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bow line 23-Aug-2006 At 4:25:27 PM PreferKnitting

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looky here, quite an interesting read....

The Secret Flaw of a Bowline (http://www.allaboutknots.com)

"...Many experienced not tyers are surprised to discover that the Bowline, which they esteem so highly, has a secret flaw. This knot has long been the favorite fixed-loop knot because it is so easy to tie and it works so well. Everyone knows that it holds securely when arranged and applied in the normal way, with the standing part attached at one end and a weight suspended from the loop at the other end. What few knot users seem to realize is that a sharp jerk that pulls the tail to one side can deform a Bowline. If you happen to snag it so that the tail and the right leg of the loop are yanked hard in opposite directions, the structures may not be stable enough to resist deformation. The bight can straighten out and disappear and the hitch that circles the bight can be transformed into a slip knot. If the knot is deformed in this way, the hitch will no longer have either squeezing power or anything to squeeze against. It will not be able to create enough friction to hold the knot together and can be easily stripped off.

Every time I demonstrate this marvel to a group of knot tyers, someone responds “Wow,” and someone else calls out “Do that again.”

These responses indicate that there is a gap between the way unstable knots behave and our awareness and understanding of their instability. The fatal flaw of a Bowline is that it depends on the stability of one exposed bight. Although the tail is protected somewhat by its position inside the right leg, it can easily be snagged. Ashley comments that “Properly tied in ordinary rope, there is little or no danger of a Bowline Knot’s capsizing before the breaking point of the rope itself is reached” (186). But he says nothing about the effect of a strong snag or yank to the side on the tail.

Analysis of a few examples of unstable knots reveal some of the complexities of studying knot stability. Although these knots are quite secure when they are loaded in the way they were designed for, they can be unstable and become insecure when they are not loaded that way. The study of knot stability leads in numerous fascinating directions, with many applications, both practical and theoretical...."