Friday, January 27, 2023

How to zip safely into summer

June 12, 2012  

Zip-line rides are popular at The Stunt Ranch on Fitzhugh Road off Highway 290 West.

By Bobbie Sawyer

On May 1st, Aimee Copeland, a 24 year-old student from Georgia, fell from a homemade zip-line and contracted a flesh-eating virus known as necrotizing fasciitis from a minor cut. Infection led to the amputation of Copeland’s leg, hands and remaining foot as doctors raced to stop the infection from spreading. Copeland’s story captivated the nation, and comes at a time when zip-lines are at the height of popularity with hundreds of central Texas families.

Steve Wolf, a stunt coordinator for television and movies, and founder of Science in the Movies, Inc., an organization that uses stunts to teach kids about physics and chemistry, said that while flesh-eating viruses are rare, zip-line accidents are not.

Zip-lines consist of a rope or cable secured between two objects, and an attached pulley that carries riders sliding down the line, and briefly experiencing flight.

Wolf said most zip-line problems are due to improper setup by well-intentioned adventure seekers, anxious to get in touch with their inner Evel Knievel in their own backyards.

“Zip-lines are certainly one of the most fun, popular and inexpensive pieces of backyard recreational equipment you can own, and most people build their own,” Wolf said. “But problems with zip lines can be related to their design, construction or usage.”

Despite their potential danger, Wolf said, when constructed properly, zip-lines provide a safe and invaluable experience.

“One of the reasons that zip-lining is a significant experience for people is that it takes them out of their normal realm of experiences where they are are earthbound and gives them a chance to experience flight,” Wolf said. “But in order to experience flight one must often climb to uncomfortable heights. I think this is a very important lesson for people. If you want to achieve things out of the ordinary you may have to step out of your comfort zone.”

A zip-liner flies over water

Wolf is well versed in expanding his comfort zone and helping others to follow suit.  He’s built over 400 zip-lines, the first of which he created back when he still had to ask his parents’ permission.

“By the time I was six years old I was very interested in ropes, pulleys and rigging and had attached ropes in, on and around most of my home,” Wolf said. “By the time I was eight, I had built a zip-line going from our third story balcony out into the trees in our backyard.”

Wolf’s early-interest in physics and stunt work eventually led him to a 24-year career creating stunts and special effects for television and feature films, such as “Cast Away,” “The Firm,” “Three Men and a Baby” and “Do the Right Thing.”

“For me, stunt and special effects work is about safely using science to create the illusion of danger,” Wolf said. “Of all of the ways that science is used in society, stunt work is undoubtedly one of the most exciting applications.”

While working on MTV’s “Call to Greatness,” Wolf coordinated a zip-line ride in which five people rode side by side on a specially designed trolley for over 800 feet, setting a world record for most people on a tandem zip-line.

Wolf owns and operates Stunt Ranch, an educational getaway for people of all ages. Stunt Ranch provides visitors the opportunity to experience pyrotechnics, get tactical handgun training, and, of course, ride the 180-foot long zip-lines, flying between two sturdy trees at speeds of around 25 miles per hour.

“Students visiting Stunt Ranch all get an opportunity to ride a zip-line, climb on the ropes course, see how movie snow and smoke is created, and learn how chemistry is used to create an enormous movie fireball” Wolf said.

Wolf’s children have absorbed their dad’s passion and knowledge of stunt work. Dashton, age 7, can easily spout off the formula for fake-blood used in a movie shootout (water, red dye, corn syrup) and the procedure for making artificial snow.

Perhaps that’s because science and adventure have always been a part of their lives. Wolf’s home office is the perfect fit for a teacher, scientist and inventor. The shelves are towering with countless science books and the walls are adorned with gears, pulleys and a rock climbing wall. There’s even a small working trapeze and net.

Wolf is so confident in his constructions that Dashton began riding the family’s back yard zip-line when he was just 9 months old, using a specially designed harness.

“I think what’s most surprising about that experience is that my wife Maegan let me do it,” Wolf said.

Below, Wolf shares 10 tips for staying safe while enjoying one of summer’s most popular recreational activities.

1. Know Your Materials

“Failing to use the correct materials is the largest contributor to zip-line failures,” said Wolf, explaining that because of the angles involved in supporting a moving load, forces on the cable can exert tensions of 10 to 20 times the weight of the rider. Wolf advises to “estimate the weight of your heaviest rider at 300 pounds, and then add a safety factor of 10 times. This means that you should be using cable that is designed with a working load limit of at least 3000 pounds.”  3/8′ cable is reliable, but don’t use anything thinner.

2. Let’s Bolt

When securing the cable, make sure the hardware you’re using is one size up from the thickness of the cable, Wolf said. For 3/8″ cable, use 1/2″ hardware.  If using trees as anchor points, Wolf advises builders to drill through the tree, securing the eye bolt through the trunk or a major limb by using large washers and locking nuts. Be sure to back up the connection point to protect in the event of anchor failure.  Bolting a tree, despite what you’d think, is actually much easier on the tree than wrapping it.

3. Not To Loose, Not Too Tight

Securing the cables too tightly will not ensure a safer ride, Wolf said. As a rule, the cable should have a 10 percent flexion factor. For example, a 10-foot cable should sag at least one foot.

4. Measure Your Angles

“Another mistake in design is that people think they need a much steeper angle of declination than is necessary or safe,” said Wolf, who suggests a one degree angle of declination. “For every 10 feet of horizontal run, a drop of only a few inches is more than sufficient.” To ensure that riders are high enough so that their feet don’t touch the ground at mid-ride, set the launch point from a raised platform.

5. Build A Stairway

“If your (launch) platform is more than a few feet off the ground, make sure to use safe stairs with a railing and have a platform at the top that is railed and large enough for the rider and a supervisor to stand comfortably side by side,” Wolf said.  “More than a few kids have been injured zip-lining simply by falling off the platform.  And only allow one rider on the platform at a time.”

6. Brake Time

A braking system is an essential component of zip-line construction, Wolf said. Move the lower anchor point up to force the rider to slow down as they travel uphill.

7. Clear Your Path

Parents or supervisors should check that the glide path is clear before every launch. “It’s best to secure the glide path physically with the use of barricades, cones or other means of keeping kids out of the glide path,” Wolf said.

8. Harness Your Fears

Wolf suggests using three-foot sling harnesses placed over the rider’s head and underneath their arms and advises against grip-only harnesses. “When kids are highly excited their hands become sweaty, induced by high temperatures or stress.” Wolf said. “Relying on a child’s grip to keep them from landing face first on the ground is a poor bet.” Helmets are also highly recommended.

9. Get An Assistant

Have an assistant to catch kids, help them out of their harness, clip the harness from the cable and ensure that they stay out of the glide path.

10. Know When To Say ‘No’

“A zip-line should only be used when both the rider and the supervisor are alert and happy,” Wolf said. Avoid using a zip-line if either party is tired or cranky. “Once kids have ridden the zip-line once, they’re incredibly eager to do it again immediately, over and over until you’re sick of it,” Wolf said. “But if you’re tired or your attention is elsewhere shut down and take a break. Most accidents are preceded by an ignored feeling that something was wrong.”

If building your own zip-line seems too daunting, they are plenty of options for satisfying your need for high-altitude endeavors. Wolf’s team can build one for you, or you can zip along at a professional zip-line park.

Wimberley Zipline Adventures provides 15 mile views of the Wimberley Valley over the course of eight zip-lines stretching through the Hill Country greenery.

Sarah Draves, a zip-line guide at Wimberley Zipline Adventures, describes the experience as exhilarating.

“I would say it’s not as crazy as skydiving,” Draves said. “You feel a lot safer doing it but it definitely gives you a rush.”

If the thought of zipping through the air 90 feet above ground makes you squeamish, Draves assures that the guides at Wimberley Zipline Adventures are well-trained to provide a safe, comfortable and welcoming experience for all thrill-seekers, walking riders through each step of the process and allowing them to do a practice run on a zip-line closer to the ground.

“Safety and the customer having fun, above all, are our priorities,” Draves said.

To schedule a tour at Wimberley Zipline Adventures call 512-847-9990 and visit for more information. For more information on Steve Wolf, Science in the Movies, Inc. or Stunt Ranch, and a free guide to zip-line construction, visit


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