A few pointers on recovery equipment Ropes, shackles etc.

I decided to collect & compile this information…most of it from various sites…because of the overwhelming number of incredibly dangerous things I see people doing during vehicle recovery – in my own group as well as in magazines, and in pictures on the ‘net.
This is another one of those areas where there is an incredible amount of misinformation out there and everybody seems to think that they know everything.

Common things that can be seen people doing wrong all the time include:

1) Improper selection of rope, shackles, winches etc. without understanding load ratings and safety margins

2) Improper use of gear – side loading shackles, improper use of wire-rope clips, hooking straps and cables to themselves without understanding the significant loss of load rating incurred, etc.

3) Unsafe practices – not keeping the area clear, handling wire rope with bare hands, etc.

This article will attempt to clear up all of these and more. It focuses on the proper selection and use of equipment for off-road vehicle recovery using an electric winch. It does not go into great detail about how to actually operate the winch or rig a winching operation – there are many other good sources for this information.

What it will focus on is all the other important info that isn’t contained anywhere else, or at least not in any place or format readily accessible to recreational offroaders. The information regarding rigging and equipment apply equally well if applying the force with a come-along, Hi-Lift jack or hand winch.

So…here goes…

HOISTING vs. WINCHING:
Hoisting refers to the vertical lifting of materials. This covers everything from Search and Rescue equipment/aircraft to enormous building cranes. There is an entire industry devoted to the safe and efficient practice of hoisting. Engineering is thorough and industry standard’s are strict. In marked contrast, there are few, if any, industry standard for recreational vehicle winching (winching being the movement of objects in a horizontal, or mostly horizontal, plane), either in terms of safety, engineering and design practices, or whatever. As such, manufacturers can (and do) make all sorts of claims about product fitness and ratings based on no established standards. You will understand this thoroughly after having read this entire article. This little-known fact is another one of the primary reasons I am writing this article – so that consumers, users, and even bystanders can be better educated about what they are dealing with, the risks involved, and what some of the physics involved is…because there is no safety in simply relying on what’s printed in a manufacturer’s glossy catalogue. Often they don’t tell the whole story, and even if they did – it wouldn’t be based on industry, government, or accepted scientific standards. A lot of the information I have drawn upon in writing this article comes from the hoisting industry, simply because that is where the accurate and factual data is to be found. A complete list of references appears at the end of the article. Where there are marked differences between hoisting and winching in the subject I am discussing, I have attempted to alert the reader. The hoisting and lifting industry has strict safety standards, and for obvious reasons, as the vertical lifting of equipment and personnel is an inherently dangerous and risky business. This is the reason why I have recommended the adoption of as much of the hoisting industries safety practices, strict though they are – because I consider 4×4 recovery no less dangerous or risky than hoisting – especially when one considers how many people often crowd around the operation no matter how much you try to keep them clear, and in particular the woefully undersized wire ropes (cables) used on all recreational 4×4 recovery winches (much more on this later).

LETHAL BUSINESS:
If you take nothing else away from this article, know this: EVERY time you mount an operation to recover a stuck 4×4, be it by winching, jacking, yank strap or whatever, you are playing with lethal force. The damage caused by equipment failure, or improper operation, can and WILL maim and kill people. NEVER underestimate it. There is a line in a movie that expresses it best. I forget to what it was the speaker was referring, but he may as well have been talking about any piece of recovery gear – particularly the winch and wire rope. He said “The minute you stop respecting this, it kills you.” KEEP THAT IN MIND AT ALL TIMES.

THE WEAKEST LINK:
This is a very simple, but crucial, and yet almost universally unknown or ignored concept. It’s the one most likely to get one hurt or killed, or wreck your rig. It is the one I shall harp on about most in my article. The concept is this:

Every single piece of tackle used in a recovery operation, from tow hook to shackle to winch hook to wire rope end termination to the wire rope itself to the winch and to the winch mounting and structure of the vehicles themselves absolutely MUST be capable of SAFELY handling the loads that will be imposed. Let me say it again…EVERY PIECE. It’s no good having a 12,000lb winch with a honking new 1/2″ thick wire rope, if that wire rope terminates in an underrated hook, or even less obvious, has an improperly done end termination (very common – particularly the improper use of wire rope clips – more on this later).

I see this all the time, and I believe some major manufacturers are not terribly good about informing the buyers and users of their products of this concept.

A MAJOR contributor to the abuse of this concept is the huge lack of knowledge that exists regarding how maintenance (or lack thereof) or improper rigging (ever seen someone loop a winch cable around something then just slip the hook over itself?) DRASTICALLY effects the Safe Working Load (SWL) of the equipment. Sure everyone’s read that you’re not “supposed” to hook the winch cable back onto itself – but many, many people do. Why? Because they don’t know what the real effect is, and often they have no real appreciation of the forces in play. Read on, dear friend, and I shall make it all perfectly clear (I hope!)

CALCULATING THE FORCE OF A RECOVERY OPERATION:
This is a critical step in both the conduct of a winch recovery (because you need to be absolutely sure that EVERY single piece of equipment used in the task is strong enough and will not fail and thereby endanger life and limb), and in the selection/purchase and decision to use a piece of recovery equipment. It is a calculation where, quite frankly, the manufacturer’s recommendations are woefully inadequate. Why? Simply because if they let you in on how large the forces really are, it would leave you realizing that they are unable to economically produce a winch of sufficient capacity in anything resembling a small, light, or economical enough package. They get away with it, because, as I said, there are virtually no regulations or standards governing the industry. I’m not saying all 4×4 winches are inadequate, dangerous, or useless. But I am saying that the forces involved are often much greater than the manufacturer’s would have you believe, and you will be far more capable and SAFER if you approach your 4×4 recovery KNOWING THIS, and knowing the real numbers. Realize, that for reasons of practicality and economics, your 4×4 recovery equipment is almost certainly undersized…..you can still do the job, using the correct techniques, but you will be much SAFER if you keep this in mind. Enough of the pre-amble.

Most, if not all, winch manufacturers will tell you to select a winch based on 1.5 times the gross vehicle weight. This often leads to less than satisfactory results for 2 reasons:

1) Most people are terrible at actually estimating the gross weight of their rig as it sits on the trail, full of gas, tools, equipment, food, camping gear, people, the dog…everything. Heck, in some cases the real figure can actually exceed the GVWR of the vehicle. Simple advice here – either err WAY on the heavy side, or get your rig weighed in trail trim.

2) More importantly, the “effective weight” of a “stuck” 4×4 is very often FAR more than 1.5 times the GVW. The following data on how to more accurately estimate the “effective weight”, is taken from the world of professional heavy recovery – the guys that recover Tractor-trailers that have flipped on their side for instance, as well as U.S., Canadian, and UK Military recovery manuals.

Once you have accurately estimated or measured the trucks loaded weight (LW) you can calculate the resistance to be overcome in any recovery situation (this is commonly known as the ROLLING resistance). There are 4 types of resistance that must be accounted for to accurately assess the resistance that must be overcome. These are surface resistance, damage resistance, mire (stuck) resistance and grade (slope) resistance. Calculate them all as follows:

Surface resistance

A pull of 1/10 LW will cause a free wheeling truck to move on a hard, level surface.

A pull of 1/3 LW will cause a free wheeling truck to move on a softer surface, such as grass or gravel,

Damage resistance:

A pull of 2/3 LW will be required to move if the wheels cannot rotate (as if the brakes were fully applied), the pull required to overcome the resistance (drag) the truck id 2/3 or 67% of the LW. Damage resistance includes surface resistance (i.e. you only use one or the other)

Stuck (mire) resistance:

A pull of 100% of LW will be required if the truck is stuck to a depth of the sidewall on the tires.

A pull of 200% of LW will be required if the truck is stuck to the hubs.

A pull of 300% of LW will be required if the truck is stuck to the frame..

Mire resistance includes damage resistance (i.e. you only use one or the other)

Grade (slope) resistance:

Upgrade (vehicle has to be recovered up a slope or grade)

15 degrees – add 25% of LW

30 degrees – add 50% of LW

45 degrees – add 75% of LW

Vehicle recovery on level ground – no correction

Downgrade (vehicle has to be recovered down a slope or grade)

15 degrees – subtract 25% of LW

30 degrees – subtract 50% of LW

45 degrees – subtract 75% of LW

Final figure:

Add surface or damage or mire resistance and grade resistance, and this is your final figure or rolling resistance. This is the amount of pull the winch must apply in order to recover the stuck vehicle.

Example:

My trail rig fully kitted out weighs in at 5000 lbs. I get stuck down a rock ravine that’s about 45 degrees steep, and there are big rocks up to the frame hanging it up. Rolling resistance is 5000lbs x 3 + (5000 x 0.75) = 18,750 lbs. As you can see, this is significantly more than the 5000lbs x 1.5 – 7500lbs the manufacturers would have you believe. You may be wondering how one could ever possibly recover the vehicle in this example, given that the largest commercially available 4×4 recovery winch is 15000 lbs and that most are in the 8-9000lb range. The answer is by using multi-line rigging, which we shall explore in a moment.

WIRE ROPE:
The least understood, most abused, most critical part of your winch – the wire rope (often called the winch cable, or just cable). As you read the information below – remember this. Wire rope is a machine – a complicated machine made of many moving parts. Learn all you can about it, how to safely handle, use, and maintain it, and of course, remember The minute you stop respecting this, it kills you.

ELASTIC PROPERTIES OF WIRE ROPE
Wire rope is an elastic member; it stretches or elongates under load. This elongation can be permanent or recoverable. The extent of elongation will depend on the wire rope used and the design factor chosen. While it may be acceptable for many wire rope uses to neglect its elastic properties, they are of critical importance for 4×4 vehicle recovery uses, as a stretched-under-load wire rope stores enormous potential energy that can be explosively released (converted to kinetic energy) when the rope or a fitting fails. The result of this can be severe injury or death caused by a scything cable or high velocity projectile that was once part of the recovery rigging. Pre-stretching or breaking-in wire rope will only remove some of the constructional stretch and will not totally eliminate elongation under load.

WINDING WIRE ROPE ON DRUMS
Installation of wire rope on a plain or grooved drum requires a great deal of care. Make certain the wire rope is properly attached to the drum. Keep adequate tension on the wire rope as it is wound onto the drum. Guide each wrap as close to the preceding wrap as possible, or follow the groove in case of a grooved drum.

RATED CAPACITY
Rated capacity is the load which a new wire rope may handle under given operating conditions and at assumed design factor. A design factor of 5 is chosen most frequently for hoisting with wire rope. (Operating loads not to exceed 20% of Nominal Breaking Strength.) Operating loads may have to be reduced when life, limb or valuable property are at risk or other than new rope is used. A design factor of 10 is usually chosen when wire rope is used to carry personnel. (Operating loads not to exceed 10% of catalog Breaking Strength.)

WIRE ROPE STRENGTH
In order to know the strength of your wire rope, you need to know it’s class and material. For example, is it 6×19 Improved Plow Steel, or is it 7×19 Galvanized (aircraft) cable? Most winches sold for the 4×4 market come with 5/16″ or 3/8″ diameter 7×19 galvanized wire rope. Below is a table listing the specifications for 7×19 Galvanized – the most common type supplied with and replaced on 4×4 winches. Also shown is 7×19 Type 304 Stainless Steel.

It’s easy to see the potential for problems when taking into account the factors described above. If your Warn HS9500 winch came with 5/16″ wire rope, it has a nominal breaking strength of approximately 9,800 lbs. Remember, that’s at 100% efficiency under laboratory conditions ONLY. Add some fittings, wind it on a drum, and use it a couple of times and the breaking strength can be way below the force the winch can generate…which can be very dangerous if not understood and respected. Also, remember that’s BREAKING STRENGTH, not Safe Working Load with a design factor. Just for illustrative purposes, if one were to apply hoisting industry guidelines and use a design factor of 5, that brand new 5/16″ rope would have a safe working load of 9,800 / 5 = 1960lbs under ideal conditions. If the cable was well used, not particularly well maintained, and had a less than optimal end termination (sound like any you’ve seen?) that could drop it’s efficiency to 70% or less, so keeping the same design factor (although admittedly the purpose of the design factor is to account for such losses in efficiency) would mean a SWL of 1960 x 70% = 1372 lbs !!!!!!

Add the fact that you totally stuck rig could easily have a rolling resistance of up to 10-15,000 lbs, is it any wonder these things fail and people get hurt!

Bottom line – understand your gear and it’s limitations, maintain it well, replace when worn, and treat it as lethal, and you’re much more likely to have an effective and SAFE winching experience.

USING WIRE ROPE
Attachments must have at least the same Working Load Limit as the wire rope used
Clips, sockets, thimbles, sleeves, hooks, links, shackles, sheaves, blocks, etc. must match in size, material and strength to provide adequate safety protection. Proper installation is crucial for maximum efficiency and safety

Avoid shock loads
Avoid impacting, jerking or swinging of load. Working Load limit will not apply in these circumstances because a shock load is generally significantly greater than the static load

Wire Rope Lubrication
The lubrication ropes receive during manufacture is adequate only for initial storage and the early stages of the rope�s service life. A winch’s wire rope should be maintained in a well-lubricated condition. It is important that lubricant be applied as part of the maintenance program. The lubricant must be compatible with the original lubricant, so the rope manufacturer should be consulted. The lubricant applied should be of the type that does not hinder visual inspection. The surface of some ropes may become covered with dirt, rock dust or other material during their operation. This can prevent field-applied lubricants from properly penetrating into the rope, so it’s a good practice to clean these ropes before you lubricate them.
The lubricant you apply should be light-bodied enough to penetrate to the rope’s core. You can normally apply lubricant by using one of three methods: drip it on rope, spray it on or brush it on. In all cases, you should apply it at a place where the rope is bending, such as around a sheave. We recommend you apply it at the top of the bend because that’s where the rope’s strands are spread by bending and are more easily penetrated.
In addition, pressure lubricators are available commercially. Your rope’s service life will be directly proportional to the effectiveness of the method you use and the amount of lubricant that reaches the rope’s working parts. A proper lubricant must reduce friction, protect against corrosion and adhere to every wire. It should also be pliable, and not crack or separate when cold, yet not drip when warm. Never apply heavy grease to the rope because it can trap excessive grit, which can damage the rope. Nor should you apply used “engine oil” because it contains materials that can damage the rope.

Before Initial Load Cycle
After wire rope replacement, and before the initial load cycle, verify the following conditions.

1. The rope attachment points to the hoist drum and dead end (if applicable) are properly installed.

2. Fasteners are properly torqued.

3. Reeving is in accordance with the manufacturer’s recommendations.

Initial Cycle
After rope replacement and before returning the equipment to service, it is recommended that the winch be cycled from maximum rope out to fully spooled in eight to ten times with 10 percent to 20 percent of rated load. A new rope will stretch and unlay slightly, after initial cycling as described, the wire rope should be carefully re-spooled so as to allow flat, even wraps on the drum. A rope should not be stored on the drum in a twisted or kinked fashion. After the initial load cycle has been completed, you should verify that the fasteners on drum and/or dead end have been retorqued.

Inspect wire rope regularly
Check the general condition of the wire rope. Also, look for localized damage and wear, especially at wire rope attachments. Inspect all parts that come in contact with the wire rope. Poor performance of wire rope can often be traced back to worn or wrong-sized sheaves, drums, rollers, etc. Look for kinks, broken wires, abrasions, lack of lubrication, rust damage, crushing, reduction of diameter, stretch or other obvious damage. If any of these conditions exists or if there is any other apparent damage to the wire rope, retire the wire rope according to the instructions below.

When in doubt about the extent of the damage, retire the wire rope in question immediately. Without laboratory analysis, it is impossible to determine the strength of damaged or used wire. Thus, you will not be able to tell whether wire rope with any amount of damage is safe to use.

Daily Inspection

Every day you intend or may use the winch, a visual observation of the wire rope should be made. These visual observations should be concerned with discovering gross damage that may be an immediate hazard, such as the following:

1. Rope distortion such as kinking, crushing, unstranding, birdcaging, main strand displacement, or core protrusion

2. Corrosion

3. Broken or cut strands.

Monthly Inspection

At the start of the wheeling season, and monthly during the season you should inspect the wire rope for:

1. Reduction of rope diameter below nominal diameter as a result of loss of core support, internal or external corrosion, or wear of outside wires

2. A number of broken outside wires and the degree of distribution or concentration of such broken wires

3. Worn outside wires

4. Corroded or broken wires at end connections

5. Corroded, cracked, bent, worn, or improperly applied end connections

6. Severe kinking, crushing, cutting, or unstranding.

Wire Rope Replacement Criteria

The following criteria determine when a wire rope is no longer acceptable for service:

1. 12 randomly distributed broken wires in one lay or four broken wires in one strand in one lay (A rope lay is that length of rope in which one strand makes one complete revolution about the core)

2. One outer wire broken at the contact point with the core of the rope, which has worked its way out of the rope structure and protrudes or loops out from the rope structure

3. Wear of one-third the original diameter of outside individual wires

4. Kinking, crushing, birdcaging, or any other damage resulting in distortion of the rope structure

5. Evidence of heat damage from any cause

6. Reduction from nominal diameter greater than those listed in the following:

Rope Diameter (inch)
Maximum allowable reduction from Nominal Diameter (inch)

Less than or equal to 5/16 1/64
More than 5/16 to 1/2 1/32
Destroy, rather than discard, wire rope to be retired

Wire rope that is not destroyed might be used again by someone not aware of the hazard associated with that use. Destroying wire rope is best done by cutting it up into short pieces.

How to select a rope for winching
All wire ropes feature design characteristic trade-offs. In most cases, a wire rope cannot increase both fatigue resistance and abrasion resistance. For example, when you increase fatigue resistance by selecting a rope with more outer wires, the rope will have less abrasion resistance because of its greater number of smaller outer wires.

When you need wire rope with greater abrasion resistance, one choice is a rope with fewer (and larger) outer wires to reduce the effects of surface wear. But that means the rope’s fatigue resistance will decrease. That’s why it’s important to choose a wire rope the same way any other machine is chosen-very carefully. You must consider all operating conditions and rope characteristics.

So how do you choose the wire rope that’s best suited for your job? Consider these seven important characteristics:

1. Strength – Wire rope strength is usually measured in lbs or tons. In published material, the strength is shown as minimum breaking force-calculated strength figures that have been accepted by the wire rope industry.

When placed under tension on a test device, a new rope should break at a figure equal to (or higher than) the minimum breaking force shown for that rope. The minimum breaking force applies to new, unused rope. A rope should never operate at or near the minimum breaking force. The minimum breaking force must be divided by the appropriate design factor to obtain the maximum allowable working load. During its useful life, a rope gradually loses strength due to natural causes such as surface wear and metal fatigue.

2. Fatigue resistance – Fatigue resistance is the rope’s resistance to broken wires from metal fatigue. To have high fatigue resistance, ropes must be capable of bending repeatedly under stress (for example, passing over a sheave).

Increased fatigue resistance is achieved in a rope design by using a large number of wires. In general, a rope made of many wires will have greater fatigue resistance than a same-size rope made of fewer, larger wires because smaller wires have greater ability to bend as the rope passes over sheaves or around drums. To overcome the effects of fatigue, ropes must never bend over sheaves or drums with a diameter so small as to bend wires excessively. There are precise recommendations for sheave and drum sizes to properly accommodate all sizes and types of ropes.

Every rope is subject to metal fatigue from bending stress while in operation; therefore, the rope’s strength gradually diminishes as the rope is used.

3. Crushing resistance – Crushing is the effect of external pressure on a rope, which damages it by distorting its cross-sectional shape, its strands, or its core. It normally is the result of multiple layer spooling on a drum.

Crushing resistance, defined as a rope’s ability to withstand or resist external forces, is a term generally used to express comparison between rope. When a rope is damaged by crushing, wires, strands, and core are prevented from sliding and adjusting normally during operation.

In general, ropes with an independent wire rope core (IWRC) are more crush resistant than fiber core ropes. Regular lay ropes are more crush resistant than lang lay ropes. Six-strand ropes have greater crush resistance than 7-strand, 8-strand, or 19-strand ropes. Compacted strand ropes are more crush resistant than standard round-strand ropes.

4. Resistance to metal loss and deformation – Metal loss refers to the actual wearing away of metal from the outer wires of a rope, and metal deformation is the changing of the shape of outer wires of a rope. In general, resistance to metal loss by abrasion, or abrasion resistance, refers to a rope’s ability to withstand metal being worn away along its exterior. This reduces the strength of a rope.

The most common form of metal deformation is generally called peening because outside wires of a peened rope appear to have been hammered along their exposed surface. Peening usually occurs on drums and is caused by rope-to-rope contact during spooling. It may also occur on sheaves.

Peening causes metal fatigue, which in turn may cause wire failure. The hammering-which causes the metal of the wire to flow into a new shape-realigns the grain structure of the metal, thereby affecting its fatigue resistance. The out-of-round shape also impairs wire movement when the rope bends.

5. Stability – The word “stability” is most often used to describe handling and working characteristics of a rope. It is not a precise term because the idea expressed is to some degree a matter of opinion and is more nearly a personality trait than any other rope feature. For example, a rope is referred to as stable when it spools smoothly on and off a drum-or it doesn’t tend to tangle when a multi-part reeving system is relaxed.

Strand and rope construction contributes mostly to stability. Preformed rope is usually more stable than non- preformed, and regular lay rope tends to be more stable than lang lay. A rope made of seven-wire strands will usually be more stable than a more complicated construction with many wires per strand. There is no specific measurement of rope stability.

6. Bendability – Bendability relates to a rope’s ability to bend easily in an arc. The primary factors that affect this capability are the diameters of wires that make up the rope; rope and strand construction; metal composition and finish; and type of rope core. Some rope constructions are by nature more bendable than others. Small ropes are more bendable than big ones. Fiber core ropes bend more easily than comparable IWRC ropes. As a general rule, rope containing many wires is more bendable than same-size rope made with fewer, larger wires.

7. Reserve strength – Reserve strength is the percentage of a rope’s minimum breaking force represented by the inner wires of the outer strands. This recognizes that outer wires should be the first to be damaged or exhibit wear.

Usually, the more wires in each strand of rope, the greater its reserve strength. This is true because of the geometry of a circle: Increasing the number of outer wires in a strand also increases the cross-sectional area occupied by inner wires.

Rotation-resistant rope, due to its construction, can experience different modes of wear and deterioration than standard rope. Therefore, reserve strength is based on the percentage of the metallic area represented by the core strand plus the inner wires of the strands of both the outer and inner layers. Reserve strength is especially important where the consequences of rope failure are great.

More on use and care of Wire Rope
1. Wire rope WILL FAIL IF WORN OUT, OVERLOADED, MISUSED, DAMAGED, or IMPROPERLY MAINTAINED.

2. In service, wire rope loses strength and work capability. Abuse and misuse increase the rate of loss.

3. The MINIMUM BREAKING STRENGTH of wire rope applies ONLY to a NEW, UNUSED rope.

4. The Minimum Breaking Strength should be considered the straight line pull with both rope ends fixed to prevent rotation, which will ACTUALLY BREAK a new, UNUSED, rope. The Minimum Breaking Strength of a rope should NEVER BE USED AS ITS WORKING LOAD.

5. To determine the working load of a wire rope, the MINIMUM or NOMINAL Breaking Strength MUST BE REDUCED by a DESIGN FACTOR (formerly called a Safety Factor). The Design Factor will vary depending upon the type of machine and installation, and the work performed. YOU must determine the applicable Design Factor for your use.

For example, a Design Factor of “5” means that the Minimum- or Nominal Breaking Strength of the wire rope must be DIVIDED BY FIVE to determine the maximum load that can be applied to the rope system.

Design Factors have been established by OSHA, by ANSI, by ASME and similar government and industrial organizations.

No wire rope should ever be installed or used without full knowledge and consideration of the Design Factor for the application.

(NOTE that with the wire ropes supplied on almost, if not, every recreational 4×4 winch the design factor is non-existent or negligible. This is the industry’s “dirty little secret” and if not understood and accounted for – could get you hurt. This fact, in my mind, is the single biggest and best argument for using synthetic winch rope, and what makes it worth every penny of it’s admittedly high price.)

6. WIRE ROPE WEARS OUT. The strength of a wire rope slightly increases after the break-in period, but will decrease over time. When approaching the finite fatigue life span, the breaking strength will sharply decrease. Never evaluate the remaining fatigue life of a wire rope by testing a portion of a rope to destruction only. An in depth rope inspection must be part of such evaluations.

7. NEVER overload a wire rope. This means NEVER use the rope where the load applied is greater than the working load determined by dividing the Minimum Breaking Strength of the rope by the appropriate Design Factor.

8. NEVER ‘SHOCK LOAD’ a wire rope. A sudden application of force or load can cause both visible external damage (e.g. birdcaging) and internal damage. There is no practical way to estimate the force applied by shock loading a rope. The sudden release of a load can also damage a wire rope.

9. Lubricant is applied to the wires and strands of a wire rope when manufactured. This lubricant is depleted when the rope is in service and should be replaced periodically.

10. Regular, periodic INSPECTIONS of the wire rope, and keeping of PERMANENT RECORDS SIGNED BY A QUALIFIED PERSON, are required by OSHA and other regulatory bodies for almost every rope installation. The purpose of inspection is to determine whether or not a wire rope may continue to be safely used on that application. Inspection criteria, including number and location of broken wires, wear and elongation, have been established by OSHA, ANSI, ASME and other organizations.

IF IN DOUBT, REPLACE THE ROPE.

Some inspection criteria on rope, sheaves and drums are outlined further in this Technical Information section.

11. When a wire rope has been removed from service because it is no longer suitable, IT MUST NOT BE RE-USED ON ANOTHER APPLICATION.

12. Every wire rope user should be aware of the fact that each type of fitting attached to a wire rope has a specific efficiency rating which can reduce the working load of a rope assembly or rope system, and this must be given due consideration in determining the capacity of a wire rope system.

13. Some conditions that can lead to problems in a wire rope system include:

� Sheaves that are too small, worn or corrugated can cause damage to a wire rope.
� Broken wires mean a loss of strength.
� Kinks permanently damage a wire rope.
� Environmental factors such as corrosive conditions and heat can damage a wire rope.
� Lack of lubrication can significantly shorten the useful service life of a wire rope.
� Contact with electrical wire and the resulting arcing will damage a wire rope.

How much rope will fit on a winch?
END TERMINATIONS:
It is critical that the proper end-termination be used on your winch rope. Not only that, but it is critical to understand the effect the type of end termination you use has on the efficiency (strength) of your wire rope. Note that the values differ for wire rope core and fibre core ropes. Note the relatively low value of 80% on the very commonly seen wire rope clips. Imagine the 5/16 7/19 galvanized wire rope on your 9500lb winch. Brand new, under ideal conditions, it’s nominal breaking strength is 9800lbs (NO design factor). Put your hook on with wire rope clips, and even if you do it perfectly, that figure drops to 9800×80%=7840lbs….SCARY!!!

Type of termination

Efficiency

IWRC Rope

FC Rope

Wire Rope Socket (Spelter or Resin) 100% 100%
Swaged socket (Regular Lay Ropes only) 100% Not Recommended
Mechanical Spliced Sleeve (Flemish eye) 1″ dia. and smaller 95% 92.5%
Loop or Thimble Splice – Hand Spliced (tucked) Carbon steel rope up to 1/2″ 86% 86%
Loop or Thimble Splice – Hand Spliced (tucked) Stainless steel rope up to 1/2″ 76% /
Wedge Sockets * 75-80% 75-80%
Clips * 80% 80%

Using Wire Rope Clips

If you must use wire rope clips as the end termination of your winch rope, understand the effect on strength (reduces 20%), and it is CRITICAL you use them properly as shown below:

Requirements and guidelines for wire rope clamps are as follows:
1. Clamps (also called clips) shall meet or exceed the requirements of Federal Specification FF-C-450, �Clamps, Wire Rope.�
2. Clamps shall be legibly and permanently marked with size and the manufacturer�s identifying mark.

Inspection criteria for wire rope clamps follow:
1. Before use, clamps shall be visually inspected for damage, corrosion, wear, and cracks.
2. Verify that the clamp components are marked properly.
3. Ensure that the assembled clamp contains the same size, type, and class parts.

FITTINGS:
Now you know all about wire rope strength, working load limits, design factors, and the magnitude of the forces involved, it’s important to examine some of the other “fittings” or pieces of tackle commonly employed in 4×4 recovery winching. It is worth repeating, any piece of gear you use ABSOLUTELY must have a WLL that is up to the task. The entire operation is only as strong as it’s weakest link – don’t be one of those people improperly side-loading a shackle or using a puny, under-rated hook on your winch.

Hooks
Some rigging hooks (e.g., grab hooks and sorting hooks) are designed to carry the load near the point as well as in the bowl or saddle of the hook. Maximum safe working loads normally apply only when the load is in the bowl or saddle. Rigging hooks shall be used within the limits specified by the manufacturer. Forged alloy steel hooks generally make the best rigging hooks. The manufacturer’s identification shall be forged or die-stamped on the hook. Safe working loads or Working load limits for rigging hooks shall be equal to or exceed the rating of the chain, wire rope, or other suspension member to which it is attached. Where this is not feasible, special precautions shall be taken to ensure that the rated load limit of the hook is not exceeded. Welding on hooks, except by the hook manufacturer, is not allowed. Never repair, alter, rework, or reshape a hook by welding, heating, burning, or bending. Requirements and guidelines for rigging hooks are as follows:

The SWL for a hook used in the manner for which it is intended shall be equal to or exceed the rated load of the chain, wire rope, or other suspension member to which it is attached. The designated SWL applies only when the load is applied in the bowl or saddle of the hook.
The manufacturer’s identification shall be forged or die-stamped on a low-stress and non-wearing area of the hook.

There are many types of hooks available – some good, some not-so-good. Most use some type of Sling Hook on the winch wire rope – either an eye sling hook or clevis sling hook is acceptable, providing they are appropriately rated. Regardless of the hook used, it should have a throat latch that ridges the throat opening of the hook for the purpose of retaining slings, chains, or similar parts under slack conditions. Note that the latch is not intended to support the load. Most winches are supplied from the manufacturer with a clevis sling hook that I believe is not a particularly good hook, and should be thought of as the absolute minimum acceptable. Manufacturers cut corners (and costs) here in my opinion. Much better options are available, and should be used. In order of preference:

Positive locking hooks or the Printle hook, commonly found on the Labdcruiser’s or Patrol’s rear bumper here in the Middle East. These are the best hooks in my opinion, as it is virtually impossible for the fitting or sling to which the hook is attached to slip out either when it is loose or under tension. Opening and closing the hook requires thumb-activation of a small locking tab.
Inspection:
Regardless of the type of hook, as with all other recovery gear, an inspection program is required for the life of the equipment and safety of you and those around you during recovery.
Hook visual inspection should be conducted daily (before use) to identify the following:
a. Cracks, nicks, gouges
b. Deformation. Damage from chemicals.
d. Damage or malfunction of the throat latch, if provided.

Weekly to Monthly inspection should consist of checking for:

a. Distortion, such as bending, twisting, or increased throat opening

b. Wear

c. Cracks, nicks, or gouges

d. Latch engagement, damaged or malfunctioning latch (if provided)

e. Hook attachment and securing means.

Quarterly inspection should consist of checking for:

a. Deformation. Any bending or twisting exceeding 10 degrees from the plane of the unbent hook.
b. Throat Opening. Any distortion causing an increase in throat opening exceeding 15 percent.
c. Wear. Any wear exceeding 10 percent of the original section dimension of the hook or its load pin.

If any of these conditions are found, the hook should be retired and replaced.

Shackles
One of the most useful, but also most often misused/abused pieces of recovery gear is the common clevis or shackle.

Common errors include:

– use of unmarked/unrated shackles – often from cheap off-shore sources

– use of undersize or improperly rated shackles

– improper rigging

The following should set things straight and allow you to safely and properly make use of the venerable shackle.

Shackle specifications:
For shackles 3/16 to 2 3/4 inches, the specifications are derived from Federal Specification RR-C-271, �Chains and Attachments, Welded and Weldless.�

Shackles are manufactured in two configurations for use in rigging: anchor shackle and chain shackle. Both are available with screw pins, round pins, or safety bolts.

Shackles are sized by the diameter of steel in the bow section rather than the pin size.
Design Factors: Shackles manufactured in accordance with RR-C-271 and MIL-S-24214 have a minimum design factor of 5. Shackles manufactured to the requirements of ASTM A148M have a minimum design factor of 4.

Each shackle body shall be permanently and legibly marked by the manufacturer. Marking will be raised or stamped letters on the side of the shackle bow with an identifying manufacturer�s name or trademark, shackle size, and safe working load (SWL).

Inspection:
Before each use, shackles should be inspected to the following criteria.
a. Shackle pins shall fit freely without binding. (Seated screw pin shackles shall be disassembled by hand after the first-half turn.)
b. The pin shall show no sign of deformation.
c. The shackle shall have no defect that will interfere with serviceability.

Operating practices and guidelines:
1. The shackle pin shall never be replaced with a bolt; only a properly fitted pin shall be used. Bolts are not intended to take the load that is normally applied to the pin
2. Shackles shall not be used if the pin cannot be completely seated
3. Shackles shall never be pulled at an angle because the capacity will be tremendously reduced. Centralize whatever is being hoisted on the pin by suitable washers or spacers
4. Screw pin shackles shall not be used if the pin can roll under load and unscrew
Slings
What is a sling and why should you care? A sling is the term the hoisting industry uses for a device that attaches between the load hook on a crane or hoist, and the actual load. There is a great deal to know about the safe use of slings, as the way in which the are rigged can have a dramatic effect on their strength.
Depending on how it is rigged, it is usually a choker hitch or horizontal basket hitch. In both cases, the angle from the anchor to the rig winching is very important as it effects the rating / efficiency of the sling. Also, a length of chain with hooks on the end is also technically a “single leg sling”. The following pics show some typical types of slings. Again, in our use, the loads will be applied horizontally (or mostly horizontally) rather than vertically, but it is easy to see that different types of slings are often used in 4×4 recovery or using a 4×4 winch to move objects.

Blocks (sheave, pulley, snatch block)
The following data is critically important to us, as all of the following are examples of sheaves and pulley’s that we use:

The strength reduction (efficiency) of a recovery rigging setup using any kind of block or sheave is based on the D/d ratio, where D is the pin or sheave diameter, and d is the rope diameter. For example, a rope bent around a pin of equal diameter will have a D/d ratio of 1. The efficiency will be 50 percent. The rope will have only 50 percent of the nominal strength attributed to it. This factor applies to your roller fairlead too, as it is a sheave.

Sheave (pulley) diameters and rope bending diameters:
To assure maximum efficiency and safety, sheaves for wire ropes should be no less than eight times the rope diameter. The sheave groove diameter should be no less than ten percent greater than the rope diameter. The sheave groove should be round in shape. Sheaves with �V� shaped grooves should be avoided, as they tend to pinch and damage the rope through excessive friction and crushing of the rope fibers. Sheave surfaces should be kept smooth and free of burrs and gouges. Bearings should be maintained to ensure smooth rotation of sheaves.
Any sharp bend in a rope under load decreases its strength substantially and may cause premature damage or failure. Where a rope bends more than ten degrees in bending across any surface, the diameter of that surface should not be less than three times the diameter of the rope. Stated another way, the diameter of the surface should be at least three times the rope diameter. A four-to-one ratio (or larger) would be better yet because the durability of the rope increases substantially as the diameter of the surface over which it is worked increases. This factor applies to your roller fairlead too, as it is a sheave.

Roll-over stiff-leg

Here’s a very cool idea borrowed from the professional recovery business:

TOWING AND YANKING VEHICLES FOR RECOVERY.
A common, quick and easy method of extracting a stuck vehicle is to connect another mobile vehicle to it and yank, pull, or tow it free. Because of the enormous forces generated in this type of operation, extreme care should be exercised. NEVER EVER use chain, wire rope, or a winch to yank another vehicle free. The shock loads developed can multiply the force applied many times, so that a stuck truck requiring a 10,000 lb steady pull to free, can cause a shock-load of 50 000 lbs if jerked or yanked suddenly. This is extremely dangerous to man and machine. As such, only properly designed, constructed, and rated recovery straps should ever be used for yanking vehicles free. DO NOT ever use tow ropes, tow straps, emergency tow ropes etc. These are designed only for easy flat road towing of a non-running vehicle (and are dubious for that, in my opinion) – not for the rigors of off-road extraction and recovery.

Off-road recovery straps.

The proper recovery straps are designed to stretch when yanked, storing potential energy, which they then release as they “rebound” providing tremendous kinetic energy to free the stuck vehicle, in the safest manner possible. It is best and safest to use recovery straps that have no metal fittings, but rather just sewn loop ends (called eye and eye by industry). The following diagram shows suitable types:

Make absolutely certain that the anchor points on the vehicles in question are capable of handling the loads imposed. Do not ever use recovery straps in combination with wire rope or chains or other devices. Do not join 2 recovery straps together by knotting them.

Care and inspection of nylon recovery straps is extremely important for safe operations, and almost EVERYONE neglects and abuses them (me included!). They should be stored free from water, dirt, and other chemicals. Before use they should be inspected carefully.

Recovery straps are a specialized type of Synthetic Web Sling and as such, the following information, taken from the hoisting industry, regarding synthetic web slings, should be adhered to:

The webbing from which the strap is constructed should have the following characteristics:
1. Sufficient certified tensile strength to meet the sling manufacturer’s requirements
2. Uniform thickness and width
3. Full woven width, including selvage edges
4. Webbing ends sealed by heat, or other suitable means, to prevent unraveling
5. Stitching shall be the only method used to form eyes.

Synthetic web slings may be coated with suitable material that will impart the following desirable characteristics:
1. Abrasion resistance
2. Sealing to prevent penetration of foreign particles and matter
3. Increased coefficient of friction
4. Protection from sunlight or ultraviolet degradation.

Marking:
Synthetic web slings shall be labeled (a sewn-on leather tag is recommended). The label shall state the following:
1. Manufacturer’s name or trademark
2. Manufacturer’s code or stock number
3. Rated loads for the types of hitches used
4. Type of synthetic web material

Design Factor. The design factor for synthetic web slings shall be a minimum of 5.

High radiation or chemically active environments can destroy the strength of synthetic web slings. Sling materials can be susceptible to caustics and acids.

Inspection:
Synthetic web slings shall be removed from service if damage such as the following is visible:
1. Acid, phenolic, or caustic attack
2. Melting or charring on any part of the sling
3. Holes, tears, cuts, or snags
4. Broken or worn stitching in load-bearing splices
5. Excessive abrasive wear
6. Knots in any part of the sling
7. Other visible indications that cause doubt as to the strength of the sling, such as loss of color that may indicate the potential for ultraviolet light damage

Operating Practices:
The following operating practices are applicable to the use of synthetic web slings:
1. Slings having suitable characteristics for the type of load, hitch, and environment shall be selected.
2. The weight of load shall be within the rated capacity of the sling. (The rated capacity is less than or equal to the rated load after sling angles and hitch type are considered.)
3. Slings shall not be shortened or lengthened by knotting or other methods not approved by the sling manufacturer.
4. Slings that appear to be damaged shall not be used unless they are inspected and accepted as usable in accordance with the inspection requirements stated above
6. Sharp corners in contact with the sling should be padded to minimize damage to the sling.
7. Portions of the human body should be kept from between the sling and the load, and from between the sling and the crane hook or hoist hook.
8. Slings should not be pulled from under a load when the load is resting on the sling.
9. Slings should be stored in a cool, dry, and dark place to prevent environmental damage.
10. Twisting and kinking the strap shall be avoided.
11. In a basket hitch, the load should be balanced to prevent slippage.
12. Slings should not be dragged on the floor or over an abrasive surface.
13. Nylon and polyester web slings lose strength from extensive exposure to sunlight or ultraviolet light. Possible strength loss may be indicated by loss of color in the pick threads or outer jacket. If the user suspects sunlight or ultraviolet light damage the sling shall be taken out of service pending inspection by a qualified person.
14. Hard or brittle spots in the fabric of synthetic slings may indicate a substantial reduction in strength as a result of damage from chemicals or excessive heat.

This is an almost endless subject but I guess the basic points have been covered here…so enjoy and Play safe!!