Winch Drum Line Pull by Layer
The derated line pull, mean diameter, and increased speed of a winch drum at a given rope layer (Pn = rated x drum / (drum + (2n-1) x rope)). The rated pull is a bare-drum first-wrap figure that fades 30-40% on the outer layers -- plan the pull for the layer you finish on, not the nameplate.
Formula and source
Dn = drum_dia + (2n - 1) x rope_dia; Pn = rated_pull x drum_dia / Dn; Vn = drum_speed x Dn / drum_dia; wraps_per_layer = floor(barrel_width / rope_dia).
Wire-rope drum mechanics / SAE winch rating convention, by name.
Audience
This tile is built for trades and the adjacent professions in the Rigging and Heavy Lift group. The interactive calculator runs entirely in your browser. No account, no fee, no advertising, no tracking.
Related tools
Posture
Rough Logic answers the math question the working professional asks on the job. The site is a calm, fast, ad-free, account-free, ever-free reference. It does not interpret code. It does not replace the licensed professional. It does not store your inputs. The Authority Having Jurisdiction governs all installations and inspections.