Which term describes an imaginary line that runs down the center of a ship?

The term that describes an imaginary line running down the center of a ship is "Centerline." This concept is crucial in naval architecture and design, as the centerline serves as a reference point for various measurements and alignments on the vessel. It divides the ship into port (left) and starboard (right) sides, helping in maintaining balance, stability, and symmetry during design, construction, and operation.

Understanding the significance of the centerline is essential for navigation, load distribution, and maintenance activities, as well as for ensuring the accurate placement of equipment and systems on the ship. The centerline helps in assessing the vessel's performance and operational capabilities, making it a fundamental aspect of maritime practices.