Page 229 - Bob Holtzman "The Field Guide to Knots How to Identify.."

17. Square Knot

Also known as: Reef Knot, Hercules Knot

Composed of one Half Knot on top of another, the Square Knot is
supremely useful both as a binding knot (when tying the rope to itself
around another object), and as a bend (to tie the ends of two ropes
together). A good mnemonic for tying it correctly is “right over left; left over
right.” It can be readily reversed, tying it “left over right; right over left.”

Uses: packages, bundles, reefing sails; bending ropes end-to-end
Pros: simple to tie and untie; fairly secure

Cons: can slip; works as a bend only with ropes of equal diameter; difficult to untie if under load;
difficult to tighten as a binding

Instructions

1. Make a Half Knot with the right working end over then under the left working end.

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