Strength of Knots

If a knot or hitch of any kind is tied in a rope its failure under stress is sure to occur at that place. Each fiber in the straight part of the rope takes its proper share of the load, but in all knots the rope is cramped or has a short bend, which throws an overload on those fibers that are on the outside of the bend and one fiber after another breaks until the rope is torn apart. The shorter the bend in the standing rope the weaker the knot. The approximate strength of several types of knots in percent, of full strength of a rope is given in the table below, as an average of four tests.

1.Full strength of dry rope100%
2.Eye splice over an iron thimble90%
3.Short splice in rope80%
4.Timber hitch, round turn and half hitch65%
5.Bowline, slip knot, clove hitch60%
6.Square knot, weaver’s knot, sheet bend50%
7.Flemish loop, over—hand knot45%