Bowline/ˈbaʊlaɪn/ Definition 1 of 2Pro Tip 1/3Sailing Essential Essential for sailors to learn for safety and effective sail management. He mastered the bowline, an essential knot in his sailing training. Pro Tip 2/3Non-Slipping Loop Creates a fixed loop at the end of a rope that won't slip or bind. When you need a loop that won't close up, use a bowline. Pro Tip 3/3Emergency Use Useful in rescue situations to secure a person without tightening. The rescue team used a bowline to lift the injured hiker.