What does it mean when a vessel is said to be "underway"?

When a vessel is referred to as "underway," it means that the vessel is in motion and not secured to a dock, anchored, or aground. This status indicates that the vessel is capable of navigating through the water. Being underway is significant for various navigation rules and safety protocols, as it affects how the vessel interacts with other vessels and navigational markers.

In this context, a vessel that is underway may be operating under its own power or drift due to current or wind, as long as it is not immobilized by mooring or anchoring. Understanding this definition is crucial for boat operators, as it helps them comply with navigational laws and maintain safety on the water.