Dolly knots come to us from the United Kingdom. This knot works on the same principle as a pulley and is used for tying a rope around a load going on to a trailer. This enables the trucker or whoever is using it to lift the heavy load as you would with a pulley instead of just a rope. You can intertwine more than one knot together, which increases the amount the rope can hold while reducing the amount of energy expended. Learning to tie this knot is easy and requires no special equipment.
Fold the rope in half to form a loop and hold it in your right hand. The loop should be pointing up.
Pick up the left end of the rope in your left hand, with the rope end pointing up. Bring the loop in your right hand behind the rope in your left hand.
Hold the loop in your right hand together with the side of the rope in front of it. Use your left hand to bring the left side of the lower loop behind and around the ropes in your right hand.
Twist the lower loop two complete times and pass the loose, right end of the rope through the lower loop.
Pull the rope through the loop to form a small loop hitch. Pull the rope back through the loop to undo the dolly knot.
You should practice performing dolly knots frequently if you do an emergency work like car servicing.
Do not leave a knot out in the rain or it will become very difficult to undo once it is dry.