AIS navigational status 2: Not under command

What status 2 means

"Not under command" (NUC) means that through some exceptional circumstance the vessel cannot manoeuvre as the rules require and so cannot keep out of the way of others — typically a main-engine or steering failure.

What should go with it

Usually low and erratic, often a drift track with the heading not matching the course.

Navigational status is entered by hand on the bridge; speed, course and position come from a satellite receiver. Read the status as testimony and the rest as measurement. Where they agree you have learned something. Where they disagree, the measurement is usually right.

How it goes wrong

Occasionally appears from a mis-keyed menu rather than a real casualty. Look for corroboration — a drift track, a heading that no longer matches the course — before treating it as an incident, and never act on it from this site.

The matching lights and shapes

The AIS status mirrors a state defined in the International Regulations for Preventing Collisions at Sea (COLREGs), which also say what the vessel should display:

Rule 27(a) — two balls in a vertical line by day; two all-round red lights at night.

Summary for orientation only. The COLREGs text is the authority; this site is not a navigation reference.

All sixteen codes

For the field as a whole — and how this site handles it — read AIS navigational status codes, all sixteen.