The only knot you need to learn for indoor sport climbing is the double figure eight, also known as the figure eight knot. The double figure eight is common, easy to learn and clearly visible when tied correctly.
Here the Swedish Climbing Federation describes how to tie a perfect double eight:
The eight-knot step by step
- Start by making a bend in the rope about 1 meter from the end of the rope (picture 1).
- Then make a single figure eight (Figure 2-4) by threading the rope around itself one turn and then back through the loop.
- Thread the end of the rope through both tie-in loops in the harness and thread the end of the rope back into the single eye (Figure 5).
- Then follow the rope back through the single eye until your end comes out parallel to the end going to the belayer (Figures 6-8).
The rope should be doubled throughout the figure eight. Aim for the rope to be parallel throughout the figure eight. Be sure to check your figure eight before you start climbing. The free end of the rope should protrude at least 10 cm and a maximum of 25 cm beyond the finished figure eight.
Easy to control
Sometimes climbers can be seen using other knots to tie into the harness, but the double rat is most common.
One of the advantages of the double rope is that it is clearly visible if it is not tied correctly. Get into the habit of always checking the double rat one more time, both when you are climbing and when you are belaying someone else.
Stop knot
There should always be a stop knot at the end of the rope that is on the ground. This prevents the end of the rope from slipping through the brake if the rope runs out during the descent. The single eye is an excellent stop knot, provided it is at least half a meter from the rope end.