“Chain, chain, chain….?”
Relax, I am not about to break out into that ole Motown song, chain of fools by non-other than the Queen of Soul Aretha Franklin. She sang that much better than the rest of us!
I want to look into a cornerstone piece of rigging the “chain”. In our industry, chains are deployed on a routine basis for a variety of purposes: towing (hitching or used as a secondary or “safety”), tying down a ‘load’ (securement), or in recovery applications. No matter what application an operator needs to utilize this rigging staple, there are some essential and basic considerations for its applied use. The basics in chain selection are: identifying the size, grade and working load limit (WLL). This can be done a couple of different ways, such as the I.D. tag on the chain assembly or gaging the link for size and checking the links for the grade classification. Once this is known, a chart on the towing unit or perhaps a rigging handbook can be referenced. Prior to deploying, it is key to consider a few more essential elements to its application.
- The ‘load’: it is essential to identify the load that is going to applied to the chain in its applied configuration.
- The configuration: identify which of the key configurations is being used, vertical, choker, basket or bridle.
- The configuration WLL: each of the configurations mentioned above offer a different working load limit for the selected chain. The operator must be certain of this limit when utilizing the chain in the chosen position / configuration. For example, a choker position can be a reduced WLL vs. the vertical (WLL) use of the chain when the load is applied. Moreover, if used as a bridal, the angle of the legs of chain can influence the WLL as well. There is a significant difference in WLL when using at a 30-degree angle vs. say a 60-degree angle to the attachment point at the load.
- Chain protection: In our industry chains are often exposed to sharp edges and potentially small surface areas. It is key to provide a suited radius and / or edge protection to the chain to prevent point loading which can cause severe damage if not pre-mature chain failure.
While this is not an all-inclusive list of the uses and considerations when utilizing this staple in our rigging box, it is well worth it to bring these elements to light each and every time the chain is being pulled from the box for use.
Whether the operator is new to the industry or an industry veteran, it is an essential practice of the basics that will provide for efficient and effective uses of chain and the consequential success of the tow or the recovery. That old saying ‘back to the basics’ warrants a memory jog in the exercising of rigging practices. Rig well my friends…