Cargo securement has been a problem since the days when wooden ships carried most cargo (after all, we still call transportation “shipping”). Securing cargo was critical on ships not only because whatever got loose in a storm could hurt the crew, but also because shifting weight could make the ship unstable, and even cause it to sink.
Smart truckers know that the same principle applies to them: Proper loading and lashing of cargo makes for a more stable vehicle, and a safer and easier ride not just for the other traffic, but for truckers themselves.
Cargo securement is a lot like braking: The name of the game is friction, says Jim Feddern, motor carrier enforcement manager at the Ohio State Highway Patrol and chair of the Commercial Vehicle Safety Alliance vehicle committee. Summing up the whole science of cargo securement, he observes, “It’s not about tying cargo to the trailer. It’s about maximizing the friction between the cargo and the trailer. That’s why blocking and bracing are so effective, and why using rubber mats can also be a great aid to cargo safety.”
Know your cargo
Feddern believes when it comes to loading cargo, “The main thing is to know the weight and other characteristics of the cargo.” Is it slippery like steel or dressed lumber, or will it develop friction like concrete pipe? And there’s a big difference between a 40,000-pound load and something that weighs 20,000 pounds.
Start out with a clean deck. Then, know the size and working load limit of each tie-down.
Larry Strawhorn, vice president of engineering at the American Trucking Associations, points out that tie-down materials are rated using a safety factor of three. In other words, if a chain breaks under 3,000 pounds of tension, its working load limit is 1,000 pounds. Both experts explain that you simply find out the total weight of what you’re securing, then make sure you install enough tie-downs. You have enough when the sum of all their working load limit ratings equals one half the cargo’s weight (that’s the applicable rule in the Federal Motor Carrier Safety Regs). Doing the math this way will be a big help in operating safely and passing roadside inspections.
Then, if possible, use blocking or bracing to block movement. “Use sturdy timbers, not just a piece of a 2×4,” says Feddern. Ideally, any block will have a beveled edge so the cargo will have a wider surface to rest against and be less likely to crush the wood and work its way loose.
Strawhorn says one critical issue is “getting the right torque on the reel hubs. Most truckers believe that if a 200-pound man pulling on a 6-foot bar is good, then a 300-pound man on an 8-foot bar is better. It’s not true! Obviously, if you’re bending protectors and links, you’re going much too far.”
It’s normally not a good idea to use a cheater of any kind, or substitute another pry bar – the one provided by the winch or tensioner maker is designed to help you apply the right amount of torque. Then, says Strawhorn, “You have to calibrate yourself.” That’s not easy because most suppliers don’t seem to give torque ratings for tightening their straps or chain. He suggests you contact a dealer or distributor who has a relationship with the manufacturer for training materials, then study them.
This cargo is secured properly, with straps and chains attached to built-in winches and attachment points, and protective materials also in use.
Avoiding classic mistakes
“Gravity is not a load securement device,” says Feddern. Roadside inspectors see plenty of trucks loaded with dense materials like concrete block piled neatly, but otherwise unsecured. Just because it’s heavy doesn’t mean it’ll stay in place. Tie everything down, no matter how heavy it is.
Truckers also get into trouble because they make a good-faith effort to tie down the cargo, but don’t do the job scientifically and end up a bit short. Know the cargo weight and ratings of your tie-downs, calculate carefully on paper or with a calculator, and then use enough tie-downs to satisfy the rule.
Strawhorn says it’s important to use the right grade of chain. Grade 8 is hard and brittle, and it can chip. Bigger may not necessarily be better, so he doesn’t recommend Grade 10. By far the best is Grade 7, which is labeled “transport” for good reason. While manufacturers’ type codes differ, if there’s a 7 in the code, that means it’s Grade 7 chain.
Take time occasionally to do a thorough inspection of your straps, chain and attachments. Lay each item out and go over every inch to make sure it all looks good. Inspectors often find everything up to snuff except that the stitching on a strap is coming apart in just one spot, or a chain link is slightly distorted. Lots of citations are written referring to a “damaged area” of a tie-down.
Tying stuff down is a lot like putting on a wheel, as there is an initial period when everything settles out. So, the first 25 miles will see the tie-downs loosening up a lot. Since the object of the game is to keep stuff from even starting to move, this is a critical point. Both experts stress the need to stop after that 25 miles, cinch everything up, and look it over. After that re-tightening, the cargo usually settles down a bit.
Remember, too, that you need to stop again and look everything over at least every two hours on the road.
Watch how your chain and straps wrap around the cargo. Strawhorn says to watch for strapping going around sharp corners or over sharp edges that can cut or at least weaken it. When using chain, watch for links hung up on the corners of items. This can give a false impression that the torque on your tensioner is actually tensioning the chain. You often end up with tension on one side of the cargo, but not on the other.
The two methods of securing steel coils with their eyes lengthwise show the effective use of blocking. Method 1 requires 4×4-inch blocks at the sides. Method 2 requires front and rear blocks that are 2×4 inches.
What should you use?
There’s no hard and fast rule as to what type of tie-down to use when hauling a certain cargo. In general, it doesn’t matter if you use a few chains or many straps, as long as the working load limits add up to half the cargo weight.
Keep in mind that there is also a rule requiring one tie-down for each 10-foot length of most flat materials loaded along the length of a trailer, and every 8 feet for metal cargoes of this type.
Strawhorn points out that shippers often specify how you should tie their stuff down to ensure protection. Follow their orders. Aluminum coils require straps instead of chain, or perhaps protectors. Even steel coils can be dimpled by chain, and since rolled sheet steel is often later pressed into automotive body parts, even a tiny dimple is a critical concern. Obviously, fabric straps should never be used with cargo that could cut or damage them during carriage.
Are walls the solution?
For many items, the walls of a trailer should be ignored as containment devices. As Feddern says, “Side kits help, but they’re not the whole solution to cargo securement.”
There are exceptions that depend on the weight of the cargo and the space it takes up. If you’re carrying something light like lampshades and the cargo nearly fills the trailer so it cannot shift, you won’t need to tie it down. The applicable regulations actually state that cargo that’s properly contained by bulkheads and side curtains or walls need not be restrained.
But when you’re hauling 4,000-pound iron ingots in the center of a van trailer, the walls surely don’t get rid of the need to fasten them down. In a sharp curve, they could easily slide to one side, gain momentum relative to the trailer, and come crashing through the van’s wall.
Remember also that securement can be important even when the walls can contain the cargo. Many drivers have been hurt after opening trailer doors as cargo fell out on their heads. Feddern says load locks can be very helpful in van trailers.
The Specialized Carriers & Rigging Association offers an excellent booklet entitled “Steel Cargo Securement & Protection on Motor Vehicles” for $6.25. Although the booklet focuses on metal securement, it offers an excellent review of all the basic regulations and illustrates acceptable tie-down techniques. SC&RA was kind enough to allow us to reproduce several illustrations from the booklet in this article.
J.J. Keller & Associates, Inc.
Tel. (800) 327-6868
National Association of Chain Manufacturers
Tel. (703) 299-8414
Fax: (703) 971-9233
Specialized Carriers & Rigging Association
Tel. (703) 698-0291
Web Sling & Tie Down Association
Tel. (410) 931-8100
Fax: (410) 931-8111