What distinguishes a heaving line from standard mooring lines?

A heaving line is designed specifically for the purpose of being thrown from one vessel to another or from a vessel to the dock. Its lightweight construction allows it to be thrown with ease, making it practical for situations where a heavier rope would be cumbersome or difficult to manage. The design typically features a heavier weighted end, which helps it travel further and more accurately when thrown.

In contrast, standard mooring lines are generally much heavier and are used primarily for securing the vessel to a dock or other fixed structure. Their weight and sturdiness are designed to withstand the forces exerted on a vessel in mooring situations, yet these attributes would make them impractical for throwing.

Thus, the lightweight and suitable design of a heaving line distinguishes it from standard mooring lines, which are not intended for such applications.