Thumb knots move under pressure and are a total nightmare to untie, plus they remove an enormous amount of strength from the line.

There's a nice touch with the can't-come-loose trick line which goes through a hole drilled in the tip moulding before being fixed with a simple thumb knot.

It is also known as the Thumb Knot and can be used to stop the ends of rope from unravelling or as a stopper knot, for example, between beads on the necklace.

It is a knot to use with thin material like string because it weakens the material that it is tied in and it is often difficult to untie without damaging the string. The thumb knot can be used as a stopper knot for sewing thread.

One small problem is the variety of names that mey be applied to the one knot, for examle, a Granny is a False Knot, a Clove Hitch is a Waterman's Knot, an Overhand Knot is a Thumb Knot.