What is the visibility angle of the stern light?

• A. 135 Degrees
• B. 112.5 Degrees
• C. 90 Degrees
• D. 180 Degrees

Answer: (A)

The visibility angle refers to how wide the light beam must be seen around the stern. The stern light is white and mounted at the stern, and it must be visible over 135 degrees. That means it can be seen from 67.5 degrees to port of the stern axis to 67.5 degrees to starboard, covering the rear sector of the vessel. This helps other boats detect you and understand your orientation when you’re seen from behind or from the sides. The other options don’t fit because they correspond to different light arcs: 112.5 degrees is typical for sidelights, 90 degrees is too narrow, and 180 degrees would imply visibility straight behind across a wider front, which isn’t how the stern light is defined. So the correct visibility angle is 135 degrees.