http://fishing-live-bait.com | Half Blood Knot w. tuck | How to tie the Half Blood Knot. Instructions on how to tie the half blood knot - video The Half Blood Knot is a high strength multi purpose fishing knot. use the half Blood Knot to attach swivels, hooks and lures to the main fishing line. The Half Blood knot is reliable and easy to tie. The half Blood Knot.