Vessel not under command

NUC

A vessel not under command is a vessel that, through exceptional circumstances, is unable to maneuver as required by the Rules and therefore cannot keep out of the way of another vessel.

This is a defined legal status.

An ordinary recreational boat with an engine failure is not automatically NUC. If it remains able to maneuver effectively by sail, anchor, auxiliary propulsion, current management or another means, the legal analysis can differ.