A vessel’s light indicating its direction of travel at night is white and visible over an arc of 135 degrees, fixed to the stern. This light is mandated by international maritime regulations for vessels underway, not at anchor, or aground. A practical example is a sailboat navigating at night; this light allows other vessels to discern its course, preventing collisions.
This illumination plays a critical role in navigational safety, particularly in low-visibility conditions. It helps prevent collisions by clearly communicating a boat’s direction of travel to other vessels in the vicinity. The standardization of this light’s color and placement evolved over time, driven by the need to establish universally understood maritime signaling practices for accident prevention. Its presence signifies an active vessel and aids in distinguishing it from anchored or stationary objects.