Sternlight

A white navigation light showing over an unbroken 135-degree arc centred directly astern.

Under the collision regulations it is arranged to show from dead astern to 67.5 degrees on each side of the vessel. Its required visibility range, height and relationship to other lights depend on vessel type, length and status.

A sternlight identifies an aspect and status only when interpreted with the complete light pattern. Lens sectors, vertical alignment, obscuration, power supply and bulb or LED condition require checking, and a bright work light must not impair recognition of prescribed lights.