Stern Light

A white navigational light mounted at the rear of a vessel, visible from directly behind and within a specified arc, used to indicate the vessel’s position and heading to other boats during nighttime or low-visibility conditions.

A stern light is an essential component of a vessel’s navigation lighting system, as mandated by the International Regulations for Preventing Collisions at Sea (COLREGs). It is specifically positioned at or near the stern (the aft-most part of the vessel) and is designed to emit a steady white light visible over an arc of 135 degrees, centred directly aft. This arc ensures that the light is seen only by vessels approaching from behind or from slightly to the sides, helping to indicate the vessel’s orientation and direction of travel. 

The stern light plays a critical role in maritime safety, particularly during night-time navigation or in conditions of reduced visibility, such as fog or heavy rain. It allows other vessels to determine the presence, heading, and relative position of the boat displaying the light, reducing the risk of collisions. The stern light is distinct from other navigational lights, such as masthead lights or sidelights, which serve different purposes and cover different arcs of visibility. It is typically mounted at a height sufficient to ensure it is not obscured by the vessel’s structure or equipment and is powered by the boat’s electrical system. Proper maintenance of the stern light, including regular checks for functionality and cleanliness, is vital for ensuring compliance with maritime regulations and safeguarding the vessel and its crew.