A square knot, or a reef knot, is used to connect two lines of equal diameter, or two ends of the same line. This knot is secure and is easy to untie. It is useful in tying around something to hold it shut or folded, such as a sail. While it is useful for many purposes, it is not a strong knot and should not be used as a bend or to connect two ropes that will come under strain. It is also commonly used to reef a sail. If the knot is tied incorrectly, as it often is, it can become a thief knot or a granny knot.
To tie a square knot, you are using the same basic knot you use to start tying your shoes. The phrase, "right over left and left over right" is commonly used to help remember the sequence for tying this knot.
Things You Will NeedA Rope
Hold the two ends of the line in each hand. Cross the line in your left hand over the line in your right hand.
Step 2Bring the end under as if you're tying your shoe.
Cross the line in your right hand over the line in your left hand
Pass the end under again as if you're tying you shoe. Pull the knot tight.
When tied incorrectly, the knot probably looks like this picture. The most common reason the knot is tied incorrectly, is the same side is passed on top twice. If you can remember - right over left and left over right, you should be able to remember this knot.
As with any knot, practice it with your eyes closed, behind your back, on your head, or anyway to make sure you really know how to tie it.
To learn other knots check out: