Editing Knot (section)

===Security===
Even if the rope does not break, a knot may still fail to hold. Knots that hold firm under a variety of adverse conditions are said to be more secure than those that do not.

The following sections describe the main ways that knots fail to hold.

====Slipping====
The load creates tension that pulls the rope back through the knot in the direction of the load. If this continues far enough, the working end passes into the knot and the knot unravels and fails. This behavior can worsen when the knot is repeatedly strained and let slack, dragged over rough terrain, or repeatedly struck against hard objects such as [[mast (sailing)|masts]] and [[flagpole]]s.

Even with secure knots, slippage may occur when the knot is first put under real tension. This can be mitigated by leaving plenty of rope at the working end outside of the knot, and by dressing the knot cleanly and tightening it as much as possible before loading. Sometimes, the use of a [[stopper knot]] or, even better, a [[backup knot]] can prevent the working end from passing through the knot; but if a knot is observed to slip, it is generally preferable to use a more secure knot. Life-critical applications often require backup knots to maximize safety.

====Capsizing====
[[File:Bowline (PSF).jpg|right|thumb|[[Bowline]]]]
To capsize (or spill) a knot is to change its form and rearrange its parts, usually by pulling on specific ends in certain ways.<ref name="hsok-ch10"/> When used inappropriately, some knots tend to capsize easily or even spontaneously. Often the capsized form of the knot offers little resistance to slipping or unraveling. A [[reef knot]], when misused as a bend, can capsize dangerously.

Sometimes a knot is intentionally capsized as a method of tying another knot, as with the [[Bowline#Tying|"lightning method"]] of tying a [[bowline]]. Some knots, such as the [[carrick bend]], are generally tied in one form then capsized to obtain a stronger or more stable form.

====Sliding====
In knots that are meant to grip other objects, failure can be defined as the knot moving relative to the gripped object.  While the knot itself is not untied, it ceases to perform the desired function. For instance, a simple [[rolling hitch]] tied around a railing and pulled parallel to the railing might hold up to a certain tension, then start sliding. Sometimes this problem can be corrected by working-up the knot tighter before subjecting it to load, but usually the problem requires either a knot with more wraps or a rope of different diameter or material.