Boy oh boy have harnesses changed! In the 60's I used to work in the old steel oil derricks (133 ft to the crown, working board at 90 ft). The derrick mans "safety harness" was a thick web belt, about four inches wide, with a single "D" ring on the back, and a thin steel cable from that to the anchor point on the rig. If you fell off of the working board (which happened more often than you would suspect), the worker really had to fight to keep from going head down, and possibly slipping right out of the belt. I won't even get into the "safety slide" you rode to make an emergency exit from the top of the rig...