Usage: The Square Knot or Reef Knot is an ancient and simple binding knot used to secure a rope or line around an object. In addition to being used by sailors for reefing and furling sails, it is also one of the key knots of decorative macrame textiles. The knot lies flat when made with cloth and has been historically used for tying bandages.

Also known as:

• Square Knot
• Hercules Knot

Related:

• Thief Knot
• Surgeon’s Knot

ABOK: 1204

Classification: Binding

Structure: When the Square/Reef Knot is correctly tied, the two tails lie on the same side of the knot. If the tails lie on diagonally opposite sides, it is a Thief Knot.

Strength/Reliability: Although the Square Knot is often seen used for tying two ropes together, it is not recommended for this purpose due to potential instability of the knot — use a Sheet Bend or Double Sheet Bend instead. Knotting authority Clifford Ashley claimed that misused Square/Reef knots have caused more deaths and injuries than all other knots combined.