The vessel being overtaken is always:

The vessel being overtaken is always referred to as the stand-on vessel. This concept is rooted in the navigational rules that dictate how vessels should interact on the water to promote safety and avoid collisions.

When one vessel is overtaking another, the overtaking vessel has the responsibility to maneuver safely around the vessel it is passing. In this dynamic, the vessel being overtaken maintains its course and speed, which is why it is designated the stand-on vessel. The stand-on vessel does not need to take action to avoid a collision; instead, it has the right of way.

This rule helps to provide clarity in the often-chaotic situations that can arise on the water, ensuring that overtaking vessels act with caution. Understanding this principle is crucial for boaters to navigate safely and responsibly, especially in crowded waterways.

The other options touch on different roles that vessels may have in various situations, but in the specific context of overtaking, it is the vessel being overtaken that stands firm in its maneuver, thus aligned with the definition of a stand-on vessel.