Are homemade knotted daisy chains made from one-inch tubular webbing safer than sewn ones? How do knotted daisy chains perform versus the sewn daisy chains for dynamic falls? I saw the BD video on daisy-chain failure, and I’m scared.
—Emiel Tijhuis via rockandice.com
The video you reference depicts in stark detail the phenomenon of how, if you clip the same carabiner to two of the sewn pockets and the stitching rips … presto! You are no longer clipped
to anything. It’s a potentially deadly sleight of hand that would have Houdini scratching his head.
If you are considering a knotted daisy chain because it might be stronger in a fall, your entire philosophy is dangerously wrong. Daisy chains—ALL
of them—are not for shock loading. These slings don’t stretch and a two-foot static fall can generate loads in excess of 2,000 pounds,
potentially causing a number of grisly outcomes, from internal-organ rupture to anchor failure, to breaking the daisy chain or its pockets
and whatever terrible consequence would ensue from that. The same length of a climbing rope in the same fall generates a force of approximately
half that of static daisy chains. Only use the rope for your anchor or pro connection.
Daisy chains are simple keeper cords for aiders and gear you place overhead, usually on aid routes. Daisy chains are useful for connecting to ascenders
(only clip one pocket) and for attaching yourself to an anchor, as you might do for rappelling a multi-pitch wall when the rope isn’t available.
Your question is, nevertheless, interesting. The strength of a sewn pocket compared to a knotted one depends on the use for each, and the
stitching. We do know a knot will reduce the strength of webbing. An overhand bend, the type commonly used to tie daisy chains, reduces the
strength of the material by about 30 percent.
Still, I suspect that a knotted daisy chain is stronger than a sewn one, due to the angle of loading. When a sewn daisy chain pocket is loaded, only
the front row of stitching—instead of the entire series of bar tacks—bears the brunt of the load. While a daisy chain clipped on each
end might rate to 16 kN, an individual pocket can be as weak as 3 kN (Black Diamond Nylon Daisy Chain). When this stitching rips, it creates a
series of self- propagating reactions, a chain reaction, if you will.
This zippering of bar tacks sounds bad, but it is actually a good thing, turning a daisy chain into a “screamer,” a sling intentionally designed
with rip- apart stitching. The failure of the tacks absorbs some load and adds dynamics to the catch. This could save the day during an accidental
shock loading. As long as you haven’t clipped two pockets with one carabiner, of course.
There are several alternatives to the standard sewn daisy chain. The Metolius Personal Anchor System is a series of interlocking sewn rings that
are each full strength, and prevent the scenario shown in the BD video. CAMP just came out with a daisy chain (see Field Tested) that puts
a twist in the webbing, eliminating the pocket-rip-out-and-unclip sleight of hand. Gear Guy has spoken!
This article was published in Rock and Ice issue 219 (July 2014).