Ever wondered who makes those lifeline cords essential for bungy jumpers?
I was lucky enough to visit a long attic storage room at Thrillseekers Adventures in Hanmer Springs as staffer Graham Nicholson was two hours into fabricating a new bungy cord. He said it would be finished in another four.
Rain splashes against the windows. The Waiau River is rising and looking angry. It’s the ideal day for the task Graham tells me.
“Wet days mean no interruptions.”
The long attic is also ideal. The working area has to be free of grit or other foreign objects getting in between the wraps of latex rubber. Such intrusions would cause friction and prematurely wear the cord.
Graham says he has absolute confidence in his work. He will sleep well tonight knowing his new bungy cord will never fail.
“Bungy jumpers need to have confidence in our work.”
He fabricates about three new cords a year. A bungy is retired after 500 jumps and cut into short lengths to ensure it cannot be used again. The short lengths are sold as trendy souvenirs.
Bungy cords are made to cater for three weight categories. The 50 mm wide latex rubber is sourced from Singapore. The wraps are laid out at 5.7 metres before being stretched to 11 metres and turned in on itself, then tied off at four equal lengths. The strength of a cord is determined by the number of wraps. The cord being made by Graham is an intermediate strength of 24 wraps for jumpers weighing in at 63 to 80 kg. It will be identified by a red sleeve on an end bobbin.
Graham’s next task is to cross-bind the wraps. It is more cosmetic than anything but also prevents objects, including fingers, getting caught between layers of latex. He uses thin rounds of rubber, locking each cross bind with a reef knot.
The New Zealand bungy cord style is known as ‘exposed latex’ resulting in a softer, longer bounce.
When cross binding along the 11 metre cord is complete, the bungy will be tied to a tree and stretched in stages up to four times its length. When relaxed it will be measured and all details recorded on a spec sheet.
The final stage will be to test the cord with dummy minimum and maximum weights tumbling from the 35-metre high historic Ferry Bridge. An assistant in a jet boat will ensure the dummy weight drops no lower than three metres above the water. This is another safety issue owing to Thrillseekers not offering water dips.
“The river has rocks,” Graham wryly tells me.
He says the Thrillseekers bungy jump offers a thrilling ground rush and rebound.
“Some people do one jump to tick off the experience. Others become bungy jumping junkies.
“For all, sheer terror transforms into an adrenalin-induced buzz. Everyone feels so grateful after the jump,” says Graham.