The Reef Knot is a simple knot. Easy to both tie and untie. It takes its name from its use to secure reefs in sails. Reefing a sail is where you make it smaller to cope with a heavier wind. Normally this involves tying up the spare sail, which is where the Reef Knot comes in. it is also used on everything from bandages to parcels. It is also known as a Square Knot.
Instructions for the Reef Knot can be found here:
www.animatedknots.com/square-knot
