The Uni-Knot is used to attach a rope to a cleat. A Uni-Knot is unlikely to loosen up but can be undone quickly if you need them to. This knot is most frequently used to secure a boat to a dock. It is also used for fastening halyards, dinghy bow lines, out hauls and down hauls.

To Tie a Uni-Knot:

Thread the eye of the hook with the line so the hook is suspended on a loop.Uni Knot 1
Encircle the main line with a tag so another loop is formed.Uni Knot 2
Wrap the double strand inside the loop with the tag.Uni Knot 3
Make four wraps in all, leaving the tag protruding from the loop.Uni Knot 4
Close the knot but do not pull it tight just yet.Uni Knot 5
Slide the knot down onto the eye of the hook, pull it tight and trim the tag.Uni Knot 6