Monday, December 9, 2019

Train Your Kids in Proper Rigging - Not Like This!

     Pictured here is a load attaching method of hoisting an I-Beam some 250 feet in the air via a Tower Crane on a large industrial job site. The crane operator, about 275 feet away from where the beam is to be landed. He has little input as to  how the load is connected to “his Crane.” Yet, he and his Employer will feel the harmful effects of a dropped load, if someone should get hurt – it will be costly.

     The operations are 100% depending upon this rigger’s decisions; that will be made in a matter of seconds – based on his training and experience! He’s performed this “choker hitch,” a hundred times before (let’s assume) with no failures. The hitch may be the same – but are the working conditions that affect the outcome all the identical?

     What’s so wrong here that I am taking your time to “rail” about anyway? If I were testing someone in an entry-level Rigging 101 course, he would fail. Aside from the obvious of not running the eye through the yellow oblong link that re-duces wire wear and D/d ratio stress on the body of the sling, as the sling Manufacture intended. There is no kinking protection (softeners) between the beam/sling contact points. However, there is a much more important error.

     These experienced Ironworkers know that this thirty-foot, W 14 x 82 beam weighs about 2,460 pounds, (1,230 each end) is not going to break the 3/4" diameter wire rope sling they are using. So, they feel justified in abusing their employer’s equipment; after all, men will be men! So, bothersome soften-ers and sling body wear/stress is “kids stuff” not to slow down production and make this work harder than it is. There is some logic here, and I had witnessed an overuse of personal protection equipment (PPE), making things harder for the workers when no hazards existed, frustrating the people.

     The real “violation” here is the lack of control that could cause the beam to slip and fall from the choker hitch on its 250-foot journey over the heads of numerous workers - not the breaking of the sling. All manners of forces can occur to dislodge the beam along its route. To name a few; excessive swing speed, sudden starts/stops, beam caught on the obstacle, weather conditions, or setting one end down and releasing the “bite” allowing the beam to slip and fall. A bundle of metal studs from a single wrap choker hitch like this, occurred at a hotel under construction at Disney, killing one.

Corrected: Double Wrap, Softeners, and a Shackle in the “bite.”
     Simply a “double” wrap choker hitch would have provided all the necessary control, yes, a little more annoying for the riggers – but so much safer. A bad meth-od is a bad method no matter how many times you get away with it! And, it’s a terrible OJT example for the kids. These experienced riggers may have “fallen prey” to complacency.

     The camera is everywhere nowadays, catching us in the “act” as it were. Companies slogans like “Safety First, If you can’t do it right, don’t do it,” etc. will not stop an unsafe act, skills training helps. We ask ourselves why people take “short-cuts” why don’t people do it right all the time – oh yes, people were never made perfect!

As printed in the August 2018 issue of Wire Rope News and Sling Technology.

Dennis can be emailed at

Thursday, December 5, 2019

Synthetic Ropes, "to be or not to be " on Mobile Cranes - that is the question

     There is a long-established belief that “if it ain't broke, don’t fix it.” Steel wire rope has been used successfully on cranes since the 1800s. Now some are replacing steel ropes with synthetic ropes. At the last two conferences that I attended, held by the Crane Certification Association of America (CCAA), synthetic rope manufacturers (Samson and Yale respectively) gave presentations as to why replacing steel ropes with synthetic ropes on cranes makes sense.

     What the crane industry has experienced in the past is fiber roped being easily cut when they are used as slings, blocks, and tag lines. Fig. 1 There is an established “belief” this material is too soft to be used on multipart reeving. It’s said that facts and words do little to alter a belief, experiences are what one trusts. Crane owners have required the installed synthetic rope be removed from their crane based on this weakness belief. Yet, no evidence of damage was evident.

Fig. 1

     The popularity of synthetic ropes on cranes is growing just by the number of companies offering the product. They call it in sales terms, “market push” The Heavy Lift off-shore Oil industry is a major user of these products due to their reduced weight.

     The benefits of synthetic rope over steel are lighter weight, more flexibility, anti-spin, and no need for lubrication to prevent corrosion. Some synthetic rope manufacturers claim a fourfold increase in rope life, thereby reducing operating costs – a true advantage if proven. The benefit of reduced weight has caught the attention of the crane industry.

     Let’s do a little arithmetic. Let’s assume the weight of eight parts of 7/8” steel wire rope at 1.42 pounds per foot at a 100’ hook height (1.42 x 8 x 100 = 1,136 pounds) add a 3,800 pounds load block. Now have 4,936 pounds suspended over the crane’s boom point. Replace the steel rope with synthetic rope, as pictured in Fig. 2, will see a reduction of the weight of the rope by 80%. The weight of the block will also be further reduced because the overhaul weight requirement will be approximately 65% of its original weight. The new total weight in the hypothetical situation is approximately 1,352 pounds, a 3,584 pound reduction. This weight decrease really gets crane manufacturers excited, especially the ability to reduce weight at the boom point. Also, note the nylon point sheaves a further weight reduction over steel.

Fig. 2

     Synthetic ropes have been installed on utility truck winches used in the power industry for decades. Synthetic ropes are less conductive than steel wire ropes, an advantage when working around powerlines. For most operations, the synthetic rope on utility truck winches is used in a one-part configuration. Now we are looking at synthetic ropes being used as multi-part configuration on a mobile crane, greater wear.

     At various locations the Navy, Grove, and others have conducted trial tests of synthetic ropes on cranes, and the performance of the rope was reported satisfactory. I question how safe it is to trust a synthetic rope that can be cut with a knife, to lift 80-ton loads? Especially since I have witnessed synthetic ropes damaged when used for rigging slings and tag lines. How will the rope last in “real” job activities?

     When a crane is operated and used conservatively, the synthetic rope should be as reliable as steel ropes. That is the rub. When we factor humans into the equation, things get complicated, job pressures increase. What “predictable misuse” should be expected. I think of the ABBA song “Take a Chance on Me.” Do I take a change when not knowing if the crane will be properly operated and maintained some months down the line? I believe that synthetic rope needs the “test of time” to show the crane community how it survives in the real-world struggles of a modern job site.

As printed in the December 2019 issue of Wire Rope News and Sling Technology.

Dennis can be emailed at