Coiling and storing rope (butterfly coil)

Every rope has a kind of memory for twist. If you wind it in circles around your hand and elbow, it gains one full rotation around its own axis per turn. On a long rope that adds up to many rotations, which come back out as curls and kinks when you lay it out. Braided ropes cope with this a little better than twisted (laid) ropes, but they twist too.

In the butterfly coil each bight – each U-shaped fold – lies next to the previous one, but on the opposite side. The rope is only folded back and forth, not twisted. That is why it runs out smoothly later when you open the bundle and pull one end. The wraps around the middle hold the folds together, and the bight tucked through the top stops the wraps from coming undone.

Leave enough rope free at the start. The tails have to be wrapped around the middle several times and then tucked through the bight; if they are too short, the bundle will not hold. If you want to carry the bundle on your back, you need even longer tails to tie it around your body or pack.

Make the bights as equal in length as you can. Uneven bights slip out more easily while you carry the bundle, and it becomes shapeless. Pull the wraps around the middle snug, but do not strangle the rope – it should hold together, not be crushed.

You can recognise a good bundle like this: it is flat, the bights lie neatly side by side, the wraps sit tight in the middle, and when you shake it no loop slides out. When you open it, the rope should pay out in one go without knots.

Ropes age mainly through moisture, UV light, heat, dirt and chemicals. Wet rope does not belong tightly coiled in a cupboard; lay it out loosely or hang it in loose loops somewhere shady and airy. Do not dry it on a heater or by a fire; synthetic fibres can be damaged by heat even if you cannot see it straight away.

Try not to step on ropes or lay them in sand or mud. Fine grit can get between the fibres and wear them from the inside. Keep ropes away from battery acid, solvents and fuel – a rope that has been in contact with them is not used for load-bearing purposes again.

Coiling is a good moment for a visual check. Let the rope run through your hands and look for abrasion, hard or stiff sections, shiny, glazed spots, discolouration and lumps. A suspicious rope gets a clear mark or is retired.

The most common mistake is to fall back into laying circles out of habit. You still get a bundle, but the next time you pay it out you get curls. A second classic: the tails end up too short, and there is not enough rope left to tie off. Better to be generous at the start.

The method is less suited to very thin cord; winding it onto a spool or a piece of card, or using a chain sinnet, is more practical. For ropes on a pack, for the lines of a large tarp or for the rope in the car boot, the butterfly coil is ideal. The mountaineer's coil is an alternative that can be more compact on a pack but tends to cause more twist.

For climbing and mountaineering ropes: how to coil, store and inspect them is taught in a training course. Life-safety use only after proper training with certified equipment.