Knot cavers, arborists, rescue professionals, stagehands, fishermen, linemen and surgeons. The International Guild of Knot Tyers is an organization dedicated to the Promotion of Knot tying. Truckers in need of securing a load may use a trucker's hitch, gaining mechanical advantage. Knots can save spelunkers from being buried under rock. Many knots can also be used as makeshift tools, for example, the bowline can be used as a rescue loop, and the munter hitch can be used for belaying. The diamond hitch was widely used to tie packages on to donkeys and mules. In hazardous environments such as mountains, knots are
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