What night signal indicates a vessel restricted in her ability to maneuver?

The correct indication for a vessel restricted in her ability to maneuver is represented by the night signal of red over white over red lights. This specific arrangement of lights serves a crucial purpose in maritime navigation, as it communicates to other vessels that the vessel exhibiting this signal is facing limitations in its movement due to navigation constraints or operational reasons.

Here's how the lights are interpreted: the red light on top signifies that the vessel is restricted in her ability to maneuver; the white light in the middle indicates the situation more specifically, and the red light on the bottom clarifies that the vessel's maneuverability issues are significant. This signal is vital for ensuring the safety of navigation, as it allows other vessels to understand that they may need to give way or adjust their routes accordingly to avoid potential collisions.

The other options do not represent a vessel restricted in her ability to maneuver. For instance, two white lights signify a vessel engaged in fishing or a similar operation, while three green lights could denote a vessel that is constrained by draft, and red over red indicates a vessel that is at anchor or not under command. This distinction is essential for proper communication and safe navigation in busy waterways.