The reef knot (or square knot) is a knot. It is often used to tie two ropes together. It is used to “reef” sails on sailboats. That is, reduce the sail area when the wind gets stronger.
- ↑ Iggulden, Hal; Iggulden, Conn (2007). "The Five Knots Every Boy Should Know". The Dangerous Book for Boys. New York: HarperCollins. p. 9. ISBN 978-0061243585.