Sidelights are visible from which angle?

Sidelights are specifically designed to indicate the port and starboard sides of a vessel and are visible from an angle that extends from right ahead to 22.5 degrees abaft (behind) the beam on each side. This means that a vessel approaching from the front can see the sidelights, as well as vessels positioned slightly to the sides of it, but not those positioned directly behind or at extreme angles beyond the 22.5-degree limits.

Understanding this visibility is crucial for navigation, especially during nighttime or in reduced visibility conditions, as it helps determine the direction and intentions of other vessels. The design of the sidelights aids in ensuring safe passage and collision avoidance by clearly marking the sides of the vessel to oncoming traffic. In contrast, the visibility of sidelights is very limited beyond this defined angle, emphasizing the importance of adhering to the navigational rules that guide the use of sidelights in maritime operations.