What does NUC stand for in maritime navigation terms?

In maritime navigation, NUC stands for "Not Under Command." This term is used to describe a vessel that is unable to maneuver as required by the International Regulations for Preventing Collisions at Sea (COLREGs). A vessel classified as "Not Under Command" typically is engaged in a situation where it cannot take effective action to avoid collision due to circumstances such as engine failure or other significant operational limitations.

Understanding this term is crucial for navigation safety and communication at sea. It conveys to other vessels that the affected ship may not be able to follow the navigational rules regarding movement and therefore requires caution from nearby vessels. This designation enhances situational awareness among mariners, helping to prevent collisions and ensure safe passage.

Other terms, while they may seem plausible, do not accurately depict the standard terminology used in maritime navigation in the same way that "Not Under Command" does.