For traction sheaves the radius of the groove is usually adapted as closely as possible to the radius of the rope to obtain maximum traction. The rope is supported in the best possible manner if the arc of contact with the groove contour can be deg. This corresponds to a throat angle of 30 degrees. However, with a large fleet angle or with oscillating loads, the throat angle should be larger up to 60 degrees to avoid undue wear of the rope and sheave flanges.

The height of the flanges should be at least 1. The rope and groove are inevitably subject to wear during operation. Since the diameter of a rope becomes smaller due to abrasion and stretch, it will wear out the groove to the smaller diameter of the worn rope. If a new rope is laid in such a worn groove, it will get wedged in the narrow groove and this will have a very adverse effect on its life. It is also possible that the rope cuts its profile into the groove.

Therefore the grooves should be inspected before installing a new rope and if necessary they must be re- machined, preferably with a profile cutting tool. If a groove shows excessive wear, this may be an indication that the sheave material is too soft. In this case a sheave of a harder grade steel must be used which better resists the abrasive effect of the rope, or a larger diameter sheave should be taken.

When this angle is too large, the rope in this extreme position will be pressed with great force against the flange of the sheave which causes undue friction and wear of both the rope and the sheave.

With a plain faced drum a large fleet angle will, in addition, cause the rope to travel too fast from the side to the centre of the drum thereby leaving gaps between the wraps. When winding a second layer, the rope is forced into these gaps which results in serious deterioration.

When, on the other hand, the rope is wound past the centre of the drum, a too large fleet angle will cause the next wrap to scrub against the preceding wrap as the rope runs more towards the side of the drum. If the fleet angle is too small, the rope does not travel fast enough towards the centre of the drum and, apart from scrubbing, at a certain moment the wraps will pile up ie the next wrap is laid on top of the preceding one and is then pressed to the side of the preceding wrap with great force.

This has a detrimental effect on the rope and the equipment on which it is used shock loads. The starting position should be at the correct drum flange so that each wrap of the rope will wind tightly against the preceding wrap. See illustration on p 4. Here too, close supervision should be maintained throughout installation. This will help ensure: 1 the rope is properly attached to the drum 2 appropriate tension on the rope is maintained as it is wound on the drum 3 each wrap is guided as close to the preceding wrap as possible, so that there are no gaps between turns 4 there are at least two dead wraps on the drum when the rope is fully unwound during normal operating cycles Loose and uneven winding on a plain smooth faced drum, can and usually does create excessive wear, crushing and distortion of the rope.

Also, for an operation that is sensitive in terms of moving and spotting a load, the operator will encounter control difficulties as the rope will pile up, pull into the pile and fall from the pile to the drum surface. The ensuing shock can break or otherwise damage the rope. The proper direction of winding the first layer on a smooth drum can be determined by standing behind the drum and looking along the path the rope travels, and then following one of the procedures illustrated on page 4.

The diagrams show: the correct relationship that should be maintained between the direction of lay of the rope right or left , the direction of rotation of the drum overwind or underwind , winding from left to right or right to left. DRUMS Wires should be installed using spooling machines that can apply back tension to the winch.