About this tool
Headroom, the spread between your pick points, sling length, angle. Give it any two and it draws the rest.
How it is worked out
A two-leg pick is two right-angled triangles back to back. Half the distance between the pick points is the base, the headroom is the height, and the sling leg is the hypotenuse. Everything else is Pythagoras and one bit of trigonometry:
- Sling leg = √( headroom² + half-spread² )
- Angle from horizontal = arctan( headroom ÷ half-spread )
- Headroom = √( sling leg² − half-spread² )
- Angle factor = 1 ÷ sin(angle) — what each leg’s share gets multiplied by
Worth knowing. Rigging charts normally stop at 30° from horizontal. Below that the tension climbs faster than most people expect and the load starts trying to crush itself sideways. If the answer here comes back under 30°, the fix is more headroom or a shorter spread — not a bigger sling.
Geometry is rounded to the nearest, not up — it is a measurement, not a safety margin. Put the angle into the sling tension tool to see what it costs you.