Offshore Swivel Knot Instructions:
Put the end of the double line through the eye of the swivel.
Rotate the end half a turn, putting a single twist between the end of the loop and the swivel eye.
Pass the loop with the twist over the swivel. Hold the end of the loop, together with the double, with one hand, and allow the swivel to slide to the end of the double loops that have formed.
Continue holding the loop and the lines with the right hand. Use the left hand to rotate the swivel through both loops 6 times or more.
Keep pressure on both parts of the double line. Release the loop. Pull on the swivel and loops of line will start to form.
Holding the swivel with pliers, or (better still) attaching it with a short length of line to the rigging, push the loop down towards the eye while keeping pressure on the double line.