NEWS for North Dakotans
Agriculture Communication, North Dakota State University
7 Morrill Hall, Fargo, ND 58105-5665

September 16, 1999

Mired Equipment Means Risky Business for Farmers

Recent heavy rains across the state means harvest equipment is likely to become mired in muddy fields. The stress of harvest can be compounded by those difficult conditions, but clear thinking is a key to safe extraction, says a North Dakota State University agricultural safety specialist.

"Valuable harvest time is consumed in extricating stuck equipment from soft spots and in wrestling with chains, cables and nylon tow ropes. It can be a real headache," acknowledges George Maher of the NDSU Extension Service. "Thinking through situations clearly and keeping a margin of safety is essential at those times."

Towing materials and equipment always have some element of danger because they all have a breaking point, Maher notes. Any combination of tow chains, cables, ropes and hooks will always break at the weakest link.

"That's why extra care is necessary in selecting towing equipment for pulling out stuck farm equipment," he says. " Tremendous energy will be released when that weak link gives way. When there is a hook or other heavy metal fixture at the end of the rope, it will rocket through the air with extreme speed and force."

A 1-inch nylon rope is likely to break at about 25,000 pounds. But the average tow rope used for large farm equipment usually has a hook with a lower breaking strength. Consequently, the hook frequently breaks first. When it does, the rope, chain or cable will throw what is left of it with deadly force -- easily injuring any human in it's path. Tractor cab windows are no barrier to broken hooks, cables, ropes and chains. The broken hook will easily pass through and still have more enough energy to injure or kill.

Tow-rope materials all react differently when they break. Chain does not recoil in a straight line but flings wildly and will wrap viciously around anything in its path. The broken hook on the end will hit with very destructive force as it wraps around an object. Steel cable tends to whip about wildly and hit the pulling tractor in a random pattern. Nylon rope frequently rebounds in a somewhat straight line toward the other end.

"They are all too unpredictable to safely guess where the impact will be," Maher says.

He also notes that a number of variables make every pulling situation different: the available traction; the weight of the stuck machine; the resistance of the mud; soil moisture; soil type; and the breaking point of towing materials. Stress placed on towing materials can reduce the breaking strength of towing materials each time they are used.

"These situations are too varied to predict," Maher says. "That's why they're so dangerous. It's essential to allow generous margins for safety."

Increase your safety margin by following some basic rules to reduce some of the danger in pulling stuck equipment from the mud.

• Use only tow ropes, cables or chains that are in excellent condition. Inspect every inch of your towing equipment before using it. Avoid using ropes or cables with breaks in the fibers, kinks or worn spots. Never use chains that have repaired links -- cold or welded.
• Always use a thimble on ropes and cables. The thimble reduces wear and prevents the rope or cable from bending too sharply.
• Never use a hook that has been stretched, bent, cracked or re-shaped.
• Attach tow ropes and chains only to the drawbar on the pulling tractor and to an equally strong location on the stuck equipment. Drawbar leverage will reduce the chance that the tractor will tip backward.
• Use a standard four-wheel-drive tractor for pulling rather than a two-wheel drive tractor or a front-wheel-assist tractor whenever possible.
• Pull in a straight line to the mired equipment whenever possible. Pulling at an angle increases the danger level.
• Apply power slowly and smoothly. Avoid a sudden application of power and jerking. These maneuvers are dangerous and put excessive strain tow ropes and chains.
• Avoid lunging with a nylon rope to use its rebound energy. This is an extremely dangerous practice.
• Use more than one tractor for pulling and coordinate their efforts. Be sure each tractor has its own towing equipment. Use a side-by-side arrangement, not single file, when adding another tractor.

###

Source: George Maher (701) 231-8288
Editor: Tom Jirik (701) 231-9629

Click here for a pdf version of this graphic. (23KB b&w information graphic)