AIS navigational status 3: Restricted manoeuvrability

What status 3 means

Restricted in ability to manoeuvre (RAM): the nature of the vessel’s work stops it keeping out of the way of others. Dredging, cable or pipe laying, underwater operations, replenishment at sea, launching or recovering aircraft and some towing operations all qualify.

What should go with it

Slow and localised around a work area, or a steady low speed along a cable or pipe route.

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

Sometimes left set during a transit between jobs. A RAM status on a vessel steaming straight at normal speed is more likely a status nobody cleared.

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(b) — ball, diamond, ball in a vertical line by day; red, white, red all-round 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.