Final answer:
The lights and day shapes for a vessel not under command are used to indicate to other vessels that the vessel is unable to control its movement.
Step-by-step explanation:
The lights and day shapes for a vessel not under command are used to indicate to other vessels that the vessel is unable to control its movement. In terms of lights, a vessel not under command must exhibit two all-round red lights in a vertical line.
These lights should be visible from all directions.
As for day shapes, a vessel not under command should display two black balls, one above the other, during the day. These day shapes are typically displayed on a mast or the hull of the vessel.