Note: Many of these articles are very old, and although the technical information is still relevant the equipment mentioned may not be (for example a Stormy cooker was state of that art in 1995, but not in 2021).
Making a cordelette is cheap and easy, and although you can buy ready-made slings (Wild country Cordlette 135g £20), making your own has many advantages. The length varies depending on how much flexibility you want, varying between 5 to 7 metres of 7mm perlon cord (£1 / 33g per metre). 7 mm perlon is perfect as it has a high breaking strain (11kn when new!), yet is still compact enough to be clipped to the back of your harness. Perlon has a higher stretch than Dyneema which means the legs of the cordelette both absorb more impact force while allowing that force to be spread more evenly. Ideally, someone like Beal or Mammut should come out with a dedicated 7mm fully dynamic cord for this role (If you don’t ask you don’t get I suppose). Tie the cord into a loop with two double fisherman’s knots, leaving 15cm of the tail, and rack it by forming it into a 60cm loop, tie a knot in the middle, and clip both ends together. The beauty of making it out of inexpensive cord is that you’re more willing to use it for abseil anchors.
TIPS ON USING YOUR CORDLETTE
• Most importantly of all, in order to limit the advertised chance of loading a single leg of the cord, try and keep all strands as close as possible in length. This may mean using a sling or extender on a faraway piece, rather than just using the cordelette as normal. Having very short, or very long legs (compared to the other pieces), will create higher impact forces on those strands.
• Retire your cordelette every 12 months, as perlon will degrade with age. Those with Dyneema cordelettes should be aware that although stronger, Dyneema has a much shorter life span, made shorter still by its high impact force. If in doubt chuck it out.
• Try and keep the angles low when setting gear in order to maximise their strength. Keep in mind you want your belay matrix to look like a closed fan, not an open one.
• Tie a figure of eight rather than an overhand knot if you have enough cord as this will increase the impact absorption of the cordelette (if you have lots of cord then tie two knots).
• When tying the knot(s) don’t be sloppy. Pull down tight, maintain pressure above where you will tie the knot. Tie the knot then pull down so that all the strands are equally loaded.
• If you’re faced with sideways loads or an upward pull, then don’t forget to take this into account. You can either use a strand of your cordelette to pre-empt this, or the belayer may use a strand of their rope once in position.
• It is good practice to use two karabiners when clipping into the master point (the main loop on the cordelette), although you can back yourself up by clipping one or both your ropes into anchors with clove hitches or figure of eights.
• If you wish to have an indirect belay when bringing up the second then you can use one of the following methods, listed in order of security.
1. Extend yourself below the master point by using your rope, and run the belay rope through the master point using a second karabiner.
2. If the knot in the cordelette is a sufficient distance from your harness, clip a karabiner into one or two legs of the cordelette.
3. Clip a karabiner to the strongest anchor and run the rope through this.