Bowline on a bight advocate the use of a figure eight twisted version of the Bowline on a bight. This knot can be used to provide a toe hold in the middle of a rope; to make an emergency bosun's chair; and to create an upper rope "block" to make a crude purchase by threading the rope round an anchor point and then back up through the loop. It is sometimes used in sport climbing to tie into two anchor bolts independently. This knot is convenient when a dependable loop is required but neither end of the line is available. It's also commonly used
Marlinespike hitch this hitch is not allowed to collapse into that shape. When it does capsize into a traditional noose, it can jam against the rod, making it much more difficult to release. The hitch is frequently used by hammock campers to attach whoopie slings to tree huggers. By passing the working end through the marlinespike hitch, this knot can be used as an alternative method of tying the Bowline knot. Passing through in the opposite direction will give you the Cowboy bowline (also known as the left-hand bowline, Dutch marine bowline or winter bowline). Below is a basic method of tying.