How would I tie a double figure of eight knot for attaching to a rock climbing harness?
First things first:
Please be careful when rock climbing. Learning information on the internet is no substitute to proper training from an experienced and knowledgeable guide.
Please don't use this information to put yourself in a situation where you may be in danger.
You will need around one arms span of rope (about 1m).
First off make a loop in your hand thus, do not let go of the rope until specified:
Take the loose and and pass it over your wrist pulling it round to the front:
Pass the loose end back through the loop your holding in your hand:
Pull the loose end tight downwards. If it doesn't look like a figure 8, below, you've done it wrong. Untie everything and start again:
Now pass the loose end though whatever you want to attach the rope to (I'm using a carbiner here):
You now need to rethread the loose end back though the original figure eight, this produces the double in the double figure eight. Essentially you simply follow the line of the original loops.
First off pass the loose end back up though loop nearest whatever your attached to:
Follow the rope around the first loop:
Then around the top of the rope and back down, going though the loop nearest the attachment point:
now loop back around the base of the knot and back up though the top loop: