ABOK #74
Animated Knots
Troop Resources
Let's Get Knotting
One of the best but most misused of knots is the Reef or Square Knot. Employed as a Binding Knot, to reef and furl sails or to tie up parcels, it is invaluable. ''But employed as a bend (to tie two rope ends together), the Reef Knot is probably responsible for more deaths and injuries than have been caused by the failure of all other knots combined.'' In fact the ease with which it is capsized by jerking at one end is its chief recommendation as a Reef Knot.
"To finish a bandage or reefing a sail, a reef knot the role will fulfill;
but for tieing two ends, you must always use bends,
as a reef knots a sure way to kill!"
[climbing.com] The square knot—the first knot many people learn besides tying their shoes—may be the single greatest hazard in rope-related activities, due to its default use in sketchy rigging scenarios by reckless amateurs.