Bowline draws tighter as tension is placed on the standing part of the rope. The "Birmingham bowline" has two loops; the working part is passed twice around the standing part (the "rabbit" makes two trips out of the hole and around the tree). Other two-loop bowline knots include the Spanish bowline and the bowline on the bight; these can be tied in the middle of a rope without access to the ends. A triple bowline is used to make three loops. A Cossack knot is a bowline where the running end goes around the loop-start rather than the main part and
Bowline on a bight a climbing harness by tying a regular bowline knot and then re-threading it, such as is done with a figure eight knot. However, it is "critical" to use a strong backup knot with plenty of tail beyond the knot, as the knot may untie during long climbs. The advantage of using this knot instead of the figure eight knot is that it can be easily untied after a severe fall. The bight of rope is initially used to make a bowline in the usual way (picture on right). However, the bowline is "not" completed by going on round the standing