How to Tie a Reef Knot

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Step 1

Reef knot step 1
Photo © Tom Lochhaas.

A reef knot is used to tie a line in a loop around something, like a square knot, but with the ability to quickly and easily release the knot. Reef knots are commonly used to tie up the baggy foot of a reefed mainsail around the boom.

A reef knot is very similar to a square knot. If you’re not sure you can tie a square knot correctly, check those steps first, then return to see what is different about a reef knot.

The main difference in a reef knot is that for the second overheard knot, you use a loop rather than the bitter end. Then to release the knot quickly, you jerk on the bitter end of that loop and pull the knot apart.

Step 1

Begin with a simple overhand knot. Note that at least one of the ends should be long enough to form a loop. (In this photo, the line end originating at the left side is intentionally longer for making the loop in the next step.)

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Step 2

Photo © Tom Lochhaas.

Step 2

Before making the second overhand knot, form a loop with the longer of the line ends. This loop will pass through the second overhand knot the same as in a square knot, as you’ll see in the next step.

This is rather like tying your shoelaces, except with just one loop rather than two.

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Step 3

Photo © Tom Lochhaas.

Step 3

Now complete the knot by bringing the right-hand loop under the left-hand end, as shown. The loop should exit to the left alongside the original line entering from the left.

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Step 4

Reef knot step 4
Photo © Tom Lochhaas.

Step 4

Pull the reef knot tight, being careful not to pull on the bitter end of the loop (in the photo, the end with the white whipping), which releases the knot.

Notice how a correctly tied reef knot looks somewhat like a square knot. This appearance is important because it shows you have not accidentally tied a granny knot, as shown in the next page. A granny knot will eventually slip.

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Reef Knot Incorrectly Tied in Granny Knot

Reef knot in granny knot
Photo © Tom Lochhaas.

This is what an incorrectly tied “granny” reef knot looks like. If the second overhand knot is not tied to oppose the first overhand knot (in steps 2 and 3 earlier), you can end up with a granny knot the same way an incorrectly tied square knot ends up a granny knot.

Danger: this knot will not hold!