What lights must a vessel constrained by draft display at night?

A vessel constrained by draft must display three all-around red lights at night to indicate its limited capacity to navigate due to its draft. This signaling is important because it informs other vessels of the specific navigation restrictions the constrained vessel is facing, helping to prevent collisions and ensuring safe passage in confined or shallow waters. The red lights signify that the vessel is not able to maneuver as freely as other vessels, prompting others to take caution.

Displaying this combination of lights is a standardized marine practice that promotes maritime safety by alerting other vessels to the presence of less mobile vessels, thus facilitating better situational awareness and planning for encounters at sea or in harbors.