What does it mean when a ship is "underway"?

When a ship is described as "underway," it means that the vessel is actively moving through the water and is not stationary at a dock, mooring, or anchorage. This status is significant in maritime operations and navigation as it impacts the vessel's navigational rules and responsibilities. A ship that is underway has left its berth or anchorage and is capable of maneuvering, which involves being under command and able to respond to navigational hazards or instructions. The other choices describe states where the vessel is not in motion: being in a repair yard indicates the ship is out of service, anchored signifies it is secured to the sea floor, and moored means it is tied up at a pier, all of which would mean the ship is not underway.