What shape must a vessel fishing at night display?

A vessel engaged in fishing at night is required to display a specific combination of lights to indicate its activity and ensure safe navigation around it. According to the COLREGs, when fishing at night, the appropriate configuration is a white light over a red light. The white light indicates that the vessel is underway, while the red light signifies that the vessel is engaged in fishing operations. This configuration helps other vessels understand that the fishing vessel is not only in operation but also has specific navigation rights and potential restrictions on its ability to maneuver, such as needing to maintain its course and speed while fishing.

This signal assists other vessels in recognizing the type of vessel they are dealing with to avoid collisions. Therefore, the requirement to display a white light over a red light reflects an essential safety protocol established in maritime navigation to promote safety at sea.