Uni-Knot

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