US Patent 7226042 Winch and winch drum

Disclosed is a winch drum for rotation about a rotation axis. The winch drum has a rope-receiving surface with a plurality of raised ridges defining substantially helical channels between them. The channels provide guidance for rope along the rope-receiving surface at least during rope release. The ridges have a meandering shape extending around the drum, formed from a series of alternating circumferential and axially inclined ridge elements.