Bowline loop may pass around or through an object during the making of the knot. The knot tightens when loaded at (pulled by) the standing part of the line. The bowline is commonly used in sailing small craft, for example to fasten a halyard to the head of a sail or to tie a jib sheet to a clew of a jib. The bowline is well known as a rescue knot for such purposes as rescuing people who might have fallen down a hole, or off a cliff onto a ledge. This knot is particularly useful in such a situation because
Reef knot reef knot must emerge both at the top or both at the bottom, otherwise a thief knot results. Although the reef knot is often seen used for tying two ropes together, it is not recommended for this purpose because of the potential instability of the knot, and over-use has resulted in many deaths (see Misuse as a bend). The reef knot is at least 4,000 years old. The name "reef knot" dates from at least 1794 and originates from its common use to reef sails, that is to tie part of the sail down to decrease its effective surface area