Reef Knot
F5. The Reference Layer: Glossary, Units, Signals and Information SourcesDefinition
Square knot for reefing or tying small lines.
The reef knot, or square knot, joins two ends of the same line, classically to reef a sail, and is tied right-over-left then left-over-right. It is a binding knot, not a bend: it can capsize and spill under uneven or shock loading and must never join two separate lines of different size or material, where the sheet bend is correct. Mis-tied as a granny knot it slips entirely.