I started in the sling and rigging industry 34 years ago, and early in my career I was asked to present a seminar at a large copper mine in Southern Arizona. Naturally enough, I took the approach that the responsible rigger should always select the sling type that is most suitable for the job in terms of the type of load, hitch and environment.

During the seminar I presented three sling types – chain, wire, and web – all 1.82m in length, with approximately the same vertical workload limit of 2,700kg. The chain sling weighed 32kg, the wire rope sling at 15kg, and the web sling at 1kg.

I posed the question that, assuming all three slings were for suitable for the intended use, which would be the sling of choice and polled the participants? Most of the votes went for the wire rope and chain slings, and only a small percentage of the students selected the synthetic option. I have distinct memories of one of the more passionate voters who expressed his sentiment by stating that he would not use “that rag piece of garbage”, referring to the web sling, to lift anything in the mine.

Much has changed in the intervening three decades. If it were possible to reassemble the same group and tabulate their response to the sling choice, I have no doubt that the synthetic sling would win the vote.

There are a couple of primary reasons for the wide popularity in the use of synthetic slings.

First, they are user friendly and were ergonomically sound and proven long before ergonomics were in vogue. Of the thousands of sling users and inspectors that I’ve trained, not one could claim that they had suffered hand injuries or back problems as a result of synthetics. Clearly, the strength to weight ratio is favorable for the synthetics.

Secondly, the synthetic sling is “load friendly” because synthetic slings are disposable commodities. The synthetic is designed to wear out, so that the object being handled is not damaged. In other words, it is scrubbed or worn away to protect the finish, texture, shape, and color of the object being manipulated.

The laws of physics and motion state that two objects cannot occupy the same space simultaneously. Automobile body repair shops are one example of a business that exists as a direct result of this law! Synthetic slings also rely on it because the synthetic commits “sling suicide” to prevent damage to the object.

Synthetics are lightweight, convenient and flexible. They handle the most delicate metallic surface without damage and are equally gentle on non-metallic loads. With synthetics we say that we have the strength of steel in a velvet glove.

Having said all this, synthetic slings are not the absolute answer in every situation, and they have limitations. For example, they are susceptible to:


Heat damage.

Ultraviolet light degradation.

Cutting: Wear protection devices have been developed to mitigate the effects of cutting, but it is important for sling users to realize that the load edge need not be “razor” sharp to inflict damage. A moderate edge, combined with movement, ie, the sling sliding across the edge due to non-positive sling to load engagement, can severely damage the sling.

Cut proof wear protection devices do not exist, cut resistant ones do. A couple of examples would be the magnetic corner protector or the Cornermax® device offered by Slingmax®.

Heat damage: Heat is another limitation and temperatures above 194 deg F (90 deg C) must be avoided. Here, chain slings are likely to be more appropriate. Having said that, a specialty synthetic sling using high performance fibres – the Twin-Path® Sparkeater® – is available for use in applications of 300 deg F (149 deg C). The combination of aramid lifting fibers and the Nomex outer sheath also provides protection against weld splatter. Synthetic webbing, wire rope and even chain slings are seriously damaged in applications where they are exposed to welding operations.

Ultraviolet light degradation: Synthetics loose strength as they are exposed to sources of ultraviolet light. Nylon and polyester web slings can loose approximately 30-60% of their strength when continuously exposed. Nylon web slings loose at a slower rate, initially, but continues to loose as the exposure time is extended. Polyester web slings loose strength at a greater rate, initially, but the loss seems to level off, after the first twelve months.

The details of a 36-month study completed by the Web Sling and Tiedown Association (WSTDA) in 2003 are available at the WSTDA web site, www.wstda.org

When slings are not in use, store them in a dry, dark, cool location that is free of environmental and mechanical damage to maximize service life.

Perhaps the greatest advantages that synthetics offer over the “heavy metal” alternatives are their ability to be fabricated for special design applications, and the ever-increasing strength to weight ratio advantage.

The synthetic webbing sling has, by virtue of the components and fabrication techniques, been adapted to specific designs that enable the efficient handling of specialised materials such as drums and compressed gas cylinders.

In addition, synthetic materials and specific constructions, such as polyester rope have enabled sling fabricators to manufacture synthetic rope slings that are adjustable. For years, students attending my seminars made the same observation: “If you could just come up with an adjustable sling”.

The adjustable rope sling was initially developed to handle pole and pad mount transformers. There is nothing to prevent riggers in any industry from enjoying the benefits of an adjustable sling, assuming that the application is proper. The positive effects on inventory reduction are also realised as sling users enjoy the “one sling fits many loads” scenario. The versatility of this sling design, available in single or multiple leg configurations has profound implications for the rigging and material handling industries.

Of all the items in our exhibition booth at a recent Specialized Crane and Rigging conference, visitors were most intrigued by the four-leg adjustable rope sling and its ability to be shortened or lengthened.

Perhaps the greatest single advance in the history of rigging, and certainly in the realm of synthetic slings, is the introduction of high performance fibres. Aramid and high-density polyethylene materials have revolutionised the rigging industry.

Imagine my thoughts 34 years ago if someone had told me that I would one day build slings that were 3m long, weighed 9kg, and broke at 225,000kg. I would have not only been sceptical, but also strongly questioned the sobriety of the person making the statement.

High performance fibre slings like the Twin-Path Extra allow sling users to get more done with less effort. Auxiliary equipment such as forklifts and lorries are no longer required to transport large capacity, “heavy metal” slings. Support cranes are no longer needed to place large wire rope slings on to the hook of the lifting crane as riggers easily handle equivalent strength high performance fibre slings.

Shipyards are efficiently handling ship modules that can weigh as much as 1,200t with high performance fibre slings. The super strong-ultra light slings make handling a breeze, and also allow the user the luxury of owning a single set of slings that will handle multiple load weights. Again, with a favorable strength-to-weight ratio, multiple slings with varying capacities are no longer required.

From a rigging perspective, the favorable strength-to-weight ratio allows the user to “over” rig in lower capacity situations, without any cumbersome side effects.

Three decades ago my attitude, and that of other responsible parties, was “the right sling for the job”, and today the same approach is correct. We often caution against the suggestion that a single sling will be the solution to all rigging dilemmas and applications.

It is extremely important for responsible riggers to analyze all variables and to carefully strategize and execute a successful rigging plan. There are multiple “correct” ways to rig and manipulate any object. There are just as many methods that are not as “correct”. The prevailing thought should always be to develop the best method, given the nature of the load, the type of hitch to be used, and the mechanical and environmental factors present.

The result of your planning should be the successful completion and prosecution of our plan to minimise exposure. An important step in this process is to use the right sling for the job, be it web, wire or chain.