What distinguishes a vessel that is making way?

A vessel that is making way is defined by its ability to move through the water and create a discernible wave as a result of its propulsion. This means that the vessel is actively traveling forward, indicating that its engines are functioning and it is not merely floating in place. The actions of generating a wave are a direct consequence of the vessel's speed and movement relative to the water surrounding it.

The other scenarios described do not involve any movement through the water. Being anchored at the pier, drifting without propulsion, or tied to a dock all indicate that the vessel is stationary or not actively navigating, thus not making way. To summarize, a vessel making way is clearly distinguished by its movement through the water, which is visually evident by the waves it generates.