Round turn and two half hitches

When a rope runs around a round object, friction builds up. The more turns, the more that friction grows – and not just a little, but markedly with each extra turn. It is the same principle as a bollard in a harbour or a winch on a sailing boat. A full round turn can therefore take a large share of the pull before it even reaches the knot.

The two half hitches together form a clove hitch around the rope's own standing part. Their main job is to hold the end so the round turn does not unwind. Because they carry only a small load, they do not pull very tight – which is why the knot usually still unties easily after a hard pull.

On the object you see two turns lying neatly side by side without crossing. On the standing part sit two half hitches that look alike and together form a clove hitch: both hitches lie parallel, and the end comes out from under the second hitch.

If the second hitch is made the opposite way, you get a cow hitch (lark's head). It looks more symmetrical but holds the end less well. A simple test: if you spread the two hitches apart a little, they should look like two identical wraps, not two wraps twisted against each other.

Finally, slide the hitches right up to the round turn and pull them snug. The tail should stick out clearly. A tail that is too short can work its way out, especially if the line flaps in the wind.

This knot is a true all-rounder for anything tied to a tree, post, ring or branch: the end of a tarp ridgeline, a washing line, a line to a fence post. It is especially handy when the line is already under tension. You take the round turn, hold the end for a moment, and then tie the hitches calmly.

It shows weaknesses with very slick synthetic rope and with lines that flap a lot. There the half hitches can loosen over time. A third hitch, a finish with a stopper knot or another knot such as the anchor bend or the buntline hitch can help. It also uses a little more rope than a plain clove hitch.

Typical mistakes are: only one wrap instead of a full round turn – then the hitches carry much more load and pull tight; the second hitch the wrong way; and a tail that is too short. Look at the object itself too. Rough edges, sharp metal parts or rotten branches can damage the rope or give way, even if the knot is perfect.

Check lines that stay up for a long time now and then, especially after wind or rain. The round turn and two half hitches is a knot for gear and camp, not for securing people. Life-safety use only after proper training with certified equipment.

Practise first on a chair leg or stair rail. Tie the knot ten times in a row and check each time that the two hitches look alike. Then practise under tension: have someone pull on the other end, take the round turn and feel how little effort you need to hold the end.

Finally, pull hard on the line and then untie the knot. You will notice that it usually comes undone easily despite the load. This behaviour is exactly what makes it so popular in camp.