In what situation would a vessel be classified as 'not under command'?

A vessel is classified as 'not under command' when it is unable to maneuver as required to keep out of the way of other vessels. This classification typically applies when a vessel cannot follow the navigational rules due to exceptional circumstances, such as an engine failure, a steering malfunction, or other malfunctioning equipment that prevents it from responding to navigational commands.

'Not under command' is a critical designation in maritime navigation because it indicates an increased risk of collision, therefore other vessels must exercise increased caution when approaching. This status differentiates the vessel from those at anchor, docking, or simply completing their journey, which are all situations where the vessel still has the capacity to maneuver or manage navigation accordingly.