The shape that a skyline assumes while hanging under its own weight (and the carriage's weight which is assumed to be negligible compared to the cable's weight) but without the weight of a load of logs, is called a catenary curve. It is similar to a portion of a parabola, but not quite the same. The addition of the load of logs would cause the skyline to assume a shape approximating that of two straight lines from each support to the carriage and logs.

Shown below is a convex cable profile with an unloaded, simplified single span skyline. This convex ground profile is the most favorable for maximizing load carrying capability because it alloows for maximum deflection of the skyline under load.