A load hung mid-span on a tensioned line — tarp ridge line, highline, tow strap between two anchors — pulls far harder on the anchors than its own weight once the line runs anywhere near straight. Set the span, sag and load below to see the anchor tension and sag angle update live.
Caution above 10×, danger above 20× — that's how much harder each anchor is pulled than if the load just hung straight down.
T = W / (2 · sin θ) — tension per leg equals the load divided by twice the sine of the sag angle. As the line flattens (θ → 0), tension climbs toward infinity, which is why a "dead straight" rigged line is dangerous under any load at all.
Simplified two-straight-legs model (not a full catenary), symmetric load at the midpoint only. Good for practical rigging estimates — not a substitute for a manufacturer's working-load rating.