What term describes the sagging of tow lines between a tug and barge?

The term that describes the sagging of tow lines between a tug and barge is "catenary." This term refers to the curve that the tow line or cable takes due to the influence of gravity, creating a sagging effect when the line is held between two points at different heights.

In a marine context, when a tugboat is towing a barge, the tow line will not be taut; instead, it will hang in a curve, resembling a catenary shape. This sagging can be important for various reasons, such as providing necessary slack to accommodate changes in the movement of the tug and barge due to waves, currents, or changes in speed.

Understanding catenary effects is crucial for safe towing operations because it affects the tension within the tow line and can influence the handling characteristics of both the tug and the barge. Proper management of this sagging helps in maintaining control and operational efficiency during towing operations.