The "crtical point test" (aka "scissors test") requires that if any one item fails, nobody should be injured.
A "bend" is a knot that joins two ropes.
A "hitch" is a type of knot that that must be tied around another object.
The "whistle test" requires that if all rescuers let go, nobody should be injured.
As with all "bends," the figure 8 bend joins the ends of two ropes. After holding a heavy load, the figure 8 bend is easier to untie than most bends (e.g., a double fisherman's bend, ring bend, or water knot). Once you are familiar with tying figure 8 knots, it's easy to remember how to tie a figure 8 bend. Note that the figure 8 bend is a little bulkier than other bends and it takes a little longer to tie and dress.
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