What does "underway" mean in maritime terms?

In maritime terms, "underway" refers specifically to a vessel that is not at anchor, not made fast to the shore, and is actively moving through the water. This definition encompasses any situation where the vessel is in motion, whether it is under its own power or drifting due to currents or wind.

By understanding the term "underway," one can recognize that it differentiates between various operational states of a vessel. When a boat is tied to a dock or secured at a designated anchorage, it is not considered underway, as it is not free to maneuver in the water. Similarly, being aground indicates that the vessel is stranded on the seabed, which also does not meet the criteria for being underway. Therefore, the correct understanding of "underway" is critical for proper navigation and adherence to maritime regulations.