Cordage
A rope is always weaker than the fibres in it. The lay length decides how much weaker, and short lays cost the most.
— kN
After twist geometry and process losses
A cosine-squared model captures the geometry and nothing else — real conversion also depends on strand balance, lubrication and how evenly the load shares between strands. Lifting, mooring and life-safety cordage must be proof-tested and certified; this is construction planning, not a rating.
Twisted Rope Lay Length & Strength Conversion Calculator — free, with the formula and a worked example, at Textile School.