What do the lights red over white over red indicate?

Red over white over red lights indicate that a vessel is restricted in its ability to maneuver. This specific configuration of lights is used to signify that the vessel is constrained by its draft or other circumstances, which limits its capacity to take evasive action or change course.

Understanding this configuration is crucial for other mariners, as it alerts them to the unique navigation challenges posed by such vessels. When encountering a vessel displaying these lights, other vessels must proceed with caution, as they may not be able to maneuver as expected.

The other options reflect different situations but do not align with the specific light arrangement described. For instance, towing vessels typically show a different light configuration, sailboats do not exhibit red over white over red, and anchored vessels indicate their status with a single white light.