I never knew that tying a knot in a cord weakens it so much at that point. Seems you can only count on any cord holding half its rated weight since ie isn't going to hold anything at all unless you tie a knot in it some where. Loss of strength is not cumulative. That is, if one knot decreases strength by half, two knots doesn't make it 1/4 as strong. Just means that each spot where there is a knot or bend the cord now has a weak spot.