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
Stopper knot climbing, rope rescue, and other safety-of-life situations. Common knots used for this purpose are: In nautical settings, a stopper may refer to a length of rope that is belayed at one end with the other end attached to a tensioned main line using a friction hitch in order to tension the stopper and thereby slacken the portion of the tensioned main line behind the friction hitch. For example if a sheet becomes jammed on a winch while under sail, a "stopper" can be used to temporarily take the strain off the winch while the riding turn is cleared. Stopper knot