A winch drum is disclosed. In a first aspect, a first set of teeth are positioned around an outer perimeter of a drum. The first set of teeth taper from a first crown to a first base. A second set of teeth are positioned around the outer perimeter of the drum. The second set of teeth taper from a second crown to a second base. The second set of teeth are offset from the first set of teeth such that a gap between the first bases and the second bases forms a sinusoidal channel for a line to follow the first set of teeth and the second set of teeth becomes a guide for the line so that the line can engage the sinusoidal channel. The line follows the sinusoidal channel and each change of direction along the sinusoidal path causes the line to engage by friction with the first bases and the second bases. In a second aspect, the drum includes a trough that follows a sinusoidal path and wherein the trough is narrower at its bottom than at its top.