What is meant by 'heaving line' in deck terms?

A 'heaving line' refers to a lightweight line, typically thrown by hand to assist in securing a heavier line, such as a mooring line or a towing line. The purpose of the heaving line is to facilitate the transfer of the heavier line from one vessel to another or from a vessel to a dock, making it easier to handle the heavier line, which may be difficult to throw or manage directly due to its weight and rigidity.

In many maritime operations, especially in docking or anchoring, the ability to throw a light line accurately is crucial. Once the heaving line reaches its target, it can be secured to the heavier line and pulled back, bringing the heavier line along with it for secure handling. This efficient method enhances safety and effectiveness on deck, as it reduces the physical effort required to handle heavier lines directly.

The other options refer to lines with different purposes, such as towing, communication, or anchoring, and do not pertain to the specific use or function of a heaving line.