Granny knot its possible use tying the necks of grain sacks. When attempting to tie a reef knot (square knot), it is easy to produce a granny knot accidentally. This is dangerous because the granny knot can slip when heavily loaded. A tightened granny knot can also jam and is often more difficult to untie than the reef knot. It is better to tie a reef knot in nearly all circumstances. One way to distinguish them is that in the reef knot each loop passes completely over, or completely under (not through) the neck of the other. The reef knot is commonly
Double bowline is easier to untie after being weighted in a fall, and so is used by sport climbers who take multiple lead falls and then have trouble untying their figure eights. The disadvantages of the double bowline are that it is less secure than a figure eight knot, takes longer to tie, and is not as easy to check. Unlike the figure eight, there are many variations of the bowline, with ambiguous names, and some are not safe for climbing. The Bowline on a bight, when re-threaded instead of being tied on a bight, can also be used for tying into