These knots are used in the end of a rope or yarn. They can also be used to prevent a piece of yarn or rope from unfolding.
The simplest and most frequently used stopper knot, the overhand is not a very strong knot and reduces the strength of the yarn or rope by about 50%. It should not be used in situations where great force is expected on the yarn or rope.
The Double Overhand
The double overhand knot is beautiful, thicker than the common overhand knot, but not any stronger. The double overhand knot is also called the bloodknot when it is used at the end of a whip. This knot has several ways of tying and in principle two ways of working up. Both ways of tying shown here also show both results. The bloodknot shown in the middle is the preferred way of working up the second way of tying marked with the crosses. The bloodknot is very hard to untie after it has been under stress. If you put an object through the cross-marked hole the knot will work up as the strangleknot. It is usefull to practice this way.
If you make more than two turns in the overhand knot it wil be fatter. (But hardly stronger.) In twined rope it is important to work up the knot very carefully. (It will not only look neater, it wil prevent 'kinking' which will weaken the rope even more!)
The (Flemish) Eight
Stronger and larger than the overhand. This knot is used by sailors. This knot is not for bend support.