What does a white light displayed at the stern of a vessel indicate?

A white light displayed at the stern of a vessel serves a specific purpose in navigation and indicates that the vessel is underway. According to maritime regulations, specifically the International Regulations for Preventing Collisions at Sea (COLREGs), vessels are required to display certain lights to communicate their status to other vessels. The white light at the stern indicates the vessel is being propelled through the water, ensuring that other vessels can recognize its position and movement.

Understanding the function of navigation lights is crucial for safe maritime practices. The requirement to display a stern light when underway helps to prevent collisions by allowing other vessels to ascertain the direction and status of the vessel from a distance. The visibility of this light contributes to safety and situational awareness in busy waterways, further reinforcing the importance of proper lighting based on the vessel’s activity.

In contrast, lights indicating that a vessel is anchored or a specific type of vessel (like a fishing boat) would differ from the white stern light and are defined separately under maritime rules. For example, an anchored vessel displays a different configuration of lights, including an all-round white light, while a sailing vessel would demonstrate different lighting altogether, including sidelights and a stern light, depending on its status.