What characteristic defines a towing hawser?

A towing hawser is specifically designed to be flexible and strong enough to withstand the stresses and strains that occur during the towing process, making its ability to absorb shock during towing a defining characteristic. This capability is crucial because towing often involves sudden changes in direction and speed, which can create significant forces that a non-shock-absorbing line would not handle well, potentially leading to equipment failure or accidents.

The other characteristics listed do not accurately describe the primary purpose or design of a towing hawser. For instance, while some towing hawsers can be used in mooring scenarios, they are not intended to be permanent mooring lines. Additionally, though a towing hawser can be made from various materials, including fiber or other synthetic materials, it is not limited to steel cable, which is more rigid and less effective for shock absorption. Finally, the utility of a towing hawser extends beyond small boats; it is employed for vessels of all sizes, including large ships, thereby refuting any limitations regarding size usage.