Little is published regarding the little loops of string that hold our suspension lines to our risers. Various versions began appearing on the scene in the mid-1980s, nudging out the racetrack shaped steel (and later stainless-steel) links of various sizes with load ratings ranging from around 500 to almost 1,000 pounds. Those links had in turn replaced the bulky 2,500-pound steel L-bar links used on mains from the beginning and up into the 1970s.
Canopy manufacturer Performance Designs introduced the design of reusable fabric soft links, called SLinks (for Soft Links), literally buttoning the canopy to the risers. Credit for PD’s SLinks goes to the late Ian Bellis, who went on to manage international parachute conglomerate Aerodyne Research. (We lost Bellis when a car struck him while he was riding his bicycle.)
By the late 1990s, most everyone had seen SLinks on PD’s popular line of canopies. PD also sold SLinks separately—$25 for four cleverly fingertrapped and sewn pieces of string and tape, patent pending. PD doesn’t publish a load rating for SLinks, but your risers would probably break first. Their version for reserves is even stronger. Soon, clones and various adaptations began to appear.
All current soft links follow the same button-buttonhole principle with a double-back for extra security. The loop at the end of the link passes through a small passage under the button before going over top. By wrapping the link through the lines and risers two or three times before buttoning the ends together, you get a very strong connection. Tight manufacturing tolerances make them a little hard to assemble and even harder to get off.
Like SLinks, some versions use all-fabric hammerheads for the buttons. They eliminate brass or stainless-steel slider grommets smacking steel connector links, as well as any potential for corrosion. Others substitute with metal rings. They also make a good connection but introduce metal back into the interface.
This series from Icarus World demonstrates the assembly steps of a ring-style soft link.
These three different brands of soft links were all removed from service, although they probably have plenty of life left in them. The PD SLink is shown at the bottom left.
Nothing is ever perfect, of course. Read the rudimentary instruction sheet that comes with your SLinks, for example. It tells you to keep a close eye on them for the first 15-20 jumps after installation to make sure the assembly is forming good habits. Like other synthetics used in parachutes, the material in most soft links takes a set under load. Soft links shape themselves into triangles. With all-cloth, button types, the base of the triangle needs to form with the buttons hidden inside the end of the risers. That’s important to make the links last longer. Some manufacturers offer soft-link covers to reduce wear and to help keep the buttons in place, and there’s an option to tack them into position.
All ring-type soft links require the rigger to tightly hand-tack the rings to keep them hidden. Otherwise, they’ll sneak out the sides. Slider grommets striking an exposed ring can damage themselves and accelerate wear on the link at the strike point. The tackings are notorious for coming loose or undone over time and need to be renewed.
So, how long your soft links will last may depend on how well you care for them. In essence, your soft links should be good if they look good. If you see enough wear that you need to ask, the rigger will likely suggest replacing the links. Some say at least replace the links with the lines, and PD once told an assembly of riggers that’s not a bad idea.
If you get a little nervous that only a couple of wraps of string and a button connect you to your parachute, then a worn assembly should really make you shudder.
Kevin Gibson | D-6943 and FAA Designated Parachute Rigger Examiner
Rahlmo’s Rigging at Skydive Orange in Virginia