Navigation Lights (Lts)

Lights displayed by a vessel to indicate its presence, aspect, type, size or operational status to other vessels.

Common navigation lights include red and green sidelights, a white sternlight, white masthead lights and all-round lights. The required colour, arc, number, vertical and horizontal arrangement, and range of visibility depend on the vessel’s length, propulsion, activity and circumstances.

The applicable collision regulations specify when lights must be shown and how they combine with day shapes and sound signals. Correct installation, sector alignment, unobstructed visibility and regular testing are necessary because an incorrect or obscured light can give another mariner a false impression of the vessel.